• 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:
    • Veiga, M.
    • Pelissari, A.
    • Moraes, A.
    • Balbinot Junior, A.
    • Dieckow, J.
    • Nesi, C.
  • Source: Revista de Ciencias Agroveterinarias
  • Volume: 8
  • Issue: 1
  • Year: 2009
  • Summary: Animal trampling is one of the major causes of soil compaction in areas subjected to integrated crop-livestock system. The objective of this work was to evaluate the effect of winter annual pasture grazing, in crop-livestock system, and other winter soil uses on soil compaction. The experiment was carried out from May 2006 to February 2007 at three sites of the North Plateau of Santa Catarina State, Brazil. Five winter treatments were investigated on each site: (1) intercropping with black oat+ryegrass+vetch+arrow leaf clover without grazing and nitrogen fertilization (multicropping cover); (2) the same intercropping, with grazing and 100 kg ha -1 of nitrogen, (grazing with N); (3) the same intercropping, with grazing and without nitrogen fertilization (grazing without N); (4) oil seed radish, without grazing and nitrogen fertilization (oil seed radish); and (5) natural vegetation, without grazing and nitrogen fertilization (fallow). Undisturbed cores were collected from the layers 2 to 7 cm and 10 to 15 cm, at three times: experiments implantation (May 2006), at maize sowing in succession of winter soil use (November 2006) and close to maize physiological maturity (February 2007). Soil total porosity, bulk density and soil resistance to penetration were evaluated in these samples. According to the environmental and management conditions, as well as the time of experimentation, the livestock presence in winter pastures, winter cover crops and fallow did not affect the variables related to soil compaction.
  • Authors:
    • Dieckow, J.
    • Pelissari, A.
    • Veiga, M.
    • Moraes, A.
    • Balbinot Junior, A.
    • Carvalho, P.
  • Source: Ciencia Rural
  • Volume: 39
  • Issue: 8
  • Year: 2009
  • Summary: Soil use and management during the winter can affect soil physical properties, reminiscent straw and performance of the crop cultivated in succession. The effect of winter soil use on these variables, cultivating black bean ( Phaseolus vulgaris) under no tillage system in summer, was investigated. Three experiments were carried out in the North Plateau of Santa Catarina State, Brazil, during 2007/08 crop season, with five strategies of soil use during the winter: (1) multicropping with black oat+ryegrass+commom vetch+arrow leaf clover ( Trifolium vesiculosum) without grazing and N application (multicropping cover); (2) the same multicropping, with grazing and 100 kg N ha -1 application (pasture with N); (3) the same multicropping, with grazing and without N application (pasture without N); (4) oil seed radish, without grazing and N application (oil seed radish); and (5) natural vegetation, without grazing and N application (fallow). The highest straw dry mass was verified in multicropping cover, but the strategies of winter soil use did not affect significantly the soil bulk density and macroporosity. The soil use with winter annual pasture in crop-livestock system, cover crops and fallow did not affect the black bean performance in succession, under no tillage system.
  • Authors:
    • Gonzalez, A.
    • Luciano, R.
    • Bertol, I.
    • Barbosa, F.
    • Vazquez, E.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 33
  • Issue: 2
  • Year: 2009
  • Summary: Where nutrients are lost by water erosion, the eroded soil is impoverished and crop productivity is reduced, apart from the water contamination. Soluble N in the runoff is biologically available and contributes to eutrophication of the water and, depending on the form and content in the water, may be toxic to aquatic organisms. In order to evaluate the N content in the form of ammonium and nitrate in the runoff water, an experiment was conducted with simulated rainfall from April to November 2006, on an Inceptisol under conventional tillage. A combination of three factors was studied: crop type, sowing form and simulated rainfall test. The crops black oat ( Avena strigosa) [ Avena nuda] and common vetch ( Vicia sativa) were studied, as well as the sowing forms: mechanical, along rows in slope direction; broadcast by hand; and mechanized along contour lines; and five simulated rainfall tests, at a constant and planned intensity of 64 mm/h and rainfall duration of 1 h. The first four rainfall tests were applied during the crop cycles and the fifth on the crop residues maintained on the soil surface. Nitrogen application to oat as urea cover dressing, immediately before rainfall test 1, resulted in a higher N-NH 4+ content in the runoff water from oat than from vetch, exceeding the acceptable level for the aquatic community. The residues decomposition on the soil surface under rainfall, the content of soluble N-NO 3- in the runoff water was higher in the crops of contour sowing than of slope sowing. The contents of soluble N-NH 4+ and N-NO 3- in the runoff water decreased from the beginning to the end of the crop cycles, but increased in the rainfall test on vetch mulch, to higher values than in the treatment with oat residue.
  • Authors:
    • Comin, J. J.
    • Lovato, P. E.
    • Bittencourt, H. von H.
    • Lana, M. A.
    • Altieri, M. A.
  • Source: ACTA SCIENTIARUM-AGRONOMY
  • Volume: 31
  • Issue: 4
  • Year: 2009
  • Summary: The effect of the winter cover crops rye, oat, ryegrass, vetch and fodder radish (and their mixtures) in no-tillage systems was investigated on soil cover, cover crop biomass and summer weed biomass during the critical competition stage with common bean. Bean yield was also evaluated. The experimental design was randomized complete blocks and four repetitions. The highest soil cover during winter was observed in the treatments rye+vetch, rye+vetch+fodder radish and oat+vetch. The highest values of cover crops biomass production were observed in the treatments rye+vetch+fodder radish. Weed suppression was higher in the ryegrass monoculture and in the rye+vetch+fodder radish association, and there was no correlation between cover crop biomass and summer weed suppression; the best bean yields were achieved with the following treatments: ryegrass in monoculture, oat in monoculture and rye+vetch, producing 1,950, 1,730 e 1,790 kg ha -1 respectively. The monocultures of ryegrass and oat showed the lowest costs with seeds and the highest economic returns.
  • Authors:
    • Santos, V. P.
    • Antedomenico, S. R.
    • Borges, D. C.
    • Inomoto, M. M.
  • Source: Tropical Plant Pathology
  • Volume: 34
  • Issue: 1
  • Year: 2009
  • Summary: The black oat ( Avena strigosa), the white oat ( A. sativa) and the Algerian oat ( A. byzantina) have been widely used as cover crops under succession with soybean, cotton, bean, potato and carrot, which are crops highly damaged by Meloidogyne incognita. The management of M. incognita may have as a component the use of oat genotypes that reduce the nematode population density. Three greenhouse experiments were carried out in order to evaluate the host suitability of five genotypes of black oat ('CPAO 0010', 'Common', 'Embrapa 29', 'Embrapa 140' and 'IPFA 99006'), one of white oat ('UFRGS 17') and one of Algerian oat ('Sao Carlos') to three isolates of M. incognita race 4 (BA, SP and MT). The black oats increased the population density of the nematode. The oats 'UFRGS 17' and 'Sao Carlos' reduced or caused a small increase in the population of M. incognita race 4, and neither differentiated from Crotalaria spectabilis. Therefore, the white oat 'UFRGS 17' and the Algerian oat 'Sao Carlos' should be used in preference to black oats as cover crops in areas infested with M. incognita race 4.
  • Authors:
    • Mazurana, M.
    • Debiasi, H.
    • Trein, C.
    • Levien, R.
    • Conte, O.
  • Source: Ciencia Rural
  • Volume: 39
  • Issue: 4
  • Year: 2009
  • Summary: This study evaluates the effect of machine traffic, soil mobilization, soil cover by crop residues and water supply on corn under no tillage on a Paleudult. Machine traffic intensity, working depth of driller shank furrow opener for fertilizer deposition and amount of residues covering the soil surface, with and without irrigation, were evaluated. The experimental design used was split plot, with 36 plots being 18 with irrigation and 18 without irrigation. The treatments were quantities (0, 2, 4, 5, 6 and 8 Mg ha -1) of black oats ( Avena strigosa) and vetch ( Vicia sativa) residues, two driller shank depths for fertilizer deposition (6 and 12 cm) and traffic machine conditions (tractor and combine) in a triple factorial design with three replicates. Corn was sowed in 12/10/2005, using 62.000 seeds per hectare. A basal dressing of NPK 5-20-20 was applied at a rate of 400 kg ha -1. Two top dressing nitrogen applications were performed, totalizing 180 kg ha -1 of N. Corn grain yield, plant population and root dry matter were evaluated. Corn yield and plant population were influenced by presence or absence of irrigation. None of the above parameters were modified by working depth of driller shank furrow opener for fertilizer deposition. Wheel traffic conditions affected corn yield and plant population.
  • 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:
    • Eastridge, M. L.
    • Dick, R. P.
    • Barker, D. J.
    • Sulc, R. M.
    • Fae, G. S.
    • Lorenz, N.
  • Source: Agronomy Journal
  • Volume: 101
  • Issue: 5
  • Year: 2009
  • Summary: The benefits of cover crops within crop rotations are well documented, but information is limited on using cover crops for forage within midwestern United States cropping systems, especially under no-tillage management. Our objective was to evaluate plant, animal, and soil responses when integrating winter cover crop forages into no-till corn ( Zea mays L.) silage production. Three cover crop treatments were established no-till after corn silage in September 2006 and 2007 at Columbus, OH: annual ryegrass ( Lolium multiflorum L.), a mixture of winter rye ( Secale cereale L.) and oat ( Avena sativa L.), and no cover crop. Total forage yield over autumn and spring seasons was 38 to 73% greater ( P≤0.05) for oat+winter rye than for annual ryegrass. Soil penetration resistance (SPR) in May 2007 was 7 to 15% greater ( P≤0.10) in the grazed cover crops than in the nongrazed no cover crop treatment; however, subsequent silage corn yield did not differ among treatments, averaging 10.4 Mg ha -1 in August 2007. Compared with the no cover crop treatment, cover crops had three- to fivefold greater root yield, threefold greater soil microbial biomass (MB) in spring 2008, and 23% more particulate organic carbon (POC) concentrations in the 0- to 15-cm soil depth. Integration of forage cover crops into no-till corn silage production in Ohio can provide supplemental forage for animal feed without detrimental effects on subsequent corn silage productivity, with the added benefit of increasing labile soil C.
  • Authors:
    • Haber, S. M.
    • Fetch, T. G.,Jr.
    • Chong, J.
    • Ames, N.
    • Duguid, S. D.
    • Brown, P. D.
    • Fetch, J. W. M.
    • Menzies, J. G.
    • Stadnyk, K. D.
  • Source: Canadian Journal of Plant Science
  • Volume: 89
  • Issue: 1
  • Year: 2009
  • Summary: Jordan is a high-yielding, white-hulled spring oat ( Avena sativa L.) cultivar postulated to carry the crown rust resistance combination Pc38, Pc39, and Pc68, which was effective against the prevalent pathotypes of crown rust races on the Canadian prairies at the time of its release. It has very good resistance to loose and covered smut, moderately good resistance to most of the prairie stem rust races (likely due to the presence of Pg2 and Pg13) and moderate tolerance to barley yellow dwarf virus (BYDV). Jordan has high kernel weight, high percent plump kernels, and low percent thin kernels. Jordan exhibits high yielding capacity in the oat growing areas of western Canada. Jordan was supported for registration at the Prairie Grain Development Committee Meeting in February 2005.