• Authors:
    • McSorley, R.
    • Bhan, M.
    • Chase, C. A.
  • Source: Nematropica
  • Volume: 40
  • Issue: 1
  • Year: 2010
  • Summary: Two field experiments were initiated in summer 2006 in north-central Florida to compare the effects of integrating cover crops, living mulches, and intercropping on plant-parasitic nematode populations, as well as the effect of fall and spring vegetables on the multiplication rate of root-knot nematodes. Treatments consisted of seven organic cropping systems that included a summer cover crop followed by fall and spring vegetables. The summer cover crop included: pearl millet (Pennisetum glaucum), sorghum sudangrass (Sorghum bicolor x S. bicolor var. sudanense), sunn hemp (Crotalaria juncea), velvetbean (Mucuna pruriens var. pruriens), weedy fallow, mixture of pearl millet-sunn hemp, and mixture of sorghum sudangrass-velvet bean. One experiment utilized fall yellow squash (Cucurbita pepo) and spring bell pepper (Capsicum annuum) as vegetable crops, and fall broccoli (Brassica oleracea) and spring sweet corn (Zea mays) were used in the other experiment. Nematode populations were monitored at the end of the cover crop and vegetable seasons. Summer cover crops of sorghum-sudangrass or pearl millet increased root-knot nematode (Meloidogyne incognita) population levels in some instances while sunn hemp suppressed it in the broccoli-sweet corn experiment. The multiplication rate of root-knot nematodes was lowest when broccoli was planted in the cropping system. Systems with sorghum-sudangrass (alone or in mixture) increased population densities of ring (Mesocriconema spp.) and lesion (Pratylenchus spp.) nematodes, and occasionally increased stubby-root nematodes (Paratrichodorus spp.). Cover crops that increased nematode numbers when planted alone usually gave the same result when planted in mixtures with another cover crop. Other cropping systems failed to suppress plant-parasitic nematodes but maintained low densities similar to weedy fallow.
  • 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:
    • Kochsiek, A. E.
    • Knops, J. M. H.
    • Walters, D. T.
    • Arkebauer, T. J.
  • Source: Agricultural and Forest Meteorology
  • Volume: 149
  • Issue: 11
  • Year: 2009
  • Summary: The litter carbon (C) pool of a single litter cohort in an agroecosystem is the difference between net primary productivity and decomposition and comprises 11-13% of the total C pool (litter and soil 0-15 cm depth) post-harvest. This litter-C pool is highly dynamic and up to 50% can be decomposed in the first 12 months of decomposition. Thus, understanding litter-C dynamics is key in understanding monthly and annual total ecosystem carbon dynamics. While the effects of management practices such as irrigation and fertilization on productivity are well understood, the effects on decomposition are less studied. While irrigation and fertilization increase productivity, this will only lead to increased litter-C residence time and litter-C pool accretion if these techniques do not also result in equivalent or greater increases in decomposition. Management could potentially have impacts on litter-C accretion by increasing litter inputs, changing plant-C allocation, plant tissue quality, or decomposition rates. We examined carbon loss of one annual cohort of maize litter using in situ nylon litter bags for 3 years in three no-till fields with differing management regimes: irrigated continuous maize with a pre-planting fertilization application and two fertigation events, irrigated maize-soybean rotation with the same fertilization regime as the irrigated continuous maize management regime, and rainfed maize-soybean rotation with a single pre-planting fertilization event. We addressed the effects of these different management regimes on net primary productivity and litter inputs, litter nitrogen (N) concentrations and carbon quality measures, plant C allocation, decomposition rates and the potential changes in the overall litter-C balance. We found that irrigation/fertigation management increased litter inputs, led to changes in plant tissue quality, had no effect on carbon allocation, and increased decomposition rates. This balance of both greater litter inputs and outputs of C from the irrigated management regimes led to a similar litter-C balance for this litter cohort in the irrigated and rainfed management regimes after 3 years of decomposition. Our data clearly show that merely increasing litter-C inputs through irrigation/fertigation practices is not sufficient to increase litter-C residence time because decomposition rates also increase. Therefore, close monitoring of decomposition rates is essential for understanding litter-C pool dynamics.
  • Authors:
    • Balasubramanian, A.
    • Lakshmi, K. V.
    • Sankaran, N.
  • Source: Madras Agricultural Journal
  • Volume: 96
  • Issue: 1-6
  • Year: 2009
  • Summary: A field experiment was conducted during North East Monsoon season of 2002 and 2003 at Tamil Nadu Agricultural University, Coimbatore to study the productive and economically viable integrated rainwater and nitrogen management practice for dryland maize under different rainfall situations. It is concluded that for early withdrawal of rainfall around 45 DAS, two supplemental irrigations given at tasseling and silking stages through run off recycling from farm pond increased growth, yield parameters, grain yield by 134 percent and net returns by Rs.3389 ha -1 over rainfed maize in 2002. For moisture stress at tasseling and soft dough stages, two supplemental irrigation increased growth, yield attributes, grain yield by 88 percent and net return by Rs. 3305 ha -1 over rainfed maize in 2003. Application of 40 kg N ha -1 with intercropping and incorporation of either sunnhemp or cowpea at 45 DAS increased yield and net returns of maize over sole maize with out inorganic nitrogen.
  • Authors:
    • Nel, A. A.
  • Source: South African Journal of Plant and Soil
  • Volume: 26
  • Issue: 3
  • Year: 2009
  • Summary: Crop rotation is known to enhance crop yields. It is therefore recommended, regardless of rainfall and soil type, as a counter measure for the risks associated with monoculture maize ( Zea mays). Experience in the western Highveld where rainfall is low and erratic, has shown that the yield of maize does not necessarily improve as expected when preceded by alternative crops, but in fact, is often reduced. The present study was initiated to determine the effect of crop rotation with cowpea, groundnut, soyabean, sunflower or fallow on the yield and rainfall use efficiency of maize under marginal conditions on the western Highveld. Dryland maize was grown in five crop rotation systems on Mutton type soils at the farms Holfontein (four years) and Noodshulp (five years), both situated close to Ottosdal (2649′S; 2600′E). The soil profiles had an effective depth of >1.5 m at Holfontein and 1.25 m at Noodshulp. Crop rotation systems consisted of two-year rotations of cowpea-, groundnut, soybean-, sunflower-, and fallow-maize; as well as groundnut-, soybean-, and sunflower-fallow. A continuous monoculture maize treatment was included to serve as control. At Noodshulp where the rainfall was more variable, crop rotation induced maize yield deviations from the monoculture control occurred more often than at Holfontein. Apart from yield neutral and positive effects, instances of a decline in maize yield in some years due to crop rotation with cowpea, groundnut and sunflower also occurred. Taking the long-term rotational effect and the possibility of a yield decline into account, fallowing and the rotational crops ranked from best to worse were groundnut, soyabean, fallowing, cowpea and sunflower. The long-term effect of cowpea on the yield of maize was neutral and that of sunflower negative. The mean rainfall use efficiency of monoculture maize was, with the exception of maize preceded by groundnut, similar to that of maize grown in rotation.
  • 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:
    • Phillips, R. L.
    • Tanaka, D. L.
    • Archer, D. W.
    • Hanson, J. D.
  • Source: Journal of Environmental Quality
  • Volume: 38
  • Issue: 4
  • Year: 2009
  • Summary: Microbial production and consumption of greenhouse gases (GHG) is influenced by temperature and nutrients, especially during the first few weeks after agricultural fertilization. The effect of fertilization on GHG fluxes should occur during and shortly after application, yet data indicating how application timing affects both GHG fluxes and crop yields during a growing season are lacking. We designed a replicated ( n=5) field experiment to test for the short-term effect of fertilizer application timing on fluxes of methane (CH 4), carbon dioxide (CO 2), and nitrous oxide (N 2O) over a growing season in the northern Great Plains. Each 0.30-ha plot was planted to maize ( Zea mays L.) and treated similarly with the exception of fertilizer timing: five plots were fertilized with urea in early spring (1 April) and five plots were fertilized with urea in late spring (13 May). We hypothesized time-integrated fluxes over a growing season would be greater for the late-spring treatment, resulting in a greater net GHG flux, as compared to the early-spring treatment. Data collected on 59 dates and integrated over a 5-mo time course indicated CO 2 fluxes were greater ( P<0.0001) and CH 4 fluxes were lower ( P<0.05) for soils fertilized in late spring. Net GHG flux was also significantly affected by treatment, with 0.840.11 kg CO 2 equivalents m -2 for early spring and 1.040.13 kg CO 2 equivalents m -2 for late spring. Nitrous oxide fluxes, however, were similar for both treatments. Results indicate fertilizer application timing influences net GHG emissions in dryland cropping systems.
  • 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.