Impact Of Conservation Tillage Research Articles

Long-term Tillage and Nitrogen Fertilization Effects on Soil Properties and Crop Yields

Long-term Tillage and Nitrogen Fertilization Effects on Soil Properties and Crop Yields

Tillage influence on biophysical soil properties: The example of a long-term tillage experiment under Mediterranean rainfed conditions in South Spain

Long-term field experiments are important to provide information about how soil carbon (C) dynamics is affected by soil tillage systems. In this study we directly diagnose the influence of the topsoil's (0–5 cm depth) C concentration on soil quality in an Entisol under Mediterranean conditions, testing a new statistical method. The objective was to estimate the impact of conservation tillage (RT) as a C management practice, versus a traditional tillage (TT) system on biophysical soil properties. We analyzed the impact of the soil C management on biological (microbial biomass C, dehydrogenase and β-glucosidase activities), physical soil properties (aggregates stability, conductive mean pore diameter, aggregation index) and CO 2 fluxes. The concentrations for total organic carbon (TOC), the active carbon (AC) normalised by the total carbon (AC TOC −1), served as a combined proxy for the soil C management related to the tillage system. Soil C management accounted for 0–46% of the change of biophysical soil properties in RT versus TT. The RT led to a C increase (18.9%) of microbial activities, especially in the top 0–5 cm depth. Related to the physical soil properties, less C in TT led to a lower aggregation index, although this tendency was not observed for other physical parameters. The impact of soil C management was better correlated with soil microbial than with the physical properties. Our analysis directly quantified for the first time that the increase in the soil's carbon concentration could only explain a small fraction of the beneficial change in biophysical soil properties due to RT. In general the RT contributed to the long-term sustainability of the agroecosystem by improving biological and physical soil characteristics under dryland semi-arid Mediterranean conditions.

Impact of conservation tillage under organic mulches on the reproductive efficacy and yield of quality protein maize

The present study was carried out to evaluate the efficacy of conservation tillage under organic mulches on the reproductive developments and production potentials of Quality Protein Maize (QPM) cv. Pozarica during the period from November 2007 to April 2008. The study included tillage and zero tillage conditions and four indigenous mulches viz. water hyacinth, rice straw, rice husk and ash. All the mulches significantly modified microclimatic parameters in both tillage and zero tillage conditions. However, under non-tilth condition water hyacinth and rice straw mulches reduced the maximum soil temperature at 5 cm depth by 3.5-4.2°C and 2.4-2.7°C, respectively at 14:00 hrs and raised the minimum temperature by 1.5-2.3°C and 1.2-1.4°C at 06:00 hrs. The water retentive capacity of the mulched soil under zero tillage condition was higher at all the stages of plant growth and ranked in the order of water hyacinth>rice straw>rice husk>ash>control. The reproductive developments in mulched plants were advanced by about 1 to 10 days. Mulching practices also enhanced the number of ears plant-1, ear height, length and diameter, tassel length, number of seed rows ear-1 and seeds row-1, 1000-grains weight, weight of rachis ear-1, grain yield and higher harvest index (HI). The grain yield of mulched plants notably water hyacinth was nearly double (8.73 t ha-1) than unmulched plants (4.93 t ha-1) under non-tilth condition. The indigenous mulches especially water hyacinth and rice straw, irrespective of tilth or non-tilth conditions, appeared to be great suppressants of weed growth allowing to produce less than one third of the total biomass compared to that of control. The residual mulching effect had little or no influence on physical properties of the soil under both conditions. However, the chemical properties were favourably influenced for the follow-up crops. Key words: Conservation tillage; organic mulches; soil moisture conservation; yield; QPM. DOI: 10.4038/jas.v5i2.2782The Journal of Agricultural Sciences, 2010, vol. 5, no 2 pp.52-63

Effect of tillage system and straw management on organic matter dynamics

The choice of cultivation system in arable agriculture exerts a strong influence not only on soil health and crop productivity but also on the wider environment. Conservation tillage using non-inversion methods conserves soil carbon, reduces erosion risk and enhances soil quality. In addition, conservation tillage has been shown to sequester more carbon within the soil than inversion tillage, reducing carbon dioxide losses to the atmosphere. Stable, well structured topsoils that develop following long-term conservation tillage lead to more energy efficient systems due to the reduced power requirements for cultivation. Long-term experiments, e.g. more than 20 years, that confirm the impact of conservation tillage over an extended period are not common. Here we evaluate the impact of different tillage methods and winter wheat straw management, either incorporated or removed, on organic matter turnover and soil quality indicators. No-till, chisel and mouldboard ploughing was carried out for 23 years on a silty clay loam soil in South West England that was not considered suitable for non-inversion tillage due to weak soil structure. In order to assess the effect of contrasting cultivation and straw disposal method on soil carbon dynamics, a range of assays were conducted, including water extractable organic carbon, hot water extractable carbohydrate, microbial biomass carbon, activity of β-glucosidase and acid phosphatase enzymes, C sequestration and the natural abundance of 13C. Our results show that the soil organic carbon concentration in the topsoil was greater under no-till than mouldboard ploughing, while a reverse trend was observed in the lower depths. A 14–17% increase in soil organic carbon was observed in the topsoil for chisel plough and no-till treatments compared to mouldboard ploughing. Water extractable organic carbon was found to constitute only 1–7% of the microbial biomass carbon. Hot water extractable carbohydrate was one of the most sensitive indicators of soil quality and had a significant a negative correlation with bulk density and positive correlation with soil organic carbon microbial biomass carbon β-glucosidase and acid phosphatase. The choice of cultivation method exerted a major control on microbial and carbon dynamics. No-till and chisel ploughing maintained carbon in the soil surface horizons, which will benefit the stability of this weakly structured soil, but mouldboard ploughing distributed carbon more uniformly throughout the soil profile, particularly when straw was incorporated, hence leading to the retention of more carbon in the soil profile.

Evaluation of Tillage Systems for Grain Sorghum and Wheat Yields and Total Nitrogen Uptake in the Texas Blackland Prairie

Recently, there has been an increased interest in cropping systems such as conservation-tillage; however, determining the best alternative between cropping system options is often complicated by disparities in research results due to seasonal variability. The economic cost of the systems further complicates the determination of the best alternative for sustainable crop production. To evaluate tillage systems using experimental data, a computer simulation approach called fuzzy multi-attributive decision-making (MAMD) can be applied. In this study, MAMD was applied to research the impact of conservation tillage and conventional tillage systems with and without raised wide beds on yield and nitrogen (N) uptake in grain sorghum and wheat for soils of the Texas Blackland Prairie. Results of yield and N uptake data for 4 years (1994–1997) indicated that the various tillage systems had merits and demerits across the different years of study. The economic conditions of the cropping systems were also utilized in the evaluation. Utilization of this technique indicated that the no-tillage cropping system with wide beds was the best tillage system of the ones evaluated.

Conservation Tillage, Rotations, and Cover Crop Affecting Soil Quality in the Tennessee Valley: Particulate Organic Matter, Organic Matter, and Microbial Biomass

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 POMc. 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.

Long-term impact of conservation tillage on stratification ratio of soil organic carbon and loss of total and active CaCO 3

Under semi-arid conditions, the properties of many soils are influenced by the presence of organic matter and calcium carbonate (CaCO 3). However, the influence of different tillage systems on the development of these properties has scarcely been studied under semi-arid Mediterranean conditions. We studied the effect of long-term conservation tillage (CT) and traditional tillage (TT) on the stratification ratio of soil organic carbon and on CaCO 3 content. The study was conducted in a wheat ( Triticum aestivum L.)–sunflower ( Helianthus annuus L.) crop rotation established in 1991 under rainfed conditions in Southwestern Spain. As is traditional in this area, wheat was fertilised, but sunflower was not. Conservation tillage was characterised by reduced number of tillage operations and leaving crop residues on the soil surface, while TT was with mouldboard ploughing. Stratification ratio of soil organic C was calculated from C contents in the 0–5 and 5–10 cm soil layers divided by that in the 25–40 cm. Stratification ratio of soil organic C under the CT (>2) was significantly greater than under TT (<2); values >2 indicating better soil quality. Our results show a loss of CaCO 3 under both tillage systems. However, the loss of CaCO 3 was significantly higher under TT than under CT. Also, P and K accumulated in the soil surface and stratification ratio for both nutrients was greater in CT than in TT.

Impact of conservation tillage and nutrient management on soil water and yield of cotton fertilized with poultry litter or ammonium nitrate in the Georgia Piedmont

Cotton has become a dominant crop in the southeastern USA, but only about 12% of the 620,000 ha of cotton ( Gossipium hirsutum L.) in Georgia, for example, is under conservation tillage. Georgia and bordering states produce about 42% of the poultry in the United States and in Georgia alone, this results in over 1.6 million Mg of poultry litter (PL) annually. The fertilizer value of PL is well-recognized but much of it is applied to pastures and only a small percentage is applied to crop land. Limited information is available on the response of cotton to PL as fertilizer in conservation tillage systems in the Southeast. The performance of cotton under two tillage and two fertilizer treatments was evaluated from 1996 to 1999 to highlight management options for increased adoption of conservation tillage and PL use. Cotton, followed by a rye ( Secale cereale L.) cover crop, was grown under a factorial arrangement of tillage (no-till (NT) vs conventional tillage (CT)) and fertilizer (ammonium nitrate, as conventional fertilizer (CF) vs PL) on a Cecil sandy loam (clayey, kaolinitic thermic Typic Kanhapludult; Chromi-Alumic Acrisol) near Watkinsville, Georgia. Average lint yield from 1996 to 1999 was in the sequence no- till poultry litter ( NTPL)> no- till conventional fertilizer ( NTCF)> conventional tillage poultry litter ( CTPL)> conventional tillage and fertilizer ( CTCF) . Differences were significant at P≤0.05 for NTPL vs CTPL, NTPL vs CTCF, and NTCF vs CTCF. Average yield differences were also significant between NT and CT but not PL and CF. PL yielded more than CF only in 1997. NT generally had a more favorable soil water regime than CT. Yield differences among treatments occurred during the first 3 years only. Drought in the fourth year reduced yield across all treatments and negated treatment effects. Lint yield would increase in the southeastern USA and an additional outlet for the PL would be created by adopting NT and fertilizing with PL in cotton production.

Conservation Tillage

Conservation production systems combine tillage and planting practices to reduce soil erosion and loss of water from farmland. Successful conservation tillage practices depend on the ability of farm managers to integrate sound crop production practices with effective pest management systems. More scientific information is needed to determine the relations between tillage practices and physical, chemical, and biological soil factors that affect plant and pest ecology. There is a need to devise improved pest management strategies for conservation tillage and to better understand the impact of conservation tillage on water-quality, especially as it is related to use of agricultural chemicals. While savings in fuel, labor, and soil have induced many farmers to adopt conservation tillage, improved methods and equipment should increase adoption even more.