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  Subjects -> AGRICULTURE (Total: 669 journals)
    - AGRICULTURAL ECONOMICS (73 journals)
    - AGRICULTURE (447 journals)
    - CROP PRODUCTION AND SOIL (88 journals)
    - DAIRYING AND DAIRY PRODUCTS (25 journals)
    - POULTRY AND LIVESTOCK (36 journals)

AGRICULTURE (447 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: 3)
Advances in Agriculture & Botanics     Open Access   (Followers: 10)
Advances in Agriculture, Sciences and Engineering Research     Open Access   (Followers: 11)
Advances in Agronomy     Full-text available via subscription   (Followers: 11)
Advances in Life Science and Technology     Open Access   (Followers: 6)
AFBM Journal     Open Access  
Africa Development     Open Access   (Followers: 8)
Africa Research Bulletin: Political, Social and Cultural Series     Hybrid Journal   (Followers: 8)
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: 4)
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: 5)
Agribusiness : an International Journal     Hybrid Journal   (Followers: 5)
Agricultura Tecnica     Open Access   (Followers: 6)
Agricultura Tropica et Subtropica     Open Access   (Followers: 2)
Agricultural Advances     Open Access   (Followers: 4)
Agricultural and Food Science     Open Access   (Followers: 17)
Agricultural Economics     Hybrid Journal   (Followers: 45)
Agricultural History     Full-text available via subscription   (Followers: 179)
Agricultural Research     Hybrid Journal   (Followers: 3)
Agricultural Science     Full-text available via subscription   (Followers: 6)
Agricultural Sciences     Open Access   (Followers: 8)
Agricultural Sciences in China     Full-text available via subscription   (Followers: 4)
Agricultural Systems     Hybrid Journal   (Followers: 21)
Agricultural Water Management     Hybrid Journal   (Followers: 15)
Agriculture     Open Access   (Followers: 5)
Agriculture & Food Security     Open Access   (Followers: 11)
Agriculture (Poľnohospodárstvo)     Open Access   (Followers: 1)
Agriculture and Agricultural Science Procedia     Full-text available via subscription   (Followers: 1)
Agriculture and Human Values     Hybrid Journal   (Followers: 10)
Agriculture, Ecosystems & Environment     Hybrid Journal   (Followers: 31)
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: 14)
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   (Followers: 1)
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: 4)
Asian Journal of Plant Sciences     Open Access   (Followers: 2)
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   (Followers: 1)
Bangladesh Journal of Agricultural Research     Open Access   (Followers: 2)
Bangladesh Journal of Scientific Research     Open Access   (Followers: 1)
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: 18)
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: 6)
Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca : Food Science and Technology     Open Access  

        1 2 3 4 5 | Last

Journal Cover Biosystems Engineering
   Journal TOC RSS feeds Export to Zotero [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  [2566 journals]   [SJR: 0.757]   [H-I: 58]
  • Finite element method model of the mechanical behaviour of Jatropha curcas
           L. bulk seeds under compression loading: Study and 2D modelling of the
           damage to seeds
    • Abstract: Publication date: November 2014
      Source:Biosystems Engineering, Volume 127
      Author(s): Michal Petrů , Ondřej Novák , David Herák , Ivan Mašín , Petr Lepšík , Petr Hrabě
      This article is focused on comprehensive research of a pressing process of Jatropha curcas L. bulk seeds during linear compression. Compression experiments were performed and the strain and brittle fracturing of the seeds visualised. The mechanical behaviour and stress distribution at the volumetric strain of bulk seeds in pressing cylinders and semi-cylinders with diameters of 60, 80 and 100 mm were described by 2D FEM models. It has been determined that the study of nonlinear visco-elastic and plastic strain seed interactions and the damage and crack growth in such seeds can be significantly improved through computer simulations using an explicit FEM algorithm. In this study, the compressibility of ripe J. curcas L. bulk seeds was analysed and compared depending on the volume strain and energy performance of the linear pressing process. Empirical equations and differential deformation theory describing the seeds interacting beyond the oil point were reported. In addition, the issue of contact theory in numerical modelling of the point contact of interacting seeds was also described. Statistical results showed that the 2D FEM model can be used to study the volumetric strain, stress and damage of J. curcas L. bulk seeds. These studies suggest that FEM models may be considered an important tool to assess the energy performance of the pressing process of J. curcas bulk seeds and can provide valuable information for the design and optimisation of pressing equipment.


      PubDate: 2014-09-18T00:24:06Z
       
  • Soil translocation by narrow openers with various bent leg geometries
    • Abstract: Publication date: November 2014
      Source:Biosystems Engineering, Volume 127
      Author(s): Aliakbar Solhjou , John M. Fielke , Jacky M.A. Desbiolles , Chris Saunders
      No-till farmers in Australia often use narrow point openers to place seed and fertiliser in furrows in conjunction with the spraying of pre-emergence herbicides. These openers can produce excessive soil throw which creates problems such as increasing the depth of soil cover on adjacent furrows, herbicide contamination above seed in adjacent furrows, increased stimulation of weed seed germination and furrow moisture loss. This study evaluated the effect of a range of bent leg narrow opener geometries on soil movement when operating at 120 mm depth and 8.2 kmh−1. Results showed that a bent leg opener geometry combined with a chamfered face could loosen a furrow without throwing soil laterally out of the furrow due to the shank being offset (bent) away from the central upheaval of soil. The bent leg openers were also able to loosen soil with minimal mixing of soil layers. Increasing the shank offset from the furrow centre reduced the surface soil interaction with the vertical shank section operating in the furrow. Decreasing the side bend angle from 65° to 45° reduced surface tracer lateral movement. Adding a leading foot to a bent leg opener reduced the loosened cross sectional area by 13% due to the shallower engagement of the side-leg portion. These findings have implications for optimising no-till seeding practises through better control of soil throw, aiming to: reduce weed seed germination and soil moisture loss, enable narrower row spacing options, the safer use of pre-emergence herbicides incorporated when seeding and higher operating speeds.


      PubDate: 2014-09-18T00:24:06Z
       
  • Estimating aboveground green biomass in desert steppe using band depth
           indices
    • Abstract: Publication date: November 2014
      Source:Biosystems Engineering, Volume 127
      Author(s): Hongrui Ren , Guangsheng Zhou
      Estimation of aboveground green biomass is essential for evaluating grassland productivity and functioning. This study aimed to explore the potential of band depth indices for estimating aboveground green biomass in grassland with low canopy cover. Field spectral and biomass measurements were conducted during 2009 and 2010 growing seasons in desert steppe of Inner Mongolia. Band depth (BD), band depth ratio (BDR), normalised band depth index (NBDI), band depth normalised to area (BNA), maximum band depth (BDmax), and area of absorption region (BDarea) extracted from red absorption region (650–740 nm) were utilised as band depth indices. Results indicated that: (1) BD at individual bands between 655 and 716 nm showed good accuracy for aboveground green biomass estimation; (2) BD at 698 nm yielded the best accuracy (R 2 = 0.7, RMSECV = 29.6 g m−2 for calibration; RMSE = 32.4 g m−2, rRMSE = 26.9% for validation); (3) BDR, NBDI, and BNA at all bands were not reliable estimators of aboveground green biomass (R 2 < 0.3, RMSECV > 45 g m−2 for calibration; RMSE > 46 g m−2, rRMSE > 39% for validation); (4) although the performance of BDmax (R 2 = 0.65, RMSECV = 32.1 g m−2 for calibration; RMSE = 34.5 g m−2, rRMSE = 28.7% for validation) and BDarea (R 2 = 0.69, RMSECV = 30.2 g m−2 for calibration; RMSE = 33.1 g m−2, rRMSE = 27.6% for validation) was slight lower than that of BD698nm, the performance was far better than that of BDR, NBDI, and BNA. Our results suggest that BD698nm has good potential to estimate aboveground green biomass in grassland with low canopy cover. The performance of BD698nm needs to be further tested using space-borne hyperspectral images.


      PubDate: 2014-09-18T00:24:06Z
       
  • Comparison between a rollover tractor dynamic model and actual lateral
           tests
    • Abstract: Publication date: November 2014
      Source:Biosystems Engineering, Volume 127
      Author(s): Bruno Franceschetti , Roland Lenain , Valda Rondelli
      Despite the progress in tractor design with respect to safety, one of the most dangerous situations for the driver under operating conditions on agricultural machines is the lateral rollover. Several accidents involving tractor rollover have indeed been encountered, requiring the design of a robust Roll-Over Protective Structure (ROPS). A mathematical model representing the behaviour during a generic tractor lateral rollover, with the possibility of modifying the geometry, the inertia of the tractor and the environmental boundary conditions is herein proposed. The purpose was to define a method allowing the prediction of the elasto-plastic behaviour of the impacts occurring in the rollover phase. In particular, this paper proposes a tyre impact model capable of analysing the influence of the wheels on the energy to be absorbed by the ROPS. Different tractor design parameters that affect the rollover behaviour, such as mass and dimensions, were considered and their influence on the energy absorbed by the ROPS was determined. The model was designed and calibrated with respect to the results of actual tests carried out on a narrow-track tractor. The results of the model showed a good match with the dynamic behaviour and energy absorbed by the ROPS in experimental lateral rollover tests. This should permit good prediction of the amount of energy to be absorbed in some accident situations, and therefore assist in the design of protective structures.


      PubDate: 2014-09-18T00:24:06Z
       
  • Microwave-assisted treatment for continuous olive paste conditioning:
           Impact on olive oil quality and yield
    • Abstract: Publication date: November 2014
      Source:Biosystems Engineering, Volume 127
      Author(s): Antonia Tamborrino , Roberto Romaniello , Riccardo Zagaria , Alessandro Leone
      Olive paste conditioning using microwave technology was integrated into an olive oil extraction plant using industrial-scale microwave-assisted apparatus. This first effort at integrating microwave technology contributed significantly to the continuous conditioning of the olive paste. The components of the equipment were designed and sized for optimal efficiency in an earlier preliminary study. With the aim of improving the operation of the extraction plants towards providing a continuous management of the process, an investigation of effects of optimal scheduling on olive oil quality was conducted. The objective was to evaluate the impact of the microwave treatment used to condition the olive paste on olive oil quality and yield and comparing it with the conventional industrial malaxation. The short process time of the rapid microwave treatment resulted in a low oxidation of the olive oil and consequently a reduction in the peroxide value compared with the conventional method. Using the microwave treatment, a higher concentration of volatile compounds in the oil was obtained with a lower content of phenolic compounds that are associated with spicy and bitter notes. No significant differences were found with extraction yield. Microwave processing was therefore confirmed as an attractive alternative to the conventional malaxation, with the main advantages being the rapid processing time and the high olive oil quality.


      PubDate: 2014-09-18T00:24:06Z
       
  • Measurements of emission factors from a naturally ventilated commercial
           barn for dairy cows in a cold climate
    • Abstract: Publication date: November 2014
      Source:Biosystems Engineering, Volume 127
      Author(s): Ngwa M. Ngwabie , Andrew Vanderzaag , Susantha Jayasundara , Claudia Wagner-Riddle
      Emission rates of CH4, N2O and NH3 were measured in a commercial free-stall barn that housed 141 lactating dairy cows, and 75 dry cows and replacement heifers. Animal activity, measured using the ALPRO™ dairy herd management system was used together with the CO2 balance method to calculate the ventilation rate. Methane emission was also modelled using the IPCC Tier 2 method. Animal activity variations similar to reported patterns indicated that the activity monitoring system provided high resolution measurements since all cows were considered. Diurnal variations were observed in the emissions with mean values of 12.2–13.9 g CH4 LU−1 h−1, 0.43–0.64 g NH3 LU−1 h−1 and 29.4–41.3 mg N2O LU−1 h−1. Modelled enteric CH4 emission was 312 g CH4 head−1 d−1 (10.58 g CH4 LU−1 h−1). It was estimated that indoor manure emitted 73 g CH4 head−1 d−1 (2.5 g CH4 LU−1 h−1), with enteric fermentation representing 81% of the total barn CH4 emission. Lactating cows emitted about 363 g CH4 head−1 d−1 (11.42 g CH4 LU−1 h−1) while non-lactating cows emitted 241 g CH4 head−1 d−1 (9.67 g CH4 LU−1 h−1).


      PubDate: 2014-09-18T00:24:06Z
       
  • Improved pig slurry mechanical separation using chitosan and biochar
    • Abstract: Publication date: November 2014
      Source:Biosystems Engineering, Volume 127
      Author(s): Popovic Olga , Gioelli Fabrizio , Dinuccio Elio , Balsari Paolo
      The efficient separation of pig slurry into its solid and liquid components is useful on a farm where the removal of excess nutrients is desired. This study investigates the effectiveness of two pre-treatments (chitosan, and biochar) in separating pig slurry using two methods of mechanical separation (screw press SP and centrifugation CENT). Several indicators—high dry matter and phosphorus in solids, and low P, Cu, and Zn content in liquids—informed the evaluation. Overall, results showed that chitosan addition changed the elemental content in both fractions of the SP group, but not in liquid fractions of the CENT group. Chitosan produced loosened flocs sensitive to SP pressure, but more resistant to centrifugation. Added biochar increased mass efficiency by 2–3% in both separation methods, but had little effect on the chemicals tested, except for the elemental content of solids produced in the SP group. The combination of chitosan and biochar performed worse than when treated with chitosan alone. Based on simple and reduced separation indices, no treatments affected the separation efficiency of the mechanical separators. Despite pre-treatment failures, there is some indication that under different experimental conditions, these pre-treatments may be beneficial when separating manure.


      PubDate: 2014-09-18T00:24:06Z
       
  • Multispectral fluorescence imaging for detection of bovine faeces on
           Romaine lettuce and baby spinach leaves
    • Abstract: Publication date: November 2014
      Source:Biosystems Engineering, Volume 127
      Author(s): Hoyoung Lee , Colm D. Everard , Sukwon Kang , Byoung-Kwan Cho , Kuanglin Chao , Diane E. Chan , Moon S. Kim
      Hyperspectral fluorescence imaging with ultraviolet-A excitation was used to evaluate the feasibility of two-waveband fluorescence algorithms for the detection of bovine faecal contaminants on the abaxial and adaxial surfaces of Romaine lettuce and baby spinach leaves. Correlation analysis was used to select the most significant waveband pairs for two-band ratio and difference methods in distinguishing contaminated and uncontaminated leaf areas. For this investigation, two-band ratios using bands at 665.6 nm and 680.0 nm (F665.6/F680.0) for lettuce and at 660.8 nm and 680.0 nm (F660.8/F680.0) for spinach effectively differentiated all contamination spots applied to the lettuce and spinach leaves, respectively. The fluorescence emission peaks for the faecal matter of animals that consume green plant materials and for chlorophyll a occur in close proximity in the red spectral region. Consequently, a high spectral resolution would be required for multispectral imaging with these two-band ratios for online implementation to detect bovine faecal contamination on leafy greens such as Romaine lettuce and baby spinach.


      PubDate: 2014-09-18T00:24:06Z
       
  • Modelling soil erosion risk for pipelines using remote sensed data
    • Abstract: Publication date: November 2014
      Source:Biosystems Engineering, Volume 127
      Author(s): Herbert K. Winning , Mike J. Hann
      This paper presents a method of using GIS and public domain remote sensed data to perform a preliminary soil erosion risk analysis aggregated into 1,000 m sections for onshore pipeline corridors. The results obtained using this method correspond well with the soil erosion risk assessment carried out in the field, with over 69% in agreement and 95% of the results obtained being within ±1 erosion classification identified by the field data. The areas where this method fails to correctly classify the soil erosion risk are identified and are largely confined to major river crossings and areas of seismic activity, which would require field verification irrespective of the results obtained for these sections using this method. The limitations of the proposed method due to the lack of detailed soil data and strategies to mitigate poor soil data are discussed. Using this method it is possible to identify areas along the pipeline corridor where there is potential for soil erosion risk early on in the project design; this enables the route selection process to consider this important environmental aspect, as well as providing a basis for focusing any subsequent field investigation. The proposed method enables the erosion risk to be quickly reassessed to compare different route options or to revise the proposed pipeline route.


      PubDate: 2014-09-18T00:24:06Z
       
  • Detecting crop water status in mature olive groves using vegetation
           spectral measurements
    • Abstract: Publication date: Available online 15 September 2014
      Source:Biosystems Engineering
      Author(s): Giovanni Rallo , Mario Minacapilli , Giuseppe Ciraolo , Giuseppe Provenzano
      Full spectral measurements (350–2500 nm) at tree canopy and leaf levels and the corresponding leaf water potentials (LWP) were acquired in an olive grove of Sicily, at different hours of the day, during summer season 2011. The main objective of the work was to assess, on the basis of the experimental data-set, two different approaches to detect crop water status in terms of LWP. Specifically, using existing families of Vegetation Indices (VIs) and applying Partial Least Squares Regression (PLSR) were optimised and tested. The results indicated that a satisfactory estimation of LWP at tree canopy and leaf levels can be obtained using vegetation indices based on the near infrared–shortwave infrared (NIR–SWIR) domain requiring, however, a specific optimisation of the corresponding “centre-bands”. At tree canopy level, a good prediction of LWP was obtained by using optimised indices working in the visible domain, like the Normalized Difference Greenness Vegetation Index (NDGI, RMSE = 0.37 and R 2 = 0.57), the Green Index (GI, RMSE = 0.53 and R 2 = 0.39) and the Moisture Spectral Index (MSI, RMSE = 0.41 and R 2 = 0.48). On the other hand, a satisfactory estimation of LWP at leaf level was obtained using indices combining SWIR and NIR wavelengths. The best prediction was specifically found by optimising the MSI (RMSE of 0.72 and R 2 = 0.45) and the Normalized Difference Water Index (NDWI, RMSE = 0.75 and R 2 = 0.45). Even using the PLSR technique, a remarkable prediction of LWP at both tree canopy and leaf levels was obtained. However, this technique requires the availability of full spectra with high resolution, which can only be obtained with handheld spectroradiometers or hyper-spectral remote sensors.


      PubDate: 2014-09-18T00:24:06Z
       
  • Bulk properties of densified hop cones related to storage and throughput
           measurements
    • Abstract: Publication date: October 2014
      Source:Biosystems Engineering, Volume 126
      Author(s): František Kumhála , Jiří Blahovec
      Hop is one of the most important materials for beer production. Nevertheless the material density of hop is little known even though this information is needed for the harvesting, processing and storage of the hop cones. To fill this gap in knowledge, densification experiments were carried out during 2013 harvesting season with wet and dry hop cones of different varieties. It was shown that for hop cones of all varieties in dry state that pressure increased with increasing material density. In a wet state, Sladek and Vital varieties showed different behaviour. Higher initial densities meant greater hardness of those two varieties. The densification process caused significant increase in the densification curve slope at the initial and final points. The initial slope was very high for the Sladek and Vital varieties in a wet state. Resulting pressure values were statistically different for most of the tested varieties. The differences in densification parameters were in all cases transferred from the wet to dry states. Differences found between varieties can significantly influence hop material throughput during harvesting as well as the behaviour of hop cones during post-harvest processing and storage.


      PubDate: 2014-09-04T22:47:12Z
       
  • Greenhouse gas emissions during composting of dairy manure: Influence of
           the timing of pile mixing on total emissions
    • Abstract: Publication date: October 2014
      Source:Biosystems Engineering, Volume 126
      Author(s): Walter Mulbry , Heekwon Ahn
      The effect of the timing of pile mixing on greenhouse gas (GHG) emissions during dairy manure composting was determined using large flux chambers designed to completely cover replicate pilot-scale compost piles. Approximately 50–70% of total CO2 and 75–80% of CH4 emissions occurred within the first two weeks of composting. Total GHG emissions from compost piles that were mixed at 2, 3, 4, or 5 weeks after initial construction were not significantly different from the emissions from unmixed (static) piles during a six week trial period. Although delaying initial pile mixing (2, 3, 4, or 5 weeks) generally lead to decreases in CO2 emissions, delaying mixing did not significantly affect CH4 or total GHG emissions. When normalised for degraded volatile solids (VS), CO2, CH4, N2O, and total emissions values ranged from 600--700, 130--150, 50--100, and 800–950 g CO2-eq per kg VS degraded, respectively. Carbon dioxide, methane, and nitrous oxide accounted for 75%, 14–19%, and 6–12%, respectively, of total GHG emissions from static and mixed piles.


      PubDate: 2014-09-04T22:47:12Z
       
  • Non-destructive technology associating PIV and Sunset laser to create wood
           deformation maps and predict failure
    • Abstract: Publication date: October 2014
      Source:Biosystems Engineering, Volume 126
      Author(s): Tomé M. Souza , Ellem W.N.F. Contado , Roberto A. Braga , Henrique C. Barbosa , José T. Lima
      Mechanical tests on wood specimens are usually made using a Universal Testing Machine (UTM) which allows the monitoring both of deformation and the moment of failure. However, besides the destruction of the samples, it is not possible to evaluate through these tests the distribution of deformations and the intensity of the forces involved throughout the sample, particularly in heterogeneous materials such as wood. Among the non-destructive techniques, optical approaches are available associated with image analysis that can overcome the destruction of samples and can even be used when one cannot remove a piece of wood installed in a building structure. This study presents an optical approach using particle image velocimetry (PIV) to create deformation maps of wood specimens under loading, without contact. A laser beam was placed parallel to the wood surface emphasising the irregularities, which are used as particles in the PIV method, and are monitored during the deformation of three different wood species during tests in the UTM. The results showed that the optical approach, using a Sunset laser in conjunction with the PIV method, could monitor the deformation of the samples in a non-destructive way, mainly in the elastic region. It was possible to predict the failure of the specimen earlier than by the UTM. In addition, the method presented a deformation map of the wood specimens allowing additional understanding of the phenomena.
      Graphical abstract image

      PubDate: 2014-09-04T22:47:12Z
       
  • Editorial Board
    • Abstract: Publication date: October 2014
      Source:Biosystems Engineering, Volume 126




      PubDate: 2014-09-04T22:47:12Z
       
  • Comments on “Weed recognition using image blur information” by
           Peng, Z. &amp; Jun, C., Biosystems Engineering 110 (2), p.
           198–205
    • Abstract: Publication date: October 2014
      Source:Biosystems Engineering, Volume 126
      Author(s): Jan Flusser , Tomáš Suk , Barbara Zitová
      This research note is in reaction to a recent paper on weed recognition using image analysis (Peng & Jun, 2011). Here, the correct use of moment invariants in a weed recognition system is presented.


      PubDate: 2014-09-04T22:47:12Z
       
  • System dynamics modelling of an integrated pig production supply chain
    • Abstract: Publication date: November 2014
      Source:Biosystems Engineering, Volume 127
      Author(s): Kullapapruk Piewthongngam , Prasert Vijitnopparat , Supachai Pathumnakul , Sawvapark Chumpatong , Monchai Duangjinda
      The supply chain for pigs is a long chain that is not resilient to environmental changes. The most vulnerable point in the chain occurs at the pig production level, which consists of breeding units, great grandparents, grandparents, parents and fattening units. Similar to other agricultural chains, the pig chain is susceptible to disruptions, such as disease outbreaks. The reaction to any disruptions in supply or demand can take several months or even years. A manager might be unable to anticipate changes in the production units and, thus, be unable to effectively manage the chain. In this study, we develop a system dynamics model as a tool for managers to visualise the movement of the entire production chain. This tool enables the integration of important factors at each breeding level that will affect the number of fattening pigs. Scenarios were applied to explore the mechanism of the model, and case studies were developed to represent an integrated pig company.


      PubDate: 2014-09-04T22:47:12Z
       
  • Fatigue life assessment of a four-rotor swather based on rainflow cycle
           counting
    • Abstract: Publication date: November 2014
      Source:Biosystems Engineering, Volume 127
      Author(s): Dimitris S. Paraforos , Hans W. Griepentrog , Stavros G. Vougioukas , Dietrich Kortenbruck
      Assessing the fatigue life of agricultural machinery is a challenging task, especially when the machine assumes different configurations in various operating modes. In such cases, assessing fatigue life requires the recording of loads at high stress points on the machine chassis during every possible mode of operation. In this paper strain data were recorded at critical, high-stress points of a four-rotor swather, along with acceleration data on the main axle. All data were georeferenced using a global navigation satellite system (GNSS). Measurements were performed while the machine was transported on asphalt and along unmade roads that are typically used by farmers. Additionally, data were acquired during swathing operations in grass fields with different conditions and speeds. For each experiment performed the rainflow cycle counting method was used to extract load cycles from stress data, and the Palmgren-Miner method was used to determine the fatigue damage from each individual cycle, as well as the total accumulated fatigue damage. The results indicated the ability of the system to identify and quantify the damage that was accumulated in every operation mode of the swather. The transition between these operating modes, e.g. lifting the rotors for headland turning, proved to have a high impact on machine fatigue life. Fatigue damage under working conditions in grass fields was also increased by surface irregularities.


      PubDate: 2014-09-04T22:47:12Z
       
  • Environmental analysis of geothermal heat pump and LPG greenhouse heating
           systems
    • Abstract: Publication date: November 2014
      Source:Biosystems Engineering, Volume 127
      Author(s): Giovanni Russo , Alexandros S. Anifantis , Giuseppe Verdiani , Giacomo Scarascia Mugnozza
      The use of low-impact energy sources for greenhouse cultivations is growing quickly due to environmental demands, constrained by the increased price of fossil energy sources, market demand for low cost greenhouse production, and need for air pollution reduction. This paper demonstrates via environmental analysis the efficiency of a Photovoltaic-Geothermal Heat Pump integrated system (PV-GHP) as a greenhouse heating system, compared to a conventional hot air generator using liquefied petroleum gas (LPG-HG). The tests were carried out in twin experimental greenhouses in the Mediterranean area (Valenzano-Italy). In order to evaluate the environmental performance of a heat pump system with electricity supplied from the national grid, a scenario (GHP Geothermal Heat Pump) was realised. The microclimatic conditions in the two greenhouses, the thermal energy produced, and the electricity consumption were analysed. Furthermore, in order to evaluate the long-term environmental impact, an environmental analysis was conducted using life cycle assessment (LCA) methodology, carried out according to standard UNI EN ISO 14040. The interpretation of the results using method CML2001 (Centre of Environmental Science, Leiden, Netherlands) showed that neither system is more advantageous from an environmental point of view and that the GHP scenario has the higher environmental burdens. Limiting the analysis to the emissions responsible for the greenhouse effect, the plant with the geothermal heat pump and photovoltaic panels reduces carbon emissions by 50%. In order to assess the sustainability of the geothermal heat pump plant, the estimated payback-time for energy and for carbon emissions were 1 year and 2.25 years, respectively.


      PubDate: 2014-09-04T22:47:12Z
       
  • Design criteria for structural design of silage silo walls
    • Abstract: Publication date: October 2014
      Source:Biosystems Engineering, Volume 126
      Author(s): Hans E. von Wachenfelt , N. Christer Nilsson , Göran I. Östergard , N. Anders Olofsson , J. Marie Karlsson
      Existing Swedish design guidelines (JBR) cover silo wall heights up to about 3 m. These guidelines presumably overestimate the forces and pressures exerted by silage juice when silo walls are more than 3 m high, which could result in over-sizing, material waste and increased capital costs. This study determined silage physical properties in terms of horizontal wall pressure and evaluated silage juice levels in silos with a wall height of 3 m or more. Wall pressure was measured by transducers mounted on a steel ladder rack placed vertically along the internal silo wall. The ladder rack also permitted measurement of silage juice levels in slotted steel pipes. The pressure on the transducers was recorded by a data acquisition system displaying static and total loads (pressures imposed by silage material without and with the compaction machine, respectively). The static pressure at the bottom of the silo wall (4 m) was 16 kPa during filling and compaction, and 22 kPa 1–4 months after filling. The silage juice did not interact with compaction. The wall pressure increased by 30% after filling, but the increase was only significant at 1 m from the silo bottom. The dynamic load was 17 kPa when the compaction machine passed 0.1 m from the silo wall. New guidelines are proposed based on the results and on the Eurocode for ultimate limit states (ULS) for two stages; filling and the utility period. The design bending moment for ULS was 21% lower than specified in JBR.


      PubDate: 2014-08-18T21:03:41Z
       
  • Advances in agricultural machinery management: A review
    • Abstract: Publication date: October 2014
      Source:Biosystems Engineering, Volume 126
      Author(s): Dionysis D. Bochtis , Claus G.C. Sørensen , Patrizia Busato
      The introduction of intelligent machines and autonomous vehicles to agricultural operations will allow for increased efficiency as well as for reduced environmental impact. Currently, innovative sensing and actuating technologies together with improved information and communication technologies provide the potential for such advancements. However, the full exploitation of these engineering advances requires the traditional agricultural machinery management process to be revisited. As a result, traditional agricultural operations planning methods, especially the job-shop planning methodology, must be supplemented with new planning features, such as route planning and sequential task scheduling. The objectives of this review are to outline current and required advances in agricultural machinery management to prepare for future intelligent manned and/or autonomous sustainable operations in agriculture. In the following sections, five key management tasks for agricultural machinery management are selected that span the various management phases and levels. These tasks are i) capacity planning (strategic level), task times planning (tactical level), scheduling (operational), route planning (operational level), and performance evaluation (evaluation level). For each of the management tasks, a definition is provided, and the most recent related literature is presented. Finally, the future requirements which will facilitate and set the framework for the development efforts necessary for fully implementing future agricultural management models and tools are discussed.


      PubDate: 2014-08-14T20:47:20Z
       
  • The impact and retention of spray droplets on a horizontal hydrophobic
           surface
    • Abstract: Publication date: October 2014
      Source:Biosystems Engineering, Volume 126
      Author(s): Ingrid K. Zwertvaegher , Micheline Verhaeghe , Eva Brusselman , Pieter Verboven , Frederic Lebeau , Mathieu Massinon , Bart M. Nicolaï , David Nuyttens
      Spray retention, i.e. the overall capture of spray droplets by plants on initial or subsequent impact, and after loss due to run-off, is an important stage in the spray application process as droplet losses may result in reduced efficacy, economic loss, and environmental contamination. The aim of this exploratory study is to determine whether a new method based on calculating the volumetric proportions per impact type, i.e. adhesion, rebound and shatter, can be used to predict spray retention. These volumetric proportions are calculated based on logistic regression models, derived from vision-based droplet characteristics and impact assessments, and laser-based spray characteristics. The advantages and limitations of such a method are explored. The volumetric proportions per impact type on a horizontal, synthetic hydrophobic surface were determined for four different nozzles (XR 110 01 VS flat-fan nozzle, XR 110 04 VS flat-fan nozzle, XR 110 08 VS flat-fan nozzle and AI 110 08 VS air-induction nozzle) under controlled realistic conditions, and compared to the results of a retention test. The volumetric proportions of adhesion were much lower than the relative retentions, indicating that a considerable amount of rebound and shatter also contributed to final retention. The method should thus be improved by including the droplets retained after first impact and the retained proportions of partial droplet fragmentation but it is nevertheless considered a promising technique.


      PubDate: 2014-08-14T20:47:20Z
       
  • Carbon dioxide production from a fattening pig building with partial pit
           ventilation system
    • Abstract: Publication date: October 2014
      Source:Biosystems Engineering, Volume 126
      Author(s): Chao Zong , Guoqiang Zhang , Ying Feng , Ji-Qin Ni
      Carbon dioxide (CO2) is useful for determining ventilation rates in livestock buildings and its release from manure plays an important role in ammonia emission. CO2 production in a fattening pig house with a partial pit ventilation system was investigated under working conditions. The influences of animal mass, animal activity, and ventilation rate on CO2 concentrations and emissions were assessed. Results showed that the CO2 production rate increased with growing pig body mass. A mathematical model of CO2 production was developed based on the measured data. The measured CO2 productions ranged from 30.3 to 99.0 g h−1 pig−1 for pigs from 30.1 to 111.5 kg. Comparing the last days of the fattening period with and without pigs, it was found that 2.3–3.4% of the total CO2 production was released from manure. Higher pit ventilation rates resulted in higher CO2 concentration in pit air and higher emission rates via pit exhaust, but had limited influence on the total emission rate (via room + pit exhaust). However, higher room ventilation rates resulted in lower CO2 concentrations in room air but higher room and total emission rates. Diurnal variations in CO2 productions were mainly influenced by animal activities. Four models of CO2 production in literature were reviewed and compared with the model developed in this study. The CO2 production model developed in this study had similar values with the CIGR model for a pig under 80 kg and the TCER model for a pig above 60 kg.


      PubDate: 2014-08-14T20:47:20Z
       
  • Co-robotic intra-row weed control system
    • Abstract: Publication date: October 2014
      Source:Biosystems Engineering, Volume 126
      Author(s): Manuel Pérez-Ruíz , David C. Slaughter , Fadi A. Fathallah , Chris J. Gliever , Brandon J. Miller
      The automation of intra-row weed control in row crop production systems is very challenging. This work describes the development and in-field assessment of an automatic intra-row, hoe-based weeding co-robot system with real-time pneumatic hoe actuation based on an accurate odometry sensing technique. The US National Science Foundation has identified a need for robots (called co-robots) that serve as co-workers and work beside, or cooperatively with, people. These co-robots have a symbiotic relationship with a human partner, where, as a team, they combine their relative strengths to jointly perform a task. Such co-robots should be relatively inexpensive and easy to use. In this work, mechanical weed control was achieved by a co-robot actuator that automatically positioned a pair of miniature hoes into the intra-row zone between crop plants. The design was tested in a precision transplanted row crop and may also be suitable for direct seeded row crops. Co-robot cost was minimised by limiting the system to a single, simple odometry sensor. Co-robot hoe actuation was controlled using pre-programmed knowledge of the crop planting pattern and real-time odometry data as the control input for hoe positioning. Low-frequency drift in the odometry control points relative to the actual plant locations was corrected occasionally as needed in real-time by a human partner monitoring system performance. The co-robot was evaluated in an experimental trial conducted on the UC Davis campus farm. Assessment was based upon the follow-up hand hoeing required after automated intra-row weeding in comparison to the labour required to manually hoe a control plot. The mean person hours required for hand hoeing weeds in the control were 0.241 h for the 100 m2 plot, while only 0.102 h 100 m−2 were required in follow-up labour to complete the weed removal in the plots weeded by the co-robot. This represents a 57.5% reduction in hand labour requirements for intra-row weed control and indicates that the co-robot could help reduce traditional hand hoeing labour requirements with mechanised weed control in intra-row areas between the crop plants.


      PubDate: 2014-08-14T20:47:20Z
       
  • Randomised kinodynamic motion planning for an autonomous vehicle in
           semi-structured agricultural areas
    • Abstract: Publication date: October 2014
      Source:Biosystems Engineering, Volume 126
      Author(s): Mohamed Elbanhawi , Milan Simic
      A randomised motion planner is presented that operates within a suitable timeframe for constrained mobile robots in agricultural environment. The core of this approach relies on splitting planning into two efficient phases to reduce its computational time. The effectiveness of sampling based planners is combined with the robustness of parametric vector-valued splines. The first phase involves relaxed two-dimensional path planning using rapidly-exploring random trees (RRT). Recent advances in sampling based planning are leveraged to improve the performance of the planner. Detailed implementation of the RRT approach and parameter selection are highlighted using comprehensive analysis and simulations. Feasible continuous paths with bounded curvature for nonholonomic robots are generated using B-spline curves. Curve segment parameters are formulated with respect to vehicle specifications. Manoeuvres satisfying maximum curvature constraints and path continuity are designed based on the segment parameters. Numerical experiments are used to validate the practicality of the proposed two-phase planner in solving kinodynamic motion queries, in real-time and replanning under limited sensing conditions.


      PubDate: 2014-08-14T20:47:20Z
       
  • Determination of the elastic constants of Scots pine (Pinus sylvestris L.)
           wood by means of compression tests
    • Abstract: Publication date: October 2014
      Source:Biosystems Engineering, Volume 126
      Author(s): José R. Aira , Francisco Arriaga , Guillermo Íñiguez-González
      This presents an exploratory analysis of a method for the determination of elastic constants using strain gauges in compression tests. The elastic constants of Scots pine (Pinus sylvestris L.) wood from the “Valsaín” sawmill (Segovia, Spain) were obtained. Compression tests were performed on small clear specimens, varying grain direction with respect to the direction of the load applied. Deformations were measured by strain gauges bonded on specimen surfaces. The modulus of elasticity parallel to the grain was obtained for prismatic specimens measuring 20 × 20 × 60 mm. The modulus of elasticity perpendicular to the grain in both radial and tangential directions was obtained for 16 × 16 × 48 mm prismatic specimens and for 48 × 48 × 48 mm cubic specimens. The shear modulus in the LR, LT and TR (longitudinal (L), radial (R) and tangential (T)) planes was obtained for 16 × 16 × 48 mm prismatic specimens with the grain at 45°. Larger stiffness values than typical average values for softwood were obtained. It can be concluded that this method is suitable for determining the modulus of elasticity (longitudinal and transversal), and that the values obtained are greater than the average values for softwoods. On the other hand, the Poisson ratios obtained parallel to the grain were similar to values in the literature, though values for ν RT and ν TR were greater.


      PubDate: 2014-08-05T20:00:15Z
       
  • Source of airborne sunflower dust generated during combine harvester
           operation
    • Abstract: Publication date: October 2014
      Source:Biosystems Engineering, Volume 126
      Author(s): Joseph P. Polin , Zhengrong Gu , Daniel S. Humburg , Kevin J. Dalsted
      The sunflower harvest season presents challenges for many farmers when an abundance of airborne dust is carried by surrounding winds and allowed to relocate on equipment surfaces. Combine fires are a serious problem resulting from the ignition of biomass dust that settle and accumulate on the combine harvester. Farmers' anecdotal evidence indicates that harvesting sunflowers can produce more airborne dust than other commodity crops. The source of this airborne sunflower dust was investigated using various methods to analyse different parts of the sunflower: whole heads, outer stalk, and inner stalk pith. These samples were compared to a collected amount of bulk sunflower dust field sample taken directly from a horizontal surface on a combine harvester during the 2011 harvest season. All testing methods; proximate and ultimate analyses, biomass dust particle density analysis, Fourier transform infrared spectroscopy, and scanning electron microscopy; suggest the sunflower bulk field sample is comprised of mostly inner stalk pith rather than dust particles from the outer stalk and whole sunflower heads. By confirming the source of the airborne sunflower dust field sample, the arrangement of combine harvester equipment could be modified to reduce the amount of sunflower dust generated during operation.


      PubDate: 2014-08-05T20:00:15Z
       
  • Editorial Board
    • Abstract: Publication date: September 2014
      Source:Biosystems Engineering, Volume 125




      PubDate: 2014-08-01T19:26:23Z
       
  • Feasibility study on the potential of electrical conductivity sensor
           Veris® 3100 for field mapping of topsoil strength
    • Abstract: Publication date: October 2014
      Source:Biosystems Engineering, Volume 126
      Author(s): Mojtaba Naderi-Boldaji , Ahmad Sharifi , Abbas Hemmat , Reza Alimardani , Thomas Keller
      With advances in technology for precision agriculture, numerous attempts have been made towards development of on-the-go sensors for measuring soil compaction. Most of the on-the-go sensors developed so far have been mechanical sensors providing a soil strength parameter that can be related to degree of soil compactness. In this study, a commercial electrical conductivity sensor (Veris® 3100) in combination with a previously developed combined horizontal penetrometer (equipped with a dielectric sensor for water content) were tested in a field in order to examine whether the apparent electrical conductivity (ECa) within the 0–0.3 m depth (ECa-shallow) could be helpful in detecting the topsoil strength (here the horizontal penetrometer resistance). Interpolated field maps of horizontal penetrometer resistance (PR), volumetric water content (θ v) and ECa showed comparable patterns within some areas (but not over the field). No significant correlation (but a negative trend) was found between ECa and dry bulk density. A significant correlation between ECa and PR/θ v (a previously proposed water content-independent PR) was found (R 2 = 0.37, P < 0.0001). However, ECa was strongly affected by soil water content and texture. It was concluded that PR may be indirectly related to ECa through θ v, which greatly affects both ECa and PR. The results suggested that the EC sensor could potentially be helpful for detecting zones of high soil strength (i.e. high PR/θ v). Further studies are suggested to address whether ECa is better related to the state of soil compaction at dry state of soil due to more significant effect of soil–soil electrical conductivity.


      PubDate: 2014-08-01T19:26:23Z
       
  • Composting of solids separated from anaerobically digested animal manure:
           Effect of different bulking agents and mixing ratios on emissions of
           greenhouse gases and ammonia
    • Abstract: Publication date: August 2014
      Source:Biosystems Engineering, Volume 124
      Author(s): Md Albarune Chowdhury , Andreas de Neergaard , Lars Stoumann Jensen
      We investigated the effects of bulking agents (BA) and mixing ratios on greenhouse gas (GHG) and NH3 emissions from composting digested solids (DS), separated from anaerobically digested manure and other bio-wastes, in small-scale laboratory composters. BA evaluated were plastic tube pieces (PT), woodchips (WC), bio-char (BC), barley straw (BS) and lupin residues (LR) and were included at a DS:BA of 3:1 or 6:1, resulting in nine treatments: CTDS (control, DS only), PT3:1, PT6:1, WC3:1, WC6:1, BC3:1, BC6:1, BS3:1 and LR3:1. Depending on treatment, C losses via CO2 and CH4 emissions accounted for 41.2–65.3 g C kg−1 initial total solids (TS) and 4.4–191.7 mg C kg−1 TS (8.4–16.1% and 0.001–0.05% of initial total-carbon), respectively, while N losses as N2O and NH3 emissions comprised 2.1–13.6 mg N kg−1 TS and 2.7–4.8 g N kg−1 TS (0.01–0.04% and 9.1–13.0% of initial total-nitrogen), respectively. Most of the CH4 emissions occurred during the thermophilic temperature phase, which had little or no effect on N2O emissions. BS addition to DS resulted in the lowest cumulative NH3-N and N2O-N losses. BC was as effective as BS in reducing cumulative NH3-N losses, but had non-significant effect on CH4-C emissions. Decreasing the mixing ratio from 6:1 to 3:1 reduced losses of CH4-C and N2O-N (except for BC) without any increase in NH3-N losses. BC and BS proved most effective in reducing emissions of total GHG (as CO2-equivalents). Composting of DS with C-rich BA can thus be an effective means of conserving N in DS, while also reducing GHG emissions.


      PubDate: 2014-07-27T19:03:35Z
       
  • An application of the vehicle routing problem to biomass transportation
    • Abstract: Publication date: August 2014
      Source:Biosystems Engineering, Volume 124
      Author(s): Carlos Gracia , Borja Velázquez-Martí , Javier Estornell
      Pruning is a cultural operation linked to Mediterranean agricultural management and it offers through its wastes the chance to procure biofuels. Currently, these residues are disposed of by burning or shredding, not being exploited because of several technical difficulties in extraction, handling and transport as well as because of the lack of accurate data on the quantity and suitability of these residues. However, recent work has reported methods of supplying new biomass detection models and concentration locations. These make it possible to tackle reliable collection plans as a part of the decision support system in a biomass supply management information system. This paper addresses the biomass collection problem, as an application of the classical vehicle routing problem, where minimum cost routes have to be calculated for a fleet of several agricultural vehicles (chippers, trucks, tipper trailers and tractors). A hybrid approach based on genetic algorithms and local search methods is presented to solve a real case study. Results show a significant improvement in the operational efficiency obtained by applying such methods that come from the industrial engineering domain.


      PubDate: 2014-07-27T19:03:35Z
       
  • Characterisation of ventilation rate in naturally-ventilated buildings
           using heat dissipation from a line source
    • Abstract: Publication date: August 2014
      Source:Biosystems Engineering, Volume 124
      Author(s): Ivan Lule , Sezin Eren Özcan , Daniel Berckmans
      To determine air exchange in naturally-ventilated buildings, Eren Özcan, Vranken, and Berckmans (2009) used heat dissipation from a heat source close to an inlet to measure ventilation rate through the opening. Because their method used a bulky heat source, which caused an obstruction to airflow, they were unable to cover the whole of the inlet opening, and therefore, an improved technique was required. This study extended the earlier method to investigate heat dissipation by using a line heat source that covered the whole vertical extent of the inlet. Steady state experiments were performed with a constant heat source, and dynamic experiments, where the heat source was turned off during the ventilation process. A two-dimensional temperature distribution around the ventilation opening was obtained by infrared thermal imaging. Using data-based mechanistic approach, well-mixed temperature zones were used to predict the volumetric concentration of fresh air supply, and to investigate the effect of buoyancy on the heat plume. Results obtained revealed that ventilation rate can be predicted using data-based mechanistic approach with an error of 8%.


      PubDate: 2014-07-27T19:03:35Z
       
  • Advanced exergoeconomic evaluation of a heat pump food dryer
    • Abstract: Publication date: August 2014
      Source:Biosystems Engineering, Volume 124
      Author(s): Zafer Erbay , Arif Hepbasli
      In this study, the results of conventional and advanced exergoeconomic analyses of the performance of a pilot scale air-source heat pump food dryer were compared for the first time. The contributions of the components of the drying system to the exergetic cost effectiveness of the dryer were evaluated, and the effects of changing the inlet drying temperature were determined. The most important system component was determined to be the heat recovery unit, followed by the condenser with respect to the reducing potentials for the total costs of the overall system. Decreasing temperature caused an increase in the cost performance of drying. The modification of the system components for improving the efficiency of the system can be effectively determined through advanced exergoeconomic approach by stating the realistic potential improvements and the priorities in the system.


      PubDate: 2014-07-27T19:03:35Z
       
  • Ultrasound-assisted enzymatic hydrolysis of sugarcane bagasse for the
           production of fermentable sugars
    • Abstract: Publication date: August 2014
      Source:Biosystems Engineering, Volume 124
      Author(s): Felipe C. Lunelli , Pâmela Sfalcin , Matheus Souza , Eduardo Zimmermann , Valéria Dal Prá , Edson L. Foletto , Sérgio L. Jahn , Raquel C. Kuhn , Marcio A. Mazutti
      The effects of ultrasound irradiation on enzymatic hydrolysis of sugarcane bagasse were evaluated to obtain fermentable sugars. The influences of temperature, enzyme concentration and moisture content were evaluated with and without ultrasound irradiation. The hydrolysis yield achieved using ultrasound irradiation was significantly higher than that without. The highest amount of fermentable sugars obtained in the presence of ultrasound was 0.26 g [sugar] g−1 [dry sugarcane bagasse], which was around twice the value obtained without, at the temperature of 50 °C, 10% mass of enzyme and a moisture content of 75% (dry basis), after 240 min of reaction. The ultrasound irradiation appears to be a promising technology to be used in enzymatic reactions due to its positive effects on the reaction yield.


      PubDate: 2014-07-27T19:03:35Z
       
  • Automation and the situation awareness of drivers in agricultural
           semi-autonomous vehicles
    • Abstract: Publication date: August 2014
      Source:Biosystems Engineering, Volume 124
      Author(s): Behzad Bashiri , Danny D. Mann
      The effects of in-vehicle automation and driving assistant systems on the situation awareness of drivers have been the subject of much research with the implications of automation in such man-machine systems being identified. With the introduction of advanced automated systems in agricultural machinery, farmers are now working with semi-autonomous vehicles. A human factors perspective is needed to ensure the safe and efficient operation of such systems. This simulator study investigated the effects of automating vehicle steering and implement control and monitoring task automation on the situation awareness of drivers. Experiments were conducted using a tractor driving simulator located in the Agricultural Ergonomics Laboratory at the University of Manitoba. Thirty young, experienced tractor drivers participated in this study. It was found that implement control and monitoring task automation significantly affected the situation awareness of operators. Situation awareness increased as the level of automation support increased although the highest level of automation, where the participants were removed from the task loop, resulted in low situation awareness at a level similar to the condition with no automation support. The highest level of situation awareness was observed when the simulator suggested the required action to be taken by the operator. Vehicle steering task automation reduced the attentional demand of the task.


      PubDate: 2014-07-27T19:03:35Z
       
  • Modelling of transpiration rate of grape tomatoes. Semi-empirical and
           analytical approach
    • Abstract: Publication date: August 2014
      Source:Biosystems Engineering, Volume 124
      Author(s): Georgios T. Xanthopoulos , Athanasios A. Athanasiou , Diamanto I. Lentzou , Andreas G. Boudouvis , Grigorios P. Lambrinos
      Transpiration is a well known physiological process of water loss from fresh products, associated with visual and texture degradation and loss of market value. A loss of 3–5% of the initial mass may cause in fresh products loss of freshness and visual attractiveness. Grape tomato has been increasingly accepted by consumers as “snacking tomato” and as an ingredient in mixed salads of fresh-cut vegetables. An experimental procedure was developed to record the associated with transpiration, water loss in grape tomatoes (Solanum lycopersicum, Lobello F1), at temperatures 10, 15 and 20 °C and relative humidity 70, 80 and 92%. Water activity was calculated and correlated with the respective mass loss; its average value was found 0.988 ± 0.01. The mean transpiration rates ranged between 0.012 and 0.058 mg cm−2 h−1 for water vapour pressure deficit range of 0.061–0.662 kPa. A semi-empirical and an analytical model were developed to correlate the mass loss of grape tomatoes with the storage conditions (temperature and relative humidity) and storage time. Both provided satisfactory fit to the experimental data. Finally, the air-film mass transfer coefficient (ka) and skin mass transfer coefficient (ks) were calculated and the ks coefficient correlated efficiently with an exponential equation with the respective water vapour pressure deficit.


      PubDate: 2014-07-27T19:03:35Z
       
  • Editorial Board
    • Abstract: Publication date: August 2014
      Source:Biosystems Engineering, Volume 124




      PubDate: 2014-07-27T19:03:35Z
       
  • Active air flushing in a sensor-controlled fresh produce container system
           to maintain the desired modified atmosphere
    • Abstract: Publication date: September 2014
      Source:Biosystems Engineering, Volume 125
      Author(s): Yun Hee Jo , Duck Soon An , Dong Sun Lee
      Modified atmosphere (MA) containers equipped with an on/off-controlled perforation that can respond to real-time gas concentrations can contribute to maintaining the quality of fresh produce. In this study, an active flushing system was devised to flush the air promptly responding to the real-time O2 concentration, and its capability to maintain the target O2 level was compared to that of an O2 switched passive diffusion tube system. A model container with dimensions of 32 × 23 × 18 cm was filled with 350 g spinach and submitted to storage testing under different control regimes and temperatures. The gas concentration in the spinach container was programmed to stay either exactly at 11% or in the range of 11–13%. While the O2 switched passive diffusion tube system could properly control the O2 concentration in the container at the desired level or range when the container was at the low temperature of 10 °C, it could not do so at 20 °C, resulting in O2 concentrations that were too low and CO2 concentrations that were too high. The active flushing system was effective and satisfactorily controlled the gas concentration in the container at the desired level or range at both 10 and 20 °C. Compared to the O2 switched passive diffusion tube system, the active flushing system was more prompt in its response to deviating atmospheric conditions, which was more pronounced in the range control mode. The container with the controlled MA was better at preserving the quality of the produce compared to a perforated control package.


      PubDate: 2014-07-27T19:03:35Z
       
  • Structural design of corrugated boxes for horticultural produce: A review
    • Abstract: Publication date: September 2014
      Source:Biosystems Engineering, Volume 125
      Author(s): Pankaj B. Pathare , Umezuruike Linus Opara
      Corrugated boxes are used extensively for transporting and storing fresh produce in the horticultural industry. These boxes protect their contents from mechanical damage due to drops, impacts, vibration and compression loads. The analysis and prediction of the stacking compression load capacity of corrugated boxes is important to study the response of existing packaging to mechanical stress or to design new boxes to meet postharvest handling conditions. Good design of vented packaging is important in optimising the cooling and ventilation uniformity, minimising quality deterioration of packed produce and maintaining the mechanical integrity of the box. Various experimental and modelling tools are used to investigate the design and mechanical performance of packaging. Experimental studies on mechanical performance of packaging include compression, impact and vibration analysis. Finite element analysis and simulation is useful for study and structural design of ventilated corrugated packaging, considering the shape, location and size of the vent. Advances in information and communication technologies offer new prospects for development of user-friendly software toward integrated design and performance analysis of fresh produce packaging.


      PubDate: 2014-07-27T19:03:35Z
       
  • Foreground detection of group-housed pigs based on the combination of
           Mixture of Gaussians using prediction mechanism and threshold segmentation
           
    • Abstract: Publication date: September 2014
      Source:Biosystems Engineering, Volume 125
      Author(s): Yizheng Guo , Weixing Zhu , Pengpeng Jiao , Jiali Chen
      In this paper, a foreground detection method to obtain the foreground objects of pigs in overhead views of group-housed environments is proposed. The method is based on the combination of Mixture of Gaussians (MoG) using prediction mechanism (PM) and threshold segmentation algorithm. First, the “valid region” is manually set according to a priori knowledge. Second, the foreground objects of pigs are detected using the PM-MoG algorithm. The algorithm uses the detected binary image of the previous frame to predict the current frame in the valid region for pixels that fulfil background updating conditions. Different update strategies are used to update the background for different circumstances. Third, the maximum entropy threshold segmentation algorithm is used according to the colour information of foreground objects. Finally, the results of the two previous steps of foreground detection are fused. The experimental results show that the method is effective and can extract relatively complete foreground objects of pigs in complex scenes. These complex scenes include light changes, the influence of ground urine stains, water stains, manure, and other sundries, pigs' slow movement patterns, and varying colours of foreground objects. The average foreground detection rate is approximately 92%. The experimental results set the foundation for further exploration of individual identification of group-housed pigs, their behaviour analysis, and other objectives.


      PubDate: 2014-07-27T19:03:35Z
       
  • Vis/NIR spectroscopic measurement of selected soil fertility parameters of
           Cuban agricultural Cambisols
    • Abstract: Publication date: September 2014
      Source:Biosystems Engineering, Volume 125
      Author(s): Ahmed Chacón Iznaga , Miguel Rodríguez Orozco , Edith Aguila Alcantara , Meilyn Carral Pairol , Yanet Eddith Díaz Sicilia , Josse de Baerdemaeker , Wouter Saeys
      The conventional methods frequently used in Cuba to determine some fertility parameters important for sugarcane production, such as organic matter (OM), available phosphorus (P) and potassium (K2O), are difficult, costly, and time-consuming procedures. This study was undertaken to build and validate Visible/Near Infrared Reflectance (Vis/NIR) calibration models of these parameters at landscape level and within a field, by taking into consideration their correlation coefficients with the OM. The parameters P and K2O, which are not spectrally active in the Vis/NIR range should be better predicted when are highly correlated with OM. Also, the wavelength intervals to simplify this methodology were selected. Samples were air-dried before scanning using a diode array spectrophotometer covering the wavelength range from 399 to 1697 nm. The regression models were built by using the linear multivariate regression method Partial Least Squares (PLS), and the nonlinear multivariate regression methods Support Vector Machines (SVM) and Locally Weighted Regression (LWR). At landscape level the best correlations between soil spectra and OM (0.90 ≤ R 2 ≤ 0.93; 0.12 ≤ RMSEP≤0.14) were obtained with LWR, followed by K2O with LWR (0.77 ≤ R 2 ≤ 0.79; 3.47 ≤ RMSEP≤3.62), Olsen P (0.69 ≤ R 2 ≤ 0.81; 0.27 ≤ RMSEP≤0.35) and Oniani P (0.64 ≤ R 2 ≤ 0.65; 3.31 ≤ RMSEP≤3.61) both with SVM. Also, the nonlinear regression models gave the best results within a field. The higher values for OM (R 2 = 0.92; RMSEP = 0.14) and Olsen P (0.68 ≤ R 2 ≤ 0.83; 0.27 ≤ RMSEP≤0.34) were observed with SVM, while for K2O (0.16 ≤ R 2 ≤ 0.63; 5.13 ≤ RMSEP≤5.88), and Oniani P (0.70 ≤ R 2 ≤ 0.72; 2.32 ≤ RMSEP≤2.52) were obtained with LWR. The soil fertility parameters studied at landscape level and within a field were best estimated by using nonlinear regression models.


      PubDate: 2014-07-27T19:03:35Z
       
  • Vegetation segmentation robust to illumination variations based on
           clustering and morphology modelling
    • Abstract: Publication date: September 2014
      Source:Biosystems Engineering, Volume 125
      Author(s): Xiaodong Bai , Zhiguo Cao , Yu Wang , Zhenghong Yu , Zhu Hu , Xuefen Zhang , Cuina Li
      Vegetation segmentation from images is an essential issue in the application of computer vision in agriculture. In this paper, we present a new vegetation segmentation method based on Particle Swarm Optimisation (PSO) clustering and morphology modelling in CIE L ∗ a ∗ b ∗ colour space. At the off-line learning stage, a new method is put forward to determine the clustering number. Secondly, the tools of morphological dilation and erosion are employed to establish the vegetation colour model. At the online segmentation stage, the PSO-based k-means is used to cluster the vegetation image into vegetation classes and non-vegetation classes. Afterwards, the established colour model is used to distinguish the vegetation classes and give the segmentation result. In the experiments, the proposed method was applied to segment 200 smaller regions of the full camera images of rice and 100 smaller regions of the full camera images of cotton. The means of segmentation qualities reached 88.1% and 91.7% respectively. Moreover, the proposed method was compared with three well-known vegetation segmentation methods and two skin segmentation methods. Experiments demonstrate that the proposed method yielded the highest mean of segmentation qualities and lowest standard deviations of segmentation qualities. In addition, the vegetation colour models built with different structuring element types are analysed.


      PubDate: 2014-07-27T19:03:35Z
       
  • Within-row spacing sensing of maize plants using 3D computer vision
    • Abstract: Publication date: September 2014
      Source:Biosystems Engineering, Volume 125
      Author(s): Akash D. Nakarmi , Lie Tang
      Within-row plant spacing plays an important role in uniform distribution of water and nutrients among plants which affects the final crop yield. While manual in-field measurements of within-row plant spacing is time and labour intensive, little work has been done on an alternative automated process. We have attempted to develop an automatic system making use of a state-of-the-art 3D vision sensor that accurately measures within-row maize plant spacing. Misidentification of plants caused by low hanging canopies and doubles were reduced by processing multiple consecutive images at a time and selecting the best inter-plant distance calculated. Based on several small scale experiments in real fields, our system has been proven to measure the within-row maize plant spacing with a mean and standard deviation error of 1.60 cm and 2.19 cm, and a root mean squared error of 2.54 cm, respectively.


      PubDate: 2014-07-27T19:03:35Z
       
  • Water and nitrogen budgets under different production systems in Lisbon
           urban farming
    • Abstract: Publication date: September 2014
      Source:Biosystems Engineering, Volume 125
      Author(s): Maria R. Cameira , Sara Tedesco , Teresa E. Leitão
      Public concern is growing over soil and groundwater contamination from the use of agrochemicals in urban farming. Heavily used nitrogen (N) fertilisers are converted to nitrates that can be a health hazard. In this study, water and N budgets over a 1-year period are presented for typical urban vegetable gardens in Lisbon. A conceptual analysis supported by an integrated methodology of field experiments and modelling identified the N surpluses associated with conventional and organic gardens. It is concluded that the gardening systems are continuously cropped using high N and water application rates. For all of the case-study allotments, the N inputs, mainly from organic amendments with diverse N release rates, were higher than the crop uptake generating surpluses that were lost by different processes. On one study site a drainage flux of 280 mm yr−1 was calculated, with a mean concentration of 295 mg NO3 − l−1. On another site N accumulated in the lower soil depths at a rate of 420 kg NO3 − ha−1 yr−1. The cumulative impact of N surpluses on the environment and human health must be considered. To minimise adverse impacts, we propose the selection of organic fertilisers with N release rates close to the crop N uptake, the prevention of excess irrigation to minimise N leaching and gaseous losses and the inclusion of the non-fertiliser N sources in the fertiliser calculations. It is shown how an integrated model can be used to predict the N release dynamics from the organic fertilisers as affected by the moisture conditions.


      PubDate: 2014-07-27T19:03:35Z
       
  • Evaluation of the thermal properties of Jatropha curcas L. kernels using
           near-infrared spectroscopy
    • Abstract: Publication date: September 2014
      Source:Biosystems Engineering, Volume 125
      Author(s): Jetsada Posom , Panmanas Sirisomboon
      The determination of the thermal properties, including thermal diffusivity, thermal conductivity, and specific heat, of Jatropha curcas L. kernels was conducted using near-infrared (NIR) spectroscopy. A total of 100 samples of whole kernels from green, yellow and black fruits and oven dried kernels were scanned using a Fourier transform NIR spectrometry over the range of 1,250,000–400,000 m−1. Models correlating the spectral data and the thermal properties measured by a reference method were developed by partial least squares regression and validated by test set validation. The results showed that for thermal diffusivity, thermal conductivity at 40 °C and 100 °C and specific heat at 40 °C and 100 °C, the coefficients of determination (R 2) were 0.5968, 0.7592, 0.7509, 0.4211 and 0.6396%, respectively; the root mean square errors of prediction (RMSEP) were 1.1 × 10−6 m2 s−1, 0.0169 W m−1 °C−1, 0.0685 W m−1 °C−1, 5.88 kJ kg−1 °C−1 and 15.8 kJ kg−1 °C−1; the biases were −2.52 × 10−7 m2 s−1, 2.85 × 10−3 W m−1 °C−1, 2.52 × 10−2 W m−1 °C−1, 1.83 kJ kg−1 °C−1 and 4.69 kJ kg−1 °C−1; and the ratios of prediction to deviation (RPD) were 1.57, 2.04, 1.98, 1.28 and 1.64, respectively. These show the possibility of using NIR spectroscopy as an alternative method to estimate the properties of Jatropha kernels, especially the thermal conductivity at 40 °C and 100 °C.


      PubDate: 2014-07-27T19:03:35Z
       
  • Effect of excitation position of a handheld shaker on fruit removal
           efficiency and damage in mechanical harvesting of sweet cherry
    • Abstract: Publication date: September 2014
      Source:Biosystems Engineering, Volume 125
      Author(s): Jianfeng Zhou , Long He , Qin Zhang , Manoj Karkee
      As labour cost keeps rising and labour availability remains increasingly uncertain, growers are seeking mechanical harvesting solutions for fresh-market tree fruit production. To fulfil this need, this research aimed at assessing the effect of excitation position on fruit removal efficiency and fruit damage using a hand-held limb shaker for harvesting sweet cherry. In this study, four excitation positions were selected on each randomly selected limb of “Y” trellis cherry trees. The total number of fruit being removed from five fruiting zones of each limb and those remaining on the tree after harvesting was counted, and harvest-induced damage was assessed. Results showed that fruit removal efficiency from each zone was highly affected by the distance of the zone to the excitation position. The overall fruit removal efficiency was 84% when shaken at the lowest excitation position, and 77%, 51% and 72% respectively as the excitation position moved up the limbs. The fruit damage rates from low to high excitation positions were 20%, 28%, 20% and 23%, which was approximately 10% higher than that of handpicked fruit. No significant difference was found in the fruit damage rate when comparing different excitation positions. It was observed that the fruit removal efficiency may reach up to 97% when the limbs were excited at both the lowest and the highest excitation positions, and adopting such an excitation method could lead to a high fruit removal efficiency with not much increase in fruit damage.


      PubDate: 2014-07-27T19:03:35Z
       
  • Specification and implementation of a continuous microwave-assisted system
           for paste malaxation in an olive oil extraction plant
    • Abstract: Publication date: September 2014
      Source:Biosystems Engineering, Volume 125
      Author(s): Alessandro Leone , Antonia Tamborrino , Roberto Romaniello , Riccardo Zagaria , Erika Sabella
      An industrial prototype continuous microwave-assisted system (MWS) to condition olive paste was specified, built and implemented as an industrial process. The developed system was tested to assess its performance during implementation in an industrial olive oil extraction plant. The extraction efficiency of the olive oil plant was investigated for different operating conditions of the MWS and compared with conventional methods to condition the olive paste. The results indicate that exposing the olive paste to microwaves determines the thermal and non-thermal effects that influence the coalescence phenomena and the extraction efficiency. The experiments showed the feasibility of the continuous microwave-assisted prototype and great the potential to become an alternative technique to effectively condition olive paste. The MWS removes the limitations of the batch malaxation process and produces an olive oil extraction process that is truly continuous.


      PubDate: 2014-07-27T19:03:35Z
       
  • Relaxation behaviour of Jatropha curcas L. bulk seeds under compression
           loading
    • Abstract: Publication date: September 2014
      Source:Biosystems Engineering, Volume 125
      Author(s): David Herak , Abraham Kabutey , Michal Petru , Petr Hrabe , Petr Lepsik , Satya Simanjuntak
      The relaxation behaviour of Jatropha curcas L. bulk seeds, expressed as the dependency of compressive force in relation to time, was determined for deformations 45, 50, 55, 60 and 65mm respectively from Jatropha bulk seed of initial pressing height 80mm using the pressing vessel diameter 60mm. The normalised force, the rate of normalised force and the second derivative of normalised force, all versus relaxation time, were described for different deformations of Jatropha bulk seeds. It was observed that at the beginning of the relaxation process the normalised force at the oil point produced minimal amount suggesting that the oil point can be determined directly from the relaxation process which is also dependent on the rate and second derivative of the normalised force. However, the oil point of Jatropha bulk seeds can equally be determined by observation of the relaxation process. The dependency of compressive force versus relaxation time of Jatropha bulk seeds for different deformations showed a linear dependency within 2s of relaxation time and after 10s of the relaxation process, the rate of normalised force was constant and the relaxation process showed no internal dynamic forces and stresses on the bulk seeds. From observations after 100s the whole relaxation process of Jatropha bulk seeds was completed.


      PubDate: 2014-07-27T19:03:35Z
       
  • Characterisation of the dielectric properties of rubber latex from 0.5 to
           33 GHz
    • Abstract: Publication date: September 2014
      Source:Biosystems Engineering, Volume 125
      Author(s): Sakol Julrat , Mitchai Chongcheawchamnan , Ian D. Robertson
      This paper presents a detailed characterisation of the dielectric properties of rubber latex over the entire microwave frequency range (0.5–33 GHz), for samples with a range of dry rubber contents and over the temperature range 10–40 °C. The relaxation processes observed are analysed and compared to pure water, as modelled with the Debye equation. It is shown that two relaxation processes exist in rubber latex, with one of these attributed to the presence of bound water molecules. The extended Debye equation is then applied to model the dielectric permittivity. Each relaxation time extracted from the modelling exposes a different physical mechanism in rubber latex. It is believed that this is the most extensive study of the microwave properties of rubber latex yet reported, and that the results are an important step in the development of microwave sensors for determining the quality of rubber latex for agriculture and industrial application.


      PubDate: 2014-07-27T19:03:35Z
       
  • Non-contact, motion-tolerant measurements of chicken (Gallus gallus)
           embryo heart rate (HR) using video imaging and signal processing
    • Abstract: Publication date: September 2014
      Source:Biosystems Engineering, Volume 125
      Author(s): Ali Youssef , Stefano Viazzi , Vasileios Exadaktylos , Daniel Berckmans
      The chicken embryo provides an excellent model organism for physiological and developmental biology studies. The chick chorioallantoic membrane (CAM) is widely used to study angiogenesis and vasculogenesis in primary tumour growth. The cardiovascular system is the first organ system to form and function in the developing embryo. Heart rate (HR) is deemed to be an important physiological parameter in such studies. The heart rate of the developing embryo can be very informative in developmental studies of cardiac rhythm. Many studies have considered developing techniques to measure avian embryonic heart rate from incubated eggs. However, the existing techniques disturb the incubation process and/or are sensitive to embryonic motion. A novel non-contact, semi-invasive, and motion-tolerant technique to measuring embryonic heart rate from chicken eggs using video imaging and signal processing is described and implemented in this paper. The technique is based on videos captured from incubated eggs to recover heart rate signals. Heart rate is estimated using frequency analysis techniques and the values obtained are in agreement with results from the literature. The technique proposed in this paper provides a real-time approach to monitoring developmental embryonic heart rate. Also it can provide a promising technique for monitoring the developing vasculature in primary tumour growth.


      PubDate: 2014-07-27T19:03:35Z
       
  • 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
       
 
 
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