• Authors:
    • Martins, M.
    • Marcelo, A.
    • Fernandes, C.
    • Seben, G.
    • Cora, J.
  • Source: Proceedings of the 19th World Congress of Soil Science: Soil solutions for a changing world, Brisbane, Australia, 1-6 August 2010. Symposium 3.2.1 Highland agriculture and conservation of soil and water
  • Year: 2010
  • Summary: The no-tillage system is utilized in approximately 100 million hectares in the world. However, this system still needs to be better adapted to tropical regions, with warm and dry winters. The adaptation of no-tillage system in tropical regions depends on the suitable choice of summer and winter crops which should contribute to improvement of soil properties and soil productive capacity. The aim of the present study was to determine the effect of crop sequences on soil physical attributes of a Rhodic Eutrudox under no-tillage system. The treatments consisted of the combination of tree summer crop sequences and seven winter crop sequences. The summer crop sequences were: maize monocrop ( Zea mays L.), soybean monocrop ( Glycine max (L.) Merrill), and soybean/maize rotation. The winter crops were: maize, sunflower ( Helianthus annuus L.), radish ( Raphanus sativus L.), pearl millet ( Pennisetum americanum (L.) Leeke), pigeon pea ( Cajanus cajan (L.) Millsp), grain sorghum ( Sorghum bicolor (L.) Moench) and sunn hemp ( Crotalaria juncea L.). The experiment began in September 2002. Lower bulk density and high soil tensile strength were found in the soybean/maize rotation after sorghum and sunn hemp. Sorghum and sunn hemp provided the highest waterstability of soil aggregates. Millet, sorghum, maize and sunn hemp provided the highest mean aggregate diameter. The water-stability of soil aggregates and mean aggregate diameter showed positive correlation with soil tensile strength. There were no differences among effects of the summer and winter crops on the soil organic matter. In general, better soil physical conditions were found in the soybean/maize crop rotation and after sunn hemp, sorghum and millet.
  • Authors:
    • Pierzynski, G.
    • Tuppad, P.
    • Janssen, K.
    • Maski, D.
    • Douglas-Mankin, K.
  • Source: Transactions of the ASABE
  • Volume: 53
  • Issue: 5
  • Year: 2010
  • Summary: Cropland best management practice recommendations often combine tillage and nutrient application improvements to reduce nutrient losses with surface runoff. This study used the Soil and Water Assessment Tool (SWAT) model to evaluate nutrient runoff yields from conventional-till and no-till management practices with surface and deep-banded fertilizer application in a sorghum-soybean rotation. The model was calibrated for three field plots (0.39 to 1.46 ha) with different combinations of practices and validated for three field plots (0.40 to 0.56 ha) during 2001 to 2004. Daily performance of the calibrated SWAT model in simulating total N for all treatments was satisfactory for median-based Nash-Sutcliffe model efficiency (E f* of 0.54 to 0.64), good to very good for percent bias (PBIAS of 31% to 7%), and satisfactory to good for median-based root mean square error to observations standard deviation ratio (RSR* of 0.72 to 0.62). Performance was slightly lower and more variable for total P calibration (E f* of 0.42 to 0.62, PBIAS of -48% to 2%, and RSR* of 0.76 to 0.62). Monthly statistics improved for total P runoff yield compared to daily performance, but changed little for total N runoff yields, probably due to the stronger influence of outliers in the N data. Based on validation results, SWAT was more robust in simulating total N runoff yields from the treatment with less soil disturbance (NT/SB) and total P for the two treatments with more soil disturbance (NT/DB and TILL). A major concern was that SWAT predicted greater annual average total N runoff yields for no-till treatments than for tilled treatments, which was contrary to measured values at the study site. This reinforces a fundamental research issue that tillage system effects on nutrient losses are still very much uncertain and thus may not be properly modeled. The SWAT model generally underpredicted monthly total N yields for all treatments in the higher-precipitation months of May and June and overpredicted total N and total P yields from September through November. Calibration for N and P resulted in identical calibration parameters for NPERCO (1.0), RSDCO (0.05), BIOMIX (0.2), PPERCO (10), PHOSKD (175), and UBP (50) regardless of tillage practice or fertilizer application method. Together with results that calibrated parameters for runoff (CN, K sat, AWC) and erosion (C min) differed among the treatments, this study found that differences in nutrient yields among tillage and fertilizer management may be adequately modeled with SWAT by calibrating runoff and sediment yields only, and that further calibration of nutrient parameters may not improve model results.
  • Authors:
    • Rosolem, C.
    • Garcia, R.
  • Source: PESQUISA AGROPECUARIA BRASILEIRA
  • Volume: 45
  • Issue: 12
  • Year: 2010
  • Summary: The objective of this work was to evaluate the influence of fall-winter and spring crops, cultivated under no-tillage system, on the aggregates and organic matter of a Rhodic Ferralsol. The experiment was performed in the 2006/2007, 2007/2008 and 2008/2009 growing seasons. Congo signal grass ( Urochloa ruziziensis), grain sorghum ( Sorghum bicolor) and sorghum mixed with brachiaria were cropped in the fall-winter to consist the main plots. In the spring, millet ( Pennisetum glaucum), 'Cober Crop' ( Sorghum bicolor * Sorghum sudanense) and Indian hemp ( Crotalaria juncea) were cultivated as subplots as well as a fallow treatment. Soybean was cropped in the summer, totaling 12 treatments. Cover crop dry matter and root growth were evaluated in 2006 and 2008. Soil samples were taken from 0-5 and 5-10 cm depths, after spring cover crops managing, in the first and third years. The mean weight diameter, geometric mean diameter, aggregate stability index, aggregates larger than 2 mm, organic matter and total organic carbon levels were evaluated in the samples of the third year. Millet and 'Cober Crop' showed higher dry matter production and root growth. The soil aggregation was improved by cover crop rotations before the summer growing season. The cultivation of 'Cober Crop' and millet influenced the macroaggregate formation in the superficial layers.
  • Authors:
    • Sweeney, D.
    • Kelley, K.
  • Source: Crop Management
  • Issue: July
  • Year: 2010
  • Summary: Field studies were conducted from 1996 through 2006 in southeastern Kansas to evaluate the influence of previous crop [corn, Zea mays L.; grain sorghum, Sorghum bicolor (L.); and soybean, Glycine max (L.) Merr.] and tillage system (conventional versus no-till) on grain yield of hard red winter wheat ( Triticum aestivum L.) and double-crop soybean in a 2-year rotation. On average, wheat yield was greater following corn or soybean than following grain sorghum. Yield of double-crop soybean averaged 20% greater when wheat followed corn or grain sorghum than when wheat followed full-season soybean. Tillage system influenced grain yield of double-crop soybean more than it influenced wheat yield. Double-crop soybean yield often was greater for continuous no-till than for conventional or one-time no-till per cropping cycle. Soil analyses at the end of the study showed that total C and total N were greater for no-till than for conventional in the 0- to 3-inch depth, but total C and total N were greater for conventional than no-till in the 3- to 6-inch depth. In the multi-cropping systems of the eastern Great Plains, both crop rotation and tillage system can significantly influence grain yield and selected soil properties.
  • Authors:
    • Tittonell, P.
    • Leveque, J.
    • Sogbedji, J.
    • Guibert, H.
    • Kintche, K.
  • Source: Plant and Soil
  • Volume: 336
  • Issue: 1/2
  • Year: 2010
  • Summary: Soil degradation in the savannah-derived agroecosystems of West Africa is often associated with rapid depletion of organic carbon stocks in soils of coarse texture. Field experiments were conducted over a period of more than 30 years at two sites in semiarid Togo to test the impact of agricultural management practices on soil C stocks and crop productivity. The resulting datasets were analysed using dynamic simulation models of varying complexity, to study the impact of crop rotation, fertiliser use and crop residue management on soil C dynamics. The models were then used to calculate the size of the annual C inputs necessary to restore C stocks to thresholds that would allow positive crop responses to fertilisers under continuous cultivation. Yields of all crops declined over the 30 years irrespective of crop rotation, fertiliser use or crop residue management. Both seed-cotton and cereal grain yields with fertiliser fluctuated around 1 t ha -1 after 20 years. Rotations that included early maturing sorghum varieties provided larger C inputs to the soil through residue biomass; around 2.5 t C ha -1year -1. Soil C stocks, originally of 15 t ha -1 after woodland clearance, decreased by around 3 t ha -1 at both sites and for virtually all treatments, reaching lower equilibrium levels after 5-10 years of cultivation. Soil C dynamics were well described with a two-pool SOM model running on an annual time step, with parameter values of 0.25 for the fraction of resistant plant material (K 1), 0.15-0.20 for the decomposition rate of labile soil C (K 2) and 8-10 t C ha -1 for the fraction of stable C in the soil. Simulated addition of organic matter to the soil 30 years after woodland clearance indicated that additions of 3 t C ha -1year -1 for 15-20 years would be necessary to build 'threshold' soil C stocks of around 13 t ha -1, compatible with positive crop response to fertiliser. The simulated soil C increases of 0.5 to 1.6% per year are comparable with results from long-term experiments in the region. However, the amounts of organic matter necessary to build these soil C stocks are not readily available to resource-poor farmers. These experimental results question the assumption that crop residue removal and lack of fertiliser input are responsible for soil C decline in these soils. Even when residues were incorporated and fertilisers used at high rates, crop C inputs were insufficient to compensate for C losses from these sandy soils under continuous cultivation.
  • Authors:
    • Zombre, P.
    • Dakuo, D.
    • Traore, O.
    • Koulibaly, B.
    • Bonde, D.
  • Source: Tropicultura
  • Volume: 28
  • Issue: 3
  • Year: 2010
  • Summary: The effect of crop residues management on crops yields and nutrients balances in a cotton-cereals cropping system was studied in a long-term experiment carried out from 1982 to 2006. The experimental design was a simple nonrandomized blocks comparing extensive management of crops residues (T1), semiintensive management of crops residues (T2) and intensive management of crops residues (T3). Crops yields, soil chemical properties and mineral balances were measured. Results showed that after 25 years, soil carbon contents decrease was respectively 44%, 15% and 13%, with an extensive, semi-intensive and intensive management of crops residues. Total phosphorus decrease was 25% in all the treatments. Exchangeable Ca and Mg declined from 2.43 to 1.37 cmol+ kg -1 and 0.9 to 0.29 cmol+ kg -1 respectively while the Sum of Exchangeable Bases declined from 3.79 to 1.79 cmol+ kg -1. Recycling crops residues to compost and manure increased cotton yields from 13 to 22%, maize yields from 45 to 60%, and sorghum yields from 19 to 44%. Mineral balance in N, P, K and S was improved after 25 years of continuous cultivation while using compost or manure. At the same time, the decline of soil properties was due to nutrients losses which need to be evaluated. This study recommends integrated crops residues management and the use of rock phosphate to improve sustainability in cottoncereals cropping systems.
  • 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:
    • Gamzatov, I.
    • Muslimov, M.
  • Source: Kormoproizvodstvo
  • Issue: 12
  • Year: 2010
  • Summary: Continuous green fodder conveyor production system allows quality fodder supply during the grazing season. Field trials were conducted in Dagestan, the North Caucasus, Russia, with Red Steppe cattle. Data are tabulated on sowing dates and period of use of fodder crops, i.e. natural pastures, winter rape, winter rye + winter vetch, pea-oat + vetch-oat, regrowth of perennial grasses after hay cutting, Sudan grass, maize and maize + Sudan grass, sorghum, regrowth of Sudan grass and sorghum, maize sown after winter cereals grown for green fodder, maize and sorghum grown for silage for additional feed rations, winter rye after pea + oat, squash, pumpkin, fodder watermelon and fodder beet, and regrowth of natural pastures and meadows. The importance of natural pastures and drought resistant plants, such as sorghum crops, for production of high yield of fodder in dry conditions of Dagestan is considered.
  • 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:
    • 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.