• Authors:
    • Silva, A.
    • Colleta, Q.
    • Matoso, S.
    • Maia, E.
    • Fiorelli-Pereira, E.
  • Source: Acta Amazonica
  • Volume: 42
  • Issue: 2
  • Year: 2012
  • Summary: The aim of this study was to assess quality indicators of a dystrophic Red Yellow Latosol (Oxisol) soil under native forest, pasture ( Brachiaria brizantha cv. marandu), conventional tillage, minimum tillage system and no till system. It was determined the soil carbon and soil nitrogen in the microbial biomass, organic carbon and total nitrogen, ratios for microbial carbon and nitrogen and relationships between organic carbon and total nitrogen (C/N tot) and between carbon and soil nitrogen in the microbial biomass (C/N mic). The soil samples were collected in the Municipality of Cerejeiras/RO, at two depths (0-10 and 10-20 cm) in five treatments with five replications. The statistical analysis consisted of outliers analysis by Chauvenet method, and assumptions of variances by Bartlett's test and Shapiro-Wilk, followed by Kruskal-Wallis, between treatments, and comparison the variables between the depths, by Mann-Whitney' test, and the group analysis using Ward's method, all at 5% probability. The results show that different uses influence the variables, except for ration C/N tot, and the microbiology variables showed themselves more sensitive to changes in land use and management than other. The conventional tillage is the treatment that has greater homogeneity among the depths. The group analysis shows that the soil under no till system, minimum tillage system and conventional tillage have similarities among well as the soil under native forest and pasture are similar.
  • Authors:
    • Weber, D.
    • Way, T. R.
    • Camargo, G. G.
    • Mirsky, S. B.
    • Ryan, M. R.
    • Curran, W. S.
    • Teasdale, J. R.
    • Maul, J.
    • Moyer, J.
    • Grantham, A. M.
    • Spargo, J. T.
  • Source: Renewable Agriculture and Food Systems
  • Volume: 27
  • Issue: 1
  • Year: 2012
  • Summary: Organic producers in the mid-Atlantic region of the USA are interested in reducing tillage, labor and time requirements for grain production. Cover crop-based, organic rotational no-till grain production is one approach to accomplish these goals. This approach is becoming more viable with advancements in a system for planting crops into cover crop residue flattened by a roller-crimper. However, inability to consistently control weeds, particularly perennial weeds, is a major constraint. Cover crop biomass can be increased by manipulating seeding rate, timing of planting and fertility to achieve levels (>8000 kg ha -1) necessary for suppressing summer annual weeds. However, while cover crops are multi-functional tools, when enhancing performance for a given function there are trade-off with other functions. While cover crop management is required for optimal system performance, integration into a crop rotation becomes a critical challenge to the overall success of the production system. Further, high levels of cover crop biomass can constrain crop establishment by reducing optimal seed placement, creating suitable habitat for seed- and seedling-feeding herbivores, and impeding placement of supplemental fertilizers. Multi-institutional and -disciplinary teams have been working in the mid-Atlantic region to address system constraints and management trade-off challenges. Here, we report on past and current research on cover crop-based organic rotational no-till grain production conducted in the mid-Atlantic region.
  • Authors:
    • Garcia, T. S.
    • Giannico, G. R.
    • Mueller-Warrant, G. W.
    • Griffith, S. M.
    • Whittaker, G. W.
    • Banowetz, G. M.
    • Pfender, W. F.
  • Source: Journal of Soil and Water Conservation
  • Volume: 67
  • Issue: 3
  • Year: 2012
  • Summary: Agricultural practices, including tillage, fertilization, and residue management, can affect surface runoff, soil erosion, and nutrient cycling. These processes, in turn, may adversely affect (1) quality of aquatic resources as habitat for amphibians, fish, and invertebrates, (2) costs of treating surface and ground water to meet drinking water standards, and (3) large-scale biogeochemistry. This study characterized the surface water sources of nitrogen (N) (total, nitrate [NO 3-], ammonium [NH 4+], and dissolved organic N) and sediment active within 40 subbasins of the Calapooia River Basin in western Oregon in monthly samples over three cropping years. The subbasins included both independent and nested drainages, with wide ranges in tree cover, agricultural practices, slopes, and soils. Sediment and N form concentrations were tested against weather and agricultural practice variables. Subbasin land use ranged from 96% forest to 100% agriculture. Average slopes varied from 1.3% to 18.9%, and surface water quality ranged from 0.5 to 43 mg L -1 (ppm) total N maxima and 29 to 249 mg L -1 suspended sediment maxima. Total N during the winter was positively related to percentage landcover of seven common agricultural crops (nongrass seed summer annuals, established seed crops of perennial ryegrass [ Lolium perenne L.], tall fescue [ Schedonorus phoenix {Scop.} Holub], orchardgrass [ Dactylis glomerata L.], clover [ Trifolium spp.], and newly planted stands of perennial ryegrass and clover) and negatively related to cover by trees and one seed crop, Italian (annual) ryegrass ( Lolium multiflorum). Results for NO 3- and total N were highly similar. Sediment concentrations were most strongly related to rainfall totals during periods of 4 and 14 days prior to sampling, with smaller effects of soil disturbance. Fourier analysis of total N over time identified four prominent groups of subbasins: those with (1) low, (2) medium, and (3) high impacts of N (up to 2, 8, and 21 mg L -1, respectively) and a strong cyclical signal peaking in December and (4) those with very high impact of N (up to 43 mg L -1) and a weak time series signal. Preponderance of N in streams draining agriculturally dominated subbasins was in the form of the NO 3- ion, implying mineralization of N that had been incorporated within plant tissue following its initial application in the spring as urea-based fertilizer. Since mineralization is driven by seasonal rainfall and temperature patterns, changes in agronomic practices designed to reduce prompt runoff of fertilizer are unlikely to achieve to more than ~24% reduction in N export to streams.
  • Authors:
    • Mukhwana, E. J.
    • Norton, U.
    • Norton, J. B.
  • Source: Soil Science Society of America Journal
  • Volume: 76
  • Issue: 2
  • Year: 2012
  • Summary: Soils typically show 20 to 40% decline in soil organic carbon (SOC) due to cultivation, most of it in the first 10 yr, but studies on SOC depletion may actually underestimate losses of the original SOC. Starting 40 to 50 yr ago, expanding use of non-inversion tillage, fertilizers, and herbicides lead to reduced disturbance and increased residue production that undoubtedly began recovery of SOC depleted during previous decades when farmers used only intensive tillage to control weeds and stimulate release of nutrients from crop residues. We measured SOC and total N stocks, density fractions, and labile C and N at 10 study sites in two rain-fed production areas in southeastern Wyoming. Systems evaluated include historic inversion-tillage-based winter wheat ( Triticum aestivum L.)-fallow with no inputs, conventional winter wheat-fallow, minimum- and no-till continuous rotations and permanent grass cover. Results were then compared to SOC under nearby native grasslands. Soils beneath historic wheat-fallow were the most depleted in SOC, with 13.8 and 17.6 Mg C ha -1 in the upper 30 cm at the two study areas, or 37% of the SOC under the two native sites. Soil OC contents were statistically similar across conventional, minimum-till, and no-till systems, ranging from 64 to 78% of native SOC levels, and significantly higher under permanent grass, with both sites having 90% of native SOC levels. Free light fraction organic carbon (LFOC) contents were lowest beneath the historic system, but increased in systems with fewer disturbances. When normalized by SOC and total N, the labile C and N pools generally increased with increasing disturbance, especially microbial biomass carbon (MBC) and dissolved organic carbon (DOC). Soil OC contents under the historic, inversion tillage system were much lower relative to native grasslands than found in other studies, which, together with other findings, suggest that SOC levels have begun to recover under the modern conventional system. Free LFOC and labile pool C and N contents indicate that conservation tillage systems in place for a relatively short time are facilitating further recovery of SOC.
  • Authors:
    • Paustian, K.
    • Ogle, S. M.
    • Swan, A.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 149
  • Year: 2012
  • Summary: The efficacy of no-till agriculture for increasing C in soils has been questioned in recent studies. This is a serious issue after many publications and reports during the last two decades have recommended no-till as a practice to mitigate greenhouse gas emissions through soil C sequestration. Our objective was to investigate the possibility that the lack of C increase in some no-till systems may be due to changes in crop productivity and subsequent C input to soils. A meta-analysis of 74 published studies was conducted to determine if crop production varies between no-till and full tillage management. The results were used to estimate the change in C input due to no-till adoption and the influence on soil organic C stocks at steady-state using the Century model. We found that crop productivity can be reduced with adoption of no-till, particularly in cooler and/or wetter climatic conditions. The influence varies, however, and crop productivity can even increase in some regions following adoption of no-till. In cases where crop production and C inputs decreased due to no-till, the potential reduction in soil organic C stocks was offset by a decrease in soil C decomposition rates, except in cases where C inputs declined by 15% or more. Challenges still remain for understanding the full impact of no-till adoption on soil organic C stocks, such as changes on C inputs in deeper subsurface horizons, the influence of variation in NT seeding methods on soil disturbance, and changes in SOM stabilization due to saturation limits in mineral soil fractions, which may further modify net C storage in soils.
  • Authors:
    • Moriasi, D.
    • Steiner, J. L.
    • Starks, P. J.
    • Saleh, A.
    • Osei, E.
  • Source: Journal of Soil and Water Conservation
  • Volume: 67
  • Issue: 2
  • Year: 2012
  • Summary: No-till farming has been identified as an important conservation practice with potential to improve soil quality and protect water quality. However, adoption of new tillage and production practices is determined by numerous economic and noneconomic factors in addition to land stewardship. The objective of this study was to assess the effects of fuel costs and crop yield on farm-level economics in no-till systems in comparison with other tillage systems for wheat production in southwestern Oklahoma. The Farm-level Economic Model, an annual economic simulation model, was used in conjunction with survey data from the Fort Cobb Reservoir Watershed in southwestern Oklahoma to determine impacts of alternative tillage practices on farm profits. Sensitivity analysis was performed using plausible ranges in diesel prices, winter wheat grain yields, herbicide costs, labor wages, and farm size. The results indicate that if winter wheat grain yields are not significantly impacted by tillage systems, no-till would be more profitable than conventional tillage or the current mix of tillage practices in the watershed. Only when there is a significant wheat yield penalty associated with no-till (10% or greater) might no-till be less profitable than conventional tillage or the status quo at reasonably high fuel prices. In general, for each 1% improvement in wheat yields under no-till relative to conventional tillage, no-till farm profits improve by US$7 ha -1 (US$3 ac -1) on farms that produce only winter wheat and an average of US$2.50 ha -1 (US$1 ac -1) if averaged across all farms in the Fort Cobb Reservoir Watershed, including those that do not produce winter wheat. The study also finds that higher diesel prices, higher labor wages, lower herbicide costs, and smaller farm sizes are all relatively advantageous to no-till.
  • Authors:
    • Penha, L.
    • Khatounian, C.
    • Fonseca, I.
  • Source: Planta Daninha
  • Volume: 30
  • Issue: 1
  • Year: 2012
  • Summary: Weed control has always been an important issue in agriculture. With the advent of no-till systems, soil erosion was reduced but herbicide use was increased. Organic no-till systems try to adjust reduced erosion to the no use of herbicides. Nevertheless, this adjustment is limited by the cost of mechanical weed control. This cost may be reduced by improved cultural weed control with cover crops mulches. In this paper we report a study on the application of compost manure on an oats winter cover crop, preceding soybean, instead of on the soybean summer crop. Treatments comprised a control without compost manure, and compost manure doses of 4 and 8 Mg ha -1 applied either on oats in winter or soybean in summer, organized in a randomized block design, with five replications. In summer, plots were split into weed-controlled or not controlled subplots. The timing of application and the manure doses did not affect the oats biomass or the soybean performance. However, in summer, without water stress, the application of manure at 8 Mg ha -1 directly on soybean has reduced weed biomass in this crop.
  • Authors:
    • Way, T. R.
    • Kleinman, P. J. A.
    • Moore, P. A.
    • Pote, D. H.
  • Source: Journal of Agricultural Science
  • Volume: 4
  • Issue: 4
  • Year: 2012
  • Summary: Poultry manure provides a rich organic nutrient source to fertilize crops and help neutralize soil acidity. However, the usual practice of broadcasting litter on the surface of pastures and other no-till systems can degrade water quality by allowing nutrients to be transported from fields in surface runoff, while much of the ammonium-N volatilizes and escapes into the atmosphere. In a previous study, we used a subsurface banding technique to move litter from the soil surface into the root zone with minimal disturbance of the grass, thatch, and soil structure; and found that nutrient losses decreased substantially. Because subsurface banding increased retention of nutrients and water in the soil, we conducted follow-up research to compare crop yield and quality from this litter application method to those from the conventional surface broadcasting method. The objectives were to determine effects of subsurface application on perennial forage yield, quality, and temporal yield distribution during the growing season. Field plots were located on silt loam soil (8-10% slopes) with well-established bermudagrass ( Cynodon dactylon L. Pers.). Poultry litter was applied (6.7 Mg ha -1, dry weight) by one of two methods: surface broadcast manually or subsurface banded using a tractor-drawn prototype implement. Each treatment was replicated three times. There were also three control plots that received no litter. Results showed that subsurface application generally increased forage quality and yield, especially in the latter part of the growing season when forage production from surface-applied litter began to decline. Under the growing conditions in this study, subsurface application increased mean forage yield by as much as 40%.
  • Authors:
    • Presley, D. R.
    • Sindelar, A. J.
    • Buckley, M. E.
    • Mengel, D. B.
  • Source: Agronomy Journal
  • Volume: 104
  • Issue: 3
  • Year: 2012
  • Summary: Grain sorghum [ Sorghum bicolor (L.) Moench] is an important grain crop grown in both highly productive and marginal areas in the central Great Plains because of the crop's ability to use the erratic precipitation observed in this region. More effective capture and storage of this limited rainfall is needed to improve the productivity and profitability of dryland agriculture. The objective of this study was to determine the effects of long-term tillage and N fertilization on soil physical and hydraulic properties after long-term continuous grain sorghum production. Variables included conventional tillage (CT) and no-till (NT) and four rates of N fertilizer. Selected soil quality indicators included soil organic carbon (SOC), bulk density (BD), wet aggregate stability (WAS), and ponded infiltration. No-till accumulated more SOC in the surface 0 to 5 cm, and was less dense at all depths than CT. When tillage was compared across all N rates, NT contained 30% greater SOC than CT at the 0 to 5 cm. Mean weight diameter (MWD) was larger with increasing N fertilization and eliminating tillage. Ponded infiltration rates were greatest for the high N fertilization rate under NT, and lowest for the 0 kg N ha -1 rate under CT. In this long-term grain sorghum system, increasing N fertilization rate and NT both positively affected soil physical properties. These improvements in hydraulic properties will aid in more effectively capturing unpredictable precipitation, and further underscore the utility of NT management practices for the central Great Plains region.
  • Authors:
    • He, J.
    • Wang, Q.
    • Rasaily, R. G.
    • Li, H.
    • Lu, C.
  • Source: African Journal of Biotechnology
  • Volume: 11
  • Issue: 4
  • Year: 2012
  • Summary: An experiment was conducted to determine the effects of tillage on soil properties in the field of maize ( Zea mays L.) and winter wheat ( Triticum aestivum L.) annual double cropping region in North China Plain. Measurements were made following six years (2005 to 2010) of three tillage treatments; no till with controlled traffic (NTCT), no till random trafficking (NTRT) and conventional tillage (CT) on a silt loam according to the USDA texture classification system soil in Daxing district, which lies in the suburb of Beijing. Long term no till with controlled traffic significantly (P<0.05) increased macro-aggregates, infiltration rate, soil moisture, together with reductions in soil bulk density, soil compaction in different layers compared with the no till random traffic and traditional mould board tillage treatment currently used in this region. Consequently, mean winter wheat and summer maize yields for the NTCT treatment were improved by 2.8 and 7.1% when compared with the soils under no till random traffic, while huge improvement was found when it was compared with conventional ploughing management (4.2 and 12.08% for wheat and maize, respectively). The long-term experiment demonstrated that no-tillage controlled traffic with residues retained, offers a potentially significant improvement over the current farming systems in annual double cropping areas of North China Plain.