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  Subjects -> AGRICULTURE (Total: 660 journals)
    - AGRICULTURAL ECONOMICS (71 journals)
    - AGRICULTURE (443 journals)
    - CROP PRODUCTION AND SOIL (84 journals)
    - DAIRYING AND DAIRY PRODUCTS (25 journals)
    - POULTRY AND LIVESTOCK (37 journals)

AGRICULTURE (443 journals)                  1 2 3 4 5 | Last

Acta agriculturae Slovenica     Open Access   (Followers: 5)
Acta Agrobotanica     Open Access   (Followers: 3)
Acta Agronomica Hungarica     Full-text available via subscription   (Followers: 1)
Acta Agronomica Sinica     Full-text available via subscription   (Followers: 6)
Acta Scientiarum. Animal Sciences     Open Access   (Followers: 1)
Acta Scientiarum. Technology     Open Access   (Followers: 1)
Acta Technologica Agriculturae     Open Access   (Followers: 1)
Advances in Agriculture & Botanics     Open Access   (Followers: 10)
Advances in Agriculture, Sciences and Engineering Research     Open Access   (Followers: 10)
Advances in Agronomy     Full-text available via subscription   (Followers: 11)
Advances in Life Science and Technology     Open Access   (Followers: 5)
AFBM Journal     Open Access  
Africa Development     Open Access   (Followers: 6)
Africa Research Bulletin: Political, Social and Cultural Series     Hybrid Journal   (Followers: 6)
African Journal of Agricultural Research     Open Access   (Followers: 1)
African Journal of Food Science     Open Access   (Followers: 1)
African Journal of Food, Agriculture, Nutrition and Development     Open Access   (Followers: 1)
African Journal of Horticultural Science     Open Access   (Followers: 2)
African Journal of Range and Forage Science     Hybrid Journal   (Followers: 5)
African Journal of Sustainable Development     Full-text available via subscription   (Followers: 3)
Agribusiness : an International Journal     Hybrid Journal   (Followers: 5)
Agricultura Tecnica     Open Access   (Followers: 5)
Agricultura Tropica et Subtropica     Open Access   (Followers: 1)
Agricultural Advances     Open Access   (Followers: 3)
Agricultural and Food Science     Open Access   (Followers: 14)
Agricultural Economics     Hybrid Journal   (Followers: 44)
Agricultural History     Full-text available via subscription   (Followers: 148)
Agricultural Research     Hybrid Journal   (Followers: 2)
Agricultural Science     Full-text available via subscription   (Followers: 5)
Agricultural Sciences     Open Access   (Followers: 7)
Agricultural Sciences in China     Full-text available via subscription   (Followers: 3)
Agricultural Systems     Hybrid Journal   (Followers: 19)
Agricultural Water Management     Hybrid Journal   (Followers: 13)
Agriculture     Open Access   (Followers: 4)
Agriculture & Food Security     Open Access   (Followers: 9)
Agriculture (Poľnohospodárstvo)     Open Access   (Followers: 1)
Agriculture and Agricultural Science Procedia     Full-text available via subscription  
Agriculture and Human Values     Hybrid Journal   (Followers: 10)
Agriculture, Ecosystems & Environment     Hybrid Journal   (Followers: 29)
Agriprobe     Full-text available via subscription  
Agrivita : Journal of Agricultural Science     Open Access   (Followers: 4)
Agro-Science     Full-text available via subscription  
Agroalimentaria     Open Access   (Followers: 1)
Agrociencia     Open Access   (Followers: 2)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Agronomía Colombiana     Open Access   (Followers: 1)
Agronomía Costarricense     Open Access   (Followers: 2)
Agronomía Mesoamericana     Open Access   (Followers: 1)
Agronomie Africaine     Full-text available via subscription  
Agronomy     Open Access   (Followers: 8)
Agrosearch     Open Access  
AI & Society     Hybrid Journal   (Followers: 2)
Alinteri Zirai Bilimler Dergisi : Alinteri Journal of Agricultural Sciences     Open Access  
Ambiência     Open Access  
Ambiente & Agua : An Interdisciplinary Journal of Applied Science     Open Access   (Followers: 1)
American Journal of Agricultural and Biological Sciences     Open Access   (Followers: 9)
American Journal of Botany     Full-text available via subscription   (Followers: 13)
American Journal of Economics and Sociology     Hybrid Journal   (Followers: 19)
American Journal of Potato Research     Hybrid Journal   (Followers: 2)
Anais da Academia Brasileira de Ciências     Open Access   (Followers: 2)
Annales UMCS, Agricultura     Open Access  
Annales UMCS, Horticultura     Full-text available via subscription  
Annals of Agricultural and Environmental Medicine     Open Access   (Followers: 1)
Annals of Agricultural Sciences     Open Access   (Followers: 1)
Annual Review of Resource Economics     Full-text available via subscription   (Followers: 10)
APCBEE Procedia     Partially Free   (Followers: 2)
Applied Economics Letters     Hybrid Journal   (Followers: 18)
Applied Financial Economics Letters     Hybrid Journal   (Followers: 5)
Arboricultural Journal : The International Journal of Urban Forestry     Hybrid Journal   (Followers: 6)
Archivos de Zootecnia     Open Access  
Arquivos do Instituto Biológico     Open Access  
Arthropod-Plant Interactions     Hybrid Journal   (Followers: 1)
Asian Economic Papers     Hybrid Journal   (Followers: 3)
Asian Journal of Agricultural Research     Open Access   (Followers: 2)
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: 5)
Australian Forest Grower     Full-text available via subscription   (Followers: 2)
Australian Forestry     Full-text available via subscription   (Followers: 4)
Australian Grain     Full-text available via subscription   (Followers: 4)
Australian Holstein Journal     Full-text available via subscription  
Australian Journal of Agricultural and Resource Economics     Hybrid Journal   (Followers: 5)
Australian Journal of Agricultural Engineering     Open Access  
Australian Sugarcane     Full-text available via subscription  
Avances en Investigacion Agropecuaria     Open Access  
Bangladesh Journal of Agricultural Research     Open Access   (Followers: 1)
Bangladesh Journal of Scientific Research     Open Access  
Berkala Ilmiah Pertanian     Open Access   (Followers: 1)
Bioagro     Open Access   (Followers: 1)
Biocatalysis and Agricultural Biotechnology     Hybrid Journal   (Followers: 5)
Biocontrol Science and Technology     Hybrid Journal   (Followers: 5)
Biodiversity     Hybrid Journal   (Followers: 16)
Biodiversity : Research and Conservation     Open Access   (Followers: 17)
Biological Agriculture & Horticulture : An International Journal for Sustainable Production Systems     Partially Free   (Followers: 13)
Biosystems Engineering     Hybrid Journal   (Followers: 1)
Biotemas     Open Access  
Bragantia     Open Access   (Followers: 2)
Brazilian Archives of Biology and Technology     Open Access   (Followers: 1)
British Poultry Science     Hybrid Journal   (Followers: 5)
California Agriculture     Open Access   (Followers: 1)

        1 2 3 4 5 | Last

Journal Cover Biosystems Engineering
   [3 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1537-5110 - ISSN (Online) 1537-5129
     Published by Elsevier Homepage  [2563 journals]   [SJR: 0.757]   [H-I: 58]
  • Use of inorganic substrates and composted green waste in growing media for
           green roofs
    • Abstract: Publication date: August 2014
      Source:Biosystems Engineering, Volume 124
      Author(s): Abigail Graceson , Martin Hare , Nigel Hall , Jim Monaghan
      Inorganic substrates are used as the primary component in green roof growing media because they can provide the desired physical properties and are thought to be physically, chemically and structurally stable over time. Inorganic substrates can be amended with organic matter to help establish vegetation on green roofs but there is little information on how this affects the physical properties; dry bulk density, water holding capacity and air filled porosity; of the resulting growing medium or whether the effects are the same for all inorganic substrates. Nine crushed brick and three crushed tile substrates obtained from five UK suppliers of aggregates were amended with 30% v/v composted green waste. The physical properties of the substrates and growing media mixes were determined using the gravitational drainage technique. Amending the inorganic substrates with composted green waste significantly improved the physical properties by reducing the dry bulk density and increasing the water holding capacity. Air filled porosity of inorganic substrates decreased with addition of fine composted green waste but aeration was always adequate for plant growth and survival. This provides evidence of the beneficial effects of inclusion of composted green waste on the physical properties of inorganic substrates for green roof growing media but highlights the fact that the responses to inclusion of composted green waste may be different for different inorganic substrates or grades of substrate.


      PubDate: 2014-06-14T15:25:37Z
       
  • Effect of nano-Si2O and nano-Al2O3 on cement mortars for use in
           agriculture and livestock production
    • Abstract: Publication date: July 2014
      Source:Biosystems Engineering, Volume 123
      Author(s): Nestor León , Jordi Massana , Francisco Alonso , Amparo Moragues , Elvira Sánchez-Espinosa
      The effect of nano-silica, nano-alumina and binary combinations on surface hardness, resistance to abrasion and freeze-thaw cycle resistance in cement mortars was investigated. The Vickers hardness, the Los Angeles coefficient (LA) and the loss of mass in each of the freeze–thaw cycles to which the samples were subjected were measured. Four cement mortars CEM I 52.5R were prepared, one as control, and the other three with the additions: 5% nano-Si, 5% nano-Al and mix 2.5% n-Si and 2.5% n-Al. Mortars were tested at 7, 28 and 90 d of curing to determine compression strength, total porosity and pore distribution by mercury intrusion porosimetry (MIP) and the relationship between the CSH gel and Portlandite total by thermal gravimetric analysis (TGA). The capillary suction coefficient and an analysis by a scanning electron microscope (SEM) was made. There was a large increase in Vickers surface hardness for 5% n-Si mortar and a slight increase in resistance to abrasion. No significant difference was found between the mortars with nano-particles, whose LA was about 10.8, classifying them as materials with good resistance to abrasion. The microstructure shows that the addition of n-Si in mortars refines their porous matrix, increases the amount of hydrated gels and generates significant changes in both Portlandite and Ettringite. This produced a significant improvement in freeze–thaw cycle resistance. The effect of n-Al on mortar was null or negative with respect to freeze–thaw cycle resistance.


      PubDate: 2014-06-14T15:25:37Z
       
  • First steps to predicting pulp colour in whole melons using near-infrared
           reflectance spectroscopy
    • Abstract: Publication date: July 2014
      Source:Biosystems Engineering, Volume 123
      Author(s): María-Teresa Sánchez , Irina Torres , María-José De la Haba , Dolores Pérez-Marín
      Near-infrared reflectance spectroscopy (NIRS) technology was used for the non-destructive measurement of melon-pulp colour (a*, b*, C* and h*), one of the main indicators of ripeness and quality. A total of 432 Cantaloupe and Galia melons were used in the construction of calibration models, testing various spectral signal pretreatments and both linear and non-linear regression algorithms. The coefficient of determination (r 2) and the standard error of cross-validation (SECV) obtained for parameters a* (0.96, 2.16), b* (0.85, 3.25), C* (0.82, 3.76) and h* (0.96, 3.64) in intact fruit confirmed the a priori viability of NIRS technology with modified partial least squares (MPLS) regression for measuring melon ripeness and quality. Moreover, the application of a local algorithm improved the ability of models to predict all the internal-colour quality parameters studied. These results suggest that NIRS technology is a promising tool for monitoring ripening in melons and thus for establishing the optimal harvesting time.


      PubDate: 2014-06-14T15:25:37Z
       
  • Energy intensity and energy ratio in producing willow chips as feedstock
           for an integrated biorefinery
    • Abstract: Publication date: July 2014
      Source:Biosystems Engineering, Volume 123
      Author(s): Mariusz J. Stolarski , Michał Krzyżaniak , Józef Tworkowski , Stefan Szczukowski , Janusz Gołaszewski
      This study examined the production of willow at a commercial plantation with an area of 10.5 ha, situated in north-eastern Poland. Its aim was to evaluate the energy intensity and energy ratio of the production of chips of new willow cultivars as feedstock for an integrated biorefinery. This study emphasises the key importance of the selection of a willow cultivar for the production of willow chips and the transport distance to a biorefinery for the energy intensity of the production process and the energy ratio of the supplied biomass. The lowest energy intensity for willow chip production was achieved for the plantation of the highest-yielding cultivar (UWM 006). When the yield exceeded 86 t ha−1 of fresh biomass, the energy intensity was 0.35 GJ t−1 of fresh matter (f.m.). The energy ratio for the product at the farm gate varied depending on the cultivar and ranged from 23.9 to 10.2, for UWM 006 and UWM 155 cultivars, respectively. The distance of biomass transport to a biorefinery significantly affected the energy ratio. When chips were transported for 25 km, the energy intensity for the production of 1 t of chips increased by 3–7% compared to its value at the farm gate. The energy intensity for the longest of the analysed transport distances increased by 23–53%. The energy ratio for each cultivar decreased significantly by 3–35% with increasing transport distance. The values of energy intensity and energy ratio for UWM 006 and UWM 043 were better than those achieved in other studies.


      PubDate: 2014-06-14T15:25:37Z
       
  • Combustion characteristics and emissions of a compression ignition engine
           using emulsified jatropha biodiesel blend
    • Abstract: Publication date: July 2014
      Source:Biosystems Engineering, Volume 123
      Author(s): Hifjur Raheman , Sweeti Kumari
      An emulsified fuel containing 10% and 15% water by volume was prepared from a diesel blend with 10% Jatropha biodiesel (JB10) to evaluate the combustion characteristics of a 10.3 kW, single cylinder, 4-stroke, water cooled, direct injection (DI) diesel engine. Initially experiments were conducted to determine the required hydrophilic–lipophilic balance (HLB). The results showed that JB10 and its emulsified fuel exhibited similar combustion stages to that of diesel with no undesirable combustion features observed such as an unacceptable increase cylinder gas pressure. With increasing percentage of water, ignition delay was longer at higher engine loads. Reductions in emission of CO, CO2, HC and NO x were observed for the emulsified fuel compared to JB10. Emulsified biodiesel can be recommended for use in place of biodiesel.


      PubDate: 2014-06-14T15:25:37Z
       
  • Two-stage procedure based on smoothed ensembles of neural networks applied
           to weed detection in orange groves
    • Abstract: Publication date: July 2014
      Source:Biosystems Engineering, Volume 123
      Author(s): Joaquín Torres-Sospedra , Patricio Nebot
      The potential impacts of herbicide utilization compel producers to use new methods of weed control. The problem of how to reduce the amount of herbicide and yet maintain crop production has stimulated many researchers to study selective herbicide application. The key of selective herbicide application is how to discriminate the weed areas efficiently. We introduce a procedure for weed detection in orange groves which consists of two different stages. In the first stage, the main features in an image of the grove are determined (Trees, Trunks, Soil and Sky). In the second, the weeds are detected only in those areas which were determined as Soil in the first stage. Due to the characteristics of weed detection (changing weather and light conditions), we introduce a new training procedure with noisy patterns for ensembles of neural networks. In the experiments, a comparison of the new noisy learning was successfully performed with a set of well-known classification problems from the machine learning repository published by the University of California, Irvine. This first comparison was performed to determine the general behavior and performance of the noisy ensembles. Then, the new noisy ensembles were applied to images from orange groves to determine where weeds are located using the proposed two-stage procedure. Main results of this contribution show that the proposed system is suitable for weed detection in orange, and similar, groves.


      PubDate: 2014-06-14T15:25:37Z
       
  • Profit maximisation algorithm including the loss of yield due to uncertain
           weather events during harvest
    • Abstract: Publication date: July 2014
      Source:Biosystems Engineering, Volume 123
      Author(s): Lazar Savin , Snežana Matić-Kekić , Nebojša Dedović , Mirko Simikić , Milan Tomić
      A general LP model and a profit maximisation algorithm for harvesting during an agrotechnical period have been created. The profit was based on the crop yields on a primary farm and the rental of combines to surrounding farms for their harvests. In contrast to the standard approach, the use of integer variables was avoided in the proposed model. The objective function included the risk of yield reduction due to bad weather conditions and the deliberate extension of the harvest on the primary farm, with the aim of higher profits from combine rentals. The model involved two conflicting criteria: the minimisation of risk during harvest on the primary farm and the maximisation of combine rentals; both of these aims were successfully incorporated into the objective function. The operational reliability of combines and tractors was taken into account in model creation. A general model was applied to a large farm (1380 ha) during a period of harvest and transport of oilseed rape, wheat and winter barley into storage (June–July). The farm that was considered is equipped with enough machinery to harvest other farms and on its own parcels simultaneously.


      PubDate: 2014-06-14T15:25:37Z
       
  • Simulation of soya bean flow in mixed-flow dryers using DEM
    • Abstract: Publication date: July 2014
      Source:Biosystems Engineering, Volume 123
      Author(s): Oleg A. Khatchatourian , Manuel O. Binelo , Rodolfo F. de Lima
      Soya bean movement in mixed-flow dryers (MFDs) is explored. A three-dimensional model of soya beans flow was developed applying the discrete element method (DEM) implementation of the Yade software package. To validate the developed model the experiments of the soya beans discharge in small MFD were carried out and the results compared with simulations. Considering the soya bean seeds as single spheres, and using the values of the principal material properties (Poisson coefficient, Young modulus, fraction angle and rolling stiffness) from the literature, satisfactory agreement was obtained between simulated and experimental results with a damping factor value of 0.05. Simulations of continuous flow detected significant non-uniformity in particle velocity and residence time.


      PubDate: 2014-06-14T15:25:37Z
       
  • A novel intelligent control system for flue-curing barns based on
           real-time image features
    • Abstract: Publication date: July 2014
      Source:Biosystems Engineering, Volume 123
      Author(s): Juan Wu , Simon X. Yang , Fengchun Tian
      Most intensive tobacco curing systems are manually operated requiring the curers to frequently observe the status of tobacco leaves and in order to achieve the desired temperature and relative humidity, curers adjust the setpoint values of dry and wet bulb temperatures and the time to change to the next setpoints. Control is therefore subjective and it is difficult to maintain consistent high quality curing. A novel intelligent control system based on the real-time image processing of the tobacco leaves images to monitor the status of the tobacco leaves was developed. A neural network based approach was designed to identify the setpoints for the dry and wet bulb temperatures, and the time to change to the next setpoints. Inputs were 12 extracted image features obtained from an image processing algorithm and the measured dry and wet bulb temperatures in the barn. Without any manual intervention by curers, the developed intelligent control system achieved real-time monitoring and management of the curing process. The effectiveness of the developed intelligent control system was demonstrated by simulation and experiment.


      PubDate: 2014-06-14T15:25:37Z
       
  • Anaerobic digestion of pig manure fibres from commercial pig slurry
           separation units
    • Abstract: Publication date: July 2014
      Source:Biosystems Engineering, Volume 123
      Author(s): Ole Thygesen , Jin M. Triolo , Sven G. Sommer
      The composition of manure fibres (MF) from 17 commercially separated pig slurries and seven raw pig slurries were characterised in terms of dry matter (DM), volatile solids (VS), protein, hemicellulose, cellulose and lignin. The average lignocellulose concentration in manure fibres and pig slurries was 790 and 370 g kg−1 [VS] respectively. Biochemical methane potential was ascertained after 60 days, revealing a trend in biochemical methane potential between the different separation technologies used: pig slurry > shaking filter and screw press combined ≈ decanter centrifuge > flocculation, belt and screw press combined ≈ screw press. The maximum methane yield of manure fibres from decanter centrifuges and the combined shaking filter and screw press was approximately 330 l [CH4] kg−1 [VS] at standard temperature and pressure (STP), while manure fibres from a screw press and a combination of belt press and screw press on average produced approximately 220 l [CH4] kg−1 [VS]. Initial methane production can be described using a first-order kinetic model. The average rate constant for manure fibres was 0.030 d−1 and for pig slurry 0.071 d−1, showing that pig slurry is digested much faster than manure fibres.


      PubDate: 2014-06-14T15:25:37Z
       
  • Long term irrigation with treated wastewater (TWW) and soil sodification
    • Abstract: Publication date: Available online 2 June 2014
      Source:Biosystems Engineering
      Author(s): Guy J. Levy , Pinchas Fine , Dina Goldstein , Asher Azenkot , Avraham Zilberman , Amram Chazan , Tzfrir Grinhut
      Use of treated wastewater (TWW) for irrigation has grown noticeably in recent years, especially in arid and semi-arid regions. The sodium adsorption ratio (SAR) in TWW is considerably higher than that in its fresh water of origin. Recently, there is evidence showing that subsurface (depth >30 cm) exchangeable sodium percentage (ESP) levels in Israeli orchards may reach 6–9 which is higher than expected following long-term irrigation with TWW having SAR <5. Our objectives were to (i) determine the ESP in soil profiles of orchards exposed to irrigation with TWW, and (ii) examine the relationships between the SAR of the irrigation water, the SAR of the soil solution and the ESP of the studied soils. Soil samples were taken from different depths (up to 120 cm) in orchards grown on two different soil types that had been irrigated for >10 years with TWW. In each soil sample non-adjusted SAR and adjusted SAR (SARadj) of the saturated paste and ESP were determined. In all sampled sites except one, accumulation of adsorbed sodium in the soil subsurface was noted. The obtained ESP levels were higher than those expected based on the SAR of the TWW. A satisfactory agreement was noted between ESP data and the non-adjusted SAR and SARadj of the soil solution. These observations suggest that a chemical equilibrium exists between the soil exchange phase and the soil solution and that the properties of the latter were not always dictated by those of the irrigation water.


      PubDate: 2014-06-14T15:25:37Z
       
  • Editorial Board
    • Abstract: Publication date: June 2014
      Source:Biosystems Engineering, Volume 122




      PubDate: 2014-06-14T15:25:37Z
       
  • Early detection of mechanical damage in mango using NIR hyperspectral
           images and machine learning
    • Abstract: Publication date: June 2014
      Source:Biosystems Engineering, Volume 122
      Author(s): Nayeli Vélez Rivera , Juan Gómez-Sanchis , Jorge Chanona-Pérez , Juan José Carrasco , Mónica Millán-Giraldo , Delia Lorente , Sergio Cubero , José Blasco
      Mango fruit are sensitive and can easily develop brown spots after suffering mechanical stress during postharvest handling, transport and marketing. The manual inspection of this fruit used today cannot detect the damage in very early stages of maturity and to date no automatic tool capable of such detection has been developed, since current systems based on machine vision only detect very visible damage. The application of hyperspectral imaging to the postharvest quality inspection of fruit is relatively recent and research is still underway to find a method of estimating internal properties or detecting invisible damage. This work describes a new system to evaluate mechanically induced damage in the pericarp of ‘Manila’ mangos at different stages of ripeness based on the analysis of hyperspectral images. Images of damaged and intact areas of mangos were acquired in the range 650–1100 nm using a hyperspectral computer vision system and then analysed to select the most discriminating wavelengths for distinguishing and classifying the two zones. Eleven feature-selection methods were used and compared to determine the wavelengths, while another five classification methods were used to segment the resulting multispectral images and classify the skin of the mangos as sound or damaged. A 97.9% rate of correct classification of pixels was achieved on the third day after the damage had been caused using k-Nearest Neighbours and the whole spectra and the figure dropped to 91.4% when only the most discriminant bands were used.


      PubDate: 2014-06-14T15:25:37Z
       
  • Olive oil quality improvement using a natural sedimentation plant at
           industrial scale
    • Abstract: Publication date: June 2014
      Source:Biosystems Engineering, Volume 122
      Author(s): Giuseppe Altieri , Giovanni C. Di Renzo , Francesco Genovese , Antonella Tauriello , Maurizio D'Auria , Rocco Racioppi , Licia Viggiani
      Olive oil extraction is mainly carried out using continuous extraction by decanter centrifuge with efficiency of approximately 80–90%. After centrifugal extraction, olive oil is generally cleaned using a vertical disc stack centrifuge separator, which is suspected of being the major cause of decreased final olive oil quality. Experiments were carried out at industrial scale to compare the olive oil properties after improved processes of sedimentation (Sedoil) or centrifugation (Cenoil) with respect to raw olive oil obtained at the decanter exit (Control). Peroxide, polyphenol, chlorophyll, carotenoid, turbidity and K232 average values were significantly different between Sedoil and Cenoil, which confirmed that the use of disc stack centrifuges represents an important source of oxidative reactions. Analysis showed that storage time dramatically affects the oxidation level of the olive oil. All parameters used to monitor the oxidation level (i.e., free acidity, peroxide value and K232) increased after 180 d of storage, and the content of natural antioxidants and pigments decreased as expected. The residual presence of water during long-term storage represented the most important source of oxidation, and an effective cleaning operation is necessary to preserve oil quality during its storage life. The analyses performed using 1H and 13C NMR showed that Sedoil was more similar in composition to Control than to Cenoil. The use of sedimentation plant allows the employment of the disk stack centrifuge to be reduced improving both energy saving and the quality of clean olive oil.


      PubDate: 2014-06-14T15:25:37Z
       
  • Effects of cover optical properties on screenhouse radiative environment
           and sweet pepper productivity
    • Abstract: Publication date: June 2014
      Source:Biosystems Engineering, Volume 122
      Author(s): Evangelini Kitta , Alain D. Baille , Nikolaos Katsoulas , Nikolaos Rigakis , Maria M. González-Real
      The effects of cover optical properties on screenhouse radiative environment and sweet pepper productivity were investigated in a Mediterranean climate (Eastern Greece) under three covering materials (i) a pearl insect-proof screen (IP-78), (ii) a white insect proof screen (IP-59) and (iii) a green shade-screen (GS-62) with values of the transmittance to photosynthetically active radiation (τ PAR) of 78%, 59% and 62%, respectively. All screens induced impoverishment in the blue wavelength band (B, 400–500 nm) and enrichment in near-infrared broadband (NIR, 700–1100 nm) with respect to photosynthetically active radiation (PAR) (400–700 nm), and modified photomorphogenetic parameters such as the ratio R:FR (Red:Far-Red). From a 2-year agronomic survey, it was found that the lowest performance in terms of crop productivity was observed in the open field, and the highest under the IP-78 screenhouse. At final harvest, aboveground dry biomass and total yield of screenhouse crops were linearly and positively correlated with τ PAR, while plant height was negatively correlated with the ratio R:FR. The results suggested that (i) the more diffuse radiation regime prevailing under screenhouse is likely to be at the root of the higher crop performances observed under the screenhouses and (ii) τ PAR and R:FR are likely to act synergistically in light capture. We conclude that both changes in transmittance and light quality must be accounted for when analysing productivity and yield regulation of screenhouse-grown crops. From a practical point of view, a shading factor no higher than 20% is recommended for sweet pepper cropping under Mediterranean conditions similar to those of this study.


      PubDate: 2014-06-14T15:25:37Z
       
  • Exergoeconomic performance assessment of a pilot-scale spray dryer using
           the specific exergy costing method
    • Abstract: Publication date: June 2014
      Source:Biosystems Engineering, Volume 122
      Author(s): Zafer Erbay , Nurcan Koca
      In this study, exergoeconomic analysis was performed to evaluate the performance of a pilot scale spray dryer during white cheese powder production by the specific exergy costing (SPECO) method. Drying experiments were carried out at an inlet drying air temperature range of 160–230 °C, an outlet drying air temperature range of 60–100 °C and an atomisation pressure range of 294.2–588.4 kPa. The components of drying system were separately analysed and the effects of operating conditions on system components and the overall system were discussed. Improvements for the drying cabinet should be focused on for process optimisation, whereas structural improvements of the atomiser should strongly be considered for reducing investment costs. Furthermore, investment costs for the feed pump used in the drying system should be decreased or the feed pump should be replaced with a cheaper one. While results showed high inlet and low outlet air temperatures caused high effectiveness for the overall system performance, the operating costs were the most important variable due to expenses.


      PubDate: 2014-06-14T15:25:37Z
       
  • Temporal variation in soil detachment capacity by overland flow under four
           typical crops in the Loess Plateau of China
    • Abstract: Publication date: June 2014
      Source:Biosystems Engineering, Volume 122
      Author(s): Yao-chuang Yu , Guang-hui Zhang , Ren Geng , Long Sun
      Accurate estimation of the temporal variation in soil detachment capacity (D c , kg m−2 s−1) by overland flow and its potential influencing factors is critical to predict rill erosion. However, detailed information on the temporal variation in D c remains limited for the cultivated lands in the Loess Plateau of China. This study was conducted to investigate the temporal variations in soil detachment capacity by overland flow using undisturbed topsoil samples collected from four typical crops (maize, millet, soybean, and potato) and to further identify the potential factors causing these changes during one growing season from early April to late September in 2012 in the Loess Plateau of China. The results showed that the measured mean D c was greatest for potato, followed by maize, soybean, and millet. Soil detachment capacity for each crop fluctuated significantly over time with a similar pattern of temporal variation. The temporal variations of soil detachment capacity were affected by tillage practices, soil consolidation, water-stable aggregates (WSA), and root growth. Soil detachment capacity of four crops could be estimated using flow shear stress, soil cohesion (SC), and root density (RD) (Nash–Sutcliffe model efficiency = 0.89). Further studies are needed to investigate the potential effects of root architecture on soil detachment capacity by overland flow under different conditions.


      PubDate: 2014-06-14T15:25:37Z
       
  • Modelling and evaluation of productivity and economic feasibility of a
           combined production of tomato and algae in Dutch greenhouses
    • Abstract: Publication date: June 2014
      Source:Biosystems Engineering, Volume 122
      Author(s): Bart Slager , Athanasios A. Sapounas , Eldert J. van Henten , Silke Hemming
      Combination of production of algae and tomato increases efficient use of available resources of greenhouse enterprises, such as controlled environment, water and nutrients, carbon dioxide, greenhouse space and infrastructure and knowledge. No information is available, however, about the potential productivity and related costs of a combined tomato and algae production in Dutch greenhouses. The objective was to determine the algae productivity in tubular photobioreactors (PBRs) and the economic feasibility of combined production of tomato and algae in Dutch greenhouses. A model was developed to predict greenhouse climate from outside climate, to predict tomato and algae biomass production and to analyse scenarios of different locations and dimensions of tubular PBR in the greenhouse with regard to algae productivity and cost price of algae production. The results show that algal productivity is low if PBRs are installed under a tomato crop due to limited light levels. Areal algal productivity was calculated to be 5–6.5 kg DM m−2 if PBRs are installed in a separate greenhouse compartment next to tomato. In this case the minimum cost prices of algae production was calculated to be €11 kg−1 DM algae, which give perspectives for the future. The proposed model is important because it gives insight into the feasibility of algae and tomato production in Dutch greenhouses. This novel model approach and the scenario results provide better knowledge about the potential productivity and related costs and returns of algae production in greenhouses.


      PubDate: 2014-06-14T15:25:37Z
       
  • Effects of different air inlets on indoor air quality and ammonia emission
           from two experimental fattening pig rooms with partial pit ventilation
           system – Summer condition
    • Abstract: Publication date: June 2014
      Source:Biosystems Engineering, Volume 122
      Author(s): Chao Zong , Ying Feng , Guoqiang Zhang , Michael Jørgen Hansen
      It has previous been demonstrated that a pit ventilation system could improve indoor air quality and reduce ammonia emission significantly from pig production if an air purification system was installed to treat the pit exhaust air. However, the knowledge about the influence of a partial pit exhaust unit treating a small part of the ventilation (10%) in a ventilation system with different types of air inlets on indoor air quality and ammonia emission from pig house is still lacking. In this study, two rooms, both with partial pit exhaust and ceiling-top room exhaust units, were used. One room was equipped with ceiling air inlet (system C) and another room was equipped with wall jet air inlet (system W). Each room had 32 fattening pigs. The maximum ventilation rate in each room was set as 3200 m3 h−1. Room ventilation rate was automatically controlled by a climate control strategy based on indoor thermal conditions, while pit ventilation rate was fixed at 10% of the maximum ventilation rate. Ammonia concentrations were measured in air inlet, room exhaust and pit exhaust for both systems. Air flow rates and ammonia concentrations were measured and recorded continuously. Results showed that ventilation rate requirement was higher in system C than in system W (22.3%, p < 0.001) to maintain the setup indoor thermal condition during the whole fattening period. In the meantime, significant higher ammonia concentrations and emissions in both pit and room exhausts were found in system W than in system C (p < 0.001). The ammonia emission ratio of pit exhaust, defined as the emission via pit exhaust divided by the total emission, in systems C and W was 48% and 47%, respectively. If applying an effective air purification system, a significant reduction of ammonia emission could be achieved. The gap of ammonia concentration difference between system C and W increased in the later stage. Higher room ventilation rate led to smaller difference of ammonia concentration in room air. Slurry depth had a positive effect on the ammonia emission from pit exhaust. No significant difference in the pigs' activity was found between the two ventilation systems.


      PubDate: 2014-06-14T15:25:37Z
       
  • Numerical simulations and experimental measurements on the distribution of
           air and drying of round hay bales
    • Abstract: Publication date: June 2014
      Source:Biosystems Engineering, Volume 122
      Author(s): Franz D. Román , Oliver Hensel
      The artificial drying of round bales offers the possibility to consistently produce quality hay by reducing field curing time and leaf shattering. Air distribution in the bale must be appropriate in order to achieve a uniform and efficient drying process. The air distribution and drying of four designs of round bale dryer were simulated using computational fluid dynamics. A round bale was modelled as a cylindrical porous media having a soft core. Bales were modelled both as being perfectly formed and as having a lower density close to their circular faces. Simulations showed that the simplest dryer design in which air enters the bale through one end, provides a deficient air distribution and inadequate drying, even when the bale is perfectly formed. Other designs studied showed, to varying degrees, an improved air distribution and drying uniformity. Simulations of a design in which an axial void is created in the bale centre, produced an optimal situation where the air and the drying front moves radially from the centre outwards. Conveying of air through both bale ends also contributed significantly to flow and drying uniformity. However, simulations for bales with a deficient density profile, as often found in practice, showed important distortions in the air distribution negatively affected drying. Therefore the uniformity of bale dry matter density is a determinant for the successful operation of any dryer. Additional efforts must be invested in the field to produce more uniform bales, particularly during raking and baling.


      PubDate: 2014-04-28T22:59:40Z
       
  • Prediction of surface temperature of figs during infrared heating and its
           effect on the quality
    • Abstract: Publication date: June 2014
      Source:Biosystems Engineering, Volume 122
      Author(s): Vipavee Trivittayasil , Fumihiko Tanaka , Daisuke Hamanaka , Toshitaka Uchino
      Fresh figs have a short shelf-life due to a fast softening rate and fungal spoilage. Infrared heating treatment as a surface decontamination technique could be applied to the ostiole, where most mould growth is observed. However, the quality of fresh fruits could be degraded if the heat treatment is too severe. The objective of this study is to find the optimal trade-off between a fungal decay reduction and a fruit quality. Figs were treated with infrared heating until they reached maximum temperatures of 50 °C, 60 °C and 70 °C. A heat transfer model was employed to calculate the treatment time required for each treatment group. Quality assessment was performed after six days of storage at 7 °C. At the lowest heating treatment group of 50 °C, a suppression of fungal development was achieved without a significant heat injury.


      PubDate: 2014-04-28T22:59:40Z
       
  • Effects of acidification during storage on emissions of methane, ammonia,
           and hydrogen sulfide from digested pig slurry
    • Abstract: Publication date: June 2014
      Source:Biosystems Engineering, Volume 122
      Author(s): Kaiying Wang , Dandan Huang , Hongchuang Ying , Haojie Luo
      The effects of acidification reduction on methane (CH4), ammonia (NH3) and hydrogen sulphide (H2S) emissions from digested pig slurry during storage were investigated. Pilot-scale experiments designed with three different pH levels including one control and two acidified treatments were conducted. Digested pig slurry was stored and tested in nine mechanically ventilated reactors. An online and continuous monitoring system was used to acquire gas emissions data during the whole storage period. Temperatures and pH in digested slurry were continuously measured with sensors. Off-gas from the reactors and air from room environment were sampled alternately then supplied to gas analysers for CH4 and H2S determination. Headspace NH3 from the 9 reactors were regularly sampled by an air sampling instrument and then determined for concentration by spectrophotometer. The study found that digested pig slurry characteristics still didn't satisfy the national standards after 95 days treatments. Both temperature and pH were crucial factors to influence CH4 and NH3 emissions from digested pig slurry. In the control group (Gn) CH4 and H2S emissions mainly occurred in the first 20 days and 12 days, respectively; while no predictable NH3 emission patterns were found in the experiment. Comparing with Gn, adjustment of initial pH to 5.5 significantly reduced CH4 emissions by 80.8% and NH3 emissions by 40.2%, but increased H2S emissions by 11,324% (average increasing emission flux was 4.1 μg m−2 min−1). Acidification with pH adjusted to 6.5 reduced CH4 emissions by 31.2%, but did not affect NH3 and H2S emissions significantly.


      PubDate: 2014-04-28T22:59:40Z
       
  • Moisture transport properties of lime–hemp concrete determined over
           the complete moisture range
    • Abstract: Publication date: June 2014
      Source:Biosystems Engineering, Volume 122
      Author(s): Paulien Strandberg-de Bruijn , Peter Johansson
      To determine the durability of a lime–hemp concrete (LHC) wall and its resistance to driving rain, moisture conditions inside the wall have to be modelled. As model input, moisture transport properties were determined. Two LHC mixes were studied. Cup tests provided moisture diffusivity results at relative humidity (RH) values up to 95%. Capillary water uptake tests provided results for the interval 95–100% RH by means of curve fitting and the simulation tool JAM-KAP. A mix containing more lime showed higher moisture diffusivity at relative humidity >95%.


      PubDate: 2014-04-28T22:59:40Z
       
  • Optimised hydrodynamic parameters for the design of photobioreactors using
           computational fluid dynamics and experimental validation
    • Abstract: Publication date: June 2014
      Source:Biosystems Engineering, Volume 122
      Author(s): Jessie Pascual P. Bitog , In-Bok Lee , Hee-Mock Oh , Se-Woon Hong , Il-Hwan Seo , Kyeong-Seok Kwon
      A numerical simulation using computational fluid dynamics (CFD) was utilised to investigate the flow hydrodynamics of cylindrical bubble column type photobioreactors (PBRs) with a 30l culture medium. To establish the reliability of the simulation study, the CFD model was validated using particle image velocimetry (PIV) computed data under various air flow rates. There were 32 simulation cases for the study comprising two PBR designs, four air flow rates and four nozzle size diameters. Hydrodynamic analyses such as % volume of dead zones, average circulation time and turbulence intensity inside the simulated PBRs were evaluated. Results have shown that the most appropriate PBR for microalgae cultivation was a design with internal baffle and an extended cone-shaped bottom section. In addition, the recommended nozzle diameter was found to be 10 mm and a minimum air flow rate of 0.10 vvm. To eliminate dead zones inside the PBR, the flow rate can be slightly increased but should not exceed 0.15 vvm. Practical evaluation through laboratory experiments has further confirmed the results of the study where the biomass concentration of Chlorella vulgaris from the proposed PBR was significantly higher compared to the standard PBR design. Based on the numerical investigation and practical evaluation, the improved PBR can be seen to be more effective in culturing microalgae particularly for larger scale mass production.


      PubDate: 2014-04-28T22:59:40Z
       
  • Prototype semi-transparent photovoltaic modules for greenhouse roof
           applications
    • Abstract: Publication date: June 2014
      Source:Biosystems Engineering, Volume 122
      Author(s): Akira Yano , Mahiro Onoe , Josuke Nakata
      Improved energy efficiency and the increased use of renewable energy are important objectives for sustainable greenhouse crop production. Two prototypes of semi-transparent-bifacial photovoltaic modules intended for greenhouse roof applications were developed. A module (PV1) using 1500 spherical solar microcells (1.8 mm diameter, crystalline silicon) with 15.4 cells cm−2 density in 108 mm × 90 mm area was produced. Thirty-nine percent of the area was covered with the cells. The remaining 61% was transparent to allow the most sunlight to enter the greenhouse for promising plant photosynthesis. Similarly, a module (PV2) was made using 500 cells with 5.1 cells cm−2 density. Thirteen percent of the area of this module was covered with the cells. The peak power output was 540 mW when the PV1 module was irradiated with 1213 W m−2 sunlight coming directly from the sky and via ground reflection. The peak power output was 202 mW when the PV2 module was irradiated with 1223 W m−2 sunlight. The conversion efficiencies from sunlight energy irradiated on the 108 mm × 90 mm area into electrical energy were 4.5% for the PV1 module and 1.6% for the PV2 module. Calculations of the annual electrical energy production per unit greenhouse land area indicated that these modules are potentially suitable for greenhouses in high-irradiation regions where electricity production could be high and winter demand low.
      Graphical abstract image

      PubDate: 2014-04-28T22:59:40Z
       
  • Drip vs. surface irrigation: A comparison focussing on water saving and
           economic returns using multicriteria analysis applied to cotton
    • Abstract: Publication date: June 2014
      Source:Biosystems Engineering, Volume 122
      Author(s): Hanaa M. Darouich , Celestina M.G. Pedras , José M. Gonçalves , Luís S. Pereira
      This study explores the use of drip and surface irrigation decision support systems to select among furrow, border and drip irrigation systems for cotton, considering water saving and economic priorities. Data refers to farm field observations in Northeast of Syria. Simulation of drip irrigation was performed with MIRRIG model for various alternatives: double and single row per lateral, emitter spacing of 0.5 and 0.7 m, six alternative pipe layouts and five self-compensating and non-compensating emitters. Furrow and border irrigation alternatives were designed and ranked with the SADREG model, considering lasered and non-lasered land levelling, field lengths of 50–200 m and various inflow discharges. A multicriteria analysis approach was used to analyse and compare the alternatives based upon economic and water saving criteria. Results for surface irrigation indicate a slight advantage for long non-lasered graded furrows; non-lasered alternatives were selected due to economic considerations. For drip irrigation, the best ranking is for systems having lower costs, mainly with double rows per lateral and larger emitter spacing. Comparing surface and drip irrigation systems, despite low cost, drip alternatives may lead to 28–35% water saving relative to improved graded furrows, and increase water productivity from 0.43 kg m−3 to 0.61 kg m−3, surface irrigation provides higher farm returns. Drip irrigation is selected only when high priority is assigned to water saving. Deficit irrigation does not change this pattern of results. Apparently, adopting drip irrigation requires appropriate economic incentives to farmers, changes in the structure of production costs and increased value of production.


      PubDate: 2014-04-28T22:59:40Z
       
  • Editorial Board
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121




      PubDate: 2014-04-28T22:59:40Z
       
  • High-precision laser scanning system for capturing 3D plant architecture
           and analysing growth of cereal plants
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121
      Author(s): Stefan Paulus , Henrik Schumann , Heiner Kuhlmann , Jens Léon
      Securing global food supply and coping with climate change requires new plant breeding approaches for the selection of favourable genotypes. This can be accomplished by introducing new non-destructive measuring techniques which allow quantifying growth processes of the same plants over a longer period of time (“phenotyping”). The use of a high-precision laser scanner coupled with a moveable articulated measuring arm to directly obtain 3D data non-invasively at sub-millimetre scale is investigated. This enabled reconstruction of the single barley organs leaf and stem as well as the architecture of the whole barley plant on the decimetre scale. The added data analysing process enabled multiple morphological plant parameters to be simultaneously derived from one scanning process which were highly correlated (R 2 0.85–0.97) to manually obtained parameters from reference measurements. By scanning every 2–3 days organ-specific growth monitoring of single leaves (area) and single stems (height) was established for the first time for cereals. The cumulated parameters of leaf area, stem height and plant volume allowed the growth dynamics of the barley to be quantified until tillering was ended. As an example, drought effect due to reduced irrigation was shown with smallest significant differences and dated precisely. The fineness of the laser scanning measurement system indicated its appropriateness for high-precision phenotyping in plant breeding as well as for detailed morphological measuring questions in the fields of biology and agronomy.


      PubDate: 2014-04-28T22:59:40Z
       
  • Sensitivity analysis of mechanistic models for estimating ammonia emission
           from dairy cow urine puddles
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121
      Author(s): Dennis J.W. Snoek , Johannes D. Stigter , Nico W.M. Ogink , Peter W.G. Groot Koerkamp
      Ammonia (NH3) emission can cause acidification and eutrophication of the environment, is an indirect source of nitrous oxide, and is a precursor of fine dust. The current mechanistic NH3 emission base model for explaining and predicting NH3 emissions from dairy cow houses with cubicles, a floor and slurry pit is based on measured data from a limited number of studies. It requires input values for numerous variables, but the empirical equations for the model parameters in the literature vary. Furthermore, many of the input variables cannot be assessed accurately, and their actual influence on the prediction is unknown. We aimed to improve NH3 emission modelling, by assessing the contribution to the variation in NH3 emission of each input variable and each model parameter related to a single urine puddle. We did so for 27 candidate models, created by each possible combination of three equations per model parameter: the acid dissociation constant, Henry's law constant, and the mass transfer coefficient. After analysing each candidate model with a Global Sensitivity Analysis we found that at least 71% of the model variation in NH3 emission for each candidate model was explained by five puddle related input variables: pH, depth, area, initial urea concentration and temperature. NH3 emission was not sensitive to the other four variables: air temperature, air velocity, maximum rate of urea conversion and the Michaelis–Menten constant for urea conversion. Based on these results we recommend simplifying the model structurally and reducing the number of input variables.


      PubDate: 2014-04-28T22:59:40Z
       
  • Modelling seasonal and multi-annual variation in bank vole populations and
           nephropathia epidemica
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121
      Author(s): Sara Amirpour Haredasht , C. James Taylor , Piet Maes , Jan Clement , Willem W. Verstraeten , Marc Van Ranst , Pol Coppin , Daniel Berckmans , Jean-Marie Aerts
      Nephropathia epidemica (NE) is a human infection caused by Puumala virus (PUUV), which is naturally carried and shed by bank voles (Myodes glareolus). The objective was to develop a dynamic model of the NE cases and the bank vole population in both Finland and Belgium by defining the periodic components with a dynamic harmonic regression (DHR) model. The defined periodic components can be further used to adapt mechanistic Susceptible and Infective (SI) models regionally. Despite the difference in bank vole population dynamics and NE cases between the Western European temperate zone and boreal zones the DHR model was able to quantify the dynamics of NE cases in Belgium and Central Finland with a coefficient of determination (R 2) of 0.70 and 0.82 respectively and to quantify the dynamics of bank vole population in Belgium and Central Finland with R 2 of 0.80 and 0.98 respectively. DHR identified 18 month cycles in the bank vole population in Belgium. This approach demonstrated two year cycles in Belgian NE outbreaks. DHR identified three year cycles in Finnish bank vole populations which in turn cause three year cycles in the NE outbreaks in Central Finland. Because the bank vole population data in Finland was contemporary with the data of NE cases, the DHR showed a three month delay between the NE cases and the bank vole population in Central Finland. This approach may help us in our understanding of the spatial and temporal dynamics of NE cases and the bank vole populations in different regions.


      PubDate: 2014-04-28T22:59:40Z
       
  • Embodied energy associated with the materials used in irrigation systems:
           Drip and centre pivot
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121
      Author(s): A.V. Diotto , M.V. Folegatti , S.N. Duarte , T.L. Romanelli
      Evaluations able to estimate sustainability indices of production systems have intensified the use of complex analysis. The energy flow methodology considers the total direct and indirect energy required by production systems. A way to determine energy flows is through material flow determination, which is used as a material inventory of processes. This study aimed to define a model to determine the indirect embodied energy for two kinds of irrigation systems, drip and centre pivot, whose variables are parameters of irrigation projects such as irrigated area, distance between irrigation assets and water source, and useful life of the equipment. Using the same scenario presented by other authors to compare the values of indirect embodied energy for centre pivot irrigation, the model results ranged from 4.10 to 2.09 GJ ha−1, where the highest value is a result of using just 10 years for the centre pivot useful life. For drip irrigation system, the indirect embodied energy ranged from 5.52 to 6.20 GJ ha−1. The participation of each part of the system differs between the scenarios evaluated. The pump system was responsible for between 0.38 and 3.14%, the filter systems had a minute share for the drip system (<0.01%), the pipeline ranged from 0 to 23% and the internal part of the irrigation systems was the most important and ranged from 75.34 to 99.62%. The model developed can be used to identify the indirect embodied energy in analysis of irrigated production systems in different project conditions.


      PubDate: 2014-04-28T22:59:40Z
       
  • Development and testing of a Jatropha fruit shelling process for
           shell-free kernel recovery in biodiesel production
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121
      Author(s): Bo Yuan Lim , Rosnah Shamsudin , Robiah Yunus
      Achieving shell-free kernel recovery from Jatropha fruits is important to improve oil yield and oil quality during oil extraction in biodiesel production. A shelling process with two stages of cracking and separation to remove the shells completely and husks partially was designed. Both stages used double-level cracking rollers and a blower with ducting as a separation unit. For the first, the performance was evaluated using five different roller clearances (9.5 mm, 10.0 mm, 10.5 mm, 11.0 mm and 11.5 mm) with a combination of five blower air speeds (8.5 ± 0.5 m s−1, 9.0 ± 0.6 m s−1, 9.5 ± 0.5 m s−1, 10.0 ± 0.4 m s−1 and 10.5 ± 0.5 m s−1). A roller clearance of 10.5 mm and air speed of 10.0 ± 0.4 m s−1 were selected as the optimal conditions with the highest separation efficiency between kernels and shells at 94.59%. The shells and husks achieved 95.88% and 12.20% removal respectively while kernel recovery achieved 98.65%. For the second stage, the performance was evaluated using five different roller clearances (5.0 mm, 5.5 mm, 6.0 mm, 6.5 mm and 7.0 mm) with a combination of five blower air speeds (6.5 ± 0.4 m s−1, 7.0 ± 0.2 m s−1, 7.5 ± 0.4 m s−1, 8.0 ± 0.2 m s−1 and 8.5 ± 0.5 m s−1). At the optimal conditions, with a roller clearance of 6.0 mm and air speed of 7.5 ± 0.4 m s−1, the maximum separation efficiency was 97.69%. Total shell and husk removal achieved for the stages were 100.00% and 45.46% respectively. A total of 2.40% kernels were lost.


      PubDate: 2014-04-28T22:59:40Z
       
  • Modelling of soil–seed contact using the Discrete Element Method
           (DEM)
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121
      Author(s): Haibo Zhou , Ying Chen , Mohammad A. Sadek
      It has long been recognised that soil–seed contact is vital to seed germination, as good soil–seed contact promotes water transfer from soil to seed. However, until today, it has not been possible to quantify soil–seed contact, due to the non-homogeneous nature of agricultural soil. This study has made a significant step in advancing the field through modelling the soil–seed regime using the Discrete Element Method (DEM). In the soil–seed model, the seed was simplified as a spherical particle, and agricultural soil was represented by an assembly of completely random individual spherical particles exhibiting cohesive and frictional behaviours. Seed placement was simulated in a fashion similar to the field planting process. Model results showed that the number of active contacts between a seed and soil particles varied from 0 to 33, and the contact area varied from 0 to 41 mm2, depending on the size and properties of the seed and soil particles. The greatest contact area was observed when the size ratio of soil to seed is 1.33 or 1.75. Higher soil particle stiffness resulted in a reduced number of contacts and smaller contact area. Simulations of press wheel effects in the model showed that when soil is compacted, both number of contacts and contact area are significantly increased.


      PubDate: 2014-04-28T22:59:40Z
       
  • Analysis of the axial pressing of bulk Jatropha curcas L. seeds using
           reciprocal slope transformation
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121
      Author(s): David Herák , Jiří Blahovec , Abraham Kabutey
      A reciprocal slope transformation (RST) with the least squares method (LSM) was used to develop mathematical equations to describe dependency between compressive force and deformation characteristic curves of Jatropha bulk seeds of varying initial pressing height from 30 mm, 40 mm, 50 mm, 60 mm, 70 mm and 80 mm in linear compression. The experimental data derived from a compression test was done using compression device (ZDM, model 50, Germany) and pressing vessel diameter, 60 mm at compression speed of 1 mm s−1 and compressive force between 0 kN and 100 kN. Statistical analysis of both experimental and fitted data coefficients of third order polynomial function was significant (p > 0.05) with high coefficient of determination (R 2). The RST method provides the fundamental step for the development of generalised model in future research where varying effect of compression factors such as moisture content, friction, compression speed and pressing temperature would be considered.


      PubDate: 2014-04-28T22:59:40Z
       
  • Growth characteristics of cabbage plug seedlings due to mutual shading
           among neighbouring seedlings
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121
      Author(s): Takashi Fukushima , Kunio Sato , Takashi Ohi , Mansu Cho
      Plug seedlings are increasingly used in vegetable cultivation in Japan, because they are suitable for machine operations and are disease resistant; however, in cabbage cultivation, variation in seedling growth affects plant growth after transplanting to the field, and eventually, harvesting all the cabbages at the same time is not possible. In this paper, a simulation model used to express the growth variation in cabbage plug seedlings is proposed to reveal their cultivation characteristics and consider a cultivation technique that would produce uniform growth among seedlings. In this simulation model, the mutual shading among neighbouring plug seedlings resulting from high-density planting, which is one of the factors of variation in seedling growth, was modelled. The model parameters were obtained from the results of a cultivation experiment comparing growth against the light quantity that seedlings could receive; however, there were differences between the growth of a single seedling in the cultivation experiment and the growth of the plug seedlings. It is believed that growth rate and mass would be greater for a single seedling than for the plug seedlings. This simulation was able to express the growth variation of the actual plug seedlings by adjusting the model parameters.


      PubDate: 2014-04-28T22:59:40Z
       
  • Image-based particle filtering for navigation in a semi-structured
           agricultural environment
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121
      Author(s): Santosh Hiremath , Frits K. van Evert , Cajo ter Braak , Alfred Stein , Gerie van der Heijden
      Autonomous navigation of field robots in an agricultural environment is a difficult task due to the inherent uncertainty in the environment. The drawback of existing systems is the lack of robustness to these uncertainties. In this study we propose a vision-based navigation method to address these problems. The focus is on navigation through a maize field in an outdoor environment where the robot has to navigate through a corridor formed by two plant rows, detect the end of the rows, navigate the headland and turn into another corridor under natural conditions. The method is based on a Particle Filter (PF) using a novel measurement model, where we construct a model image from the particle and compare it directly with the measurement image after elementary processing, such as down-sampling, excessive-green filtering and thresholding. The new measurement model does not extract features from the image and thus does not suffer from errors associated with the feature extraction process. We show how PF can be used for robust navigation of a robot in a semi-structured agricultural environment such as maize fields with inherent uncertainty. We demonstrate the robustness of the algorithm through experiments in several maize fields with different row patterns, varying plant sizes and diverse lighting conditions. To date we have logged over 5 km of successful test runs in which the robot navigates through the corridor without touching the plant stems, accurately detects the end of the rows and traverses the headland.


      PubDate: 2014-04-28T22:59:40Z
       
  • Ventilation rate measurements at a mechanically-ventilated pig finishing
           quad barn
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121
      Author(s): Lide Chen , Teng-Teeh Lim , Yaomin Jin , Albert J. Heber , Ji-Qin Ni , Erin L. Cortus , Ilker Kilic
      With concentrated animal feeding operations (CAFOs) becoming larger and more intensive, air pollutant emissions from these facilities are of increasing concern for regulators and the public, and on-farm measurements of emissions are needed. A critical step in determining air pollutant emissions from the barns at these facilities is the accurate assessment and continuous monitoring of the barn ventilation rates. One of the most recent efforts to accurately determine barn ventilation rate was to continuously monitor fan operation, differential static pressure, fan speed, and air density related environmental variables, coupled with in-situ fan performance assessments at a range of static pressures, as applied in the 24-month National Air Emissions Monitoring Study (NAEMS). Uncertainty analyses associated with these calculations aided in characterising and qualifying the measurements. This paper describes methods used in the NAEMS to determine ventilation rates of four rooms (rooms 5–8) in a mechanically-ventilated pig finishing quad barn. The overall 2-yr average daily dry-standard ventilation rates (mean ± SD) were 13.5 ± 11.3, 13.8 ± 11.6, 14.5 ± 12.9, and 13.6 ± 12.9 m3 [dry-standard] s−1 for rooms 5–8, respectively. Thorough uncertainty analyses demonstrated that the estimated uncertainty of the ventilation rate (dry-standard) under typical site conditions decreased from 9.4% to 4.1% between the minimum (3.7 m3 [ds] s−1) and maximum (45.2 m3 [ds] s−1) capacities of the ventilation system. These results confirmed that larger numbers of operating fans lead to lower relative uncertainties for barn ventilation rates and that the uncertainty of ventilation rate measurements can be reduced by improved and more frequent in-situ fan calibrations.


      PubDate: 2014-04-28T22:59:40Z
       
  • Three-dimensional discrete element modelling of tillage: Determination of
           a suitable contact model and parameters for a cohesionless soil
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121
      Author(s): Mustafa Ucgul , John M. Fielke , Chris Saunders
      Accurate modelling of soil–implement interaction is vital to optimise the design of tillage implements. Discrete element modelling (DEM) is a numerical method used for modelling the mechanical behaviour of granular materials. When DEM is used for tillage the soil is assumed to consist of distinct particles with the interactions between the particles controlled by contact models that are governed by physical laws. In previous three-dimensional (3D) DEM tillage studies the soil particles were assumed as having elastic contacts and the plastic deformation behaviour of the soil particles was not taken into account. Using EDEM software, a non-linear elastic contact model was compared with a linear hysteretic spring contact model that considers the plasticity of the soil. The DEM parameters required to run the simulations were determined from angle of repose and penetration tests, matching the simulation results to test results using a modelled spherical particle with radii of 10 mm. The simulation results of both the non-linear elastic and linear hysteretic spring (plastic) contact models were compared with experimental results from a sweep tillage tool. An improved correlation was obtained between the measured draft and vertical force results using the linear hysteretic spring (plastic) contact model. Further simulations using the linear hysteretic spring (plastic) model showed there was a quadratically increasing trend with particle size from 4 to 10 mm for the parameters of coefficient of restitution of soil–soil, friction of soil–soil and integration time step.


      PubDate: 2014-04-28T22:59:40Z
       
  • Investigation of heating and cooling potential of a modular housing system
           for fattening pigs with integrated geothermal heat exchanger
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121
      Author(s): Manuel S. Krommweh , Peter Rösmann , Wolfgang Büscher
      Against the backdrop of global reductions in fossil fuel reserves and rising energy prices, there is increasing interest in the use of geothermal heat exchangers (GHEs) in farm animal production. The modular housing concept is a housing system with an integrated GHE area where fresh air is led through a space between slurry pit and soil to condition the supply air. This modular housing system was investigated for the first time over a one-year experimental period in Warendorf (in western Germany). During this period, the temperature of outdoor, fresh, supply and section air were recorded continuously, along with the relevant air flow volume, electricity and gas consumption. The aim of the study was to quantify the heating and cooling performance of this system under practical conditions over an extended period. This kind of housing is characterised in particular by the fact that the incoming air into the sections is subject to year-round conditioning depending of the outdoor temperature (pre-heating and pre-cooling of supply air). During the investigation period, the modular housing for 1280 fattening pigs effectively provides a heat quantity of 489,820 kWh at a mean performance of 59.7 kW as well as a cooling quantity of 18,455 kWh at a mean performance of 33.3 kW. This means that there is great potential for saving fossil fuel and energy costs as well as avoiding CO2 emissions. In contrast, the investment costs are higher than for comparable conventional pig houses.


      PubDate: 2014-04-28T22:59:40Z
       
  • Band application of slurry in orchards using a prototype spreader with an
           automatic rate controller
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121
      Author(s): Fabrizio Gioelli , Paolo Balsari , Elio Dinuccio , Gianfranco Airoldi
      A prototype slurry spreader for band application in orchards was designed, constructed, and tested. The spreader comprised several components: 1) 5 m3 tank, 2) distribution device of trailing hoses to reduce ammonia emissions during application, 3) automatic rate controller to apply nitrogen per crop requirements, and 4) low-pressure, wide-section tyres to mitigate soil compaction and sward damage. The slurry tanker design fitted between tree row spacings accounting for tree shape differences. The spreading system consists of two groups of six trailing hoses; each hose group distributes slurry into two 1.0 m wide bands alongside the machine and 0.5 m from tree rows. Operator input of slurry total nitrogen content, determined by onboard hydrometer in the field, and target application rate in the control unit ensured that nitrogen was applied at a constant rate based on metering pump rotational speed as a function of machine forward speed. The rate control system was tested at different application doses and with rapid changes in machine forward speed (range of 3–9 km h−1). The machine responded promptly (<2 s) to forward speed changes, and the spreader evenly distributed slurry in both application bands (D ave < 2.5% on the treated surface). Band application of slurry by the trailing hose device reduced ammonia emissions by 63% compared to the common broadcast application system by splash plate.


      PubDate: 2014-04-28T22:59:40Z
       
  • Detecting mycorrhizal colonisation in Scots pine roots using electrical
           impedance spectra
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121
      Author(s): Tapani Repo , Anna Korhonen , Miikka Laukkanen , Tarja Lehto , Raimo Silvennoinen
      To investigate whether root colonisation of Scots pine (Pinus sylvestris L.) seedlings with symbiotic mycorrhizal fungi (Hebeloma sp. and Suillus luteus) could be detected in situ, classification analysis of the electric impedance spectra (IS) of the root system was carried out. The seedlings were inoculated either with Hebeloma or Suillus with some left as controls. The seedlings were firstly cultivated in long-day and high temperature (LDHT) conditions. Half of the seedlings remained in LDHT and half were moved to short-day and low temperature conditions (SDLT) to acclimatise to the cold. The electrical impedance spectra of the root systems were measured at a frequency range of 5 Hz–100 kHz. The results of principal component analysis (PCA) showed that current delivery through root system, sensed by real and imaginary parts of IS, depended upon the cold acclimation and mycorrhizal treatment. Comparison of SDLT to LDHT via correlation analysis indicated a 13% and a 27% change in PCA responses for the real and imaginary parts of the impedance, respectively. When the mycorrhizal treatments were compared with a non-mycorrhizal treatment, the respective changes in the correlation coefficients were 30% for Hebeloma sp. and 39% for S. luteus in the real part and 28% and 38% in the imaginary part, respectively. These changes in the correlation coefficients appear to indicate physicochemical changes (e.g. ionic behaviour) in the roots as a result of fungal colonisation.


      PubDate: 2014-04-28T22:59:40Z
       
  • Development of a 3D ego-motion estimation system for an autonomous
           agricultural vehicle
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121
      Author(s): Dawei Jiang , Liangcheng Yang , Danhua Li , Feng Gao , Lei Tian , Liujun Li
      A stereo vision based three-dimensional (3D) ego-motion estimation system was proposed and tested to enable real-time navigation for a full-scale agricultural vehicle. A stereo camera was used to track features in image sequences which were then matched to obtain 3D point clouds that can be used for motion estimation. To overcome the challenges of uneven terrains, relative rotation and translation motions were taken into consideration by registering the point clouds using the iterative closest point algorithm. A smooth-motion constraint was employed to reduce estimation outliers, and a multi-frame estimation strategy was developed to limit estimation failures and error propagations. A series of field tests were conducted on different field surfaces. In a soybean field where the vehicle was driven for 2.5 km following a typical back-and-forth route, the maximum position estimation error was 5.12 m or 0.20%; while on a grass road, where available features were limited, the maximum error was 6.21 m, or 1.61%, for a driving distance of 386 m. To evaluate the estimation of heading angles using multiple frames, the vehicle was driven following a sine-wave route for 100 m; the root-mean-square error (RMSE) of heading angle was 1.43°, which was much lower compared to a RMSE of 6.69°obtained using consecutive frames for estimation. Finally, the vehicle was driven across a 0.24 m and a 0.1 m high bumps and an estimate of pitch angle and roll angle were obtained. An RMSE of 0.30°was obtained for both angles, indicating its feasibility of navigating vehicles on uneven terrains.


      PubDate: 2014-04-28T22:59:40Z
       
  • Prediction of the spread of highly pathogenic avian influenza using a
           multifactor network: Part 1 – Development and application of
           computational fluid dynamics simulations of airborne dispersion
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121
      Author(s): Il-Hwan Seo , In-Bok Lee , Oun-Kyung Moon , Nam-Su Jung , Hyung-Jin Lee , Se-Woon Hong , Kyeong-Seok Kwon , Jessie P. Bitog
      Highly pathogenic avian influenza (HPAI) virus can be spread rapidly, resulting in high mortality and severe economic damage to the poultry industry. A prediction of HPAI dispersion is challenging considering various spread factors, such as indirect transmission by airborne spread as well as direct transmission through contact by humans, vehicles, wild animals, and migratory birds. Because of the complexity of the spread of HPAI, it is difficult to provide prompt treatments against epidemics. Moreover, there is little information on the airborne spread of the HPAI virus because of the limitations of field experiments for determining the mechanism of the spread of the disease due to the difficulty of making accurate measurements in the presence of unstable and uncontrollable weather conditions. In this study, CFD (computational fluid dynamics) was used to estimate the dispersion of the virus attached to aerosols produced by livestock using a GIS (geographical information system) to model a three-dimensional specific topography that includes the farm location, road network, and related facilities. The CFD simulation was conducted to predict the dispersion of virus from source farms according to various wind conditions. The weather conditions during the period of interest were analysed using CFD simulations to complete a frequency matrix form. The results were used as background data, to be used to take preventive measures against HPAI occurrences and spread based on the multifactor network process introduced in Part II.


      PubDate: 2014-04-28T22:59:40Z
       
  • Rapid estimation of soil engineering properties using diffuse reflectance
           near infrared spectroscopy
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121
      Author(s): Bernard K. Waruru , Keith D. Shepherd , George M. Ndegwa , Peter T. Kamoni , Andrew M. Sila
      Materials testing involve complex reference methods and several soil tests have been used for indexing material functional attributes for civil engineering applications. However, conventional laboratory methods are expensive, slow and often imprecise. The potential of soil diffuse reflectance near infrared (NIR) spectroscopy for the rapid estimation of selected key engineering soil properties was investigated. Two samples sets representing different soils from across the Lake Victoria basin of Kenya were used for the study: A model calibration set (n = 136) was obtained using a conditioned Latin hypercube sampling, and a validation set (n = 120) using a spatially stratified random sampling strategy. Spectral measurements were obtained for air-dried (<2 mm) soil sub-samples using a Fourier-transform diffuse reflectance near infrared (NIR) spectrometer. Soil laboratory reference data were also obtained for liquid limit (LL), plastic limit (PL), plasticity index (PI), linear shrinkage (LS), coefficient of linear extensibility (COLE), volumetric shrinkage (VS), clay activity number (Ac), total clay content, air-dried moisture content, and cation exchange capacity (CEC). Soil reference data were calibrated to smoothed first derivative NIR spectra using partial least squares (PLS) regression. At the calibration stage, coefficient of determination for full cross-validation (R 2) of ≥0.70 was obtained for CEC, mc, LL, PI, LS, COLE and VS. Further independent validation gave R 2 ≥ 0.70 and RPD (ratio of reference data SD and root mean square error of prediction) 1.7–2.2 for LL, PI, mc and CEC. The results suggested that NIR–PLS has potential for the rapid estimation of several key soil engineering properties. Further work should focus on extending calibration libraries using more diverse soil types and testing alternative infrared diffuse reflectance based methods.


      PubDate: 2014-04-28T22:59:40Z
       
  • Path planning for the autonomous collection of eggs on floors
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121
      Author(s): Bastiaan A. Vroegindeweij , Gerard L. van Willigenburg , Peter W.G. Groot Koerkamp , Eldert J. van Henten
      A problem in loose housing systems for laying hens is the laying of eggs on the floor; these eggs need manual collection. This job is heavy and time-consuming and automated collection is desired. For collection using a robot, a collection path is required. A novel path planning algorithm is introduced for non-uniform repetitive area coverage (NURAC) paths and evaluated based on information about floor egg distribution probability. Firstly, a spatial map was developed that describes the potential for floor eggs at each location in a poultry house. Next, paths for floor egg collection are planned with a dynamic programming approach that covers the house floor area and frequently revisits locations with a high potential on floor eggs. These paths are compared with the paths used for floor egg collection by a farmer and evaluated with help of a simulated set of floor eggs. With respect to the average time eggs are present on the floor, paths planned for a robot are compared to two collection rounds of a farmer. With respect to the structure of the path and the number of visits to locations with a high potential, the robot paths outperform the farmer. Although optimality of the path is not guaranteed, the presented results are promising for the use of a robot to collect floor eggs, and will result in a reduction of the demand for manual labour. Extending the floor egg model with feedback information could further improve the results.


      PubDate: 2014-04-28T22:59:40Z
       
  • The effect of air velocity and proximity on the charging of sprays from
           conventional hydraulic nozzles
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121
      Author(s): S. Gan-Mor , B. Ronen , K. Ohaliav
      Conventional nozzles where hydraulic pressure is used to form the spray, are widely used in agricultural spraying. In many cases they rely on air assistance to efficiently convey the spray droplets to the target. The addition of a further depositing force based on electrostatic charging can significantly improve deposition, particularly on the shaded or hard-to-reach surfaces. The positioning of induction-charging electrodes close to nozzle outlets was investigated. In the laboratory the charging of a conventional flat-fan hydraulic nozzle was investigated. Optimal spacings were found when a high ambient air velocity was used to prevent charged droplets depositing on the electrodes and their insulated mountings. The moving air also dried them continuously, thereby prevented leakage. The results show that a current of 13.9 μA per nozzle was attainable for a spray pressure of 400 kPa with a liquid flow rate of 0.45 l min−1 and droplet spectrum with a 115 μm volume medium diameter (VMD). This is equivalent to a charge-to-mass ratio of 1.85 mC kg−1. These high currents and high charging levels were achieved by using air velocities > 10 m s−1. Laboratory tests showed that the spacing between nozzles could be too small, reducing the level of charge per nozzle. A field sprayer was designed with nozzles using a higher flow rate than those investigated in the laboratory. Field tests of the prototype sprayer in a commercial vineyard showed that electrostatic charging improved the deposition of droplets containing a fluorescent tracer by 200 and 500% on the leaf undersides and the rear of grape clusters, respectively.


      PubDate: 2014-04-28T22:59:40Z
       
  • Drying process optimisation in a mixed-flow batch grain dryer
    • Abstract: Publication date: May 2014
      Source:Biosystems Engineering, Volume 121
      Author(s): Heikki T. Jokiniemi , Jukka M. Ahokas
      One of the most energy intense operations in arable farming in temperate countries is grain drying. Several studies have indicated that using higher drying air temperatures offers opportunities to save energy during grain drying, but although to a certain extent grain can tolerate drying at higher air temperatures, this may compromise the viability of the grain. The aim of this study was to examine the energy saving approaches achieved by using an elevated drying air temperature and by manipulating drying airflow in a scaled-down mixed-flow batch grain dryer. The drying airflow was reduced gradually as the drying process proceeded, and the drying air temperature was allowed to rise. The relative humidity of the exhaust air was used as a control factor to adjust the airflow. Energy savings were expected from the higher drying air temperature and, due to the reduced airflow, from the higher exhaust air humidity. The results showed energy savings of 5% for drying barley and 14% for drying oats. Increases in the evaporation rate of 5% and 17%, for barley and oats respectively. However, some degradation in grain viability was observed especially with oats. Further research is needed to find the correct control parameters and temperature limits for each cereal species.


      PubDate: 2014-04-28T22:59:40Z
       
  • Editorial Board
    • Abstract: Publication date: April 2014
      Source:Biosystems Engineering, Volume 120




      PubDate: 2014-04-28T22:59:40Z
       
  • Special Issue: Operations management
    • Abstract: Publication date: April 2014
      Source:Biosystems Engineering, Volume 120
      Author(s): Dionysis D. Bochtis , Claus G. Sørensen



      PubDate: 2014-04-28T22:59:40Z
       
  • Energy inputs and GHG emissions of tillage systems
    • Abstract: Publication date: April 2014
      Source:Biosystems Engineering, Volume 120
      Author(s): Claus G. Sørensen , Niels Halberg , Frank W. Oudshoorn , Bjørn M. Petersen , Randi Dalgaard
      Different tillage systems result in different resource uses and environmental impacts. Reduced tillage generates savings in direct energy input and the amount of machinery items needed. As the basics for holistic Life Cycle Assessments, both the influencing direct and indirect energy as sources of greenhouse gas emissions are required. Life Cycle inventories (LCI) were aggregated for a number of optimised machinery systems and tillage scenarios integrating a four crop rotation consisting of spring barley, winter barley, winter wheat and winter rape seed. By applying Life Cycle Assessments to a number of tillage scenarios and whole field operations sequences, the energy efficiency and environmental impact in terms of greenhouse gas emissions (GHG) were evaluated. Results showed that the total energy input was reduced by 26% for the reduced tillage system and by 41% for the no-tillage system. Energy used for traction and machine construction contributed between 6 and 8% of the total GHG emission per kg product. The total emission of GHG was 915 g CO2 equivalents per kg product by using the conventional tillage system, 817 g CO2 equivalents for the reduced tillage system and 855 g CO2 equivalents for the no tillage system. The no tillage system was expected to yield 10% less. The mineralisation in the soil contributed the most (50–60%) to this emission, while the fertiliser production contributed with 28–33%. The results stress the importance of applying a systems approach to capture the implications of, for example, sustained yields as otherwise the environmental benefits can be compromised.


      PubDate: 2014-04-28T22:59:40Z
       
 
 
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