19602015
  • 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:
    • Raus, L.
    • Bucur, D.
    • Jitareanu, G.
    • Ailincai, C.
    • Ailincai, D.
    • Zbant, M.
  • Source: Cercetări Agronomice în Moldova
  • Volume: 42
  • Issue: 2
  • Year: 2009
  • Summary: The influence of long-term fertilization and irrigation on wheat and maize yield and soil fertility was studied at the Agricultural Research and Development Station of Podu-Iloaiei since 1980. These experiments were carried out on a 10% slope field, on a Cambic Chernozem with clayey loam texture (423 g clay, 315 g loam and 262 g sand), a neuter to weakly acid reaction and a mean nutrient supply. The mean annual rainfall amounts, recorded in the last 28 years, were higher, with values comprised between 12.7 and 279.2 mm, compared to the multiannual mean on 80 years (542 mm) in 16 years, and lower by 25.3-236.7 mm in 10 years. Annual application of rates of N 160 P 80, in a four-year crop rotation (soybean-wheat-sugar beet-maize)+a reserve field, cultivated with legumes and perennial grasses, determined the accumulation of a reserve of mobile phosphates of 78 mg/kg soil. Under irrigated, a good plant supply with mineral elements and the increase in the content of organic carbon from soil were done by applying the rate of N 80P 70+30 t/ha manure. Nitrogen and phosphorus fertilizers, although applied at high rates (N 130+100 P 2O 5), could not prevent the decrease in organic carbon content from soil.
  • Authors:
    • Steinbach, H. S.
    • Alvarez, R.
  • Source: Soil & Tillage Research
  • Volume: 104
  • Issue: 1
  • Year: 2009
  • Summary: The Argentine Pampas is one of the most important cropping regions of the World. Limited tillage systems, and specially no-till, had widespread in recent years, occupying actually around 70% of the surface devoted to annual crops. We review results produced in field experiments installed along the Pampas to determine the effect of the adoption of these tillage systems on some soil properties and crops yield. It was performed a meta-analysis of data from experiments where plow tillage (mouldboard plow), reduced tillage (chisel plow, disk plow or harrow disk) and no-till were compared. Treatments effects were contrasted by paired t-tests between groups of paired data. Soil bulk density and cone penetration resistance of the 0-20 cm layer were higher under limited tillage systems than under plow tillage. Increases of bulk density under no-till in comparison to plow tillage were generally small, averaging 4%, but cone penetration increased by 50% in many soils. The increase of bulk density was greater in soils of initial low bulk density. Neither bulk density increases nor cone penetration changes reached critical threshold for roots development. Aggregate stability and water infiltration rate were higher in soils subjected to limited tillage systems than under plow tillage. The improvement of aggregate stability was higher in poorer structured soils, with an average increase of 70% under no-till in relation to plow tillage. Under no-till infiltration rate doubled in average that of plow tillage. Soil water content during the critical periods of sowing and flowering was generally greater under limited tillage but, conversely, nitrate nitrogen levels were greater in plow tillage. Higher soil water content under no-till in relation to plow tillage may satisfied the evapotranspiration demand of 1-3 days of crops during the critical flowering period, being nitrate nitrogen in average 21 kg ha -1 lower under no-till. Soybean ( Glycine max (L.)-Merr.) yield was not affected by tillage system, meanwhile wheat ( Triticum aestivum L.) and corn ( Zea mays L.) yields were lower under reduced tillage and no-till than under plow tillage without nitrogen fertilization. Wheat and corn no-till yields were 10-14% lower that yields under plow tillage as a mean. When fertilizers were applied, wheat and corn yield differences between tillage treatments generally disappeared. The adoption of limited tillage systems in the Pampas leads to soil improvement but also generates the necessity of increase nitrogen fertilizers utilization to sustain yields of graminaceus crops.
  • 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:
    • Domuta, C.
    • Ardelean, I.
    • Bandici, G.
  • Source: Analele Universităţii din Oradea, Fascicula: Protecţia Mediului
  • Volume: 14
  • Year: 2009
  • Summary: The paper sustain the importance of the crop rotation on quality of the wheat yield and is based on the results carried out during 2003-2006 in a long term trial out placed on the preluvosoil from Oradea in 1990. Both in nonirrigated and irrigated conditions the smallest values of the protein, wet gluten and dry gluten were obtained in wheat monocrop; the values increased in the crop rotation wheat maize and the biggest values were registered bin the crop rotation wheat-maize-soybean.
  • 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:
    • Gathala, M. K.
    • Singh, K. K.
    • Sharma, S. K.
    • Saharawat, Y. S.
    • Tetarwal, J. P.
    • Ladha ,J. K.
    • Gupta, R. K.
    • Jat, M. L.
    • Singh, S.
  • Source: ACIAR PROCEEDINGS
  • Issue: 127
  • Year: 2008
  • Summary: Resource-conserving technologies with double no-till practices represent a major shift in production techniques for attaining optimal productivity, profitability and water use in rice-wheat (RW) systems in the Indo-Gangetic Plain. Permanent raised beds (PRB) and double no-till with flat layouts are under evaluation for RW systems for a range of soils, climate, cultivars and seeding/crop establishment techniques (dry seeding, transplanting). To date, results have been inconsistent and systematic information on trials with PRB is lacking. Four researcher- and farmer-managed experiments were conducted with various tillage and crop establishment techniques for RW on PRB and flat layouts. The yield of rice on PRB was significantly lower than that on double no-till flat layouts, whereas wheat yield was highest on PRB. The total RW system yield with PRB was similar to that of other tillage and crop establishment techniques. However, irrigation and input (irrigation plus rain) water productivity (kg grain/m 3 of water) of both rice and wheat was much higher on PRB. In farmer-managed trials of transplanted basmati rice on PRB, profitability was highest on PRB (US$684/ha) and lowest with traditional practices (US$531/ha). In a researcher-managed long-term experiment, the soil physical properties (bulk density, mean weight diameter of aggregates, cone index and infiltration rate) improved significantly on PRB compared with the conventional puddled transplanted rice-tilled wheat system.
  • Authors:
    • Wang, Z.
    • Hao, M.
    • Wang, L.
    • Li, S.
    • Li, X.
  • Source: Scientia Agricultura Sinica
  • Volume: 41
  • Issue: 9
  • Year: 2008
  • Summary: Objective: Research on effects of monocropping or rotation of different crops on water and different forms of soil organic nitrogen (N) and mineral N in dryland soils is recognized to be of great significance in determining dryland crop sequences, increasing soil fertility, and optimizing nutrients management. Method: Dryland soil samples were taken from 6 cropping systems: fallowing, continuous wheat monocropping, continuous maize monocropping, continuous alfalfa cropping with no-till, pea-wheat-wheat-millet rotation and maize-wheat-wheat-millet rotation, from a 23-year long-term experimental site on the Loess Plateau, to study the effects of cropping systems on soil water, organic N, light fraction organic N and mineral N. Result: Results obtained showed that continuous long-term fallowing system contained the lowest organic N, light fraction organic N and mineral N. Long-period alfalfa cropping with no-till system could promote water storage in topsoil layers, and accumulation of organic and light fraction organic N in 0-20 cm soil layers, but increased exhaustion of water and mineral N in deep soil layers. Continuous monocropping of wheat or maize could all significantly increase soil organic and light fraction organic N contents, and the organic N were increased more by monocropping of wheat. Organic N contents in soil layers of two rotation systems showed no obvious different to monocropping of wheat. Light fraction organic N contents also were not obvious different between two rotations in 0-20 cm soil layers, but they were all significantly higher than wheat or maize monocropping. The amount of soil mineral N was found to depend on the status of crop growing or N fertilizer application at sampling time. Conclusion: Although long term monocropping of legumes without tillage can enhance organic N accumulation by increase the light fraction organic N in soil, the exhaustion of soil water in deep layers is also increased. Rotations of legumes with cereal crops or the shallow and deep root crop rotations are proved to be feasible measures to optimize soil water utilization, increase organic N accumulation in soil, and synergize soil N supply capacity.
  • Authors:
    • Munir, A.
    • Ramzan, M.
    • Mann, R. A.
  • Source: International Journal of Agriculture & Biology
  • Volume: 10
  • Issue: 3
  • Year: 2008
  • Summary: Wheat and rice are the major food staples around the globe including Pakistan. The challenge of increasing food production in the next 20 years to match population growth is daunting and warrants improvement in the quality of natural resources for growing more food from marginal and degraded lands. Cost of cultivation must be reduced and at the same time, efficiency of resources like irrigation water, fuel, fertilizers must be improved to make the crop production system more viable and eco-friendly. Resource Conserving Technology (RCT) must figure highly in this equation since it plays a crucial role in achieving the above goals. The RCTs include laser land leveling, zero-tillage, bed furrow irrigation method and crop residue management. These technologies were evaluated in irrigated areas of Punjab province where rice follows wheat. Water use efficiency was increased by 20% in laser leveled fields. Zero-tillage technology resulted in a significant saving of irrigation water (22%), fuel (78%), cultivation (88%) and herbicide use (33%) compared to conventional, thus increasing yields and farmer's profits. Soil properties and microbial population including bacteria, fungi and actinomyces improved in the zero-till fields. Planting of wheat on raised beds is making headway in low-lying and poorly drained areas. Thus, resource conservation tillage technology provides a tool for making progress towards improving and sustaining wheat production, helping with food security and poverty alleviation in Pakistan in the next few decades.