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  Subjects -> AGRICULTURE (Total: 776 journals)
    - AGRICULTURAL ECONOMICS (77 journals)
    - AGRICULTURE (526 journals)
    - CROP PRODUCTION AND SOIL (91 journals)
    - DAIRYING AND DAIRY PRODUCTS (31 journals)
    - POULTRY AND LIVESTOCK (51 journals)

AGRICULTURE (526 journals)                  1 2 3 | Last

Showing 1 - 200 of 263 Journals sorted alphabetically
Aceh International Journal of Science and Technology     Open Access   (Followers: 1)
Acta agriculturae Slovenica     Open Access   (Followers: 3)
Acta Agronomica Hungarica     Full-text available via subscription   (Followers: 1)
Acta Agronomica Sinica     Full-text available via subscription   (Followers: 5)
Acta Scientiarum. Animal Sciences     Open Access   (Followers: 1)
Acta Scientiarum. Technology     Open Access  
Acta Technologica Agriculturae     Open Access   (Followers: 1)
Acta Universitatis Sapientiae, Alimentaria     Open Access  
Advances in Agriculture     Open Access   (Followers: 2)
Advances in Agriculture & Botanics     Open Access   (Followers: 8)
Advances in Agronomy     Full-text available via subscription   (Followers: 12)
Advances in Life Science and Technology     Open Access   (Followers: 8)
AFBM Journal     Open Access  
Africa Development     Open Access   (Followers: 19)
Africa Research Bulletin: Political, Social and Cultural Series     Hybrid Journal   (Followers: 9)
African Journal of Agricultural Research     Open Access   (Followers: 3)
African Journal of Food Science     Open Access   (Followers: 3)
African Journal of Food, Agriculture, Nutrition and Development     Open Access   (Followers: 11)
African Journal of Range & Forage Science     Hybrid Journal   (Followers: 5)
African Journal of Sustainable Development     Full-text available via subscription   (Followers: 4)
Agra Europe     Full-text available via subscription   (Followers: 3)
Agribusiness : an International Journal     Hybrid Journal   (Followers: 7)
Agricultura Tecnica     Open Access   (Followers: 6)
Agricultura Tropica et Subtropica     Open Access   (Followers: 1)
Agricultura, Sociedad y Desarrollo     Open Access  
Agricultural Advances     Open Access   (Followers: 3)
Agricultural and Food Science     Open Access   (Followers: 14)
Agricultural Commodities     Full-text available via subscription  
Agricultural Economics     Hybrid Journal   (Followers: 43)
Agricultural History Review     Full-text available via subscription   (Followers: 5)
Agricultural Research     Hybrid Journal   (Followers: 3)
Agricultural Science     Full-text available via subscription   (Followers: 4)
Agricultural Science     Open Access   (Followers: 1)
Agricultural Sciences     Open Access   (Followers: 7)
Agricultural Sciences in China     Full-text available via subscription   (Followers: 3)
Agricultural Systems     Hybrid Journal   (Followers: 23)
Agricultural Water Management     Hybrid Journal   (Followers: 21)
Agriculture     Open Access   (Followers: 4)
Agriculture & Food Security     Open Access   (Followers: 7)
Agriculture (Poľnohospodárstvo)     Open Access   (Followers: 1)
Agriculture and Agricultural Science Procedia     Open Access  
Agriculture and Food Sciences Research     Open Access  
Agriculture and Human Values     Hybrid Journal   (Followers: 12)
Agriculture, Ecosystems & Environment     Hybrid Journal   (Followers: 43)
Agriprobe     Full-text available via subscription  
Agrivita : Journal of Agricultural Science     Open Access   (Followers: 2)
Agro-Science     Full-text available via subscription  
Agroalimentaria     Open Access  
Agrociencia     Open Access   (Followers: 1)
Agrociencia Uruguay     Open Access  
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Agronomía Colombiana     Open Access  
Agronomía Costarricense     Open Access   (Followers: 1)
Agronomía Mesoamericana     Open Access  
Agronomie Africaine     Full-text available via subscription  
Agronomy     Open Access   (Followers: 7)
Agrosearch     Open Access   (Followers: 1)
AI & Society     Hybrid Journal   (Followers: 4)
Akademik Ziraat Dergisi     Open Access  
Alinteri Zirai Bilimler Dergisi : Alinteri Journal of Agricultural Sciences     Open Access  
Ambiente & Agua : An Interdisciplinary Journal of Applied Science     Open Access   (Followers: 1)
American Journal of Agricultural and Biological Sciences     Open Access   (Followers: 10)
American Journal of Botany     Full-text available via subscription   (Followers: 14)
American Journal of Economics and Sociology     Hybrid Journal   (Followers: 26)
American Journal of Potato Research     Hybrid Journal   (Followers: 2)
American Journal of Rural Development     Open Access   (Followers: 3)
Anais da Academia Brasileira de Ciências     Open Access   (Followers: 2)
Annales des Sciences Agronomiques     Full-text available via subscription  
Annals of Agricultural and Environmental Medicine     Open Access   (Followers: 1)
Annals of Agricultural Sciences     Open Access   (Followers: 1)
Annals of Silvicultural Research     Open Access   (Followers: 1)
Annual Review of Resource Economics     Full-text available via subscription   (Followers: 10)
APCBEE Procedia     Partially Free   (Followers: 1)
Applied Economics Letters     Hybrid Journal   (Followers: 24)
Applied Financial Economics Letters     Hybrid Journal   (Followers: 7)
Arboricultural Journal : The International Journal of Urban Forestry     Hybrid Journal   (Followers: 6)
Archivos de Zootecnia     Open Access   (Followers: 1)
Arquivos do Instituto Biológico     Open Access   (Followers: 1)
Arthropod-Plant Interactions     Hybrid Journal   (Followers: 1)
Asian Economic Papers     Hybrid Journal   (Followers: 4)
Asian Journal of Agricultural Research     Open Access   (Followers: 3)
Asian Journal of Medical and Biological Research     Open Access   (Followers: 1)
Asian Journal of Plant Sciences     Open Access   (Followers: 1)
Australian Cottongrower, The     Full-text available via subscription   (Followers: 1)
Australian Economic Papers     Hybrid Journal   (Followers: 7)
Australian Economic Review     Hybrid Journal   (Followers: 7)
Australian Forest Grower     Full-text available via subscription   (Followers: 2)
Australian Forestry     Full-text available via subscription   (Followers: 2)
Australian Grain     Full-text available via subscription   (Followers: 3)
Australian Holstein Journal     Full-text available via subscription   (Followers: 1)
Australian Journal of Agricultural and Resource Economics     Hybrid Journal   (Followers: 3)
Australian Journal of Agricultural Engineering     Open Access   (Followers: 1)
Australian Sugarcane     Full-text available via subscription  
Avances en Investigacion Agropecuaria     Open Access   (Followers: 1)
B.E. Journal of Theoretical Economics     Full-text available via subscription  
Bangladesh Agronomy Journal     Open Access  
Bangladesh Journal of Agricultural Research     Open Access   (Followers: 1)
Bangladesh Journal of Scientific Research     Open Access  
Bioagro     Open Access  
Biocatalysis and Agricultural Biotechnology     Hybrid Journal   (Followers: 3)
Biocontrol Science and Technology     Hybrid Journal   (Followers: 6)
Biodiversity     Hybrid Journal   (Followers: 21)
Biodiversity : Research and Conservation     Open Access   (Followers: 23)
Biological Agriculture & Horticulture : An International Journal for Sustainable Production Systems     Partially Free   (Followers: 10)
Biosystems Engineering     Hybrid Journal   (Followers: 4)
Biotemas     Open Access  
Boletín Semillas Ambientales     Open Access  
Bragantia     Open Access   (Followers: 2)
Brazilian Archives of Biology and Technology     Open Access   (Followers: 1)
British Poultry Science     Hybrid Journal   (Followers: 5)
Buletin Peternakan : Bulletin of Animal Science     Full-text available via subscription  
Buletin Veteriner Udayana     Open Access  
Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca : Food Science and Technology     Open Access  
California Agriculture     Open Access  
Cambridge Journal of Economics     Hybrid Journal   (Followers: 39)
Canadian Water Resources Journal     Hybrid Journal   (Followers: 17)
Capitalism Nature Socialism     Hybrid Journal   (Followers: 11)
Ceiba     Open Access  
Cereal Chemistry     Full-text available via subscription   (Followers: 4)
CERNE     Open Access  
CESifo Economic Studies     Hybrid Journal   (Followers: 7)
Change and Adaptation in Socio-Ecological Systems     Open Access   (Followers: 1)
Chemical and Biological Technologies for Agriculture     Open Access  
Chilean Journal of Agricultural Research     Open Access   (Followers: 1)
Ciencia & Natura     Open Access  
Ciência e Agrotecnologia     Open Access  
Ciencia e investigación agraria     Open Access  
Ciência e Técnica Vitivinícola     Open Access  
Ciencia forestal en México     Open Access  
Ciência Rural     Open Access  
Ciencia y Agricultura     Open Access  
COCOS : The Journal of the Coconut Research Institute of Sri Lanka     Open Access   (Followers: 1)
Coffee Science     Open Access  
Cogent Food & Agriculture     Open Access  
Competition & Change     Hybrid Journal   (Followers: 9)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 2)
Contributions to Tobacco Research     Open Access   (Followers: 1)
Corps et culture     Open Access   (Followers: 5)
Cuadernos de Desarrollo Rural     Open Access  
Cultivos Tropicales     Open Access  
Cultural Geographies     Hybrid Journal   (Followers: 16)
Cultural Sociology     Hybrid Journal   (Followers: 27)
Cultural Studies - Critical Methodologies     Hybrid Journal   (Followers: 14)
Cultural Studies of Science Education     Hybrid Journal   (Followers: 5)
Cultural Trends     Hybrid Journal   (Followers: 13)
Culture & Agriculture     Hybrid Journal   (Followers: 10)
Culture, Agriculture, Food and Environment     Hybrid Journal   (Followers: 5)
Culture, Health & Sexuality: An International Journal for Research, Intervention and Care     Hybrid Journal   (Followers: 18)
Current Life Sciences     Open Access   (Followers: 2)
Current Research in Dairy Sciences     Open Access   (Followers: 5)
Dairy Mail Africa : Publication for the Dairy Industry in Africa     Full-text available via subscription   (Followers: 2)
Derim     Open Access  
Developments in Agricultural Economics     Full-text available via subscription   (Followers: 4)
Developments in Agricultural Engineering     Full-text available via subscription  
Diatom Research     Hybrid Journal  
Dossiers Agraris     Open Access  
Ecological Applications     Full-text available via subscription   (Followers: 112)
Economic Affairs     Hybrid Journal   (Followers: 6)
Economic and Industrial Democracy     Hybrid Journal   (Followers: 6)
Economic Bulletin     Hybrid Journal   (Followers: 4)
Economic Policy     Hybrid Journal   (Followers: 22)
Economic Record     Hybrid Journal   (Followers: 5)
Empirical Economics     Hybrid Journal   (Followers: 8)
Encuentro     Open Access  
Engineering in Agriculture, Environment and Food     Hybrid Journal  
Ensaios e Ciência: Ciências Biológicas, Agrárias e da Saúde     Open Access  
Environment and Development Economics     Hybrid Journal   (Followers: 26)
Eppo Bulletin     Hybrid Journal   (Followers: 2)
Ethology     Hybrid Journal   (Followers: 6)
EU agrarian Law     Open Access   (Followers: 3)
Euphytica     Hybrid Journal   (Followers: 7)
Eurochoices     Hybrid Journal   (Followers: 1)
European Agrophysical Journal     Open Access  
European Journal of Agronomy     Hybrid Journal   (Followers: 9)
European Journal of American Culture     Hybrid Journal   (Followers: 2)
European Journal of Health Economics     Hybrid Journal   (Followers: 17)
European Journal of Law and Economics     Hybrid Journal   (Followers: 63)
European Review of Agricultural Economics     Hybrid Journal   (Followers: 10)
EvoDevo     Open Access   (Followers: 1)
Extensão Rural     Open Access  
Farmer’s Weekly     Full-text available via subscription  
Farmlink Africa     Full-text available via subscription  
Fitosanidad     Open Access  
Folia Horticulturae     Open Access   (Followers: 1)
Food and Agricultural Immunology     Hybrid Journal   (Followers: 2)
Food and Energy Security     Open Access   (Followers: 4)
Food Biotechnology     Hybrid Journal   (Followers: 11)
Food Economics - Acta Agriculturae Scandinavica, Section C     Hybrid Journal   (Followers: 1)
Food New Zealand     Full-text available via subscription   (Followers: 3)
Food Policy     Hybrid Journal   (Followers: 27)
Forestry Chronicle     Full-text available via subscription   (Followers: 10)
Forum for Health Economics & Policy     Hybrid Journal   (Followers: 7)
Frontiers in Science     Open Access   (Followers: 1)
Frontiers of Agriculture in China     Hybrid Journal   (Followers: 2)
Future of Food : Journal on Food, Agriculture and Society     Open Access   (Followers: 1)
Geoderma     Hybrid Journal   (Followers: 6)
Ghana Journal of Agricultural Science     Full-text available via subscription   (Followers: 2)
Global Approaches to Extension Practice : A Journal of Agricultural Extension     Full-text available via subscription  
Global Economic Review     Hybrid Journal   (Followers: 6)
Global Journal of Agricultural Sciences     Full-text available via subscription  

        1 2 3 | Last

Journal Cover Biosystems Engineering
  [SJR: 0.773]   [H-I: 66]   [4 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1537-5110 - ISSN (Online) 1537-5129
   Published by Elsevier Homepage  [2970 journals]
  • Parameters and contact models for DEM simulations of agricultural granular
           materials: A review
    • Abstract: Publication date: July 2016
      Source:Biosystems Engineering, Volume 147
      Author(s): Józef Horabik, Marek Molenda
      The discrete element method has been in development since 1970s and has recently found practical application in simulations of granular assemblies to investigate natural phenomena as well as a design tool for technology. Agriculture and food engineering harvests, stores, handles or processes an enormous amount of particulate material of biological origin. Unlike mineral or plastic granular materials, these materials are usually hygroscopic and change their mechanical properties through the absorption of moisture. Information regarding material properties of granular materials of biological origin is insufficient, uncertain and dispersed across various journals. This review presents a collection of material properties that are useful for discrete element method, DEM, simulations gathered from contributions of various laboratories around the world. Peculiar behaviour of materials of biological origin requires not only a specific approach in determining the parameters but also a specific setup of simulations. This article presents findings that appear efficient at the current stage of development of granular mechanics and DEM simulations. Emerging trends in the evolution of DEM are also presented.
      Graphical abstract image

      PubDate: 2016-05-15T13:17:54Z
       
  • A CFD study on improving air flow uniformity in indoor plant factory
           system
    • Abstract: Publication date: July 2016
      Source:Biosystems Engineering, Volume 147
      Author(s): Ying Zhang, Murat Kacira, Lingling An
      Indoor plant factories are one of the alternative ways to meet the demands of food production for the increased urban dwellers. It enables growers to grow food crops consistently and locally with high quality. In an indoor plant factory, a forced convection based ventilation and circulation system is used to control the growing environment and maintain climate uniformity. Lettuce is a common leafy crop grown in indoor plant factories and an improper design could cause the tip burn of lettuces which usually occurs at inner and newly developing leaves with low transpiration rate due to the existence of a stagnant boundary layer under high transpiration demand. A three-dimensional computational fluid dynamics (CFD) model was developed and validated through simulating the growing environment in a single shelf production system. An improved air circulation system was designed and proposed to help providing a dynamic and uniform boundary layer which could help preventing tip burn occurrences in lettuce production. A perforated air tube with three rows of air jets was designed to provide vertical air flow down to the crop canopy surface. Four cases with the perforated air tubes were compared with a control treatment. The results indicated that the case with two perforated air tubes was able to provide an average air velocity of 0.42 m s−1 with a coefficient of variation of 44%, which was recommended as the optimal design of air circulation system among four cases in this study.


      PubDate: 2016-05-15T13:17:54Z
       
  • Comparison of methods for estimating the carcass stiffness of agricultural
           tyres on hard surfaces
    • Abstract: Publication date: July 2016
      Source:Biosystems Engineering, Volume 147
      Author(s): Paula A. Misiewicz, Terence E. Richards, Kim Blackburn, Richard J. Godwin
      Loading soil via pneumatic tyres is a major cause of compaction of agricultural soils, which causes damage to the soil-water-air-plant system. The loads applied to the soil and the resulting pressure influences the degree of soil compaction. This study was conducted to determine an effective method to measure the pressure distribution under a selection of pneumatic agricultural tyres. This was conducted initially on a non-deformable surface; a later study will consider pressures within the subsoil. From this the tyre carcass stiffness was determined and methods to predict carcass stiffness were evaluated. Tyre carcass stiffness is defined as an equivalent pressure resulting from the stiffness of the tyre carcass. In order to estimate the carcass stiffness of tyres a number of approaches were considered including: (i) footprint area, (ii) tyre load – deflection, (iii) pressure mapping and (iv) tyre manufacturer's specification methods. Carcass stiffness values obtained from the footprint area method gave results significantly lower (30–40%) than those obtained using the pressure mapping system. The method based on the tyre load – deflection characteristics was found to give a better estimation of the tyre carcass stiffness of the smooth rather than the treaded tyre. The technique of using the tyre manufacturer's specification data, where the estimation of the tyre carcass stiffness was calculated using the theoretical load that the tyre could support at zero inflation pressure, produced estimates that were within ±20% of the mean carcass stiffness determined using the pressure mapping system.


      PubDate: 2016-05-15T13:17:54Z
       
  • Predicting total dissolved salts and soluble ion concentrations in
           agricultural soils using portable visible near-infrared and mid-infrared
           spectrometers
    • Abstract: Publication date: Available online 14 May 2016
      Source:Biosystems Engineering
      Author(s): Jie Peng, Wenjun Ji, Ziqiang Ma, Shuo Li, Songchao Chen, Lianqing Zhou, Zhou Shi
      Soil salinization is the primary obstacle to sustainable agricultural development in arid regions. Because total dissolved salts and soluble ion content are the primary indicators of the degree of soil salinization, their accurate estimation is essential to the determination of appropriate soil salinization remediation techniques, irrigation regimes, and the agricultural distribution layout. A total of 261 soil samples were collected from agricultural fields in the province of Xinjiang, China. A portable Fourier transform (FT) mid-infrared (MIR) spectrometer (4000–600 cm−1) and a visible near-infrared (VNIR) field spectrometer (350–2500 nm) were used to obtain soil spectra. We subsequently used partial least-square regression (PLSR) and support vector machine (SVM) algorithms to establish models in VNIR, MIR, and VNIR–MIR regions. The main objectives of this study are (i) to investigate the possibility of using spectroscopic techniques to predict total dissolved salts and soluble ion content; (ii) to compare the prediction accuracy of these soil properties in the VNIR, MIR, and VNIR–MIR spectral regions; (3) to compare the prediction accuracy with linear and nonlinear algorithms. Our findings demonstrated that spectroscopic techniques are a promising way to predict total dissolved salts and soluble ion content. Good predictions were obtained for total dissolved salts content, HCO 3 − , SO 4 2 − and Ca2+, satisfactory for Mg2+, Cl−, and Na+, but poor for K+. This work demonstrates the potential of portable VNIR and MIR spectrometers as proximal soil sensors for more efficient soil analysis and acquisition of soil salinity information.


      PubDate: 2016-05-15T13:17:54Z
       
  • Effects of incorporated plant litter on soil resistance to flowing water
           erosion in the Loess Plateau of China
    • Abstract: Publication date: July 2016
      Source:Biosystems Engineering, Volume 147
      Author(s): Long Sun, Guang-hui Zhang, Fa Liu, Li-li Luan
      Plant litter can be incorporated into top soil via different approaches, which probably influence soil erosion processes controlled by overland flow. However, few studies have been conducted to quantify the effects of incorporated plant litter on the soil detachment process by overland flow. This study was performed to investigate the effects of incorporated litter rate on soil detachment capacity and soil resistance to flowing water erosion using undisturbed soil samples taken from 16 plots (three plant litter species by five incorporation rates, and one bare control) and were subjected to six different flow shear stresses in the Loess Plateau. The results showed that soil detachment capacity decreased exponentially with incorporated plant litter rate. A threshold of 0.35 kg m−2 of litter needed to be incorporated to provide protection of soil from overland flow erosion. The effects of litter incorporation rate on soil detachment capacity was not significant when the incorporation rate was greater than 0.35 kg m−2. Rill erodibility also decreased exponentially with the incorporated plant litter rate. The shape of plant litter fragments was hypothesised to account for the variations in the effects of different incorporated litter species on soil detachment capacity and rill erodibility. A distinguishable increasing linear trend was observed between critical shear stress and litter incorporated rate, but with a weak correlation. Critical shear stress also increased with incorporated rate and was related to soil cohesion.


      PubDate: 2016-05-15T13:17:54Z
       
  • Biogenic acid attack on concretes in biogas plants
    • Abstract: Publication date: July 2016
      Source:Biosystems Engineering, Volume 147
      Author(s): Andreas Koenig, Frank Dehn
      Concretes in biogas plants (BGP) are subjected to chemical damage through acids which are formed by microbiological processes. Four-year-old grass silage clamp and different concretes samples were analysed. The tests allow statements on the plant-specific damage potential and the performance of the concretes used. Acetic and lactic acids were produced in the grass silage clamp through the microbiologically-induced ensilaging process. Damage decreased inversely with pH despite the presence of rainwater (dilution effect) due to the greater microbiological activity. At pH < 4.0, significant damage (depth of 12.8 mm after four years) was found in the silage clamp. The damage potential of organic acids is based on the buffering effect (subsequent dissociation) and the high solubility of the resulting salts. If atmospheric oxygen was used inside the fermenter for desulphurisation, various bacteria of the genus Thiobacillus, such as the bacterium Halothiobacillus neapolitanus, at first produced elementary X-ray amorphous sulphur (S) and later sulphuric acid, which dissolved the hydrate phases of the hardened cement paste. The dissolved calcium reacted with sulphate to gypsum. Concretes with a low equivalent water/cement ratio, a low calcium-content in the hardened cement paste and incorporated steel fibres performed the best resistance. The results can contribute to the prevention of damage in future and for the development of new, more resistant concretes.


      PubDate: 2016-05-15T13:17:54Z
       
  • Effects of hydraulic retention time and organic loading rate on
           performance and stability of anaerobic digestion of Spirulina platensis
    • Abstract: Publication date: July 2016
      Source:Biosystems Engineering, Volume 147
      Author(s): Natthiporn Aramrueang, Joshua Rapport, Ruihong Zhang
      The effects of hydraulic retention time (HRT) and organic loading rate (OLR) were investigated during a continuous anaerobic digestion of Spirulina platensis. The continuous process operated with varying HRT (10–25 d) and OLR (1.0–4.0 [g VS] l−1 d−1) resulted in the biogas and methane yields in the range of 0.276–0.502 l [g VS]−1 and 0.163–0.342 l [g VS]−1, respectively. The methane yield decreased with the increase in OLR and the reduction in HRT. Maximum methane yield of 0.342 l [g VS]−1 was produced when the digester was operated at OLR of 1.0 [g VS] l−1 d−1 and 25 d HRT. A mathematical model was developed from a kinetic study for predicting methane yield as the function of HRT during a continuous digestion. The model performed well at OLR lower than 2.0 [g VS] l−1 d−1, at which the digestion was not limited by high ammonia levels or volatile fatty acid accumulation.


      PubDate: 2016-05-15T13:17:54Z
       
  • Detection of fungal infection and Ochratoxin A contamination in stored
           barley using near-infrared hyperspectral imaging
    • Abstract: Publication date: July 2016
      Source:Biosystems Engineering, Volume 147
      Author(s): Thiruppathi Senthilkumar, Digvir S. Jayas, Noel D.G. White, Paul G. Fields, Tom Gräfenhan
      Aspergillus glaucus and Penicillium spp. infections and Ochratoxin A contamination were detected in stored barley using a Near-Infrared (NIR) hyperspectral imaging system. Fungal infected samples and Ochratoxin A contaminated samples were subjected to single kernel imaging every two weeks, and acquired three dimensional image data were transformed into two dimensional data. The two dimensional data corresponding to each fungal infected sample and Ochratoxin A contaminated sample were subjected to principal component analysis (PCA) for data reduction, and to identify significant wavelengths. The significant wavelengths 1260, 1310, and 1360 nm corresponding to A. glaucus, Penicillium spp., and non-Ochratoxin A producing Penicillium verrucosum infected kernels and wavelengths 1310, 1360, and 1480 nm corresponding to Ochratoxin A contaminated kernels were obtained based on the highest principal components (PC) factor loadings. Statistical and histogram features from significant wavelengths were extracted and used as input for linear, quadratic, and Mahalanobis statistical classifiers. Pair-wise, two-class, and six-class classification models were developed to differentiate between sterile and infected kernels. The three classifiers differentiated sterile kernels with classification accuracy of more than 94%, fungal infected kernels with more than 80% at initial periods of fungal infection and attained 100% classification accuracy after four weeks of fungal infection. Ochratoxin A contaminated kernels can be differentiated from sterile kernels with a classification accuracy of 100%. Different periods of fungal infection and different levels of Ochratoxin A contamination were discriminated with a classification accuracy of more than 82%.


      PubDate: 2016-05-09T12:48:52Z
       
  • Design and performance of a direct and continuous ventilation measurement
           system for variable-speed pit fans in a pig building
    • Abstract: Publication date: July 2016
      Source:Biosystems Engineering, Volume 147
      Author(s): Ji-Qin Ni, Daniel Kaelin, Igor M. Lopes, Shule Liu, Claude A. Diehl, Chao Zong
      Manure pit ventilation is a common design in commercial pig-rearing buildings. However, determining accurate pit ventilation rates is technically challenging. A new pit exhaust airflow measurement assembly (PEAMA) was developed to directly and continuously measure airflow rates for tube-mounting variable-speed pit fans. The PEAMA consists of a PVC pipe, a flow straightener, and an impeller anemometer. A laboratory study revealed good linear correlations between the PEAMA signal outputs and the fan rotational speeds (R2 > 0.999). The ventilation rates measured with the PEAMA were calibrated against those with the standardised traverse measurement with a highly linear correlation (R2 > 0.996). In 2011, 24 PEAMA units were installed in twenty-four 250-mm diameter pit fans in a state-of-the-art pig research building. Multi-year field performance showed that the PEAMA greatly improved data quality during pit fan airflow monitoring compared with previously adopted techniques. This system enabled continuous and real-time ventilation outputs to be determined in volume time−1. It was easy to maintain due to the simple design and outdoor installation. The cost of the 24 units accounted for only a small portion of a comprehensive air quality monitoring setup at the pig research building.


      PubDate: 2016-05-09T12:48:52Z
       
  • Navigation of autonomous tractor for orchards and plantations using a
           laser range finder: Automatic control of trailer position with tractor
    • Abstract: Publication date: July 2016
      Source:Biosystems Engineering, Volume 147
      Author(s): Pawin Thanpattranon, Tofael Ahamed, Tomohiro Takigawa
      The autonomous control of a tractor-trailer system in orchards and plantations has frequently been observed for the transportation, loading and unloading of products between plants and trees. The objective of this research was to develop a control algorithm for a single-sensor tractor-trailer navigation system for navigating within a row plantation and travelling between plots. A control scheme for stopping the tractor-trailer for various in-field tasks, such as product loading/unloading using a laser range finder (LRF), is presented. The LRF was used to navigate a full-size autonomous agricultural tractor equipped with a two-wheeled trailer. For ease of operation in narrow rows, a sliding hitch bar (SHB) was developed to control the trailer by adjusting the position of the hitch-point between the tractor and trailer. Compared to the tractor-trailer system driven by human, the control system could navigate the tractor-trailer with the RMS differences of 0.275 m (SD: 0.009 m), 0.373 m (SD: 0.030 m) and 0.518 m (SD: 0.022 m) for wide curve, tight curve and U-turn experimental paths, respectively. The SHB unit also supported the navigation system with wider turn for the trailer than conventional single hitch point about 0.383 m (7.66% of the 5 m path width, SD: 0.028 m), 0.762 m (15.23% of 5 m path width, SD: 0.010 m) and 1.094 m (21.88% of 5 m path width, SD: 0.037 m) for wide curve, tight curve and U-turn experimental paths, respectively. The control system also stopped the tractor-trailer at the specified landmarks. The results show that the navigation of the tractor-trailer was demonstrated with satisfactory accuracy and that the trailer position was controlled by the SHB with a wider turn in the experimental paths. Therefore, this laser-based landmark navigation system, and the SHB unit, can be adopted for different applications of autonomous tractor-trailer systems with controlled trailer positioning.


      PubDate: 2016-05-04T21:57:53Z
       
  • Diagnosis of potassium nutrition level in Solanum lycopersicum based on
           electrical impedance
    • Abstract: Publication date: July 2016
      Source:Biosystems Engineering, Volume 147
      Author(s): Li Jinyang, Li Meiqing, Mao Hanping, Zhu Wenjing
      Potassium (K) is an essential element for crop growth. Tomato has a long growth cycle and large fertiliser requirement; thus, K stress often occurs and degrades crop yield and quality. It is the most suitable method to provide nutrition based on the actual requirement of crop growth. An accurate monitoring and diagnosis of nutrition during crop growth is key to realise a precise nutrient management. Crop K monitoring methods have been developed to improve K fertiliser management, and most of them are based on leaf or canopy optical property measurements. However, sensitivity to environmental interference remains an important drawback of these methods. Electrical impedance has been applied to determine the physiological and nutritional status of plant tissues, but no studies related to plant K contents have been reported. This study aims to evaluate the K nutrition level based on leaf impedance spectroscopy. Five sets of tomato samples with different K contents were grown. Total K content of leaves was determined, and electrical impedance data recorded in a frequency range of 1 Hz to 1 MHz. The measured impedance data were analysed using an equivalent circuit model for cellular tissues. The change rule of equivalent parameters was obtained, and the sensitive impedance spectroscopy characteristics of K nutrition level were extracted. Moreover, the influence of moisture content on impedance measurement is discussed and the prediction model for K content is established. Results show that electrical impedance can be applied to the detection and diagnosis of plant K nutrition status.


      PubDate: 2016-05-04T21:57:53Z
       
  • Identifying multiple plant diseases using digital image processing
    • Abstract: Publication date: July 2016
      Source:Biosystems Engineering, Volume 147
      Author(s): Jayme Garcia Arnal Barbedo, Luciano Vieira Koenigkan, Thiago Teixeira Santos
      The gap between the current capabilities of image-based methods for automatic plant disease identification and the real-world needs is still wide. Although advances have been made on the subject, most methods are still not robust enough to deal with a wide variety of diseases and plant species. This paper proposes a method for disease identification, based on colour transformations, colour histograms and a pairwise-based classification system. Its performance was tested using a large database containing images of symptoms belonging to 82 different biotic and abiotic stresses, affecting the leaves of 12 different plant species. The wide variety of images used in the tests made it possible to carry out an in-depth investigation about the main advantages and limitations of the proposed algorithm. A comparison with other algorithms is also presented, and some possible solutions for the main challenges that still prevent this kind of tool to be adopted in practice.


      PubDate: 2016-05-04T21:57:53Z
       
  • Estimation of carbon-oxide emissions of tractors during operation and
           correlation with the not-to-exceed zone
    • Abstract: Publication date: July 2016
      Source:Biosystems Engineering, Volume 147
      Author(s): Algirdas Janulevičius, Antanas Juostas, Aušra Čiplienė
      The continuing rise in fossil fuel use significantly aggravates global warming problems because of carbon dioxide (CO2) emissions. This article shows a procedure to indirectly obtain data concerning the environmental pollution of a tractor by starting from direct data. The research confirms that qualitative indicators of a tractor's work for an operational period could be identified from a database compiled from engine processors. The average work rate of tractors measured under field conditions, together with the operating time in an engine's work mode, fuel consumption, and CO2 and CO emissions, have been measured. Correlations between CO2 and CO emissions and the NTE (not-to-exceed) zones during a tractor's operational period have also been determined. The study showed that the tractors worked, on average, 51% of the operational period with the engine working modes within the NTE zone. While working in these modes, the tractors consumed approximately 73.4% of the fuel used for the whole operational period, and emitted into the environment approximately 76% of the CO2 and 9.7% of the CO of the emissions of the whole operational period. It was found that there are possibilities to reduce fuel consumption and CO2 and CO emissions during tractor operational periods by improving the tractor's operation by choosing engine work modes in a more rational way.


      PubDate: 2016-05-04T21:57:53Z
       
  • Region-based colour modelling for joint crop and maize tassel segmentation
    • Abstract: Publication date: July 2016
      Source:Biosystems Engineering, Volume 147
      Author(s): Hao Lu, Zhiguo Cao, Yang Xiao, Yanan Li, Yanjun Zhu
      Crop segmentation is a frequently occurring problem for computer vision applications in agriculture. Meanwhile, the fine-grained shape extraction of maize tassels is also an essential step in the detasselling and field-based phenotyping research. However, existing methods are usually dependent on category, which is hard to transfer to other cultivars with different colours. To address this, the goal of this study is to develop a general method that can process different colours simultaneously and that has good flexibility and expandability. Targeting maize, we proposed to segment jointly the crop and maize tassel. In particular, a novel joint segmentation dataset regarding crop and maize tassel (323 images with corresponding manually-annotated ground-truth images) is constructed, hoping that it can serve as a benchmark to facilitate related studies. Technically, a region-based approach that leverages the efficient graph-based segmentation algorithm and simple linear iterative clustering (SLIC) is developed to generate region proposals. Also, we proposed to model colours with ensemble neural networks specific to each intensity, aiming to achieve robustness to illumination. In addition, two simple but effective strategies are devised to accelerate the colour statistics extraction and ensemble model prediction. The effectiveness and efficiency of our method are demonstrated on the two segmentation tasks, respectively. Results show that our method significantly outperforms other state-of-the-art approaches on tassel segmentation, with average precision of 74.3%, and achieves comparable performance of 77.8% on the traditional crop segmentation even with the naivest colour feature. The dataset and source code are made available online.
      Graphical abstract image

      PubDate: 2016-05-04T21:57:53Z
       
  • Prediction of soil cation exchange capacity using visible and near
           infrared spectroscopy
    • Abstract: Publication date: Available online 25 April 2016
      Source:Biosystems Engineering
      Author(s): Yahya Ulusoy, Yücel Tekin, Zeynal Tümsavaş, Abdul M. Mouazen
      This study was undertaken to investigate the application of visible and near infrared (vis–NIR) spectroscopy for determining soil cation exchange capacity (CEC) under laboratory and on-line field conditions. Measurements were conducted in two fields with clay texture in field 1 (F1) and clay-loam texture in field 2 (F2) both in Turkey. Partial least squares (PLS) regression analyses with full cross-validation were carried out to establish CEC models using three datasets of F1, F2 and F1 + F2. Analytically-measured, laboratory vis–NIR and on-line vis–NIR predicted maps were produced and compared statistically by kappa coefficient. Results of the CEC prediction using laboratory vis–NIR data gave good prediction results, with averaged r 2 values of 0.92 and 0.72, root mean squared errors of prediction (RMSEP) of 1.89 and 1.54 cmol kg−1 and residual prediction deviations (RPD) of 3.69 and 1.89 for F1 and F2, respectively. Less successful predictions were obtained for the on-line measurement with r 2 of 0.75 and 0.7, RMSEP of 4.79 and 1.76 cmol kg−1 and RPD of 1.45 and 1.56 for F1 and F2, respectively. Comparisons using kappa statistics test indicated a significant agreement (κ = 0.69) between analytically-measured and laboratory vis–NIR predicted CEC maps of F1, while poorer agreement was found for F2 (κ = 0.43). A moderate spatial similarity was also found between analytically-measured and on-line vis–NIR predicted CEC maps in F1 (κ = 0.50) and F2 (κ = 0.49). This study suggests that soil CEC can be satisfactorily analysed using vis–NIR spectroscopy under laboratory conditions and with somewhat less precision under on-line scanning conditions.


      PubDate: 2016-04-29T03:33:16Z
       
  • Does rearing system (conventional vs. organic) affect ammonia emissions
           during the growing and fattening periods of pigs?
    • Abstract: Publication date: July 2016
      Source:Biosystems Engineering, Volume 147
      Author(s): Marko Ocepek, Dejan Škorjanc
      Ammonia emissions from organic (ORG) and conventional (CON) rearing systems in relation to pig growth rate and behaviour were studied. Microclimatic conditions and ammonia concentrations were monitored. Excretory behaviour was recorded in the growing and fattening periods using video cameras. Throughout the experiment, significantly lower ammonia emission was detected in facilities of the ORG pigs (P < 0.001). The differences in ammonia emission may be partially explained as a consequence of lower level of crude protein, lower feed intake and different growth performance of ORG pigs. Urination and defecation indoor (on the slatted and solid floors) were higher in the CON group (P < 0.05). The results of the present study show that the minimum requirements specified in organic legislation are well suited to normal pig excretory behaviour in both growing and fattening stages and provides pigs cleaner indoor space as well as an improved environment for human and pigs, with around 40% of reduced ammonia emission.


      PubDate: 2016-04-29T03:33:16Z
       
  • Investigation of productivity enhancement and biomechanical risks in
           greenhouse crops
    • Abstract: Publication date: July 2016
      Source:Biosystems Engineering, Volume 147
      Author(s): Raziel Riemer, Avital Bechar
      Labour is the single largest cost contributor and main limiting factor to development of the agricultural industry. Manual labour remains a major, essential factor for greenhouse-grown specialty crops. Furthermore, musculoskeletal injuries are prevalent during manual work processes performed in agricultural environments. This study aims to improve work efficiency and productivity and to identify tasks that can cause musculoskeletal injury. Working procedures were characterised using a work-study method, environmental conditions were recorded and a biomechanical analysis of the inspected task was conducted. An innovative measuring system was developed that enables synchronisation and analysis of the manufacturing, biomechanics, workload and environmental data. The study focused on the trellising and harvesting stages of pepper and tomato in greenhouses on two farms located in southwest Israel. We further conducted several experiments in which we changed the working method and assessed the effect on productivity. Another experiment was conducted to test the effect of three different trellising angles (30°, 60°, 90°) on labour and yield in tomato. The results revealed that in tomato, in comparison to current methods, picking 4 fruit per cycle will increase production rate by 17%, leaf removal from the fruit area will increase production rate by 14.4%—up to 40.2%—and the best trellising angle with respect to yield and labour will be 30°. Analysis of biomechanical risk showed that the maximum weight of lifted boxes should not exceed 12 kg, and when picking fruit growing low to the ground, the workers are exposed to medium to high risk of injury.


      PubDate: 2016-04-29T03:33:16Z
       
  • Optimal reservoir sizing in on-demand irrigation networks: Application to
           a collective drip irrigation network in Spain
    • Abstract: Publication date: July 2016
      Source:Biosystems Engineering, Volume 147
      Author(s): Argenis Izquiel, Rocio Ballesteros, Jose M. Tarjuelo, Miguel A. Moreno
      Optimal reservoir sizing in on-demand irrigation networks with a minimum cost was obtained, taking into account the variability of pressure and flow rate demanded by the network during the irrigation season. With this aim, a model called DRODIN (Design of Reservoirs of regulation in On-Demand Irrigation Networks) was developed under a holistic approach. That obtain the optimal design and management (minimum total annual cost, CT) of the water abstraction systems in an integrated manner to include the aquifer along with the pumping station, reservoir and pumping and distribution pipes in a collective irrigation network. This tool has been applied to an on-demand irrigation network located in Spain with 171 ha of drip irrigation in vineyard and olive crops. The optimal reservoir volume is approximately 5000 m3, and the CT for water lift (WL) = 100 m (the most common case for this aquifer) is 325 € ha−1 yr−1. The energy cost is the primary component of CT, both in the abstraction and the water supply to the irrigation network, representing between 57% and 80%. The operation of the pumping station determines the size of the reservoir and the annual costs of the water supply to the network for a given water supply guarantee. The CT increases linearly with the WL, primarily because of the increase in energy costs (Ce), although there is a clear relation between the investment costs (Ca), Ce and the reservoir size, which is only possible to analyse with tools such as DRODIN.


      PubDate: 2016-04-29T03:33:16Z
       
  • Sensor for monitoring rice grain sieve losses in combine harvesters
    • Abstract: Publication date: July 2016
      Source:Biosystems Engineering, Volume 147
      Author(s): Zhenwei Liang, Yaoming Li, Lizhang Xu, Zhan Zhao
      Grain sieve losses are important parameters to judge the performance of cleaning shoes in combine harvesters. To keep grain sieve loss within acceptable limits, an impact-type piezoelectric sensor was developed for real-time monitoring. Rice grain and short straw particle models were established according to their physical properties, and discrete element method (DEM) simulations were carried out to understand their collision behaviour with the sensor. The influence of grain shape, straw length and impact angle on variations of the maximum normal contact force and force rise-time were analysed in detail. Differences in normal collision force, and force rise-time occurred which lead to corresponding differences in signal frequency and voltage amplitude. A signal processing circuit, which mainly consisted of a band-pass filter circuit and a voltage comparator circuit, was designed to discriminate for full grains. Field tests results indicated that measurement errors recorded by the sensor and checked against manually measurements were <4.48%.


      PubDate: 2016-04-29T03:33:16Z
       
  • Framework to develop the mechanisation of date palm cultivation
    • Abstract: Publication date: July 2016
      Source:Biosystems Engineering, Volume 147
      Author(s): Ahmad Mostaan
      The trends in the mechanisation of date palm production were reviewed and five key obstacles were identified: structural heterogeneity, impact of economic and social factors, changing nature of production cycle, lack of innovation in crown access, and the lack of mechanisation indices. A general date palm mechanisation framework was developed which could help understanding and studying the obstacles to mechanisation and derive factors through the principal concepts of revenue loss and availability of the skilled palm-tree climbing workers. Increasing the rate of operation rate with fewer workers would advance date palm production. This trend could be encouraged through lower machinery costs and higher worker safety. Potential advantages of ground-based mechanisation methods are presented through analytical formulation of crown access methods. The ground-based approach appears to be more efficient than conventional approaches using palm climbing or elevating because it simplifies the three-dimensional nature of the working environment into less complex two dimensions. Ground-based methods have limitations due to the increased difficulty of operating in crown zone with increasing palm height. An operational index was defined to help develop the mechanisation of date palm cultivation. The index can reveal the height limits affordability for any date palm mechanisation systems. For each specific mechanisation operation there could be a minimum or maximum height limit and/or a height gap.


      PubDate: 2016-04-25T03:08:28Z
       
  • Orchard worker localisation relative to a vehicle using radio ranging and
           trilateration
    • Abstract: Publication date: July 2016
      Source:Biosystems Engineering, Volume 147
      Author(s): Stavros G. Vougioukas, Long He, Rajkishan Arikapudi
      Safe navigation of labour-aiding robots in commercial orchards will rely on accurate and continuous worker localisation. In this work, an ultra-wideband radio-based system localises a worker via trilateration of four range measurements between antennas on a vehicle and an antenna carried on the worker's belt. Performance results are presented from measurements inside ‘work zones’ around the vehicle, in open space and in an orchard. At walking speed in open space, when body placement allowed full line-of-sight (LOS) between belt and vehicle antennas, position estimate availability was 99.7% and the distance root mean square error (DRMS) was 57.9 cm. Completely blocked LOS resulted in signal outages and unacceptable performance (11.1% availability; 819.7 cm DRMS). In the orchard, full-LOS performance was similar to that in open-space: 99.3% availability and 63.4 cm DRMS error bound. Orchard trees enabled multipath signal propagation, so blocked-LOS performance was far better than in open-space (60.2% availability; 123.6 cm DRMS). Antenna motion effects were studied in open-space and orchard experiments without body interference. Motion introduced non-collocation errors (individual ranges measured at slightly different positions); DRMS error in open space and orchard were 1.6 and 2.2 times larger than respective static errors. In all experiments the 95th percentiles of the errors were almost twice as large as the DRMS errors. Sporadic large errors and signal outages could be addressed by two belt antennas and filtering. The results indicate that radio ranging offers a practicable approach to orchard worker localisation relative to a nearby vehicle operating at slow walking speeds.


      PubDate: 2016-04-25T03:08:28Z
       
  • Drop test of pear fruit: Experimental measurement and finite element
           modelling
    • Abstract: Publication date: July 2016
      Source:Biosystems Engineering, Volume 147
      Author(s): Somaye Yousefi, Habib Farsi, Kamran Kheiralipour
      Pear fruit has a soft tissue that must be protected against mechanical bruises. In this paper, the bruised area of pear fruit was determined by experimental dropping tests and then was predicted by the Finite Element Method (FEM). Three dropping heights (200, 500 and 1000 mm), two impact surfaces (steel and wood) and two fruit orientations (vertical and horizontal) were studied. In order to simulate the fruit in the ANSYS 14 software, volume, density and elasticity modulus of unripe, ripe and overripe fruits were determined experimentally using standard methods. The minimum bruised area was occurred for unripe pear falling on the wood surface at vertical orientation and 200 mm dropping height whereas the maximum value was obtained for overripe pear falling on the steel surface at horizontal orientation and 1000 mm dropping height. The minimum and maximum error for prediction of bruised area by finite element modelling was 0.00 and −60.50%, respectively.


      PubDate: 2016-04-25T03:08:28Z
       
  • Using electromagnetic induction method to reveal dynamics of soil water
           and salt during continual rainfall events
    • Abstract: Publication date: Available online 23 April 2016
      Source:Biosystems Engineering
      Author(s): Zhi-Yun Jiang, Xiao-Yan Li, Hua-Wu Wu, Xiong Xiao, Hui-Ying Chen, Jun-Qi Wei
      The spatial patterns and dynamics of soil water and salt at the field scale between rainfall events are not well understood due to a lack of appropriate instruments for measurements. In this study, we conducted time series EMI surveys and then mapped apparent electrical conductivity (ECa) to estimate the relative changes in soil water and salt in an Achnatherum splendens steppe ecosystem in Qinghai Lake watershed, China. The results indicated that ECa could be used as a surrogate for interpreting changes of water and salt content in soil. The ECa images clearly showed that ECa values increased rapidly after rainfall events, and the increased amplitudes of ECa values in soils under A. splendens (AS) were obviously greater than that of soil in the interspaces between A. splendens tussocks (IAS). This demonstrated that rainwater infiltrated faster and in greater quantity into the soils under AS because of their coarse-textured surface soils with greater macroporosity and higher hydraulic conductivity as compared to the interspace soils. Moreover, the increasing salinity in AS and decreasing salinity in IAS after rainfall events suggested that overland flow might perhaps have occurred from the interspaces into A. splendens areas. The temporal stability of ECa maps demonstrated that there was great soil variability at the study plot, especially in soil salt. This study highlighted that the time series ECa images could qualitatively capture dynamics of soil water and salt at the field scale after rainfall events, and it linked the dynamics of soil water and salt to vegetation variability.


      PubDate: 2016-04-25T03:08:28Z
       
  • Editorial Board
    • Abstract: Publication date: May 2016
      Source:Biosystems Engineering, Volume 145




      PubDate: 2016-04-17T01:52:44Z
       
  • Dielectric properties of peanut kernels associated with microwave and
           radio frequency drying
    • Abstract: Publication date: May 2016
      Source:Biosystems Engineering, Volume 145
      Author(s): Shuang Zhang, Liyang Zhou, Bo Ling, Shaojin Wang
      To develop advanced drying methods based on microwave (MW) and radio frequency (RF) heating, knowledge of dielectric properties is essential for understanding the interaction between electromagnetic fields and peanuts. In this study, dielectric properties of peanut kernels were measured between 10 and 4500 MHz using an open-ended coaxial-line probe and network analyser at temperatures between 25 and 85 °C and moisture contents between 10% and 30% on a wet basis (w.b.). The results showed that both dielectric constant and loss factor of peanut kernels decreased sharply with increasing frequency over RF range (10–300 MHz), but gradually over the MW range (300–4500 MHz). Both dielectric constant and loss factor increased with increasing moisture content and temperature. The rate of increase was greater at higher temperature and moisture levels than at their lower levels. Penetration depth decreased with increasing frequency, moisture constant, and temperature. The measured dielectric properties were finally applied to determine the temperature profiles of RF heated samples under three moisture levels using experiment and simulation. This study on dielectric properties may provide useful guidelines in developing effective dielectric drying methods with a suitable drying thickness for peanuts.


      PubDate: 2016-04-05T13:37:05Z
       
  • Grain separation in a straw walker unit of a combine harvester: Process
           model
    • Abstract: Publication date: May 2016
      Source:Biosystems Engineering, Volume 145
      Author(s): Ryszard Myhan, Ewelina Jachimczyk
      The key criteria for the assessment of combine harvester are its capacity, and the quality of obtained grain bulk. The simultaneous minimisation of grain losses and the operation time of combine harvester requires, inter alia, the optimal selection of the construction and operating parameters for the straw walker unit, whereas the phenomenon of grain separation and its determinants depending on these parameters are not yet well understood. Therefore, a mathematical model of the process was developed considering: the rheological properties of a straw layer; the phenomena associated with the dynamic strain of the layer, forced by the motion of straw walkers; and the phenomenon of grain separation from a straw-and-grain mixture. The study included natural and simulation experiments. The effects of the following parameters were analysed: the capacity of the straw walker unit; the phase shift angle of the cranks of the straw walker shafts; the angle of inclination of the straw walker sieve surface; the angular velocity; the initial grain content in the mixture. For each combination of parameters under study, the content of separated grain on selected sections of the lengths of walkers was determined. The simulation results indicate that the quality of separation should not be regarded as a simple consequence of the velocity of straw movement over the surface of walkers. The important factors affecting the quality of separation include the kinematic parameters of walkers, dependent not only on the angular velocity, but also on the phase shift angle and the throw of the crank.


      PubDate: 2016-04-05T13:37:05Z
       
  • Involving the animal as a contributor in design to overcome animal welfare
           related trade-offs: The dust bath unit as an example
    • Abstract: Publication date: May 2016
      Source:Biosystems Engineering, Volume 145
      Author(s): H.J. Ellen van Weeghel, A.P. (Bram) Bos, Sierk F. Spoelstra, Peter W.G. Groot Koerkamp
      Allowing farm animals to have active control and influence over their environment through the expression of intrinsically motivated behaviours contributes to their (positive)welfare. However, farm animals are predominantly seen as passive receivers of what husbandry systems should provide for them. Additionally, designers and engineers of farming systems neglect the animals' potential in the design of husbandry systems, resulting in disadvantageous trade-offs between animal welfare and economic and environmental sustainability aspects. This paper describes, through the application of an interactive structured design approach, how laying hens can actively contribute to the functioning of the husbandry system by exercising their own goals. The ambition of this research was to allow animals to contribute to creating opportunities that might overcome existing trade-offs between animal welfare and other sustainability goals. The Reflexive Interactive Design approach was applied to achieve this ambition. This paper presents the methodological steps of the design process to contribute to the reduction of the (fine) dust problem in laying hen husbandry using the dust bath unit as an example. Also, this paper describes how we incorporated the laying hen as a contributor in the design process. We show that facilitating intrinsically motivated laying hen dust bathing behaviour can simultaneously resolve the environmental dust problem experienced in loose housing systems.


      PubDate: 2016-03-28T01:11:13Z
       
  • Object recognition algorithm for the automatic identification and removal
           of invasive fish
    • Abstract: Publication date: May 2016
      Source:Biosystems Engineering, Volume 145
      Author(s): Dong Zhang, Dah-Jye Lee, Meng Zhang, Beau J. Tippetts, Kirt D. Lillywhite
      Invasive fish species are a growing threat worldwide, causing great harm to biodiversity and ecosystems, and leading to large economic losses. As the most introduced group of aquatic animals in the world, fish are also one of the most threatened. For species that are considered invasive, removing them is the best way to reduce the long-term cost of eradication or control. This paper proposes an object recognition algorithm to automatically identify fish species. Our previous work on general object recognition, called Evolution-COnstructed (ECO) Features, was modified and adapted to construct features and use AdaBoost to classify different fish species. The proposed algorithm does not depend on human experts to design features for fish species classification, but constructs efficient features automatically. Results from experiments show the proposed method obtained an average of 98.9% classification accuracy with a standard deviation of 0.96% with a dataset composed of 8 fish species and a total of 1049 images. Using this algorithm, a fish monitoring system can be built to remove invasive species and monitor native fish abundance, distribution, and size with minimal collateral impact and fish suffering.
      Graphical abstract image

      PubDate: 2016-03-23T00:34:37Z
       
  • Numerical simulation of wake vortices of crop spraying aircraft close to
           the ground
    • Abstract: Publication date: May 2016
      Source:Biosystems Engineering, Volume 145
      Author(s): Bin Zhang, Qing Tang, Li-ping Chen, Min Xu
      A study of the velocity field of the wake of a Thrush 510G carrying out spray application close to the ground was investigated. The aircraft normally operates in extreme ground effect and wake vortices play a major role in the dispersal and deposition of pesticide spray released behind the aircraft. The evolution of wake vortices over time, and their interaction with the ground were simulated using computational fluid dynamics (CFD) techniques. The simulation was initialised with meteorological data from a field experiment. Information given by CFD simulation included the trajectory of the wake vortices as well as circulation, which indicates the strength of vortex. This information provided insights into the velocity field in the wake, including the upwash near the wing tips and the downwash in between. The effect of turbulence intensity as well as crosswind on the wake vortices and the resulting velocity field were investigated.


      PubDate: 2016-03-23T00:34:37Z
       
  • Localisation of litchi in an unstructured environment using binocular
           stereo vision
    • Abstract: Publication date: May 2016
      Source:Biosystems Engineering, Volume 145
      Author(s): Chenglin Wang, Xiangjun Zou, Yunchao Tang, Lufeng Luo, Wenxian Feng
      The major constraints for a litchi harvesting robot were to recognise and locate litchi in an unstructured environment with varying illumination and random occlusion. A rapid and reliable method based on binocular stereo vision was developed with the aim of effectively recognising and locating litchi in the natural environment. The method involved the application of wavelet transform to a pair acquired images of litchi to normalise illumination of an object surface. A litchi recognition algorithm based on K-means clustering was presented to separate litchi from leaves, branches and background. A matching algorithm to locate litchi based on a label template was discussed. Litchis with a similar label template were matched according to the preset threshold by traversing a litchi label template of a left image in a right image to find optimal matching. The experimental results showed that the proposed recognition method could be robust against the influences of varying illumination and precisely recognising litchi, the highest average recognition rate for unoccluded and partially occluded litchi was 98.8% and 97.5% respectively. From 100 pairs of tested images of unoccluded and partially occluded litchis 98% and 94% were successfully matched, respectively. Errors had no significant difference and they were less than 15 mm when the measuring distance was between 300 mm and 1600 mm under varying illumination and partially occluded conditions.


      PubDate: 2016-03-23T00:34:37Z
       
  • Editorial Board
    • Abstract: Publication date: April 2016
      Source:Biosystems Engineering, Volume 144




      PubDate: 2016-03-23T00:34:37Z
       
  • Precision of tractor operations with soil cultivation implements using
           manual and automatic steering modes
    • Abstract: Publication date: May 2016
      Source:Biosystems Engineering, Volume 145
      Author(s): Adam J. Lipiński, Piotr Markowski, Seweryn Lipiński, Paweł Pyra
      The influence of satellite guidance on the operating precision of a John Deere 7230R tractor with a Väderstad Carrier 350 soil cultivation multi-implement was evaluated. The tractor-implement unit was operated in three steering modes: conventional when the tractor was operated manually and two steering modes, one which relied on satellite navigation with free access to the SF1 correction signal and one using paid subscription for the SF2 correction signal. The automatic steering system consisted of John Deere AutoTrac parallel tracking, StarFire 3000 antenna and GreenStar 3 CommandCenter display. In each mode, operating precision was tested at three travel speeds: 3, 6 and 12 km h−1. The experiment was carried out in 2013, on a farm in the region of Mazowsze, Poland, on a experimental plot with a surface area of 1.5 ha. Operating precision was analysed based on the combined operating width of two adjacent passes. Deviations from the optimal in-field operating routes, overlapped area (overlaps) and missed area (omissions) were determined.


      PubDate: 2016-03-15T17:00:38Z
       
  • Robot ensembles for grafting herbaceous crops
    • Abstract: Publication date: Available online 15 March 2016
      Source:Biosystems Engineering
      Author(s): Lorenzo Comba, Paolo Gay, Davide Ricauda Aimonino
      Legislation and regulation is increasingly limiting the use of pesticides or chemical fumigants to counteract soil-borne pathogens. Therefore the use of disease resistant grafted plants is increasing. However, the grafting of herbaceous crops is a labour-intensive technique, with consequent costs. These aspects have encouraged the development of automated machines able to increase productivity and rooting success rate while reducing costs. This paper presents an innovative solution for automatic grafting of vegetable crops, suitable for small to medium sized farms. The concept is to use a group of cooperative robots, adaptable in number, to meet workload specifications. The machine consists of one or more grafting units, able to cut and join scions and rootstocks, and a supplying and sorting system based on an ensemble of single-axis, identical and independent robotic modules, displacing on a unique rail, which coordinates the movement and the selection of scions, rootstocks and grafted plants. Overall productivity is given by the number of grafting units, the number of robotic modules implemented in the supply system, and the efficiency of the control and task allocation strategy. Together with the description of the innovative aspects of the machine mechanics, designed to face intrinsic variability in vegetable objects, the objective of this paper was to present the ensemble synthesis of the control policies, based on heuristic scheduling priorities, to allocate and coordinate the team of robots to a set of spatially distributed tasks.
      Graphical abstract image

      PubDate: 2016-03-15T17:00:38Z
       
  • Laser-induced fluorescence spectroscopy applied to early diagnosis of
           citrus Huanglongbing
    • Abstract: Publication date: April 2016
      Source:Biosystems Engineering, Volume 144
      Author(s): Anielle C. Ranulfi, Marcelo C.B. Cardinali, Thiago M.K. Kubota, Juliana Freitas-Astúa, Ednaldo J. Ferreira, Barbara S. Bellete, Maria Fátima G.F. da Silva, Paulino R. Villas Boas, Aida B. Magalhães, Débora M.B.P. Milori
      Over the last few years, citrus production has been threatened by diseases and plagues, especially Huanglongbing (HLB). Due to the long asymptomatic period, the most important and efficient tool for HLB management is early detection, which enables fast decisions to protect the farm. In this sense, a new methodology using a portable laser-induced fluorescence spectroscopy (LIFS) system and statistical tools was developed. It is capable of identifying not only symptomatic HLB leaves in the field, but also asymptomatic HLB trees and symptomatic citrus variegated chlorosis (CVC) trees. The differentiation reaches accuracy better than 90% and provides the ability of detecting an asymptomatic diseased tree 21 months before the symptoms appear, results supported by quantitative polymerase chain reaction (qPCR) analysis.
      Graphical abstract image

      PubDate: 2016-03-15T17:00:38Z
       
  • Composition and biogas yield of a novel source segregation system for pig
           excreta
    • Abstract: Publication date: May 2016
      Source:Biosystems Engineering, Volume 145
      Author(s): Phuong T. Vu, Roland W. Melse, Grietje Zeeman, Peter W.G. Groot Koerkamp
      The performance of a novel source segregation method for pig excreta (a V-shaped conveyor belt underneath the slatted pen floor) was compared to conventional separation methods for pig slurry (screw press, centrifugation, flocculation with/without centrifugation). For the source segregation system, a larger amount of organic matter accumulated in the solid fraction (96%) than for conventional separation systems (34–93%). Also the dry matter content, nutrient content (total N and P), and methane production of this solid was higher than for the other systems. Furthermore the volumetric methane yield was much higher than for the solid fraction from the other separation systems (1.6 vs 0.8–1.0 m3 [CH4]·m−3 [reactor]·day−1 for a CSTR). Due to the high methane yield, digestion of the solid from source segregation is expected to require a considerable smaller reactor than for slurry digestion, which would increase the economic feasibility of mono-digestion systems for animal manure.


      PubDate: 2016-03-15T17:00:38Z
       
  • Predicting moisture content of chipped pine samples with a multi-electrode
           capacitance sensor
    • Abstract: Publication date: May 2016
      Source:Biosystems Engineering, Volume 145
      Author(s): Pengmin Pan, Timothy P. McDonald, Brian K. Via, John P. Fulton, John Y. Hung
      Woody biomass is currently sold on a weight basis, practical moisture sensors are essential for fair sales, especially in energy markets. To address this need, an 8-electrode electrical capacitance tomography (ECT) sensor was built and tested for predicting moisture content of wood chips and compared with the near infrared spectroscopy (NIR) method. The goal was to find an optimal means of measuring moisture content of woody biomass in the form of chips in two situations: individual chips and bulk samples. Tests were made on chips ranging in moisture content from 4% to 140% (d.b.). Results indicated that NIR had better performance in measuring moisture of single wood chips, while ECT was more accurate and rapid in bulk moisture determination. Knowledge of the mass of wood chips under test was required in the ECT moisture prediction model, unlike in the case of NIR. Both methods had the capability to measure moisture content of biomass while in motion. From a practical standpoint, however, only a portion of the material flowing past a near-infrared sensor could be practically scanned and the sub-sampled biomass would have to be representative of the entire population to be accurate. The ECT sensor, on the other hand, could likely be designed to scan the entirety of a large quantity of moving material and provide an accurate bulk average moisture content. Compared to a single paired-plate capacitance sensor, the ECT system also provided images, through its tomography function, that displayed permittivity distribution variability throughout bulk biomass samples.


      PubDate: 2016-03-10T16:48:48Z
       
  • Non-linear temperature dependency of ammonia and methane emissions from a
           naturally ventilated dairy barn
    • Abstract: Publication date: May 2016
      Source:Biosystems Engineering, Volume 145
      Author(s): Sabrina Hempel, Chayan Kumer Saha, Merike Fiedler, Werner Berg, Christiane Hansen, Barbara Amon, Thomas Amon
      Ammonia (NH3) and methane (CH4) emissions from naturally ventilated dairy barns affect the environment and the wellbeing of humans and animals. Our study improves the understanding of the dependency of emission rates on climatic conditions with a particular focus on temperature. Previous investigations of the relation between gas emission and temperature mainly rely on linear regression or correlation analysis. We take up a preceding study presenting a multilinear regression model based on NH3 and CH4 concentration and temperature measurements between 2010 and 2012 in a dairy barn for 360 cows in Northern Germany. We study scatter plots and non-linear regression models for a subset of these data and show that the linear approximation comes to its limits when large temperature ranges are considered. The functional dependency of the emission rates on temperature differs among the gases. For NH3, the exponential dependency assumed in previous studies was proven. For methane, a parabolic relation was found. The emissions show large daily and annual variations and environmental impact factors like wind and humidity superimpose the temperature dependency but the functional shape in general persists. Complementary to the former insight that high temperature increases emissions, we found that in the case of CH4, also temperatures below 10 °C lead to an increase in emissions from ruminal fermentation which is likely to be due to a change in animal activity. The improved prediction of emissions by the novel non-linear model may support more accurate economic and ecological assessments of smart barn concepts.
      Graphical abstract image

      PubDate: 2016-03-10T16:48:48Z
       
  • Genetic algorithm optimisation of heavy timber trusses with dowel joints
           according to Eurocode 5
    • Abstract: Publication date: April 2016
      Source:Biosystems Engineering, Volume 144
      Author(s): José R. Villar, Pablo Vidal, María S. Fernández, Manuel Guaita
      This paper presents the optimisation by genetic algorithms of the members and joints of heavy timber trusses fastened by mechanical joints with dowels and metal plates. This is achieved by programming in Matlab twenty-four elitist genetic algorithm models which, in combining different variables, provide an estimate of the geometry of the truss, the cross-section dimensions, and the number of dowels required. Trusses with various numbers of nodes are evaluated, with 6, 10, and 14 segments in the top chord. After validation of the results with a preliminary bibliography, an analysis is made of the effect of slipping of the joints in accordance with current standards, studying how such slipping affects the dimensioning of the trusses. Subsequently, to achieve the greatest economy in their design, the depth of the trusses is optimised. Genetic algorithms constitute an effective optimisation tool for the design of heavy timber trusses. They led to reduced costs compared with previous techniques described in the literature. In each type of truss studied, the optimal volume of timber was very similar for all cases, regardless of the number of upper chord members or joint slip. The cost of the truss therefore depended strongly on the number of joints, with the most economical solution being that with the fewest joints. Joint slip was important when the serviceability limit state was determinant, with its inclusion increasing the cost.
      Graphical abstract image

      PubDate: 2016-03-06T16:39:21Z
       
  • Analysis of shaking-induced cherry fruit motion and damage
    • Abstract: Publication date: April 2016
      Source:Biosystems Engineering, Volume 144
      Author(s): Jianfeng Zhou, Long He, Manoj Karkee, Qin Zhang
      High percentage of shaking-induced fruit damage is the major obstacle for mechanical harvesting of fresh-market sweet cherry. This study focused on the evaluation of the effect of vibration frequency on fruit motion, detaching time and damage during mechanical cherry harvesting with a shaker. A high-speed camera was used to capture the fruit trajectory on eighteen limbs excited at the frequencies of 10, 14 and 18 Hz. Fruit detaching time and number of fruit-to-fruit and fruit-to-limb impact were extracted from the high speed videos for determining the factors affecting fruit removal and damage. Results showed that the majority of the four identified motion patterns were tilting and beam-column motion, accounting for more than 70% of all patterns. Fruit detaching time was significantly affected by vibration frequency with fast detaching at high frequencies. Vibration frequency affected the overall fruit damage percentage substantially, with the lowest damage percentage of 47.1% in 14 Hz, which might be caused by high percentage of beam-column motion during vibration at the frequency. Meanwhile, 18 Hz vibration resulted in a higher percentage (35%) of unmarketable fruits than that of 10 Hz and 14 Hz. On average, a fruit experienced 3.8 impacts against limbs and other fruit at 18 Hz excitation, substantially lower than that of 11.8 impacts at 14 Hz or 11.7 impacts at 10 Hz excitation. Overall, the results indicate that shorter duration of high-level mechanical impacts could induce higher fruit damage.


      PubDate: 2016-03-06T16:39:21Z
       
  • Digital image analyses as an alternative tool for chicken quality
           assessment
    • Abstract: Publication date: April 2016
      Source:Biosystems Engineering, Volume 144
      Author(s): Douglas F. Barbin, Saulo M. Mastelini, Sylvio Barbon, Gabriel F.C. Campos, Ana Paula A.C. Barbon, Massami Shimokomaki
      Poultry meat colour is an important quality attribute for the rapid detection of “pale poultry syndrome”, as it is affected by conditions of animal welfare during pre-mortem period. The meat processing industry demands a fast and non-contact method for accurate meat colour assessment. In the present study, computer vision was tested as a potential tool to predict colour measurements compared to CIELab attributes of chicken breast (pectoralis major) obtained by analytical reference measurements. The proposed approach using computer vision was successful in avoiding pixels with little information (specular reflection) and based on an illumination normalisation step it was obtained an acceptable correlation between colorimeter measurements and the proposed framework (Delta E = 5.2). High correlation coefficients obtained between computer vision and colorimeter validate the approach for measuring L* colour component. Results for determination coefficient was R 2 = 0.99 for L*. In addition, our framework reach R 2 = 0.74 for a*, and R 2 = 0.88 for b* component. Results suggest that computer vision methods base on an RGB device can become useful tool for fast quality assessment of chicken meat in large-scale processing plants.
      Graphical abstract image

      PubDate: 2016-03-06T16:39:21Z
       
  • Methodology to improve pumping station management of on-demand irrigation
           networks
    • Abstract: Publication date: April 2016
      Source:Biosystems Engineering, Volume 144
      Author(s): Juan I. Córcoles, José M. Tarjuelo, Miguel A. Moreno
      The energy efficiency of pumping stations in irrigation networks was examined using a methodology to determine the optimum pumping station regulation. The methodology was developed in the MATLAB® environment using the EPANET® toolkit and developed using three on-demand irrigation networks located in the Castilla—La Mancha region of Spain. In each irrigation network, the energy efficiency and energy consumption were obtained for three cases: a fixed pumping head, a pumping head that guaranteed minimum pressure head required at the open hydrant and a pumping head that minimised the absorbed power at the pumping station. With the three networks average energy savings of 3%, 7% and 30% were obtained by using the optimum pressure head compared with the current management based on fixed pressure regulation. This methodology is intended to be useful in irrigable areas to improve the management of pumping systems where the use of fixed pressure regulation is extensive. It is important to measure electrical and hydraulic parameters of pumps which make it possible to determine the energy efficiency of a pumping station for each combination of discharge and pressure head as well as the pressure head which minimises the energy consumed for the pumping station to guarantee a specific pressure at open hydrants. These results were related to the fact that with fixed pressures, and mainly low and medium discharges, the energy efficiency of pumping systems can drop.


      PubDate: 2016-03-06T16:39:21Z
       
  • Parametric, asymmetric and stochastic-based 3D CAD model of Tonda Gentile
           Trilobata hazelnut variety
    • Abstract: Publication date: April 2016
      Source:Biosystems Engineering, Volume 144
      Author(s): Stefano Tornincasa, Elvio Bonisoli, Marco Brino
      A family of parametric 3D CAD models based on stochastic distribution of not-engineering real life object has been studied. The subject considered was the Tonda Gentile Trilobata (TGT) hazelnut variety, which is the most important variety in the Langhe region in Piedmont, Italy. The aim was to obtain a master model which measured, or stochastically-obtained, values of parameters given as input, to generate a number of samples which have the same statistical distributions of the real world ones. These generated models could then be used in virtual simulations of machinery and equipment used by industries to process the hazelnut, making possible studies of modifications to improve the production process performance. A single parametric CAD model was considered with respect to several scanned models from real hazelnuts, with the possibility of generating families of solutions suitable for the simulation aims. The work was carried out in steps of increasing complexity checking accuracy using different types of comparisons to validate the different models.


      PubDate: 2016-03-06T16:39:21Z
       
  • Editorial Board
    • Abstract: Publication date: March 2016
      Source:Biosystems Engineering, Volume 143




      PubDate: 2016-02-23T16:05:26Z
       
  • A prototype band-steaming machine: Design and field application
    • Abstract: Publication date: April 2016
      Source:Biosystems Engineering, Volume 144
      Author(s): Michele Raffaelli, Luisa Martelloni, Christian Frasconi, Marco Fontanelli, Stefano Carlesi, Andrea Peruzzi
      Soil steaming is a preventive non-chemical weed control method. We designed and studied a new prototype band-steaming machine. Tests were conducted during the growing cycle of organically cultivated carrot in real-field conditions, in order to study the effect of different steam doses on crops and a natural weed seedbank, throughout the whole growth cycle. The prototype has a 3265 MJ h−1 steam generator, which applies steam in 12 soil bands, 180 mm wide. The steam was mixed with the soil by mean of an apposite rotary cultivator. Four biological steam doses (0, 1.11, 1.59, and 2.78 kg m−2) were applied in combination with 4000 kg ha−1 of CaO prior to sowing the crop. Log-logistic models were used to describe the responses of temperatures, weed density, time required for hand weeding, weed dry biomass at harvest, and carrot yield to the band-steaming application. Based on the experimental data, an economic margin was evaluated to find the optimum application dose. Overall responses were influenced by steam dose. The results showed that a maximum temperature of 63 °C at a 25 mm depth was observed with a steam dose of 2.78 kg m−2. With a 2.78 kg m−2 dose, the operative time was approximately 14 h ha−1 and total fuel consumption was 768 kg ha−1. An estimated mean steam dose of 2.3 kg m−2 could be able to provide similar yield and hand weeding times responses to the highest steam dose applied, thus reducing both the operative time and fuel consumption of the machine.


      PubDate: 2016-02-23T16:05:26Z
       
  • A review on the main challenges in automatic plant disease identification
           based on visible range images
    • Abstract: Publication date: April 2016
      Source:Biosystems Engineering, Volume 144
      Author(s): Jayme Garcia Arnal Barbedo
      The problem associated with automatic plant disease identification using visible range images has received considerable attention in the last two decades, however the techniques proposed so far are usually limited in their scope and dependent on ideal capture conditions in order to work properly. This apparent lack of significant advancements may be partially explained by some difficult challenges posed by the subject: presence of complex backgrounds that cannot be easily separated from the region of interest (usually leaf and stem), boundaries of the symptoms often are not well defined, uncontrolled capture conditions may present characteristics that make the image analysis more difficult, certain diseases produce symptoms with a wide range of characteristics, the symptoms produced by different diseases may be very similar, and they may be present simultaneously. This paper provides an analysis of each one of those challenges, emphasizing both the problems that they may cause and how they may have potentially affected the techniques proposed in the past. Some possible solutions capable of overcoming at least some of those challenges are proposed.


      PubDate: 2016-02-23T16:05:26Z
       
  • Assessing the actions of the farm managers to execute field operations at
           opportune times
    • Abstract: Publication date: April 2016
      Source:Biosystems Engineering, Volume 144
      Author(s): Gareth T.C. Edwards, Niels Dybro, Lars J. Munkholm, Claus G. Sørensen
      Planning agricultural operations requires an understanding of when fields are ready for operations. However determining a field's readiness is a difficult process that can involve large amounts of data and an experienced farm manager. A consequence of this is that operations are often executed when fields are unready, or partially unready, which can compromise results incurring environmental impacts, decreased yield and increased operational costs. In order to assess timeliness of operations' execution, a new scheme is introduced to quantify the aptitude of farm managers to plan operations. Two criteria are presented by which the execution of operations can be evaluated as to their exploitation of a field's readiness window. A dataset containing the execution dates of spring and autumn operations on 93 fields in Iowa, USA, over two years, was considered as an example and used to demonstrate how operations' executions can be evaluated. The execution dates were compared with simulated data to gain a measure of how disparate the actual execution was from the ideal execution. The presented tool is able to evaluate spring operations better than autumn operations as required data was lacking to correctly parameterise the crop model. The evaluation criteria could be used to identify farm managers who require decisional support when planning operations, or as a means of promoting the use of sustainable farming practices.


      PubDate: 2016-02-23T16:05:26Z
       
  • Evaluation of the radiometric properties of roofing materials for
           livestock buildings and their effect on the surface temperature
    • Abstract: Publication date: April 2016
      Source:Biosystems Engineering, Volume 144
      Author(s): Giuliano Vox, Angela Maneta, Evelia Schettini
      Passive systems, such as high solar reflective roofing materials, protective facades, vegetative green walls and roofs, can be used in order to control solar heat gain in buildings. These sustainable technologies can reduce the temperature of the external surface of the building envelope, so reducing the energy consumption for cooling in summer. The radiometric properties of metallic roofing materials and their effects on the surface temperature were evaluated. Nine smooth metallic materials used for livestock buildings were tested; 4 were made of aluminium and the other 5 of steel and they were characterised by different colours. Solar reflectivity and long wave infrared emissivity were evaluated by means of laboratory tests; the influence of the radiometric properties on the surface temperature was evaluated in the field by using an experimental structure in Summer. The solar reflectivity coefficient ranged from 7.1% for the brown aluminium to 40.1% for the red steel; significant differences of the temperatures were recorded when the solar radiation hitting the metallic surface was higher than 600 W m−2. A difference of 13.4% of the solar reflectivity coefficient resulted in a difference of the surface temperature of up to 8 °C. Variation of the slope from 15° to 40° resulted in an increase of the surface temperature of more than 8 °C. The value of the convection coefficient was calculated by means of the data measured in the field, and the mean value was equal to 12.2 W m−2 K−1.


      PubDate: 2016-02-18T13:57:31Z
       
  • Indirect method versus direct method for measuring ventilation rates in
           naturally ventilated dairy houses
    • Abstract: Publication date: April 2016
      Source:Biosystems Engineering, Volume 144
      Author(s): Xiang Wang, Pius M. Ndegwa, HungSoo Joo, George M. Neerackal, Claudio O. Stöckle, Heping Liu, Joseph H. Harrison
      Indirect methods are widely used for determining air exchange rates (AER) in naturally ventilated barns because they are relatively easier and cheaper than direct methods, which measure actual airflow in and out of the barns. The main goal of this study was to evaluate a common indirect method (CO2 mass balance) against a direct method, and identify factors influencing this indirect method. The mean AER based on 24-h averaging, irrespective of method, ranged from 13 to 39 h−1 during the study-periods. The CO2-balance method tended to overestimate barn AER. The cows' CO2 production rate, in the current study, was estimated at 0.178 m3 h−1 hpu−1 based on 24-h averaging. The CO2-balance method with 24-h data averaging yielded more reliable barn AER than with shorter averaging times (i.e., 1, 2, and 12 h). The 1-h averaging, however, was chosen to analyze the effects of other pertinent factors on the CO2-balance method to capture diurnal variations of AER. Both wind speed and wind direction had significant effects on barn AER as well as the difference between the CO2-balance method and direct method. Barn AER, in general, increased with wind speed. The CO2-balance method was unreliable during milking times, and when indoor–outdoor CO2 concentration and temperature differences were less than 70 ppm and 0 °C, respectively.


      PubDate: 2016-02-18T13:57:31Z
       
  • Ammonia and greenhouse gas emissions from an enriched cage laying hen
           facility
    • Abstract: Publication date: April 2016
      Source:Biosystems Engineering, Volume 144
      Author(s): Oier Alberdi, Haritz Arriaga, Salvador Calvet, Fernando Estellés, Pilar Merino
      Ammonia, methane, nitrous oxide and carbon dioxide emissions were measured during a complete production cycle in an enriched cage laying hen facility under Oceanic climate conditions. Continuous monitoring of gas concentration, ventilation rate and environmental parameters were conducted from April 2012 to September 2013. The seasonal and diurnal pattern of gas emissions was analysed. Seasonality effect was found for NH3 emission, showing an average emission of 144.9 mg d−1 hen−1 and 90.3 mg d−1 hen−1 in summer and winter, respectively. On the contrary, diurnal pattern of NH3 emission did not differ between these seasons. For CO2, mean emission values did not show seasonality, although the diurnal pattern differed between winter and summer. Results obtained for CH4 and N2O emissions did not provide sufficient evidence to determine either seasonality or diurnal effect on these gases. An NH3 emission factor of 7% of total N in manure was defined for this system. These losses increased at higher ventilation rates and lower belt cleaning frequencies. Thus, NH3 mitigation strategies at housing level should consider both parameters. Further studies would be necessary to determine how these factors regulate NH3 emission at laying hen houses.


      PubDate: 2016-02-14T13:45:56Z
       
  • Dielectric characterization of rapeseed (Brassica napus L.) from 10 to
           3000 MHz
    • Abstract: Publication date: March 2016
      Source:Biosystems Engineering, Volume 143
      Author(s): Namita Bansal, Amarjit S. Dhaliwal, Kuldip S. Mann
      Dielectric characterization of rapeseed (Brassica napus L.) in the temperature range of 20–60 °C and at moisture contents of 8.5, 12.5 and 16% wet basis (w.b.) was performed by determining the dielectric constant and loss factor at frequencies from 10 to 3000 MHz. This range of frequencies includes the ISM (Industrial, Scientific and Medical) frequencies of 13, 27, 40, 915 and 2450 MHz. An open-ended coaxial probe (Speag DAK, 12) and a vector network analyzer (Agilent Technologies, E5071C) were used to measure the dielectric properties (dielectric constant and loss factor). Compressed ground samples of rapeseed at densities nearly equivalent to seed density were used. Determined data at the ISM frequencies was fitted to polynomials to represent the dependence of the dielectric constant as well as the loss factor on temperature and moisture content. The calculated penetration depth of the electromagnetic field in rapeseed at the ISM frequencies shows that at a given moisture content and temperature, it decreases with increasing frequency. The reported data are useful in designing and developing radio-frequency (RF) and microwave (MW) applicators for dielectric heating of rapeseed.


      PubDate: 2016-01-11T20:36:13Z
       
 
 
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