• Authors:
    • Maghirang, R. G.
    • Casada, M. E.
    • Boac, J. M.
    • Harner, J. P.,III
  • Source: Transactions of the ASABE
  • Volume: 53
  • Issue: 4
  • Year: 2010
  • Summary: Experimental investigations of grain flow can be expensive and time consuming, but computer simulations can reduce the large effort required to evaluate the flow of grain in handling operations. Published data on material and interaction properties of selected grains and oilseeds relevant to discrete element method (DEM) modeling were reviewed. Material properties include grain kernel shape, size, and distribution; Poisson's ratio; shear modulus; and density. Interaction properties consist of coefficients of restitution, static friction, and rolling friction. Soybeans were selected as the test material for DEM simulations to validate the model fundamentals using material and interaction properties. Single- and multi-sphere soybean particle shapes, comprised of one to four overlapping spheres, were compared based on DEM simulations of bulk properties (bulk density and bulk angle of repose) and computation time. A single-sphere particle model best simulated soybean kernels in the bulk property tests. The best particle model had a particle coefficient of restitution of 0.6, particle coefficient of static friction of 0.45 for soybean-soybean contact (0.30 for soybean-steel interaction), particle coefficient of rolling friction of 0.05, normal particle size distribution with standard deviation factor of 0.4, and particle shear modulus of 1.04 MPa.
  • Authors:
    • Domuta, C.
    • Sandor, M.
    • Bara, L.
    • Bara, C.
    • Bara, V.
    • Domuta, C.
    • Borza, I. M.
    • Brejea, R.
    • Vuscan, A.
  • Source: Analele Universităţii din Oradea, Fascicula: Protecţia Mediului
  • Volume: 15
  • Year: 2010
  • Summary: The paper based on the researche carried out in the Agricultural Research and Development Station Oradea in the long term trial placed in 1990 on a preluvosoil. Two factors were studied: crop rotation (maize-monocrop; maize-wheat; maize-soybean-wheat) and water regime (unirrigated and irrigated). In comparison with unirrigated and irrigated monocrop, in the maize-wheat crop and especially in the maize-soybean-wheat crop rotation very significant yield gains were obtained all the three years. The irrigation determined the yield gains very significant statistically every year and in every crop rotation. The smallest protein content and protein production were registered in the variant with maize monocrop and the biggest in the variant with wheat-maize-soybean crop. The irrigation determined the increase of the protein content.
  • Authors:
    • Paltridge, N.
    • Tao, J.
    • Unkovich, M.
    • Gason, A.
    • Grover, S.
    • Wilkins, J.
    • Coventry, D.
    • Tashi, N.
    • Bonamano, A.
  • Source: Crop & Pasture Science
  • Volume: 60
  • Issue: 7
  • Year: 2009
  • Summary: In the south of the Tibet Autonomous Region of China there is a network of valleys where intensive agriculture is practiced. Although considered highly productive by Tibetans, farm incomes in the region are low, leading to a range of government initiatives to boost grain and fodder production. However, there is limited information available on current farming practices, yields, and likely yield constraints. The present paper uses available data and farmer interviews to describe the agro-climate and current systems of crop and livestock production, and considers possible strategies to boost production. Although winters in Tibet are cold and dry, summer and autumn provide ideal conditions for crop growth. Cropping systems are characterised by heavy tillage, frequent irrigation, high seeding rates and fertiliser applications, some use of herbicides, and little stubble retention or mechanisation. Spring barley and winter wheat are the predominant crops, followed by rapeseed, winter barley, and minor fodder and vegetable crops. Average yields for the main grain crops are around 4.0 t/ha for spring barley and 4.5 t/ha for winter wheat, significantly lower than should be possible in the environment. Farmers typically keep five or six cattle tethered near the household. Cattle are fed diets based on crop residues but are generally malnourished and rarely produce beyond the needs of the family. It is suggested that research and extension in the areas of crop nutrition, weed control, irrigation, seeding technology, and crop varieties should enable significant increases in grain yield. Increases in cattle production will require increases in the supply of good quality fodder. Cereal/fodder intercrops or double crops sown using no-till seed drills might enable the production of useful amounts of fodder in many areas without jeopardising food grain supply, and allow more crop residues to be retained in fields for improved soil health.
  • Authors:
    • Abrol, V.
    • Sankar, G.
    • Singh, B.
    • Sharma, P.
  • Source: Indian Journal of Agricultural Sciences
  • Volume: 79
  • Issue: 11
  • Year: 2009
  • Summary: A Field experiment was conducted during 2005-06 and 2006-07 at Dryland Research Sub Station, Dhiansar to study the influence of tillage and mulching practices on crop productivity, economics and soil properties of maize-wheat system under rainfed situation. Four different tillage methods, viz conventional, minimum, no tillage and raised bed were used in the main plots and four different mulch materials, viz straw, polyethylene, soil mulch including no mulch were used in the sub-plots. Tillage practices significantly influenced the yield of maize and wheat. Grain yield of maize and wheat was statistically at par in conventional and minimum tillage system and significantly higher than no tillage system in both the years. Mulching also resulted in increased in yield. Significantly higher mean grain yield of maize (1.91 tonnes/ha) and wheat (0.63 tonnes/ha) was recorded from polyethylene mulch, followed by straw mulch (1.77 tonnes/ha, 0.61 tonnes/ha) respectively. Minimum tillage and polyethylene mulch or straw mulch conserve more moisture and infiltration rate than other tillage methods and mulch application. The highest mean net returns (Rs 10 078) and benefit:cost ratio (1.28) was obtained with minimum tillage and lowest with conventional tillage (Rs 8 631 0.90). Minimum tillage in conjunction with polyethylene mulch or straw mulch was economically profitable and improve, the crop production and soil quality for maize-wheat sequence in rainfed condition.
  • Authors:
    • Peeyush, S.
    • Vikas, A.
    • Shankar, G.
  • Source: Research on Crops
  • Volume: 10
  • Issue: 3
  • Year: 2009
  • Summary: A field experiment was conducted during 2005-06 and 2006-07 at Dryland Research Sub-Station, Dhiansar to study the influence of tillage and mulching management on soil physical and chemical properties and crop yield on maize-wheat system under rainfed situations. Maize and wheat yield was statistically at par in conventional and minimum tillage and significantly higher over control. Increase in bulk density was higher in conventional tillage as compared to the minimum tillage. Reduction in infiltration rate was 17.24% higher in conventional tillage than minimum tillage. Minimum tillage improved the net return, benefit:cost ratio as well as fertility status. Application of plastic mulch resulted in maximum grain yield, infiltration rate and nutrient status than no mulch.
  • Authors:
    • Abrol, V.
    • Singh, J. P.
    • Hussain, S. Z.
  • Source: AMA-Agricultural Mechanization in Asia, Africa and Latin America
  • Volume: 40
  • Issue: 1
  • Year: 2009
  • Summary: Tillage is a major farm operation that consumes time, energy and expense. Dryland cultivation practices need to minimize cost of production in all crops. An experiment has been conducted on two tillage systems: (1) conventional and (2) reduced tillage, to save energy in production of maize and wheat in Jammu, India. Three tillage treatments in combination with three fertilizer treatments were used. The highest yield of maize was 20.50 q/ha with conventional tillage + interculture. The next highest yield for maize was 20.16 q/ha with 50% conventional tillage + weedicide + interculture. The highest yield of wheat was 29.33 q/ha with 50% conventional tillage + weedicide + interculture. The next highest yield of wheat was 27.87 q/ha with conventional tillage + interculture. The fertilizer treatment showed the highest average grain yield of maize of 21.90 q/ha with 100% N with inorganic fertilizer. The next highest fertilized treatment with maize was with 50% N through organic + 50% N through inorganic fertilizers for a yield of 19.85 q/ha. A similar trend was found for wheat with the highest average grain yield of 29.00 q/ha with 100% N through inorganic fertilizer. The next highest fertilized treatment with wheat was with 50% N through organic + 50% N through inorganic fertilizers with a grain yield of 28.25 q/ha. The operational energy and cost of operation were higher in the conventional tillage system (5013.8 MJ, Rs. 10 574 and 2907.53 MJ, Rs.11 347.33) than in reduce tillage (3625.39 MJ, Rs.9750 and 2227.20 MJ, Rs.10 335.30) and the benefit cost ratio ranged from 1.52: 1 to 0.36: 1 and 1.08: 1 to 1.41: 1 in production of maize and wheat, respectively.
  • Authors:
    • Wuest, S. B.
    • Siemens, M. C.
    • Gollany, H. T.
    • Williams, J. D.
    • Long, D. S.
  • Source: Journal of Soil and Water Conservation
  • Volume: 64
  • Issue: 1
  • Year: 2009
  • Summary: Conservation tillage systems that reduce Soil erosion and maintain or increase soil carbon offer long-term benefits for producers in the inland Pacific Northwestern United States but Could result in reduced grain yields due to increased pressure from weeds, disease, and insect pests. Our objective was to compare runoff, soil erosion, and crop yields from a conventional tillage, wheat-fallow two-year rotation and a no-till four-year rotation. The experiment was undertaken within a small,watershed to provide results that would be representative of conservation effectiveness at the field scale. Two neighboring drainages, 5.8 and 10.7 ha (14 and 26 ac), in the 340 mm y(-1) (13.4 in yr(-1)) precipitation zone of northeastern Oregon, were instrumented to record rainfall, runoff, and erosion over a four-year period (2001 through 2004). One drainage was cropped to a winter wheat-fallow rotation and received inversion tillage (tillage fallow). The second drainage was cropped in a four-year no-till rotation: winter wheat-chemical fallow-winter wheat-chickpea (no-till Fallow). We recorded 13 runoff events from the inversion tillage system and 3 from the no-till system. Total runoff and erosion values from inversion tillage drainage were 5.1 mm (0.20 in) and 0.42 Mg ha(-1) (0.19 tn ac(-1)) versus 0.7 mm (0.03 in) and 0.01 Mg ha(-1) (<0.005 in ac(-1)) from no-till drainage. The no-till rotation was substantially more effective in conserving soil and water in this field-scale comparison. Soil erosion observed in this research is a fraction of that reported for similar tillage practices outside of the Pacific Northwestern. Mean wheat yields did not significantly differ between inversion tillage and no-till treatment despite intensifying the rotation by replacing one year of fallow with a chickpea crop in the four-year rotation. Because of high year-to-year variability in yield and limited sample size, more study is needed to compare winter wheat yields in no-till production systems with inversion tillage. The no-till cropping system was more e effective in reducing runoff and soil erosion and provides producers with an ability to protect soil and water resources in the dryland Pacific Northwest.
  • Authors:
    • Smith, R. F.
    • Boyd, N. S.
    • Brennan, E. B.
    • Foster, P.
  • Source: Agronomy Journal
  • Volume: 101
  • Issue: 4
  • Year: 2009
  • Summary: Winter cover crops can add soil organic matter, improve nutrient cycling, and suppress weeds in organic vegetable systems. A 2-yr study was conducted on organic farms in Salinas and Hollister, CA, to evaluate the effect of seeding rate (SR) and planting arrangement on cover crop density, ground cover, and cover crop and weed dry matter (DM) with a mixed cover crop. The mix contained legumes (35% Vicia faba L., bell bean; 15% Vicia dasycarpa Ten., woolypod vetch; 15% Vicia benghalensis L., purple vetch; and 25% Pisum sativum L., pea) and 10% oat ( Avena sativa L.) by seed weight. Three SRs (112, 224, and 336 kg ha -1) and two planting arrangements (one-way versus grid pattern) were evaluated. Planting arrangement had no effect on the variables measured. When weeds were abundant, weed DM declined linearly with increasing SR from approximately 300 kg ha -1 at the low SR to
  • Authors:
    • Ferris, H.
    • DuPont, S. T.
    • Horn, M. van
  • Source: Applied Soil Ecology
  • Volume: 41
  • Issue: 2
  • Year: 2009
  • Summary: Soil food webs cycle nutrients and regulate parasites and pathogens, services essential for both agricultural productivity and ecosystem health. Nematodes provide useful indicators of soil food web dynamics. This study was conducted to determine if nematode soil food web indicators and crop yield can be enhanced by combinations of cover crops in a conservation tillage system. The effects of three cover crop treatments (vetch/pea, oat/wheat and oat/wheat/pea/vetch) with low, medium and high C:N and a bare fallow control were investigated in Davis, CA. Nematode fauna, soil properties and plant productivity were measured. Soil food web indices, including the Enrichment Index (EI), Structure Index (SI), Basal Index (BI), and Channel Index (CI), based on the composition of nematode assemblages, were calculated to infer soil food web condition. Cover cropped tomato/corn rotations had twice the number of enrichment opportunist bacterial feeding nematodes, active participants in nitrogen mineralization, than fallowed tomato/corn rotations (opportunist bacterial feeders=163 versus 98). In winter fallowed plots food webs were basal, common in disturbed, nutrient-poor conditions (BI=37). Total number of enrichment opportunist nematodes, soil NH 4-N levels, and inferred nitrogen mineralization, were higher in cover crop treatments with low to mid C:N ratios. Omnivore and predator nematodes were scarce, averaging less than 6 nematodes 100 g -1 in all treatments. In year one, plant productivity was highest after fallow. In contrast, in year two productivity was highest after cover crops with high nitrogen content and productivity significantly correlated with the structure of the soil fauna. Monitoring the abundance of enrichment opportunists may provide managers with a new tool to evaluate soil food web nitrogen mineralization and plant productivity.
  • Authors:
    • Sattler, A.
    • Faganello, A.
    • Fontaneli, R. S.
    • Vargas, L.
  • Source: Ciencia Rural
  • Volume: 39
  • Issue: 7
  • Year: 2009
  • Summary: Black oat ( Avena strigosa [ Avena nuda]), an important winter cover crop in south Brazil, is a weed problem in cool season grain crops as well as ryegrass. Two trials in a randomized complete block design were conducted in Passo Fundo, Rio Grande do Sul, Brazil, to study different oat management methods applied on black oat at anthesis and milk stages to avoid it from becoming a weed plant in wheat cropped after soyabean. The plot area was 60 m 2. Nine treatments were tested in both trials: spray herbicide; roll plus herbicide; hay harvest; silage harvest; mowing; grinding, silage; rolling; disking; and grain harvesting. The average total biomass at anthesis was 5016 kg DM/ha and at milk stage was 6050 kg DM/ha. Soyabean cropped in the summer season yield 2080 kg/ha and it was not affected by black oat treatments. During the second year, the wheat plots sprayed herbicide before planting yielded 2472 kg/ha and spike density of 355/m 2, however, plots without herbicide yielded 836 kg/ha and had 225 spikes/m 2. On black oat milk stage managements, the yield average was 1733 kg/ha and 334 spikes/m 2, on sprayed herbicide plots before planting. In opposite, the plots without herbicide, wheat plants were completely dominated by resurgent black oat plants, due to managements applied during the previous winter. Mechanical management methods applied only in black oat development stages allowed seed germination during winter crops cycle. This problem is avoided by spraying herbicide before oat anthesis, because after that any management method tested was unsuccessful to control oat after the following winter crops, so it is necessary to spray herbicide before seeding winter cash crops.