• Authors:
    • Verma, S.
    • Ranade, D.
  • Source: Soybean Research
  • Volume: 5
  • Year: 2007
  • Summary: Studies conducted between 2003 and 2005 on black soils of Malwa region brought out that deep tillage plays a vital role in increasing the productivity of the crops through reduced infestation of weeds and increased water retention capacity of soil consequent upon improvement in its physical environment as indicated by lower values in bulk density of soil. This not only led to increasing productivity of soybean but also made the planting of rabi crops feasible without pre-sowing irrigation. The studies further revealed that the waste land reclaimed by spreading excavated soil from tank can immediately be brought under cultivation for soybean based cropping system. Successful raising of rainfed soybean ( kharif) followed by gram ( rabi) has been demonstrated on such reclaimed land.
  • Authors:
    • Avila, A.
    • Spera, S.
    • Tomm, G.
    • Santos, H.
  • Source: Bragantia
  • Volume: 66
  • Issue: 2
  • Year: 2007
  • Summary: The effects of soil management systems and crop rotations were assessed from 1997 to 2003, in Passo Fundo, Rio Grande do Sul State, Brazil. Four soil management systems (no-tillage, minimum tillage, conventional tillage using disc plough, and conventional tillage using mouldboard plough) and three crop rotation systems (system I (wheat/soyabean), system II (wheat/soyabean and common vetch/maize or sorghum), and system III (wheat/soyabean, common vetch/maize or sorghum and white oats/soyabean)) were compared. The main plot consisted of soil management systems, while the split-plots consisted of crop rotation systems. Energy conversion (energy available/energy consumed) and balance (energy available-energy consumed) during the seven-year period is presented. No-tillage resulted in higher energy conversion and balance (72.44 and 190 766 MJ/ha) than minimum tillage (64.06 and 167 349 MJ/ha), conventional tillage using disc plough (54.35 and 134 982 MJ/ha), and conventional tillage using mouldboard (52.02 and 128 159 MJ/ha), respectively. Wheat in crop rotations presented higher energy efficiency than that in monoculture. Maize had the highest energy efficiency among the crops.
  • Authors:
    • Singh, K.
    • Nandita, G.
    • Sonu, S.
  • Source: Experimental Agriculture
  • Volume: 43
  • Issue: 2
  • Year: 2007
  • Summary: A two-year study was undertaken in a tropical dryland agro-ecosystem to evaluate the effect of the application of soil amendments with contrasting chemical natures on crop productivity, grain yield, N-uptake and N-use efficiencies. The treatments involved the addition of equivalent amounts of N (80 kg N ha -1) through chemical fertilizer and three organic inputs at the beginning of the annual cycle: Sesbania aculeata shoots (high quality, C/N 16), wheat straw (low quality, C/N 82) and Sesbania+wheat straw (high and low quality combined, C/N 47), together with a control treatment. Test crops consisted of an annual sequence of rice and barley, sown in the rainy and winter seasons, respectively. Fertilizer and Sesbania inputs resulted in higher total net productivity (TNP) for the rice crop (47% and 32% increases over the control, respectively) than the combined (+28%) and wheat straw treatments (+10%). During the succeeding barley crop, maximum TNP was recorded in the Sesbania+wheat straw treatment (+52%), followed by wheat straw (+43%), fertilizer (+19%) and Sesbania (+17%). The TNP and grain yields of both crops added together were higher in Sesbania+wheat straw and fertilizer treatments compared to a single applications of either Sesbania or wheat straw. The Sesbania+wheat straw and fertilizer treatments resulted in more efficient utilization of N compared to the other treatments. Crop roots played a pivotal role in N-recovery from the soil and their N concentrations differed significantly ( p
  • Authors:
    • Singh, K.
    • Nandita, G.
    • Sonu, S.
  • Source: Applied Soil Ecology
  • Volume: 36
  • Issue: 2/3
  • Year: 2007
  • Summary: A 2-year field experiment was conducted to evaluate the impact of management practices involving manipulation of quantity and quality of exogenous inputs on soil N-mineralization rate, N availability and microbial biomass in a rice-barley rotation in a tropical dryland agroecosystem. At the beginning of each annual cycle an equivalent amount of N was added through chemical fertilizer and three organic inputs: Sesbania shoot (high quality resource, C/N 16, lignin/N 3.2, polyphenol+lignin/N 4.2), wheat straw (low quality resource, C/N 82, lignin/N 34.8, polyphenol+lignin/N 36.8) and Sesbania+wheat straw (high and low quality resources mixed). The N-mineralization rate was dominated by ammonification in this dryland agroecosystem. N-mineralization exhibited a distinct seasonal pattern, decreasing from the rice period through the summer fallow period, except in Sesbania+wheat straw and wheat straw treatments which showed a slight increase during the early stages of barley period. The rate of N-mineralization showed a significant relationship with soil moisture and microbial biomass N. During the rice period, N-mineralization rate and available-N was highest in the fertilizer treatment followed by Sesbania > Sesbania+wheat straw > wheat straw. During the barley period, highest N-mineralization rate and available-N was observed in Sesbania+wheat straw followed by wheat straw > Sesbania > fertilizer. Adding Sesbania+wheat straw resulted in consistently higher levels of microbial biomass N, N-mineralization rate and available-N through the annual cycle compared to single application of Sesbania and wheat straw, indicating synergy between the two inputs, favoring more efficient utilization of N. It is suggested that mixed application of high and low quality resources can modulate N release, resulting in relatively higher synchronization which can help in minimizing N loss from agroecosystem.
  • Authors:
    • Singh, K.
    • Nandita, G.
    • Sonu, S.
  • Source: Soil Biology & Biochemistry
  • Volume: 39
  • Issue: 1
  • Year: 2007
  • Summary: The influence of exogenous organic inputs on soil microbial biomass dynamics and crop root biomass was studied through two annual cycles in rice-barley rotation in a tropical dryland agroecosystem. The treatments involved addition of equivalent amount of N (80 kg N ha -1) through chemical fertilizer and three organic inputs at the beginning of each annual cycle: Sesbania shoot (high-quality resource, C:N 16, lignin:N 3.2, polyphenol+lignin:N 4.2), wheat straw (low-quality resource, C:N 82, lignin:N 34.8, polyphenol+lignin:N 36.8) and Sesbania+wheat straw (high-and low-quality resources combined), besides control. The decomposition rates of various inputs and crop roots were determined in field conditions by mass loss method. Sesbania (decay constant, k=0.028) decomposed much faster than wheat straw ( k=0.0025); decomposition rate of Sesbania+wheat straw was twice as fast compared to wheat straw. On average, soil microbial biomass levels were: rice period, Sesbania ≥ Sesbania+wheat straw > wheat straw ≥ fertilizer; barley period, Sesbania+wheat straw > Sesbania ≥ wheat straw ≥ fertilizer; summer fallow, Sesbania+wheat straw > Sesbania > wheat straw ≥ fertilizer. Soil microbial biomass increased through rice and barley crop periods to summer fallow; however, in Sesbania shoot application a strong peak was obtained during rice crop period. In both crops soil microbial biomass C and N decreased distinctly from seedling to grain-forming stages, and then increased to the maximum at crop maturity. Crop roots, however, showed reverse trend through the cropping period, suggesting strong competition between microbial biomass and crop roots for available nutrients. It is concluded that both resource quality and crop roots had distinct effect on soil microbial biomass and combined application of Sesbania shoot and wheat straw was most effective in sustained build up of microbial biomass through the annual cycle.
  • Authors:
    • Rice, C. W.
    • Boyles, S. B.
    • Williams, J. R.
    • Pendell, D. L.
    • Nelson, R. G.
  • Source: Review of Agricultural Economics
  • Volume: 29
  • Issue: 2
  • Year: 2007
  • Summary: This study examines the economic potential of using either no-tillage or conventional tillage with either commercial nitrogen or cattle manure to sequester soil in continuous corn production. This research uses stochastic efficiency with respect to a function to determine the preferred production systems under various risk preferences and utility-weighted certainty equivalent risk premiums to determine the carbon credit values needed to motivate adoption of systems, which sequester higher levels of carbon. The results indicate that no-tillage and cattle manure increase carbon sequestration. Carbon credits or government program incentives are not required to entice risk-averse managers to use no-tillage, but are required to encourage manure use as a means of sequestering additional carbon even at historically high nitrogen prices. New environmental rules for confined animal feeding operations may increase the demand for land to apply manure as a primary nutrient source and participation in the Environmental Quality Incentives Program, Conservation Security Program, and a carbon credit market to obtain payments to offset some or all of the costs of manure application.
  • Authors:
    • Burmester, C.
    • Reeves, D. W.
    • Motta, A. C. V.
    • Feng, Y.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 38
  • Issue: 19-20
  • Year: 2007
  • Summary: The impact of conservation tillage, crop rotation, and cover cropping on soil-quality indicators was evaluated in a long-term experiment for cotton. Compared to conventional-tillage cotton, other treatments had 3.4 to 7.7 Mg ha(-1) more carbon (C) over all soil depths. The particulate organic matter C (POMc) accounts for 29 to 48 and 16 to 22% of soil organic C (SOC) for the 0- to 3- and 3- to 6-cm depths, respectively. Tillage had a strongth influence on POMc within the 0- to 3-cm depth, but cropping intensity and cover crop did not affect POW A large stratification for microbial biomass was observed varing from 221 to 434 and 63 to 110 mg kg(-1) within depth of 0-3 and 12-24 cm respectively. The microbial biomass is a more sensitive indicator (compared to SOC) of management impacts, showing clear effect of tillage, rotation, and cropping intensity. The no-tillage cotton double-cropped wheat/soybean system that combined high cropping intensity and crop rotation provided the best soil quality.
  • Authors:
    • McGawley, E. C.
    • Pontif, M. J.
  • Source: Nematropica
  • Volume: 37
  • Issue: 2
  • Year: 2007
  • Summary: Reniform nematodes that parasitize cotton and soybean can also reproduce on a wide spectrum of weed species, thereby maintaining nematode populations during the off-season. Microplot studies were conducted to evaluate the effects of three endemic weed species, morningglory ( Ipomoea lacunosa), hemp sesbania ( Sesbania exaltata), and johnsongrass ( Sorghum halepense), on reproduction of the reniform nematode, Rotylenchulus reniformison cotton (LA. 887) and soybean (Pioneer 96B21). Over two years of microplot trials, the co-culture of cotton with any of the three weed species suppressed numbers of reniform nematode juveniles in soil significantly. When grown singly, reproductive values of R. reniformis after 60 days on cotton averaged 69.0, while those for morningglory, hemp sesbania, and johnsongrass averaged 42.0, 23.5, and 18.0, respectively. Reproductive values on cotton co-cultured with morningglory averaged 38.5. Those for the cotton-hemp sesbania and cotton-johnsongrass combinations averaged 23.5 and 26.0, respectively. Nematode reproduction on soybean alone, and co-cultured with each of the three weeds, reduced reproduction of reniform nematode only in the presence of johnsongrass in two trials. Data from two subsequent 45-day duration greenhouse experiments conducted with cotton and leachates from each of the three weed species support the hypothesis that suppression of reniform nematode reproduction likely resulted from the secretion of allelopathic compounds by weed roots.
  • Authors:
    • Kumar, S.
    • Bishnoi, U. R.
    • Cebert, E.
  • Source: American-Eurasian Journal of Sustainable Agriculture
  • Volume: 1
  • Issue: 1
  • Year: 2007
  • Summary: In southeastern USA, winter wheat as a double crop has proved to be economically profitable and beneficial for soil management to the farmers. Winter rape ( Brassica napus) also has similar potential but its suitability as a double crop and in rotation with summer crops has not been evaluated. Therefore, performance of winter rape in rotation and as a double crop with soyabean, maize, sorghum, and cotton were evaluated for two years. Results showed that the effect of rotation on plant density during both years was significant. Rotational effects on number of pods per plant were non-significant than rape grown as fallow in 2003 but not in 2004. Rape grown after soyabean produced significantly higher seed yield in 2003 (2739 kg ha -1) and 2004 (3129 kg ha -1) than after other crops except maize (2938 kg ha -1) and fallow (2876 kg ha -1). Planting rape after fallow gave significantly the lowest economic returns during both years. Rape gave significantly higher economic returns when planted after maize ($1237) and cotton ($1169) than soyabean-rape and sorghum-rape and fallow-rape rotations in 2003. Similarly, cotton-rape ($1442) and soyabean-rape ($1393) gave significantly higher economic returns per hectare than maize-rape, sorghum-rape, and fallow-rape cropping systems.
  • Authors:
    • Schomberg, H. H.
    • Franzluebbers, A. J.
    • Endale, D. M.
  • Source: Soil & Tillage Research
  • Volume: 96
  • Issue: 1/2
  • Year: 2007
  • Summary: The type of conservation-tillage management employed could impact surface-soil properties, which could subsequently affect relationships between soil and water quality, as well as with soil C sequestration and greenhouse gas emissions. We determined soil bulk density, organic C and N fractions, plant-available N, and extractable P on Typic Kanhapludults throughout a 7-year period, in which four long-term (>10 years), no-tillage (NT) water catchments (1.3-2.7 ha each) were divided into two treatments: (1) continuation of NT and (2) paraplowing (PP) in autumn (a form of non-inversion deep ripping) with NT planting. Both summer [cotton ( Gossypium hirsutum L.), maize ( Zea mays L.), sorghum ( Sorghum bicolor L. Moench), soybean ( Glycine max L. Merr.)] and winter [wheat ( Triticum aestivum L.), barley ( Hordeum vulgare L.), rye ( Secale cereale L.), crimson clover ( Trifolium incarnatum L.)] crops were NT planted throughout the study under each management system. Soil bulk density was reduced with PP compared with NT by as much as 0.15 Mg m -3, but the extent of reduction was inversely related to the time lag between PP operation and sampling event. Soil organic C became significantly enriched with time during this study under NT (0.49 Mg C ha -1 year -1), but not under PP, in which poultry litter was applied equivalent to 5.7 Mg ha -1 year -1 to all water catchments. Soil maintained a highly stratified depth distribution of organic C and N fractions and extractable P under both NT and PP. Inability to perform the PP operation in the last year of this study resulted in rapid convergence of soil bulk density between tillage systems, suggesting that PP had