• Authors:
    • Chianu, J.
    • Kimetu, J.
    • Waswa, B.
    • Vanlauwe, B.
    • Kihara, J.
    • Bationo, A.
  • Source: Experimental Agriculture
  • Volume: 46
  • Issue: 1
  • Year: 2010
  • Summary: Many food production systems in sub-Saharan Africa are constrained by phosphorus (P).We hypothesized that within legume-cereal rotation systems: targeting P to the legume phase leads to higher system productivity, and that use of grain legumes leads to better economic returns than use of herbaceous legumes. Four P application regimes: (i) no P, (ii) P applied every season, (iii) P applied in season 1 only and (iv) P applied in season 2 only were tested for four seasons in three cropping systems (continuous maize, mucuna-maize rotation and soybean-maize rotation) in a split plot experiment set up in Nyabeda, western Kenya. Treatments where P was applied were better than no P treatments.While continuous cereal systems showed the need for application of P every second season, rotation systems involvingmucuna and soyabean indicated that application in one out of three seasons could be sufficient. Nitrogen fertilizer equivalence was 52 to >90 kg N ha -1 for soyabean and 37 to >90 kg N ha -1 for mucuna, depending on P fertilization and season. Analysis of marginal rates of return (MRR) showed that soybean-maize rotation with one application of P was the most economically viable option, with an MRR of at least 147% compared to other non-dominated options.
  • Authors:
    • Silva, M.
    • Goncalves, M.
    • Souza, C.
    • Souza, L.
    • Marchetti, M.
    • Mercante, F.
    • Lourente, E.
  • Source: SEMINA-CIENCIAS AGRARIAS
  • Volume: 31
  • Issue: 4
  • Year: 2010
  • Summary: Soil management practices exert important influence on biological and biochemical properties of soil. This work aimed to valuate the impact of crop rotation on soil biochemical and microbiological attributes, as well and influence on corn crop yield. The experiment was carried out during 2005/06 crop season, in Dourados - MS, Brazil. Experimental design was randomized blocks with treatments established in sub-divided plots with tree replications, which seasons were plots and management systems were sub-plots. Studied seasons were winter and summer and no tillage systems were represented by five crop rotation schemes, which involved the cultures of hairy vetch, bean, oat, forage turnip, soybean, crotalaria, corn, sorghum, pearl millet, sunflower and, in conventional tillage, with corn in winter and with soybean in summer. Native vegetation constituted one treatment and, with conventional tillage, it was used as ecosystem of reference as control for comparison between possible alterations in chemical and microbiological attributes with the establishment of a system more conservationist for soil management. There was a positive correlation among Norg, Corg, Porg and C-BMS contents with chemical attributes of soil fertility, which shows interdependence between chemical and biology of soil. The elimination of native vegetation and the substitution for cultivation system after that reduce the C-BMS. In Cerrado conditions, studied cultivation systems increased phosphorus content in soil. Crop rotation influenced corn yield after the cultivation of determined species as crotalaria and vetch in crop rotation.
  • Authors:
    • Obi, M.
    • Obalum, S.
  • Source: Soil & Tillage Research
  • Volume: 108
  • Issue: 1/2
  • Year: 2010
  • Summary: Evaluation of the impact of tillage-mulch practices under different cropping systems on soil physical properties is needed in southeastern Nigeria to identify those combinations with the potential of alleviating the physical constraints of the Ultisols predominant in the area. An investigation was carried out on a sandy loam soil at Nsukka to determine the effects of no-till (NT) and conventional tillage (CT) each with bare fallow (B) and mulch cover (M) on soil physical properties under three cropping systems [sole sorghum ( Sorghum bicolor L. Moench), sole soybean ( Glycine max L. Merrill), and sorghum-soybean intercrop]. The layout was a split-plot in randomized complete block design, with the tillage systems as the main plots and the mulch practices as the sub-plots. The treatments [no-till and bare (NTB), no-till with mulch (NTM), conventional tillage and bare (CTB) and conventional tillage with mulch (CTM)] were replicated four times. The selected key parameters evaluated after two years were density of earthworm casts, soil organic matter (SOM), bulk density (BD), total porosity (TP), pore size distribution (PSD), mean weight diameter (MWD), and saturated hydraulic conductivity (K sat). Earthworm activity was significantly ( P≤0.001) higher with NT under the intercrop system. Values were generally very low for SOM (1.06-1.48%), moderate for BD (1.34-1.51 Mg m -3) and TP (46-52%), and low to moderate for MWD (1.1-2.9 mm). The K sat was within the slow to rapid range (8.1-57.0 cm h -1). Neither the tillage nor the mulch factors influenced SOM, BD, PSD, and MWD in the cropping systems. The TP was significantly ( P≤0.05) higher in the CT compared to the NT under the sole sorghum, where interaction showed higher value in the CTM compared to the rest. There was significant ( P≤0.05) enhancement of K sat in the CT under the sole sorghum and the intercrop systems; whereas the value was significantly ( P≤0.01) higher in the bare fallow under the sole soybean. The cropping systems had more pronounced effect on the physical properties than the tillage-mulch management practices. All the measured parameters indicated significant ( P≤0.05) improvements under the sole soybean, except BD and MWD which were significantly ( P≤0.05) improved under the intercrop. Intercropping cereals and legumes on NT may be ideal for alleviating the soil's structural constraints.
  • Authors:
    • Pop, A.
  • Source: Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca
  • Volume: 67
  • Issue: 1
  • Year: 2010
  • Summary: The strategy for suppressing weeds in a minimum tillage system has to be prior and different from the classical soil tillage system. A tremendous importance must be taken for the indirect methods of weed suppressing, especially crop rotation method. The soil tillage system and weed suppressing methods play a key role for the entire weeding soybean. Especially at the first stages of plant development all the weeding crops are extremely sensible for weed activity. The most common weed species that infestate soybean crops are: Avena fatua, Echinochloa crus-galli, Setaria sp., Digitaria sanguinalis, Sorghum halepense, Agropyron repens, Amaranthus retroflexus, Chenopodium album, Galinsoga parviflora, Xanthium sp., Abutilon teophrasti, Polygonum sp., Cirsium arvense, Convolvulus arvensis. The present results where obtained in Jucu experimental plots, property of the Agricultural Faculty of Cluj-Napoca. The eco-pedological conditions consisted in: faeoziom soil with a humus content of 4.72% and a pH of 6.8, multi annual precipitation with values between 550-650 mm and the average thermal regime of 8.0-8.2C. For soybean crop, applying the minimal tillage systems, an increase in weeds number, especially of perennial di-cotyledonated ones, is observed. The weeding degree is 10,5-18,4% higher in unconventional variants. The percent of perennial di-cotyledonated weeds is 10% for plough variants and reaches 14-18% in minimal tillage systems variants. In similar working conditions and same dosage of herbicides, the higher degree of weeding in unconventional variants can be put on the working system.
  • Authors:
    • Rosolem, C.
    • Olibone, A.
    • Olibone, D.
    • Prando, M.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 34
  • Issue: 3
  • Year: 2010
  • Summary: In soils with physical and/or physical hydric restrictions for root growth, it may be a viable strategy to increase crop productivity by increasing water storage potential through improvements in water infiltration. Accordingly, the objective of this study was to determine water infiltration in a Hapludult in three crop rotations under no-tillage, with and without initial chiseling. Crop rotations consisted of: millet/soybean/sorghum/maize/sorghum; millet/soybean/Brachiaria ruziziensis/corn/Brachiaria ruziziensis; and millet/soybean/Brachiaria ruziziensis+castor bean/corn/Brachiaria ruziziensis+castor bean. Water infiltration in soil was evaluated in the field, using concentric discs at the soil surface and at depths of 0.10 and 0.20 m, in 2006 and 2007. After the first year, chiseling led to increased infiltration of water into the soil. Water infiltration was greatest in the crop rotation system with Brachiaria ruziziensis+castor bean. The activity of root systems of crops in the plots without chiseling increased the rate of water infiltration into the soil.
  • Authors:
    • Guimaraes Junior, R.
    • Marchao, R.
    • Moraes Neto, S.
    • Vilela, L.
    • Pulrolnik, K.
  • Source: Boletim de Pesquisa e Desenvolvimento - Embrapa Cerrados
  • Issue: 276
  • Year: 2010
  • Summary: The trees may improve the productivity of an agroecosystem, influencing the characteristics of soil, microclimate, hydrology and biological components associated. However, there is little information on the tree species most suitable for use in the system of integration crop-livestock-forest (SiLPF). In this context, the objective of this work was to evaluate the initial growth and survival of tree species native and exotic in different space arrangements and plant density in SiLPF in Planaltina, DF. The planting of seedling trees was conducted between January and March 2009. O design of treatments was randomized blocks with three replications of five treatments: control (tillage/grazing), native (two rows of trees and spacing between alleys of 12 m), Eucalyptus cloeziana (7 rows of trees and spacing between alleys of 22 m), Eucalyptus urograndis (2 rows of trees and spacing between alleys of 12 m) and Eucalyptus urograndis (2 rows of trees and spacing between alleys of 22 m). Among the alleys of forest species was planted sorghum in March 2009 and soybeans in December 2009 in no-tillage system with recommended fertilizer for the crop. There was no significant difference in survival between the treatments. Among the species studied native cedar species was less growth in height, while the guapuruvu, angico red mahogany and had the highest growth. Guanandi registered the worst performance and is not recommended in areas with high water deficit.
  • Authors:
    • Jajoo, S. B.
    • Kambale, P. G.
    • Atal, G. R.
  • Source: Green Farming OR Soil & Water Conservation Engineering
  • Volume: 1
  • Issue: 1
  • Year: 2010
  • Summary: A study was conducted to suggest optimal resources allocation i.e. land and water using linear programming model for Amravati district in Maharashtra State. Considering the land capability classification, availability of water in different seasons, crop water requirements, food requirements of the district, affinity towards the crops and investment capacity of peoples, crop plan was developed to maximize the net return. In existing crop plan during kharif season major area is under cotton (32.41%) followed by soybean (20.19%) whereas in proposed optimal crop plan without capital constraints major area was allocated under soybean (30%), cotton (10%) and jowar (10%) of cultivable area. In rabi major area in existing crop plan is under gram (5.2%) whereas in proposed plan area is allocated to wheat (30%) followed by gram (27%). In existing crop plan gross investment and net return were Rs. 9,268 and Rs. 4,906 per ha where as in proposed plan Rs. 16,057 and Rs. 9,642 per ha. Thus increases net return by Rs. 4,362 by increasing gross investment of Rs. 6,415 per ha.
  • Authors:
    • Kheira, A. A. A.
    • Lamm, F. R.
    • Trooien, T. P.
  • Source: Applied Engineering in Agriculture
  • Volume: 26
  • Issue: 5
  • Year: 2010
  • Summary: A 5-year field study (2004-2008) using irrigation water from an unlined surface reservoir was conducted to examine the effect of dripline depth (0.2, 0.3, 0.4, 0.5, or 0.6 m) on subsurface drip-irrigated rotational crop production of sunflower, soybean, and grain sorghum on a deep silt loam soil in western Kansas. Additional years (1999-2003) of data were included in the analysis of long-term dripline flowrates as affected by dripline depth. Crop seed germination and plant establishment with the subsurface drip irrigation system was not examined in this field study. There were no significant differences in crop yields or yield components in any year of the study with the exception of the number of soybean pods/plant in 2007. In that year, the number of pods/plant was significantly greater for the deeper dripline depths, but this improvement was not reflected in significantly greater soybean yield due to compensation from the other yield components. Measured crop water use and calculated water productivity (yield/water use) also were not significantly affected by dripline depth for any crop in any year. Crop water use varied less than 4% and water productivity varied less than 8% with dripline depth from the mean values for a given crop within a given year, but water productivity tended to be greater for the intermediate 0.4 m dripline depth. There was a tendency for the deeper dripline depths to have greater amounts of plant available soil water and this tendency was stronger as the crop season progressed and for deeper portions of the crop root zone. However, there were neither significant differences in plant available soil water in the upper (0 to 0.9 m) and lower root zones (0.9 to 2.4 m) at physiological maturity of the crop in any year, nor in the total 2.4 m soil profile. The lack of significant differences in crop yields, water use, water productivity and plant available soil water at physiological maturity suggests that dripline depths ranging from 0.2 to 0.6 m are acceptable for crop production of these three crops on the silt loam soils of the region. Measurements of plot dripline flowrates during the period 1999 through 2008 indicated a tendency for deeper disciplines to have reduced flowrates and these flowrate reductions were statistically significant in 2001, 2006, 2007, and 2008. Although the reason for these plot flowrate reductions cannot be fully ascertained, it seems likely they were caused by emitter clogging related to an interaction between dripline depth and irrigation water quality for which the rationale was not determined.
  • Authors:
    • Honeycutt, C. W.
    • Griffin, T. S.
    • Larkin, R. P.
  • Source: Plant Disease
  • Volume: 94
  • Issue: 12
  • Year: 2010
  • Summary: Seven different 2-year rotations, consisting of barley/clover, canola, green bean, millet/rapeseed, soybean, sweet corn, and potato, all followed by potato, were assessed over 10 years (1997-2006) in a long-term cropping system trial for their effects on the development of soilborne potato diseases, tuber yield, and soil microbial communities. These same rotations were also assessed with and without the addition of a fall cover crop of no-tilled winter rye (except for barley/clover, for which underseeded ryegrass was substituted for clover) over a 4-year period. Canola and rapeseed rotations consistently reduced the severity of Rhizoctonia canker, black scurf, and common scab (18 to 38% reduction), and canola rotations resulted in higher tuber yields than continuous potato or barley/clover (6.8 to 8.2% higher). Addition of the winter rye cover crop further reduced black scurf and common scab (average 12.5 and 7.2% reduction, respectively) across all rotations. The combined effect of a canola or rapeseed rotation and winter rye cover crop reduced disease severity by 35 to 41% for black scurf and 20 to 33% for common scab relative to continuous potato with no cover crop. Verticillium wilt became a prominent disease problem only after four full rotation cycles, with high disease levels in all plots; however, incidence was lowest in barley rotations. Barley/clover and rapeseed rotations resulted in the highest soil bacterial populations and microbial activity, and all rotations had distinct effects on soil microbial community characteristics. Addition of a cover crop also resulted in increases in bacterial populations and microbial activity and had significant effects on soil microbial characteristics, in addition to slightly improving tuber yield (4% increase). Thus, in addition to positive effects in reducing erosion and improving soil quality, effective crop rotations in conjunction with planting cover crops can provide improved control of soilborne diseases. However, this study also demonstrated limitations with 2-year rotations in general, because all rotations resulted in increasing levels of common scab and Verticillium wilt over time.
  • Authors:
    • Ediriwickrema, J.
    • Shao, Y.
    • Lunetta, R. S.
    • Lyon, J. G.
  • Source: International Journal of Applied Earth Observation and Geoinformation
  • Volume: 12
  • Issue: 2
  • Year: 2010
  • Summary: The Moderate Resolution Imaging Spectrometer (MODIS) Normalized Difference Vegetation Index (NDVI) 16-day composite data product (MOD12Q) was used to develop annual cropland and crop-specific map products (corn, soybeans, and wheat) for the Laurentian Great Lakes Basin (GLB). The crop area distributions and changes in crop rotations were characterized by comparing annual crop map products for 2005, 2006, and 2007. The total acreages for corn and soybeans were relatively balanced for calendar years 2005 (31,462 km(2) and 31,283 km(2), respectively) and 2006 (30,766 km(2) and 30,972 km(2), respectively). Conversely, corn acreage increased approximately 21% from 2006 to 2007, while soybean and wheat acreage decreased approximately 9% and 21%, respectively. Two-year crop rotational change analyses were conducted for the 2005-2006 and 2006-2007 time periods. The large increase in corn acreages for 2007 introduced crop rotation changes across the GLB. Compared to 2005-2006, crop rotation patterns for 2006-2007 resulted in increased corn-corn, soybean-corn, and wheat-corn rotations. The increased corn acreages could have potential negative impacts on nutrient loadings, pesticide exposures, and sediment-mediated habitat degradation. Increased in US corn acreages in 2007 were related to new biofuel mandates, while Canadian increases were attributed to higher world-wide corn prices. Additional study is needed to determine the potential impacts of increases in corn-based ethanol agricultural production on watershed ecosystems and receiving waters. Published by Elsevier B.V.