Strip Tillage Systems Research Articles

Thrips and Cotton Response to Relay Intercropping with Wheat in North Carolina

In North Carolina, double cropping cotton (Gossypium hirsutum L.) and wheat (Triticum aestivum L.) often results in sub-optimal cotton yield and minimal investment return, most often due to lack of sufficient stand as a result of moisture limitations and a short growing season. Relay intercropping of cotton in wheat prior to harvest may be an alternative to traditional double cropping. A relay intercropping system was tested at five locations over three years in North Carolina to determine thrips infestation, cotton yield, and economic return following relay intercropping of cotton and wheat. Relay intercropped wheat yield ranged from 65% to 85% of conventional wheat plantings. Cotton yields were not affected by the presence of relay-intercropped wheat, but plant maturity was delayed in some experiments. Intercropped cotton plants exhibited similar morphology to cotton planted in a traditional strip tillage system with wheat terminated two wks prior to planting with increased nodes above cracked boll, suggesting delayed plant development. In four of five locations, thrips (Thysanoptera: Thripidae) populations were lower in the intercropped cotton, most likely due to interference of the ability of thrips to locate cotton seedlings. Thrips levels when seed was treated with abamectin plus thiamethoxam plus azoxystrobin and an additional in-furrow application of aldicarb or acephate applied to foliage were less than that of seed treated with azoxystrobin alone. Estimated economic return of intercropped cotton and wheat equaled that of conventional cotton planting and exceeded double cropping of wheat followed by soybean [Glycine max (L.) Merr.] most years when cotton, soybean, and wheat prices were set at $1.98 kg-1 lint, $0.44 kg-1, and $0.25 kg-1, respectively.

Influence of tillage intensity and nitrogen placement on nitrogen uptake and yield in strip-tilled white cabbage (Brassica oleracea convar. capitata var. alba)

Field grown vegetables with wide row spacing would likely benefit from the conservation tillage practice, strip-tillage, with regards to minimizing soil erosion or increasing soil moisture contents, but there are only few studies for strip-tilled vegetables at present. For this reason, a 2-year field experiment was performed in South West Germany to investigate the effect of strip-tillage under broadcast and placed nitrogen application on nitrogen availability and yield of white cabbage (Brassica oleracea convar. capitata var. alba). The treatments were fall strip-tillage (ST), intensive strip-tillage with tillage both in fall and spring (STi; all of them with broadcast nitrogen fertilization) and intensive strip-tillage with band-placed nitrogen (STi_pN). In 2013, a fifth treatment was added, which was ST additional sowing of Phacelia (Phacelia tannacetifolia) as a cover crop (ST_Phac). A conventional tillage treatment (MP; moldboard plowing) was used as the control. No significant differences in soil mineral nitrogen (SMN) were detected in spring (20±5kgNha−1) and at harvest time (5±0.9kgNha−1) between the MP and all strip-tillage treatments from 0–90cm soil depth, except for significantly lower SMN contents in ST_Phac in spring 2013 (5kgNha−1). During the growing period, the SMN contents in strip-tillage treatments tended to be higher than in the MP control. Results of nitrogen content in plants, N-uptake, and nitrogen use efficiency (NUE) showed higher values under ST compared to the more intensive strip-tillage treatments (STi and STi_pN). The cabbage yield ranged between 65tha−1 (MP) and 74tha−1 (ST) in 2012 and 50tha−1 (STi_pN) and 58tha−1 (MP) in 2013. The fall strip-tillage treatment (ST) seems to be as effective as the conventional moldboard plowing for white cabbage in terms of N availability and yield. These results could be used to apply or improve strip-till systems with respect to other similar vegetables, which are (i) exposed to high erosion risk because of the wide row spaces and (ii) which are dependent on high N demand for adequate growth.

Crop Responses to Furrow Diking in North Carolina

Furrow diking is the practice of installing earthen dams to form small basins between crop rows to reduce water runoff and improve water retention. Furrow-diking equipment is operated shortly after planting and has been used extensively in the southern Great Plains. Research evaluating crop response to furrow diking is limited in North Carolina and other southeastern states. Experiments were conducted to determine cotton (Gossypium hirsutum L.) and peanut (Arachis hypogaea L.) yields following furrow diking in conventional and strip tillage systems. Corn (Zea mays L.) response to furrow diking was determined only in conventional tillage systems. In the experiments where tillage was compared, variability in cotton and peanut response to tillage was observed, whereas diking did not affect yield of these crops. In separate experiments with conventional tillage only, peanut and corn yields were not affected by the diking treatment. However, in one experiment conducted at five sites in conventional tillage only, cotton yield increased by 7% when furrow diking was included. Although these results indicate that peanut and corn may be nonresponsive to furrow diking on coarse-textured soils in the coastal plain of North Carolina, additional research is needed to make a concrete assessment of potential of furrow diking on these crops. While variability was noted when comparing experiments, cotton responded favorably to furrow diking.

Cover Crop Mulch and Weed Management Influence Arthropod Communities in Strip-Tilled Cabbage

Cover crop mulch and weeds create habitat complexity in agricultural fields that may influence arthropods. Under strip-tillage systems, planting rows are tilled and preestablished cover crops can remain between rows. In field experiments conducted in Michigan in 2010 and 2011, a preestablished oat (Avena sativa L.) cover crop was allowed to grow between rows of strip-tilled cabbage and killed at 0, 9-14, or 21-27 d after transplanting (DAT). The effects of herbicide intensity and oat kill date on arthropods, weeds, and crop yield were examined. Two levels of herbicide intensity (low or high) were used to manipulate habitat vegetational complexity, with low weed management intensity resulting in more weeds, particularly in 2010. Oat kill date manipulated the amount of cover crop mulch on the soil surface. Later oat kill dates were associated with higher natural enemy abundance. Reduced herbicide intensity was associated with (1) lower abundance of several key cabbage (Brassica oleraceae L.) pests, and (2) greater abundance of important natural enemy species. Habitats with both later oat kill dates and reduced herbicide intensity contained (1) fewer herbivores with chewing feeding guilds and more specialized diet breadths, and (2) greater abundance of active hunting natural enemies. Oats reduced cabbage yield when oat kill was delayed past 9-14 DAT. Yields were reduced under low herbicide intensity treatments in 2010 when weed pressure was greatest. We suspect that increased habitat complexity associated with oat mulches and reduced herbicide intensity enhances biological control in cabbage, although caution should be taken to avoid reducing yields or enhancing hyperparasitism.

Economic questions of precision maize production on chernozem soil

It is one of the main topical objective to establish the conditions of sustainable farming. The sustainable development in crop production also calls for the harmony of satisfying human needs and providing the protection of environmental and natural resources; therefore, the maximum consideratio of production site endowments, the common implementation of production needs and environmental protection aims, the minimum load on the environment and economicalness. Precision farmin encompasses the farming method which is adjusted to the given production site, the changing technology in a given plot, the integrated crop protection, cutting edge technologies, remote sensing, GIS, geostatistics, the changeof the mechanisation of crop production, and the application of information technology novelties in crop production. Modern technology increases efficiency and reduces costs. The efficiency of crop production increases by reducing losses and the farmer has access to a better decision support information technology system. In addition, we consider it necessary to examine the two currently most important economic issues: “is it worth it?” and “how much does it cost?”. During the analysis of agricultural technologies, we used the precision crop production experiment database of KITE Zrt. and the Institute for Land Utilisation, Regional Development and Technology of the Centre for Agricultural and Applied Economic Sciences of the University of Debrecen.During our analytical work, we examined three technological alternatives on two soil types (chernozem and meadow). The first technology is the currently used autumn ploughing cultivation. We extended our analyses to the economic evaluation of satellite navigationassisted ploughing and strip till systems which prefer moisture saving. On chernozem soil, of the satellite-based technological alternatives, the autumn ploughing cultivation provided higher income than strip till. In years with average precipitation supply, we recommend the precision autumn ploughing technological alternative on chernozem soils in the future. On meadow soil, the strip till cultivation technology has more favourable economical results than the autumn ploughing. On soils with high plasticity – considering the high time and energy demand of cultivation and the short amoung of time available for cultivation – we recommend to use strip till technologies.

Effects of various tillage systems on soil CO2-C fluxes and on bacteria and fungi populations in Zea mays

The objective of this study is to determine the effects of strip tillage and full-width tillage treatments on soil carbon (IV) oxide-carbon (CO2-C) fluxes, bacterial and fungal populations in growing period of Zea mays. A row-crop rotary hoe with C type blades was used to create three strip widths by changing the connection of blades of the rotary hoe on the flanges. Strip widths were 22.5 (T30), 30 (T40) and 37.5 cm (T50). The full-width tillage practice (moldboard plow + disc harrow + leveler) gave 100% surface soil disturbance (T100) and was included in the experiment to make comparisons with the strip tillage system. During the growth of theZea mays, periodic measurements of CO2-C fluxes, bacterial and fungal populations were made. Statistically significant differences in CO2-C fluxes, microbial populations and soil bulk density were observed between the different tillage systems. Highest CO2-C fluxes and bacteria populations were observed with the full-width T100 treatment and the lowest values were observed in the T30 treatment during flowering and harvesting periods. Increasing tillage intensity increased soil CO2-C fluxes and bacteria population, but decreased fungi population and soil bulk density. Key words: Carbon IV oxide-carbon flux, strip tillage, strip width.

Soil characteristics at the in-row and inter-row zones after strip-tillage

Changes in soil physical and mechanical characteristics are indicators to evaluate the strip-tillage effect on the soil environment. In this study, soil moisture content, temperature, crumbling rate, bulk density, penetration resistance and shear strength were measured at the in-row and inter-row zones for different depths after using a strip-tillage system (combined chisel-rototilling machine). The results show no significant differences in soil moisture content with depth changes, although moisture content at inter-row zone was about 18% higher than in-row zone. Removal of residues from the row reduced in-row soil moisture content in the seed bed, while conserving inter-row soil moisture. Soil temperature had an inverse relationship with the amount of residue cover. The lower soil temperature at inter-row was due to the influence of surface residue by reflecting solar irradiation and insulating the soil surface. Crumbling rate at the in-row zone for the depth of up to 15 cm (aggregates size less than 20 mm) was more than 50%. Therefore, the seedbed soil with small aggregates enhances seed germination and root growth. Bulk density, penetration resistance and shear strength significantly reduced at in-row zone especially for depths less than 15 cm. In general, the findings show that strip-tillage can contribute effectively to improve in-row physical and mechanical characteristics while it conserves the advantages of remaining residual at the inter-row zone.

Assessment of strip tillage systems for maize production in semi-arid Ethiopia: Effects on grain yield, water balance and water productivity

The Maresha, the traditional Ethiopian plow, requires repeated cross-plowing which causes increased surface runoff, less infiltration and hence lower water availability to crops. The main reasons for increased surface runoff and reduced infiltration are plowing along the slope and the formation of a plow pan at shallow depths. Conservation tillage is seen as a way to alleviate these problems. The widely advocated zero-tillage, however, is not feasible for smallholder farmers in semi-arid regions of Ethiopia because of difficulties in maintaining adequate soil cover, the practice of communal grazing, and high costs of herbicides. Strip tillage systems, on the other hand, may offer a solution. This study was initiated to test strip tillage systems and to evaluate the impacts of new tillage systems on the water balance and grain yields of maize. Experiments have been conducted in a semi-arid area called Melkawoba in the central Rift Valley of Ethiopia during 2003–2005. Strip tillage systems involved cultivation along planting lines at a spacing of 0.75m using the Maresha plow followed by subsoiling along the same lines (STS) or without subsoiling (ST). Results have been compared with traditional tillage involving 3–4 overpasses with the Maresha plow (CONV). Soil moisture has been monitored to a depth of 1.8m using a Time Domain Reflectometer (TDR) while surface runoff has been measured using a specially designed rectangular trough installed at the bottom of each plot. STS resulted in the least surface runoff (Qs=18mmseason−1) and the highest grain yields (Y=2130kgha−1) followed by ST (Qs=26mmseason−1, Y=1840kgha−1) and CONV (Qs=43mmseason−1, Y=1720kgha−1) provided sowing was carried out within a week after subsoiling. Thus, STS resulted in the highest water productivity, WP=0.60kgm−3, followed by ST (WP=0.52kgm−3) and CONV (WP=0.48kgm−3). The main conclusion of the paper is that even in dry areas reasonable yields can be obtained provided moisture conservation in the root zone is guaranteed. In this regard subsoiling is essential. Moreover, it is concluded that the time between subsoiling and planting is a key factor and should not exceed one week.

Effects of strip and full-width tillage on soil carbon IV oxide-carbon (CO2-C) fluxes and on bacterial and fungal populations in sunflower

In strip tillage system, planting lines are cultivated while the inter-row spaces are left undisturbed. The objective of this study is to determine the effects of strip tillage and full-width tillage treatments on soil carbon IV oxide-carbon (CO 2 -C) fluxes, bacterial and fungal populations in growing period of sunflower ( Helianthus annus ). A row-crop rotary hoe with C type blades was used to create three strip widths by changing the connection of blades of the rotary hoe on the flanges. Strip widths were 22.5 (T30), 30.0 (T40) and 37.5 cm (T50). The full-width tillage practice (moldboard plow + disc harrow + leveler) gave 100% surface soil disturbance (T100) and was included in the experiment to make comparisons with the strip tillage system. A randomized complete block design with three replications was used. During the growth of the sunflower, periodic measurements of CO 2 -C fluxes and bacterial and fungal populations were made. Significant (p < 0.01) differences in CO 2 -C fluxes, microbial populations, soil bulk density and total porosity were observed between the different tillage systems. Highest CO 2 -C fluxes, bacteria populations and total porosity were observed in the full-width T100 application and the lowest values were observed in the T30 treatment during flowering and harvesting periods. Increasing tillage intensity increased soil CO 2 -C fluxes and bacteria population, but decreased fungi population and soil bulk density. Key words : Carbon IV oxide-carbon flux, soil bacteria and fungi, strip tillage, full-width tillage, sunflower.

Single‐ and Twin‐Row Peanut Production within Narrow and Wide Strip Tillage Systems

Increased production costs and potential benefits of maintaining surface residue has renewed interest in conservation tillage systems for peanut (Arachis hypogaea L.) production. We determined surface residue cover from rye (Secale cereale L.) or oat (Avena sativa L.) cover crops after two strip tillage systems (narrow vs. wide) and planting operations with different row configurations (single vs. twin). We also compared plant populations, yields, and total sound mature kernels for three peanut cultivars (‘ANorden’, ‘AP‐3’, and ‘Georgia‐02C’) across each treatment combination. Seven site‐years were examined across similar soil types in Alabama and northern Florida during the 2004 to 2006 growing seasons. The highest surface residue counts were for the narrow tillage system planted in single rows. Final plant stands were influenced by an interaction between cultivar and row configuration, with ‘ANorden’ planted in single rows below recommended rates. Peanut yields were affected by strip tillage system and row configuration, but differences among cultivars were also observed. Twin‐row peanut yields were 5% greater than single‐row peanut yields in the narrow strip tillage system but were similar across strip tillage systems. Cultivars ‘AP‐3’ and ‘Georgia‐02C’ yielded 20% higher than ‘ANorden’. Total sound mature kernels were only affected by peanut cultivar, with the cultivar ‘Georgia‐02C’ producing the highest‐quality peanut, followed by ‘ANorden’ and ‘AP‐3’. These results indicate that growers interested in using twin rows for peanut production can also take advantage of a narrow strip tillage system that maximizes surface residue coverage and subsequent benefits.

Furrow diking in conservation tillage

Abstract Crop production in the Southeastern U.S. can be limited by water; thus, supplemental irrigation is needed to sustain profitable crop production. Increased water capture would efficiently improve water use and reduce supplemental irrigation amounts/costs, thus improving producer's profit margin. We quantified infiltration (INF), runoff (R), and sediment (E) losses from furrow diked (+DT) and non-furrow diked (−DT) tilled conventional (CT) and strip tillage (ST) systems. In 2008, a field study (Tifton loamy sand, Typic Kandiudult) was established with DT, ST, and CT systems. In 2009, a field study (Faceville loamy sand, Typic Kandiudult) was established with DT and ST systems. Treatments (6) included: CT − DT, CT + DT, ST1 (1-year old) − DT, ST1 + DT, ST10 (10-year old) − DT, and ST10 + DT. Simulated rainfall (50 mm h−1 for 1 h) was applied to each 2-m × 3-m plots (n = 3). Runoff and E were measured from each 6-m2 plot. ST1 + DT plots had 80–88% less R than ST1 − DT plots. Any disturbance associated with DT in ST1 systems did not negatively impact E values. For both soils, CT − DT plots represented the worst-case scenario in terms of measured R and E; ST + DT plots represented the best-case scenario. Trends for R, E, and estimated plant available water (PAW) values decreased in order of CT − DT, CT + DT, ST1 − DT, ST1 + DT, ST10 − DT, and ST10 + DT treatments. From a hydrology standpoint, ST1 − DT plots behaved more similarly to CT plots than to other ST plots; from a sediment standpoint, ST1 − DT plots behaved more similarly to other ST plots than to CT plots. DT had no effect on ST10 plots. CT − DT and ST10 + DT plots resulted in 5.9 (worst-case) and 8.1 (best-case) days of water for crop use, a difference of 2.2 days of water for crop use or 37%. Compared to the CT − DT treatment, an agricultural field managed to CT + DT, ST1 − DT, ST1 + DT, ST10 − DT, and ST10 + DT would save a producer farming the CT − DT field $5.30, $9.42, $13.55, $14.14, and $14.14 ha−1, respectively, to pump the amount of water lost to R and not saved as INF back onto the field. The most water/cost savings occurred for CT and ST1 plots as a result of DT. Savings for CT + DT, ST1 − DT, and ST1 + DT treatments represent 27%, 47%, and 68% of the cost of DT ($20 ha−1) and 37%, 67%, and 96% of the savings a producer would have if managing the field to ST for 10 years without DT (ST10 − DT) in a single 50-mm rainfall event. For row-crop producers in the Southeastern U.S. with runoff producing rainfall events during the crop growing season, DT is a management practice that is cost-effective from a natural resource and financial standpoint for those producers that continue to use CT systems and especially those that have recently adopted ST systems into their farming operations.

Optimum placement of phosphorus for corn/soybean rotations in a strip-tillage system

Optimum placement of phosphorus for corn/soybean rotations in a strip-tillage system

Optimum placement of phosphorus for corn/soybean rotations in a strip-tillage system

S trip tillage, a conservation tillage system using very reduced tillage, is attracting much attention throughout the corn-growing regions of the United States. In the northern parts of the Corn Belt, strip tillage often replaces no-till systems on the more poorly drained soils because it provides a warmer tilled seedbed for early planting and faster early growth while maintaining substantial amounts of erosion-minimizing plant residue between the tilled strips. Another benefit of strip tillage is the need for only one field operation between soybean harvest and spring planting—that is, fall strip tillage accompanied by deep-placement of fertilizer phosphorus (P) and potassium (K) in a band 15 to 18 cm (6 to 7 in) deep in the strip. No preplant tillage is needed. From an environmental perspective, deep-band placement is considered to be ideal in terms of eliminating nutrient stratification and reducing the potential for surface runoff of fertilizer P, which can easily occur when fertilizers are broadcasted on the soil surface of no-till systems. From an agronomic perspective, fertilizer placement 10 to 13 cm (4 to 5 in) directly below where the seed will be planted is thought to be ideal in terms of fertilizer P and K use efficiency, early …

Effects of Strip Tillage and Production Inputs on Soil Biology across a Spatial Gradient

Strip tillage results in soil disturbance levels similar to those of conventional tillage systems in the row locations (strip) and properties of no‐till in the interrow (between‐row) locations. In this study, biological and physical soil properties in the region spanning the row to interrow were investigated and results were compared among strip–tillage systems utilizing different inputs (conventional fertilizer and pesticides vs. USDA‐approved organic inputs) and rotation regimes (continuous tomato [Lycopersicon esculentum Mill.] vs. a 3‐yr vegetable rotation). Bulk density was significantly greater in the interrow locations. Soil respiration potential was greatest in the interrow and least in the row locations, and greater in treatments receiving organic inputs relative to synthetic inputs. No differences in soil N mineralization potential were determined. Microbial biomass C and N were greatest in interrow and least in row locations. Total soil C and N values did not vary from row to interrow locations or as a result of synthetic vs. organic inputs. The data suggest that organically managed production systems are less biologically stratified than conventional input systems under strip‐tillage management. Although net C mineralization was similar between chemical and organically managed systems, greater microbial biomass values in the organic treatment systems may have been the result of continuous additions of weed biomass during the summer. The hypothesis of a gradient effect for biological activity in strip‐tillage systems from row to interrow appears to be true in systems managed with synthetic fertilizers and pesticides, but not true of organically managed systems.

Fertilizer Management for Short-season Corn Grown in Reduced, Strip-till, and No-till Systems on Claypan Soil

Strip-till is an alternative conservation tillage system that may overcome the yield depression often seen with corn (Zea mays L.) grown with no-till on the claypan soils of the eastern Great Plains. The objective of this research was to determine the effect of conservation tillage systems and fertilizer N-P management on short-season corn. Continuous corn yields with no-till, strip-till in the fall, or strip-till in the spring declined with year compared with corn grown with reduced tillage. By the third year, corn yields with reduced tillage exceeded 45 bu/acre more than with the other tillage systems. In part, this can be attributed to a reduced plant stand in no-till and strip-till systems. Average corn yield was about 10% greater when N-P applications were made in the spring than in the fall. Similarly, knife (subsurface band) applications of N-P resulted in about 12% greater yield than dribble (surface band). Yield differences due to fertilizer timing or placement were related to similar increases in the number of kernels per ear. Strip-till done either in the fall or spring for corn grown in claypan soil did not improve yield compared with no-till and may be less than yields with reduced tillage. Knife applications of N-P fertilizer done in the spring may help mitigate this deficit if the producer prefers the conservation aspects of strip- or no-till systems.

Evaluating a crop residue cover index for determining tillage regime in a cotton-corn-peanut rotation

Conservation tillage is a well known best management practice that improves soil quality, reduces runoff and erosion, and increases infiltration. However, a rapid assessment strategy for quantifying the rate and spatial distribution of conservation tillage practices is lacking. This study was designed to evaluate the sensitivity of a remotely derived crop residue cover index for depicting conventional tillage (CT), strip tillage (ST), and no-tillage (NT) systems in a cotton-corn-peanut rotation in the southeastern Coastal Plain. Treatments consisted of CT (rip and bed operation), NT, NT with subsoiling, and ST. Remotely sensed data were acquired three times prior to canopy closure, using a handheld multispectral radiometer (485 to 1,650 nm) and thermal imager (7,000 to 14,000 nm). Using a combination of visible and near-infrared spectra, a crop residue cover index was calculated and evaluated. Results showed that crop residue cover is greatest in years planted with peanut or cotton—likely due to the later winter cover crop termination date compared to years when corn is planted. The crop residue cover index outperformed the thermal infrared, accurately separating conventional from conservation tillage treatments in four out of six data acquisitions in 2004 and 2006. Differentiation among conservation tillage treatments was inconsistent. Regression analyses showed that a strong linear relationship existed between the crop residue cover index and measured crop residue cover (<i>r</i>² = 0.51 to 0.86, alpha = 0.10). These data suggest that remotely sensed data may be used as a rapid, field-scale indicator of conservation tillage adoption. Rapid assessment methodologies are necessary to quantify the impact of conservation practice adoption on water quality/quantity, assess adoption rates, and improve the placement of conservation tillage practices at local, watershed and regional scales.

Evaluating a crop residue cover index for determining tillage regime in a cotton-corn-peanut rotation

Conservation tillage is a well known best management practice that improves soil quality, reduces runoff and erosion, and increases infiltration. However, a rapid assessment strategy for quantifying the rate and spatial distribution of conservation tillage practices is lacking. This study was designed to evaluate the sensitivity of a remotely derived crop residue cover index for depicting conventional tillage (CT), strip tillage (ST), and no-tillage (NT) systems in a cotton-corn-peanut rotation in the southeastern Coastal Plain. Treatments consisted of CT (rip and bed operation), NT, NT with subsoiling, and ST. Remotely sensed data were acquired three times prior to canopy closure, using a handheld multispectral radiometer (485 to 1,650 nm) and thermal imager (7,000 to 14,000 nm). Using a combination of visible and near-infrared spectra, a crop residue cover index was calculated and evaluated. Results showed that crop residue cover is greatest in years planted with peanut or cotton-likely due to the later winter cover crop termination date compared to years when corn is planted. The crop residue cover index outperformed the thermal infrared, accurately separating conventional from conservation tillage treatments in four out of six data acquisitions in 2004 and 2006. Differentiation among conservation tillage treatments was inconsistent. Regression analyses showed that a strong linear relationship existed between the crop residue cover index and measured crop residue cover (r2 = 0.51 to 0.86, alpha = 0.10). These data suggest that remotely sensed data may be used as a rapid, field-scale indicator of conservation tillage adoption. Rapid assessment methodologies are necessary to quantify the impact of conservation practice adoption on water quality/quantity, assess adoption rates, and improve the placement of conservation tillage practices at local, watershed and regional scales.

Soil disturbed using a strip tillage implement on a range of soil types and the effects on sugar beet establishment

AbstractThe area of soil disturbed using a single tine is well documented. However, modern strip tillage implements using a tine and disc design have not been assessed in the UK or in mainland Europe. Using a strip tillage implement has potential benefits for European agriculture where economic returns and sustainability are key issues. Using a strip tillage system a narrow zone is cultivated leaving most of the straw residue on the soil surface. Small field plot experiments were undertaken on three soil types and the operating parameters of forward speed, tine depth and tine design were investigated together with measurements of seedbed tilth and crop emergence. The type of tine used was found to be the primary factor in achieving the required volume of disturbance within a narrow zone whilst maintaining an area of undisturbed soil with straw residue on the surface. The winged tine produced greater disturbance at a given depth compared with the knife tine. Increasing forward speed did not consistently increase the volume of disturbance. In a sandy clay loam the tilth created and emergence of sugar beet by strip tillage and ploughing were similar but on a sandy loam the strip tillage treatments generally gave a finer tilth but poorer emergence particularly at greater working depth.

Cattle manure and grass residues as liming materials in a semi-subsistence farming system

A field experiment was conducted on an acid soil in a semi-subsistence farming area of KwaZulu-Natal, South Africa to investigate the possibility of using organic amendments as liming materials within a minimum tillage (strip cultivation) system to produce maize. Amendments (cattle manure, grass residues and dolomitic lime) were incorporated to a depth of 20 cm in bands 15 cm wide down plant rows at rates of 10 and 20 t ha −1 (in the amended area) for organic materials and 2.5 and 5.0 t ha −1 for lime. The remainder of the field remained untilled. Additions of cattle manure rapidly increased soil pH, and concentrations of exchangeable K, Ca and Mg and extractable P were also greatly elevated. Grass residue additions increased pH progressively and increased exchangeable K and Mg and those of dolomitic lime increased pH, exchangeable Ca and Mg. Addition of each of the amendments decreased concentrations of exchangeable Al; the effect was greatest for animal manure after 6 weeks and for lime and grass residues at harvest. At harvest, addition of all three amendments had significantly reduced concentrations of both phytotoxic monomeric and total Al in soil solution. The system not only resulted in an increase in pH and extractable nutrients in row soil compared to that in the inter-row but also an increase in the size and activity of the soil microbial community. Maize yields were increased by additions of amendments under both unfertilised and fertilised conditions and yields were generally greatest at the higher rate of addition. Under unfertilised conditions, cattle manure treatments gave the greatest yields. Fertiliser additions increased yields greatly particularly in the control, grass residue and lime treatments. It was concluded that the strip tillage system used is a practicable way of applying high rates of organic materials to soils, that cattle manure has a rapid liming effect as well as being a nutrient source and that grass residues from rangeland decompose slowly and, therefore, have a slow liming effect.

Cover crop effect on soil carbon fractions under conservation tillage cotton

Cover crops may influence soil carbon (C) sequestration and microbial biomass and activities by providing additional residue C to soil. We examined the influence of legume [crimson clover ( Trifolium incarnatum L.)], nonlegume [rye ( Secale cereale L.)], blend [a mixture of legumes containing balansa clover ( Trifolium michelianum Savi), hairy vetch ( Vicia villosa Roth), and crimson clover], and rye + blend mixture cover crops on soil C fractions at the 0–150 mm depth from 2001 to 2003. Active fractions of soil C included potential C mineralization (PCM) and microbial biomass C (MBC) and slow fraction as soil organic C (SOC). Experiments were conducted in Dothan sandy loam (fine-loamy, kaolinitic, thermic, Plinthic Kandiudults) under dryland cotton ( Gossypium hirsutum L.) in central Georgia and in Tifton loamy sand (fine-loamy, siliceous, thermic, Plinthic Kandiudults) under irrigated cotton in southern Georgia, USA. Both dryland and irrigated cotton were planted in strip tillage system where planting rows were tilled, thereby leaving the areas between rows untilled. Total aboveground cover crop and cotton C in dryland and irrigated conditions were 0.72–2.90 Mg C ha −1 greater in rye + blend than in other cover crops in 2001 but was 1.15–2.24 Mg C ha −1 greater in rye than in blend and rye + blend in 2002. In dryland cotton, PCM at 50–150 mm was greater in June 2001 and 2002 than in January 2003 but MBC at 0–150 mm was greater in January 2003 than in June 2001. In irrigated cotton, SOC at 0–150 mm was greater with rye + blend than with crimson clover and at 0–50 mm was greater in March than in December 2002. The PCM at 0–50 and 0–150 mm was greater with blend and crimson clover than with rye in April 2001 and was greater with crimson clover than with rye and rye + blend in March 2002. The MBC at 0–50 mm was greater with rye than with blend and crimson clover in April 2001 and was greater with rye, blend, and rye + blend than with crimson clover in March 2002. As a result, PCM decreased by 21–24 g CO 2–C ha −1 d −1 but MBC increased by 90–224 g CO 2–C ha −1 d −1 from June 2001 to January 2003 in dryland cotton. In irrigated cotton, SOC decreased by 0.1–1.1 kg C ha −1 d −1, and PCM decreased by 10 g CO 2–C ha −1 d −1 with rye to 79 g CO 2–C ha −1 d −1 with blend, but MBC increased by 13 g CO 2–C ha −1 d −1 with blend to 120 g CO 2–C ha −1 d −1 with crimson clover from April 2001 to December 2002. Soil active C fractions varied between seasons due to differences in temperature, water content, and substrate availability in dryland cotton, regardless of cover crops. In irrigated cotton, increase in crop C input with legume + nonlegume treatment increased soil C storage and microbial biomass but lower C/N ratio of legume cover crops increased C mineralization and microbial activities in the spring.