• Authors:
    • Feltran, J. C.
    • De Castro, C. M.
    • De Almeida, D. L.
    • Valle, Teresa L.
    • Duarte Ribeiro, R. De L.
    • Pries Devide, A. C.
  • Source: Bragantia
  • Volume: 68
  • Issue: 1
  • Year: 2009
  • Summary: Organic systems were evaluated for cassava root production directed to human comsumption in natura, at Seropedica-RJ. Treatments consisted of: cassava ('IAC 576-70') in single cropping and its intercropping with corn ('Eldorado'), cowpea ('Maua') or corn plus cowpea. The organic management was standardized and the experimental area was submitted to artificial irrigation during the period of stay of maize in the system. "Green" (immature) corn ears were harvested at the "point" required for fresh marketing and the shoot placed on the ground. The cowpea was included to function as green manure being Cut at flowering with residues left on the soil Surface. Corn and cowpea were sown between cassava rows, in an alternate design, following the first weeding of the main crop (cassava). The cultivar IAC 576-70 showed suitability with respect to organic management, yielding approximatelu 31 Mg ha(-1) of marketable roots. No significant differences were detected between cassava single cropping and any of the intercropping tested systems. Thus, corn crop has considerable potential for additional income to the growers. Yield of 'Eldorado' corn averaged 18.125 ears ha(-1) correspponding to 5,1 Mg ha-1. Residues coming from cowpea cutting brought about an input close to 12 Mg ha(-1), which meant an expressive contribution in nutrient elements, especially nitrogen (about 44 kg N ha(-1)). The legume crop, in addition, completely covered cassava inter-rows demonstrating its potential for controlling erosion and weeds. The triple intercropping becomes advantageous considering that corn harvesting would justify irrigation and that inclusion of cowpea meant benefitial effects to the system and did not interfere on cassava yield.
  • Authors:
    • Prakash, V.
    • Pandey, S. C.
    • Kundu, S.
    • Bhattacharyya, R.
    • Srivastva, A. K.
    • Gupta, H. S.
  • Source: Soil Research
  • Volume: 47
  • Issue: 6
  • Year: 2009
  • Summary: We analysed results of a long-term experiments, initiated in 1973 on a sandy loam soil under rainfed condition and in 1995-96 on a silty clay loam soil under irrigated condition, to determine the influence of using different combinations of mineral fertiliser (NPK) and fertiliser+farmyard manure (FYM) at 10 Mg/ha on soil organic carbon (SOC) content and its changes in the 0-0.45 m soil depth. Fertilisation always caused a net gain in SOC stock. Such gain was positively proportional to the amount of C incorporated into the soils. Concentration of SOC in the 0-0.45 m depth increased by 44% in NPK+FYM treated plots compared with NPK (44.4 Mg C/ha) after 32 years under rainfed condition and by 14% in the NPK+FYM treated plots compared with NPK (41.76 Mg C/ha) after 9 years under irrigation. Mean (across treatments) total C added under the rainfed and irrigated systems was 2.67 and 3.03 Mg/ha.year, respectively. It was estimated that ~20 and 25% of the gross C input contributed towards the increase in SOC content under the rainfed and irrigated systems, respectively. Carbon loss from native soil organic matter (SOM) averaged ~61 and 261 kg C/ha.year under the rainfed and irrigated systems, respectively. Furthermore, mean stabilisation of added C in the plots under the rainfed condition (~16%) was higher than that (~13%) observed under the irrigated condition. Conversion of total added C to SOC was similar in the NPK and NPK+FYM treated plots under both growing conditions. In the NPK+FYM plots, ~38 and 29% of the C added through FYM was accounted for in the form of total SOC under the rainfed and irrigated conditions, respectively. The estimated quantity of biomass C required to maintain equilibrium SOM content under the rainfed and irrigated systems was 0.29 and 1.08 Mg/ha.year. The total annual C input by the soybean-wheat rotation in the unfertilised control plots under rainfed condition was 0.87 Mg/ha.year and with N fertiliser only under the irrigated condition was 1.75 Mg/ha.year. Thus, SOC augmentation under long-term soybean-wheat cropping was due to higher annual C input than the required amount to maintain equilibrium SOM content. Although FYM addition along with NPK improved total SOC stock and carbon sequestration potential, it did not encourage the stabilisation rate of added C. Hence, C stabilisation that takes into account the total C added in the system is a better indicator of assessing SOC sequestration. In summary, mineral fertilisation improved C sequestration capacity of soybean-wheat system in the Indian Himalayas and manure addition along with mineral fertilisers further improved it.
  • Authors:
    • Raper, R. L.
    • Reddy, K. C.
    • Nyakatawa, E. Z.
    • Reddy, S. S.
    • Reeves, D. W.
    • Lemunyon, J. L.
  • Source: Field Crops Research
  • Volume: 114
  • Issue: 2
  • Year: 2009
  • Summary: Long-term field experiments are needed to fully realize positive and negative impacts of conservation tillage and poultry litter application. A study was initiated on a Decatur silt loam soil at the Tennessee Valley Research and Extension Center, Belle Mina, AL, USA in 1996 to evaluate cotton (Gossypium hirsutum L.) performance with long-term poultry litter (PL) application under different tillages and to Study the build up of phosphorus (P) With application of PL. Treatments include incomplete factorial combinations of three tillage systems [conventional till (CT), mulch till (MT), and no-till (NT)], two cropping systems [cotton-fallow and cotton-winter rye (Secale cereale L.)], and two nitrogen sources and rates [100 kg N ha(-1) from ammonium nitrate (AN), and 100 and 200 kg N ha(-1) from poultry litter (PL)]. Cotton was rotated with corn (Zea mays L.) every third year. Results from 2003 to 2008 showed that all tillages gave similar cotton lint yields with AN at 100 kg N ha(-1). Application of PL at 100 kg N ha(-1) in NT plots resulted in 12 and 11% yield reductions compared to that of CT and MT, respectively. However, NT plots with higher quantity of PL (200 kg N ha(-1)) gave similar yields to CT and MT at 100 kg N ha(-1). During corn years, higher residual fertility of PL, in terms of grain yields, was observed in NT plots compared to CT and MT. Long-term PL application (100 kg N ha(-1) year(-1)) helped to maintain original soil pH in CT and MT while AN application decreased soil pH. In NT plots, PL at 100 kg N ha(-1) was not sufficient to maintain original soil pH, but 200 kg N ha(-1) maintained original pH. Although not-significant, elevated P levels were observed in all tillages compared to original P levels which indicates possibility of P build up in future with further application of PL. Application of PL at double rate (200 kg N ha(-1)) in NT plots resulted in significant build up of P. Results indicate that NT gives similar yields to CT when received AN. but needs higher rate of PL application to achieve similar yields to CT. (C) 2009 Elsevier B,V. All rights reserved.
  • Authors:
    • Salado-Navarro, L. R.
    • Sinclair, T. R.
  • Source: Agricultural Systems
  • Volume: 102
  • Issue: 1/3
  • Year: 2009
  • Summary: Cropping schemes have developed in east-central Argentina for rainfed soybean (Glycine max Merr.) production that invariably employ no-tillage management. Often these schemes include growing soybean in a sequence of crops including wheat ( Triticum aestivum L.) and maize ( Zea mays L.). The full impact of various rotation schemes on soil water balance through a sequence of seasons has not been explored, although the value of these rotations has been studied experimentally. The objective of this work was to investigate through simulations, potential differences in temporal soil water status among rotations over five years. In this study, mechanistic models of soybean (Soy), maize (Maz), and wheat (Wht) were linked over a five-years period at Marcos Juarez, Argentina to simulate soil water status, crop growth, and yield of four no-till rotations (Soy/Soy, Soy/Wht, Soy/Maz, and Soy/Maz/Wht). Published data on sowing dates and initial soil water contents in the first year from a no-till rotation experiment were used as inputs to the model. After the first year, soil water status output from the model was used to initiate the next crop simulation in the sequence. The results of these simulations indicated a positive impact on soil water balance resulting from crop residue on the soil surface under no-till management. Continuous soybean and the two-year soybean/maize rotation did not efficiently use the available water from rainfall. Residue from maize was simulated to be especially effective in suppressing soil evaporation. Thus, the Soy/Maz simulation results indicated that this rotation resulted in enhanced soil water retention, increased deep water percolation, and increased soybean yields compared with continuous soybean crops. The simulated results matched well with experimental observations. The three-crop rotation of Soy/Maz/Wht did not increase simulated soybean yields, but the additional water retained as a result of decreased soil evaporation resulting from the maize residue allowed the addition of a wheat crop in this two-year rotation. Simulated soybean yields were poorly correlated with both the amount of soil water at sowing and the rainfall during the cropping period. These results highlight the importance of temporal distribution of rainfall on final yield. These models proved a valuable tool for assessing the consequences of various rotation schemes now being employed in Argentina on temporal soil water status, and ultimately crop yield.
  • Authors:
    • Ciesiolka, C. A. A.
    • Ghadiri, H.
    • Yu, B.
    • Sanjari, G.
    • Rose, C. W.
  • Source: Soil Research
  • Volume: 47
  • Issue: 8
  • Year: 2009
  • Summary: The time-controlled rotational grazing (TC grazing) has become popular in Australia and elsewhere in the world to provide graziers and ranchers with improved productivity over traditional practices. However, this grazing system, which involves short periods of intensive grazing, has raised concerns about sustainability and environmental impacts on water and soil resources, and ecosystem health generally. A runoff experiment at the catchment scale was established on the grazing property 'Currajong' in the south-east region of Queensland, Australia, to investigate the effects of continuous and TC grazing on runoff and sediment generation from 2001 to 2006. Sediment loss was reduced significantly under TC grazing compared with continuous grazing irrespective of the size of runoff events. This effect was more pronounced in the catchments with soils of gentler slopes and greater depths. The reduction in soil erosion was achieved despite the fact that the increase in ground cover under TC grazing had little effect on runoff coefficient or runoff depth. Decrease in runoff in relation to the increase in surface cover only occurred for small events, whereas for large rainfall events, runoff generated irrespective of the level of ground cover. This study showed that ground cover is a key driver in reducing sediment concentration, resulting in a significantly lower sediment loss under TC grazing. In the study area a minimum of 70% of surface cover as a threshold appeared to be needed to efficiently protect the soil surface from erosive forces of rain and runoff and to control soil erosion. The results also indicate that TC grazing has a superior capability to produce and maintain a higher level of ground cover (up to 90%) than continuous grazing (up to 65%). The long rest periods in TC grazing are seen as the major contributor to soil and pasture recovery after intensive defoliations by grazing animals, leading to an increase in above-ground organic material and thus surface cover over time.
  • Authors:
    • Fontaneli, R. S.
    • Santos, H. P. dos
    • Spera, S. T.
    • Tomm, G. O.
  • Source: Revista Brasileira de Ciência do Solo
  • Volume: 33
  • Issue: 1
  • Year: 2009
  • Summary: Soil physical characteristics were evaluated of a typical dystrophic Red Latosol (Typic Haplorthox) located in Passo Fundo, State of Rio Grande do Sul, Brazil, after ten years (1993 to 2003) under mixed production systems. The effects of production systems integrating grain production with winter annual and perennial forages under no-tillage were assessed. Five mixed cropping systems were evaluated: (i) wheat/soyabean, white oat/soyabean, and common vetch ( Vicia sativa)/maize; (ii) wheat/soyabean, white oat/soyabean, and annual forages (black oat ( Avena nuda) + common vetch)/maize; (iii) perennial cool season forages (fescue ( Festuca) + white clover ( Trifolium repens) + red clover ( T. pratense) + birdsfoot trefoil ( Lotus corniculatus)); and (iv) perennial warm season forages (bahiagrass ( Paspalum notatum) + black oat + ryegrass ( L. perenne) + white clover + red clover + birdsfoot trefoil). System V lucerne as hay crop was established in an adjacent area in 1994. Half of the areas under the systems III, IV, and V returned to system I after the summer of 1996 (southern hemisphere). The crops, both summer and winter, were grown under no-till. The treatments were arranged in a randomized complete block design, with four replications. Soil core samples were also collected in a subtropical forest fragment adjacent to the experimental area. The variations in soil bulk density, total porosity, microporosity and macroporosity due to grain production systems with forages were not severe enough to cause soil degradation. The soil bulk density in the production systems with perennial forages was lower and total porosity and macroporosity, in the 0-2 cm layer, higher than in the production systems of grain or of grain with annual forages.
  • Authors:
    • Wall, P. C.
    • Thierfelder, C.
  • Source: Soil & Tillage Research
  • Volume: 105
  • Issue: 2
  • Year: 2009
  • Summary: The adoption of conservation agriculture (CA), based on minimal soil movement, permanent soil cover with crop residues or growing plants and crop rotation has advanced rapidly in the Americas and Australia over the last three decades. One of the immediate benefits of CA in dryland agriculture is improved rainfall-use efficiency through increased water infiltration and decreased evaporation from the soil surface, with associated decreases in runoff and soil erosion. This paper focuses on the effect of CA techniques on soil moisture relations in two researcher-managed trials in Zambia and Zimbabwe. In 2005/2006 and 2006/2007, we found significantly higher water infiltration on both sites on CA fields compared to conventionally ploughed fields. At Henderson Research Station, Zimbabwe, on a sandy soil, a direct seeded CA treatments had a 49% and 45% greater infiltration rate than the conventionally tilled plots after a simulated rainfall in both seasons. At Monze Farmer Training Centre, Zambia, on a finer-textured soil, the same treatment had 57% and 87% greater infiltration rate than the conventionally tilled control treatment in both seasons. Treatments that included reduced tillage and surface residue retention had less water runoff and erosion on runoff plots at Henderson Research Station, Zimbabwe. On average, soil moisture was higher throughout the season in most CA treatments than in the conventionally tilled plots. However, the full potential of CA in mitigating drought was not evident as there was no significant drought period in either season. Results suggest that CA has the potential to increase the productivity of rainfall water and therefore reduce the risk of crop failure, as was apparent at the Monze Farmer Training Centre, Zambia, in 2005/2006 when a period of moisture stress at tassling affected CA treatments less than the conventionally tilled treatment. (C) 2009 Elsevier B.V. All rights reserved.
  • Authors:
    • Chen, P.
    • Gbur, E. E.
    • Popp, J. H.
    • Brye, K. R.
    • Verkler, T. L.
    • Amuri, N.
  • Source: Journal of Sustainable Agriculture
  • Volume: 33
  • Issue: 7
  • Year: 2009
  • Summary: Soil, water, and air quality can be positively impacted by alternative crop residue management practices that return residue to the soil. Double-crop production systems, particularly those with a grass included in the rotation, rely on successful residue management practices. Soil quality and overall soil tilth are often low in regions with a long history of intensely cultivated, row-crop production, such as in the Mississippi River Delta region of the mid-South. Therefore, the objective of this study was to evaluate the effects of alternative residue (i.e., tillage, residue burning, and residue level) and water management practices on soil properties, soybean [ Glycine max (L.) Merr.] production, and net economic returns, over two consecutive rotations in a wheat ( Triticum aestivum L.) - soybean double-crop system in the Mississippi River Δ region of eastern Arkansas. Initiated in 2001, this study reports results from years 4 and 5 of the experiment. Residue management effects were inconsistent among soil properties and years, and differences were generally agronomically non-significant. Averaged across irrigation treatments, soybean yield was unaffected by tillage, burning, and residue level either year. Within the non-irrigated treatment, conventionally tilled (CT) soybean yield was 38% greater ( p
  • Authors:
    • da S. Volk, L. B.
    • Cogo, N. P.
    • Volk, L. B. da S.
  • Source: Revista Brasileira de Ciência do Solo
  • Volume: 33
  • Issue: 5
  • Year: 2009
  • Summary: This work was accomplished with the purpose of establishing quantitative relationships between the D 50 index of the size distribution of the soil-eroded sediments, the runoff velocity, the SR index of the tillage-induced soil surface roughness, and the mean weight diameter (MWD) of the soil aggregates, in a soil submitted to different forms of management. The study was developed in the field, at the Agricultural Experimentation Station of the Federal University of Rio Grande do Sul (EEA/UFRGS), in Eldorado do Sul (RS), Brazil, by applying simulated rainfall on an Ultisol with a sandy clay loam texture in the surface layer and 0.115 m m -1 average slope steepness. This soil had been put into agricultural use by different manners (continuous and discontinued cultivation), with different crop sequences (winter and summer, grass and legume crop species, planted in rows, using no-tillage), for a 7.5 year period (starting at the original condition of native pasture). Seven erosion tests were performed in the study, each one of them at 63.5 mm h -1 rainfall intensity and 1.5 h duration, using the rotating-boom rainfall simulator and 3.5*11.0 m experimental plots. The referred erosion tests were performed in the following soil surface physical conditions: (a) non-mobilized soil, with complete and no cover by crop residues, and (b) soil successively mobilized by the passage of a light disc-harrow (five times, one at a time), with no cover. It was observed that the crop sequences provided values of the MWD index significantly different each other, which reflected in significantly different values of the SR index and, as consequence, of the runoff velocity and the D 50 index, with the sequences with none or less time of discontinued cultivation (in the last period of the research) having produced the best results. In the non-mobilized, completely mulch-covered soil, with a firm and smooth surface, the mulch of crop residues was the dominant factor either in reducing the runoff velocity or in trapping the eventually detached soil particles of larger size, which led to very small values of the D 50 index. In the non-mobilized, uncovered soil, where runoff reached its highest velocities, the size of the eroded sediments was determined by the consolidation of the soil surface and by the values of the MWD index, being the smaller for the greater values of the two last variables mentioned. Yet in the soil successively mobilized by the one at a time passage of a light disc-harrow and bare, with a loose and rough surface, the roughness of the soil surface created by tillage was the dominant factor either in reducing the runoff velocity or in trapping the detached soil particles of larger size, which increased the percentage of eroded sediments
  • Authors:
    • Zhang, M. H.
    • Zhang, L. X.
    • Zhang, J. Q.
    • Watson, C.
  • Source: Acta Agronomica Sinica
  • Volume: 35
  • Issue: 2
  • Year: 2009
  • Summary: A study was conducted in Stoneville, Mississippi, USA, under irrigated conditions to develop predictive models, using a simple and effective model technique which can allow producers to predict soyabean growth and development stages in their fields. The models were constructed using 4-year field data (1998-2001) and validated with the fifth year data (2002). Potential factors affecting stages of soyabean growth and development were considered for developing the models. Affecting factors, such as weeds, insects, diseases and drought stress, were controlled optimally to simplify the modelling procedures. In addition, stepwise regression (SR) analysis, artificial neural networks (ANN), and interpolation approaches were used to construct the models. The modelling of soyabean growth and development processes was separated into 2 distinct periods: vegetative growth stage (V-stage) and reproductive growth stage (R-stage). The models included 10 V-stages (up to V8) and 8 R-stages. In the V-stages models, PD (planting date) and mean relative time-span for planting to a particular stage were the only significant parameters, whereas in R-stage models, PD and MG (maturity group) were significant. The models obtained accurate predictions were only using PD, MG and mean relative time-span from planting to a particular stage. The ANN method provided the greatest accuracy in predicting phenological events, indicating that the ANN method can be effectively applied in crop modelling.