• Authors:
    • Tabil, L. G.
    • Adapa, P. K.
    • Schoenau, G. J.
  • Source: Agricultural Engineering International: the CIGR Ejournal
  • Volume: 11
  • Year: 2009
  • Summary: Agricultural biomass such as barley, rape, oat and wheat straw has the potential to be used as feedstock for bioenergy. However, the low bulk density straw must be processed and densified in order to facilitate handling, storage and transportation. It is important to understand the fundamental mechanism of the biomass compression process, which is required in the design of energy efficient compaction equipment to mitigate the cost of pre-processing and transportation of the product. Therefore, a comprehensive review of various compression models was performed and the compression behaviour of selected ground agricultural biomass was studied. Five compression models were considered to determine the pressure-volume and pressure-density relationship to analyse the compression characteristics of biomass samples, namely Jones (1960), Heckle (1961), Cooper-Eaton (1962), Kawakita-Ludde (1971) and Panelli-Filho (2001) models. Densification studies were conducted on four selected biomass samples at 10% moisture content and 1.98 mm grind size using four pressure levels of 31.6, 63.2, 94.7 and 138.9 MPa. The mean densities of barley, rape, oat and wheat straw increased from 907 to 977 kg/m 3, 823 to 1003 kg/m 3, 849 to 1011 kg/m 3 and 813 to 924 kg/m 3, respectively. The Kawakita-Ludde model provided an excellent fit having R 2 values of 0.99 for selected agricultural straw samples. It was also concluded that the ground oat and rape straw had the highest level of porosity and failure stress, respectively. The parameters of Cooper-Eaton model indicated that the ground straw samples were densified easily by the particles rearrangement method and Jones model indicated that canola and oat straw were more compressible as compared to barley and wheat straw.
  • Authors:
    • Schoenau, G.
    • Tabil, L.
    • Adapa, P.
  • Source: Biosystems Engineering
  • Volume: 104
  • Issue: 3
  • Year: 2009
  • Summary: Agricultural biomass has the potential to be used as feedstock for biofuel production. However, crop residue after harvest must be gathered, processed and densified in order to facilitate efficient handling, transportation and usage. in this study compacts were prepared by densifying material against a base plate (representing the specific energy required to overcome friction within the straw grinds) as opposed to the process that occurs in a commercial operation where compacts are formed due to back-pressure effect in the die. Densification was measured using four selected biomass samples (barley, canola (oilseed rape), oat and wheat straw) at 10% moisture content (wb) and 1.98 mm grinder screen size using a compaction apparatus which applied four pressure levels of 31.6, 63.2, 94.7 and 138.9 MPa. The specific energy required to extrude the compact was measured; this will closely emulate the specific energy required to overcome the friction between the ground straw and die. The mean densities of barley, canola, oat and wheat straw compacts ranged from 907 +/- 31 to 988 +/- 26 kg m(-3), 823 +/- 73 to 1003 +/- 21 kg m(-3), 849 +/- 22 to 1011 +/- 54 kg m(-3) and 813 +/- 55 to 924 +/- 23 kg m(-3), respectively; while the mean total specific energy for compaction of grinds ranged from 3.69 +/- 0.28 to 9.29 +/- 0.39 MJ t(-1), 3.31 +/- 0.82 to 9.44 +/- 0.33 MJ t(-1), 5.25 +/- 0.42 to 9.57 +/- 0.83 MJ t(-1) and 3.59 +/- 0.44 to 7.16 +/- 0.40 MJ t(-1), respectively. Best predictor equations having highest coefficient of determination values (R(2)) and standard error of estimate or root mean square error were determined for both compact density and total specific energy required to compress the ground straw samples. The resulting R 2 for pellet density from barley, canola, oat and wheat straw were 0.56, 0.79, 0.67 and 0.62, respectively, and for total specific energy the values of R 2 were 0.94, 0.96, 0.90 and 0.92, respectively. (C) 2009 IAgrE. Published by Elsevier Ltd. All rights reserved.
  • Authors:
    • Vicente, M. C. de
    • Andersson, M. S.
  • Source: book
  • Year: 2009
  • Summary: This comprehensive volume provides the scientific basis for assessing the likelihood of gene flow between twenty important crops and their wild relatives. The crops discussed include both major staples and minor crops that are nonetheless critical to food security, including bananas and plantain, barley, canola, cassava, chickpeas, common beans, cotton, cowpeas, finger millet, maize, oat, peanuts or groundnuts, pearl millet, pigeonpeas, potatoes, rice, sorghum, soyabeans, sweet potatoes, and wheat. Each chapter is devoted to one of the crops and details crop-specific information as well as relevant factors for assessing the probability of gene flow. The crop-specific reviews provide insights into the possible ecological implications of gene escape. For each crop, a full-colour world map shows the modelled distributions of crops and wild relatives. These maps offer readers, at a glance, a means of evaluating areas of possible gene flow. The authors classify the areas of overlap into three "gene-flow categories" with respect to the possibility of genetic exchange. The systematic, unbiased findings provided here will promote well-informed decision making and the conservation of wild relatives of crops. This book is particularly relevant to agriculture in developing countries, where most crop biodiversity is found and where current knowledge on biodiversity conservation is limited. Given the ecological concerns associated with genetically modified crops, this reference is an essential tool for everyone working to feed a growing world population while preserving crop biodiversity.
  • Authors:
    • Bolotova, N. S.
  • Source: Kormoproizvodstvo
  • Issue: 12
  • Year: 2009
  • Summary: Techniques and standards for production of haylage and silage from high-protein fodder mixtures of pea, oat, rape, vetch, barley, beans, rye, wheat and maize are discussed. Plants should be cut into 15-20 mm pieces when the protein content of fodder mixture is over 30%, and into 40-50 mm pieces when the protein content of fodder mixture is less than 20%. Bales of silage mass are wrapped in film and roll size is 1.2 m wide and 0.8-1.6 m in diameter. The high yield of maize, vetch, and oat-rape mixture achievable in the conditions of European Russia is 10.8 t/ha of dry mass and 1.2 t/ha of protein.
  • Authors:
    • Balkcom, K. S.
    • Arriaga, F. J.
    • Bergtold, J. S.
    • Stoll, M. E.
    • Price, A. J.
    • Kornecki, T. S.
    • Rap, R. L.
  • Source: Communications in Biometry and Crop Science
  • Volume: 3
  • Issue: 1
  • Year: 2008
  • Summary: Research has shown that some cover crops are allelopathic and can inhibit weed germination and growth. Additionally, negative allelopathic effects have been documented in cash crops planted into cover crop residue. However, little literature exists comparing relative the allelopathic potential of cover crops producers utilize in conservation-agriculture systems. This study assessed the effects of twelve cover crop extracts on radish ( Raphanus sativus L.) and cotton ( Gossypium hirsutum L.) radicle elongation, in three trials, using an extract-agar bioassay. In Trial 1 the cover crops were black oat ( Avena strigosa Schreb) cv. SoilSaver, crimson clover ( Trifolium incarnatum L.) cv. AU Robin, white lupin ( Lupinus albus L.) cvs. AU Homer and AU Alpha, rye ( Secale cereale L.) cv. Elbon, wheat ( Triticum aestivum L.) cv. Vigoro Grazer, and triticale (* Triticosecale Wittmack) cv. Trical 2700. In Trial 2 the cover crops were forage rape ( Brassica napus L. var. napus) cv. Licapo, sunn hemp ( Crotalaria juncea L.), Austrian winter field pea ( Pisum sativum spp. arvense L. Poir), black medic ( Medicago lupilina L.), hairy vetch ( Vicia villosa Roth), black oat cv. SoilSaver, and crimson clover cv. AU Robin. Cotton was evaluated using the same bioassay and all of the cover crops mentioned above in a single trial (Trial 3). All cover crop extracts inhibited radicle elongation compared to water. Allelopathic potential was highly variable among cultivars within a cover crop species, and within a cultivar. Allelopathic differences among cover crops give an additional weed control tool in conservation systems. However, winter cover selection may impact on cash crop performance if producers plant their crop into green residue.
  • Authors:
    • Hilbert, J.
    • Huerga, I.
    • Donato, L.
  • Source: Central theme, technology for all: sharing the knowledge for development. Proceedings of the International Conference of Agricultural Engineering, XXXVII Brazilian Congress of Agricultural Engineering, International Livestock Environment Symposium - ILES V
  • Year: 2008
  • Summary: The present study is focus on the final energy balance of bioenergy production in Argentina using soybean, sunflower, rapeseed, corn and sorghum as feedstocks. The balance considers the difference between the energy contained per unit and the amount used for its generation in all the different steps from sowing to final destination. For direct energy consumption costomaq software was employed using local fuel consumption forecast for each field labor. Particular attention is paid to the energy consumption in the agricultural steps considering the distinctive no till system spread out in Argentina that has a very low energy input. Direct and indirect energy were considered in the different steps of bioethanol and biodiesel generation. Industrial conversion consumption was based on international literature data. Comparisons were made between tilled and no till practices and considering or not the energy contained in co products. Results indicate a balance ranging from 0.96 to 1.54 not considering the co products. If co products were introduced the balances ranged between 1.09 and 4.67.
  • Authors:
    • Wei, C. F.
    • Tang, X. H.
    • Wang, Z. F.
    • Luo, Y. J.
    • Gao, M.
  • Source: Pedosphere
  • Volume: 18
  • Issue: 5
  • Year: 2008
  • Summary: The effect of different tillage systems on the size distribution of aggregates and organic carbon distribution and storage in different size aggregates in a Hydragric Anthrosol were studied in a long-term experiment in Chongqing, China. The experiment included three tillage treatments: conventional tillage with rotation of rice and winter fallow (CT-r) system, no-till and ridge culture with rotation of rice and rape (RT-rr) system, and conventional tillage with rotation of rice and rape (CT-rr) system. The results showed that the aggregates 0.02-0.25 mm in diameter accounted for the largest portion in each soil layer under all treatments. Compared with the CT-r system, in the 0-10 cm layer, the amount of aggregates >0.02 mm was larger under the RT-rr system, but smaller under the CT-rr system. In the 0-20 cm layer, the organic carbon content of all fractions of aggregates was the highest under the RT-rr system and lowest under the CT-rr system. The total organic carbon content showed a positive linear relationship with the amount of aggregates with diameter ranging from 0.25 to 2 mm. The storage of organic carbon in all fractions of aggregates under the RT-rr system was higher than that under the CT-r system in the 0-20 cm layer, but in the 0-60 cm soil layer, there was no distinct difference. Under the CT-rr system, the storage of organic carbon in all fractions of aggregates was lower than that under the CT-r system; most of the newly lost organic carbon was from the aggregates 0.002-0.02 and 0.02-0.25 mm in diameter.
  • Authors:
    • Jones, C. A.
    • Buschena, D. E.
    • Miller, P. R.
    • Holmes, J. A.
  • Source: Agronomy Journal
  • Volume: 100
  • Issue: 3
  • Year: 2008
  • Summary: Transition to no-till (NT) and organic (ORG) farming systems may enhance sustainability. Our objectives were to compare transitional crop productivity and soil nutrient status among diversified NT and ORG cropping systems in Montana. Three NT systems were designed as 4-yr rotations, including a pulse (lentil [ Lens culinaris Medik.] or pea [ Pisum sativum L.]), an oilseed (canola [ Brassica napus L.] or sunflower [ Helianthus annuus L.]) and two cereal crops (corn [ Zea mays L.], proso millet [ Panicum miliaceum L.], or wheat [ Triticum aestivum L.]). No-till continuous wheat was also included. The ORG system included a green manure (pea), wheat, lentil, and barley ( Hordeum vulgare L.) and received no inputs. Winter wheat in the ORG system yielded equal or greater than in the NT systems, and had superior grain quality, even though 117 kg N ha -1 was applied to the NT winter wheat. After 4 yr, soil nitrate-N and Olsen-P were 41 and 14% lower in the ORG system, whereas potentially mineralizable N was 23% higher in the ORG system. After 4 yr, total economic net returns were equal between NT and ORG systems on a per-ha basis. Studying simultaneous transition to diversified NT and ORG cropping systems was instructive for increased sustainability.
  • Authors:
    • Tyedmers, P.
    • Arsenault, N.
    • Pelletier, N.
  • Source: Environmental Management
  • Volume: 42
  • Issue: 6
  • Year: 2008
  • Summary: We used Life Cycle Assessment to scenario model the potential reductions in cumulative energy demand (both fossil and renewable) and global warming, acidifying, and ozone-depleting emissions associated with a hypothetical national transition from conventional to organic production of four major field crops [canola (Brassica rapa), corn (Zea mays), soy (Glycine max), and wheat (Triticum aestivum)] in Canada.
  • Authors:
    • Weisskopf, P.
    • Leifeld, J.
    • Anken, T.
    • Hermle, S.
  • Source: Soil & Tillage Research
  • Volume: 98
  • Issue: 1
  • Year: 2008
  • Summary: Soil tillage and its interaction with climate change are widely discussed as a measure fostering carbon sequestration. To determine possible carbon sinks in agriculture, it is necessary to study carbon sequestration potentials in relation to agricultural management. The aim of this paper is to evaluate the soil carbon sequestration potential of a site in north-eastern Switzerland under different tillage systems. The study was performed as a long-term (19-year) trial on an Orthic Luvisol (sandy loam) with a mean annual air temperature of 8.4 °C and a long-term precipitation mean of 1183 mm. The soil organic carbon (SOC) concentration was determined five times during the study period, with the paper focussing mainly on the year 2006. The main objective was to quantify the influence of mouldboard ploughing (PL), shallow tillage (ST), no-tillage (NT) practices, and grassland (GL) on soil organic carbon content, the latter's different fractions (labile, intermediate, and stable), and its distribution by depth. In calculating the SOC content of the whole soil profile, we included a correction factor accounting for variations in bulk density (equivalent soil mass). The total SOC stock at a depth of 0-40 cm was 65 Mg C ha-1, and although higher under GL, did not differ significantly between PL, ST, and NT. SOC concentrations per soil layer were significantly greater for NT and ST (0-10 cm) than for PL, which had greater SOC concentrations than NT and ST at 20-30 cm depth. Both SOC concentrations and stocks (0-20 cm) were largest under GL. In all treatments, most of the carbon was found in the intermediate carbon fraction. There was no significant difference in any of the three SOC fractions between NT and ST, although there was between ST and PL. A sharp decrease in C-concentrations was observed in the first 7 years after the transition from grassland to arable land, with a new equilibrium of the carbon concentration in the 0-40 cm layer being reached 12 years later, with no significant difference between the tillage treatments. Overall, the results indicate that effects of tillage on soil carbon are small in moist, cold-temperate soils, challenging conversion into no-till as a measure for sequestering C.