Plow Tillage Research Articles

Traffic-induced soil compaction during manure spreading in spring in South-East Norway

The objective of this study was to evaluate long-term effects of two tillage regimes (ploughing and minimum tillage) on the bearing capacity of a clay rich soil, by using two different slurry tankers (4.1 and 6.6 Mg wheel load) and contrasting wheeling frequencies (1 and 10 passes). The soil strength was assessed by laboratory measurements of the precompression stress (Pc) at −6 kPa in topsoil (20 cm) and subsoil (40 and 60 cm) samples. Stress propagation, elastic and plastic deformation during wheeling were measured in the field with combined stress-state-transducer and displacement transducer system. Results presented in this study show that minimum tilled soil had 74% higher Pc than ploughed soil in the upper soil layer, whilst differences were less distinct in subsoil. Wheeling increased Pc at all soil depths. Compared to ploughing, higher strength in the upper layer of minimum tilled soil led on average to 60% and 48% reductions in the major principal stress with the use of the light and heavy slurry tanker, respectively. The extent of the major principal stress was dependent on the ground pressure in the topsoil. The first pass of a wheel caused the greatest damage in some cases, but all wheelings led to accumulative plastic deformation in both vertical and horizontal directions. Wheeling with high intensity would have exceeded Pc in all cases when soil was at a matric potential of −6 kPa. The results show that soil water content is an important factor influencing bearing capacity. Drier soil (−100 kPa), in combination with minimum tillage, limited the occurrence of stresses exceeding Pc in the upper soil layer.

Tillage practices affect biomass and grain yield through regulating root growth, root-bleeding sap and nutrients uptake in summer maize

No tillage (NT) of summer maize (Zea mays L.) is the dominant agricultural practice in the annual double-cropping system of winter wheat–summer maize in the North China Plain, and the long-term NT is often unfavorable for the growth of maize roots. The aim of this study was to evaluate the effect of 2-year-old rotary tillage (RT) and plowing tillage (PT) based at NT soil on root growth, spatial distribution, nutrients uptake and grain yield in Wuqiao of the North China Plain. PT and RT significantly increased root biomass across 0–40cm soil profile in the whole growth stage. Lower bulk density under PT and RT was compared to under NT in the 0–20cm soil profile, and penetration resistance under NT was significantly higher than under PT and RT in the 0–30cm soil profile. Root length density (RLD) in the uppermost soil profile (0–10cm) had no evident differences among tillage practices at silking stage, but RLD under PT and RT was significantly greater than under NT at maturity. Moreover, RLD and root surface density (RSD) were significantly higher under PT than under NT in the topmost layer, 10–50cm soil profile, but there were no differences in RLD and RSD among tillage practices at the deeper soil profile below 60cm. PT and RT markedly improved the root-bleeding sap rate in the whole growth stages in 2011 and most growth stages in 2012. In addition, NH4+ and NO3− delivery rate under PT were significantly higher than those under RT and NT in 2011 and 2012, and under RT were significantly higher than under NT in 2012. The delivery rate of P, K, Ca, Mg, Fe and Zn in bleeding sap under PT was significantly higher than those under NT at different growing stages across the two years. Our results suggested that short-term PT and RT could increase root biomass, improve root spatial and temporal distribution, and enhance nutrients uptake, which resulted in higher biomass and grain yield of summer maize in the North China Plain.

Effects of the penetration of Artemisia vulgaris L. into maize crops as a result of the use of reduced tillage

In recent years, a significant increase in weed infestation of agricultural crops with <em>Artemisia vulgaris </em>has been observed in the south-western region of Poland. The ease of migration of this expansive species results from the fact that it does not face competition from segetal weeds and therefore poses a great threat to the ecological balance. During the period 2008–2011, a floristic study was carried out using the Braun-Blanquet method in an abandoned field adjacent to a maize monoculture grown under two tillage systems: plough and ploughless tillage. These observations allowed an evaluation of the actual risk of spread of <em>Artemisia vulgaris </em>depending on tillage system. The vicinity of the abandoned field had a significant effect on the penetration of <em>Artemisia vulgaris </em>into maize crops. Higher numbers of individuals of this species were found under ploughless tillage compared to plough tillage, regardless of the distance from the field edge, and its increased competitive effects on <em>Viola arvensis </em>L. and <em>Veronica persica </em>L. could be observed. The lowest grain yield was obtained under ploughless tillage where the strong competitive effects of <em>Artemisia vulgaris </em>were observed even in the plot most distant from the abandoned field adjacent to the maize crop.

Availability and uptake of trace elements in a forage rotation under conservation and plough tillage

After 14 years under conventional plough tillage (CT) or conservation minimum tillage (MT), the soil available Al, Fe, Mn, Cu, and Zn (0–5, 5–15, and 15–30cm layers) and their plant uptake were evaluated during two years in a ryegrass-maize forage rotation in NW Spain (temperate–humid region). The three-way ANOVA showed that trace element concentrations in soil were mainly influenced by sampling date, followed by soil depth and tillage system (35–73%, 7–58%, and 3–11% of variance explained, respectively). Excepting for Fe (CT) and Al (CT and MT), the elemental concentrations decreased with depth, the stratification being stronger under MT. For soil available Al, Fe, Mn, and Cu, the concentrations were higher in CT than in MT (5–15 and 15–30cm layers) or were not affected by tillage system (0–5cm). In contrast, the available Zn contents were higher in MT than CT at the soil surface and did not differ in deeper layers. The concentration of Al, Fe, and Cu in crops was not influenced by tillage system, which explains 22% of Mn variance in maize (CT>MT in the more humid year) and 18% of Zn variance in ryegrass (MT>CT in both years). However, in the summer crop (maize) the concentrations of Fe, Mn, and Zn tended to be higher in MT than in CT under drought conditions, while the opposite was true in the year without water limitation. Therefore, under the studied conditions of climate, soil, tillage, and crop rotation, little influence of tillage system on crop nutritive value would be expected. To minimize the potential deficiency of Zn (maize) and Cu (maize and ryegrass) on crop yields the inclusion of these micro-nutrients in fertilization schedule is recommended, as well as liming to alleviate Al toxicity on maize crops.

Effects of no-till duration on the methane oxidation capacity of Alfisols

Frequent tillage negatively affects the methane (CH4) oxidation capacity of agricultural soils. The restoration of that capacity of soils through no-tillage (NT) adoption has been suggested, but is not well documented. With the expectation of increased CH4 oxidation with longer NT duration, a tillage chronosequence study was conducted at paired sites in Ohio under conventional tillage (or plow till, PT) and NT for 9, 13, 36, and 48 years. Nearby deciduous forests were also included to estimate the maximum oxidation capacity of undisturbed local soils. Surface soil samples (0–5, 5–10, 10–20, 20–30 cm) were collected in April (soil moisture 29 %) and in August 2010 (moisture 19 %), sieved (6.3 mm), and incubated (initial CH4 5 μl L−1) to determine the CH4 oxidation capacity. The results showed a significant effect of tillage practice on CH4 oxidation. With the exception of the site under NT for 9 years, the CH4 oxidation rates were consistently higher (2–40 times) in NT than in PT soils during both the April and August sampling dates. A similar effect of NT was also observed when incubation was conducted with intact soil cores, but the rates were lower, perhaps due to restriction of CH4 diffusion in the cores. Across the sampling dates and depth, the CH4 oxidation capacity increased linearly with NT duration averaging 3.2, 4.2, 11.5, and 13.6 μg CH4-C kg−1 soil day−1 at sites under NT for 9, 13, 36, and 48 years, respectively. While the CH4 oxidation rate in PT soil was 10–12 % of the level in the forest soils, it was 36–37 % at sites under NT for >30 years. These results demonstrate the positive effect of NT on the CH4 oxidation in soils and the potential impact of continued NT maintenance on the CH4 sink strength of agricultural soils.

Effects of long-term and recently imposed tillage on the concentration and composition of amino sugars in a clay loam soil in Ontario, Canada

Tillage disturbance influences soil microorganisms and consequently the production and decomposition of microbial residues such as amino sugars. However, our understanding is still limited with respect to the changes in amino sugars which occur in soil after tillage operations. In this study, changes in amino sugars in a clay loam soil (mesic Typic Argiaquoll) in Ontario, Canada were tracked in long-term (29 years) no-tillage (NT), long-term conventional moldboard plow tillage (MP), and long-term bluegrass (Poa pratensis L.) sod (BG) as well as when long-term (13 years) NT was converted to MP, long-term MP was converted to NT, and long-term BG was converted to MP. Our objective was to determine if the quantity of amino sugars in the soil as well as their composition (i.e. whether they originate from bacterial or fungal residues) would respond to changes in tillage practices. We also wanted to evaluate the effects of converting from grassland to arable cropping (corn and soybean) on the amino sugar composition of soils. Soil samples were collected at depths of 0–5, 5–10, and 10–20cm after 1 (1997), 6 (2002), 11 (2007), and 16 (2012) years following tillage conversion. Concentrations of amino sugars were much greater under long-term BG than under both long-term NT and MP treatments. In the 0–5cm depth, long-term NT significantly increased total amino sugars and fungal-derived glucosamine (GluN) by 18 and 25%, respectively, compared with long-term MP whereas long-term NT had 26% lower MurA concentrations than long-term CT. Concentrations of total amino sugars in the 0–5cm depth were reduced significantly within the first year after conversion of long-term NT and BG to MP, due primarily to decreases in the GluN concentrations. On the other hand, concentrations of amino sugars in soil accumulated gradually after conversion of long-term MP to NT. The results confirmed our hypothesis that loss of soil amino sugars is rapid and substantial when MP is initiated after NT and BG, while their recovery is gradual when NT is initiated after MP.

Balanço energético da produção de grãos, carne e biocombustíveis em sistemas especializados e mistos

O objetivo deste trabalho foi avaliar a eficiência energética de sistemas especializados e mistos de produção de grãos e carne e o balanço energético na produção de bioenergia. Foram avaliados dados de 20 anos de cultivo com sistemas agrícolas especializados e mistos. Como sistemas agrícolas especializados, avaliaram-se: a pastagem de gramínea; a pastagem de gramínea consorciada com leguminosa; e a produção de grãos em sistema plantio direto ou em sistema convencional de preparo do solo. Como sistema misto, considerou-se a integração lavoura-pecuária em dois sistemas de manejo. Os insumos utilizados foram considerados como o ingresso energético, enquanto a produção de grãos e carne, as saídas de energia. Os produtos agrícolas nos sistemas mistos apresentaram balanço energético e produção absoluta de energia renovável compatíveis com aqueles produzidos em sistemas especializados. O balanço energético do biocombustível de soja apresentou valores positivos tanto em sistemas mistos como especializados, independentemente do sistema de preparo do solo. Entre os biocombustíveis de soja e milho analisados, o maior balanço energético foi observado no bioetanol produzido com milho. Os biocombustíveis produzidos em todos os sistemas apresentam balanço energético positivo e podem ser considerados energeticamente sustentáveis.

Tillage, Mulch and N Fertilizer Affect Emissions of CO2 under the Rain Fed Condition

A two year (2010–2012) study was conducted to assess the effects of different agronomic management practices on the emissions of CO2 from a field of non-irrigated wheat planted on China's Loess Plateau. Management practices included four tillage methods i.e. T1: (chisel plow tillage), T2: (zero-tillage), T3: (rotary tillage) and T4: (mold board plow tillage), 2 mulch levels i.e., M0 (no corn residue mulch) and M1 (application of corn residue mulch) and 5 levels of N fertilizer (0, 80, 160, 240, 320 kg N/ha). A factorial experiment having a strip split-split arrangement, with tillage methods in the main plots, mulch levels in the sub plots and N-fertilizer levels in the sub-sub plots with three replicates, was used for this study. The CO2 data were recorded three times per week using a portable GXH-3010E1 gas analyzer. The highest CO2 emissions were recorded following rotary tillage, compared to the lowest emissions from the zero tillage planting method. The lowest emissions were recorded at the 160 kg N/ha, fertilizer level. Higher CO2 emissions were recorded during the cropping year 2010–11 relative to the year 2011–12. During cropping year 2010–11, applications of corn residue mulch significantly increased CO2 emissions in comparison to the non-mulched treatments, and during the year 2011–12, equal emissions were recorded for both types of mulch treatments. Higher CO2 emissions were recorded immediately after the tillage operations. Different environmental factors, i.e., rain, air temperatures, soil temperatures and soil moistures, had significant effects on the CO2 emissions. We conclude that conservation tillage practices, i.e., zero tillage, the use of corn residue mulch and optimum N fertilizer use, can reduce CO2 emissions, give better yields and provide environmentally friendly options.

Soil Organic Carbon Stocks as Affected by Tillage Systems in a Double-Cropped Rice Field

Tillage practices can potentially affect soil organic carbon (SOC) accumulation in agricultural soils. A 4-year experiment was conducted to identify the influence of tillage practices on SOC sequestration in a double-cropped rice (Oryza sativa L.) field in Hunan Province of China. Three tillage treatments, no-till (NT), conventional plow tillage (PT), and rotary tillage (RT), were laid in a randomized complete block design. Concentrations of SOC and bulk density (BD) of the 0–80 cm soil layer were measured, and SOC stocks of the 0–20 and 0–80 cm soil layers were calculated on an equivalent soil mass (ESM) basis and fixed depth (FD) basis. Soil carbon budget (SCB) under different tillage systems were assessed on the basis of emissions of methane (CH4) and CO2 and the amount of carbon (C) removed by the rice harvest. After four years of experiment, the NT treatment sequestrated more SOC than the other treatments. The SOC stocks in the 0–80 cm layer under NT (on an ESM basis) was as high as 129.32 Mg C ha−1, significantly higher than those under PT and RT (P < 0.05). The order of SOC stocks in the 0–80 cm soil layer was NT > PT > RT, and the same order was observed for SCB; however, in the 0–20 cm soil layer, the RT treatment had a higher SOC stock than the PT treatment. Therefore, when comparing SOC stocks, only considering the top 20 cm of soil would lead to an incomplete evaluation for the tillage-induced effects on SOC stocks and SOC sequestrated in the subsoil layers should also be taken into consideration. The estimation of SOC stocks using the ESM instead of FD method would better reflect the actual changes in SOC stocks in the paddy filed, as the FD method amplified the tillage effects on SOC stocks. This study also indicated that NT plus straw retention on the soil surface was a viable option to increase SOC stocks in paddy soils.

Tillage and nitrogen fertilization effects on yield and nitrogen use efficiency of irrigated cotton

Management practices may influence yield and nitrogen (N) use efficiency of irrigated cotton (Gossypium hirsutum L.) in irrigated arid lands such as those of the Aral Sea basin. A field experiment was conducted to compare the effects of conservation tillage (permanent raised beds; PB) with conventional plow tillage (CT) under three different N application rates (0, 125 and 250kgha−1) on cotton growth, yield, N use efficiency and N balance in irrigated arid lands of Uzbekistan for two years. Raw cotton yield and yield components were not affected by tillage methods in both years. However, yield and yield components significantly increased when N fertilizer rate was increased from zero to 125kgha−1N application. When the N rate was doubled from 125 to 250kgha−1, a relatively much lower increment was observed in both tillage methods. The groundwater nitrate concentration was reduced considerably, while efficiency of applied N was increased in 2009, i.e., after introduction of the cover crop in the cotton mono cropping system, compared to 2008. The efficiency of the applied N decreased with increased N application rate. Tillage method did not affect agronomic N use efficiency in both years. However, in the 2nd year, apparent N recovery efficiency was higher in PB than in CT, while physiological N use efficiency with N-250 was 54% lower in PB than in CT. The apparent system N balance was negative with N-0 and N-125, but positive (N loss) with high N application (250kgha−1) with both tillage methods. A significant interaction effect between tillage and N level was observed; with N-0, CT had a 32% higher negative N balance than PB. With N-250, CT had a significantly higher positive N balance (N loss), more than twice as high (66kgha−1) as for PB. Thus, cotton cultivation in PB with proper N application and the introduction of a winter cover crop can be considered a viable alternative to the present unsustainable CT cotton mono-cropping system in irrigated arid lands, assuming the patterns are confirmed in the long-run.

Long-term impacts of residue harvesting on soil quality

Development of the cellulosic bioenergy industry raises the prospect of wide spread stover harvesting in the near future; however, the impact of stover harvesting on soil quality may not be apparent for several years. Here we evaluate the impact of 19 years of either zero or approximately 90% removal of above ground crop residue on soil quality. The 0–5, 5–15, and 15–30cm soil depths of Waukegan silt loam (Typic Hapludoll) from east-central Minnesota were sampled from plots after 12 and 7 years of maize and soybean cropping, respectively. On average for the 0–5 and 5–15cm depths, soil organic C was 12% less, total N was 12.6% less, N mineralization potential was 27.7% less, cation exchange capacity was 7.3% less, macro aggregation was 13.0% less, and total respiration was 12.3% less for plots with residue harvesting relative to plots where residue was not harvested. Minimal impacts of residue harvesting were apparent for the 15–30cm soil samples, except N mineralization potential which was 28% lower for plots with residue harvesting. Declines in soil quality indicators due to residue harvesting were only slightly less severe for no-tillage plots relative to chisel and moldboard plow tillage plots. We conclude that harvesting 90% of above ground residue for 19 years resulted in substantial degradation of soil quality, and that the impact on N mineralization potential was substantially larger than the loss of total N, suggesting that labile organic N was selectively depleted. We also conclude that stover harvesting for bioenergy production could cause similar degradation of soil quality unless management practices that increase C inputs to soils are also implemented.

Morfologia e propriedades físicas de solo segundo sistemas de manejo em culturas anuais

Qualidade física do solo é sua capacidade de sustentar o pleno desenvolvimento das plantas. O objetivo deste trabalho foi estudar diferentes sistemas de semeadura direta para a produção de grãos em áreas de agricultura familiar sob Latossolo Vermelho no norte do Paraná, Brasil, através do estudo da morfologia e de algumas propriedades físicas do solo. O estudo foi baseado na descrição da estrutura de solo de perfis culturais em áreas cultivadas com lavouras anuais sob diferentes sistemas de manejo de solo (semeadura direta com e sem rotação de culturas, semeadura direta com escarificação eventual e o cultivo mínimo). Concomitantemente à descrição dos perfis foi determinada a resistência do solo a penetração, a densidade do solo, a umidade do solo e o grau de floculação da argila. Cada manejo estudado foi caracterizado por um tipo de estrutura de solo a qualse correlacionou com os valores de resistência, densidade e grau de floculação e em todos os manejos estudados abaixo dos 0,30 m, os perfis analisados apresentavam condições estruturais satisfatórias ao desenvolvimento radicular.

The effects of conservation tillage practices on the soil water-holding capacity of a non-irrigated apple orchard in the Loess Plateau, China

Six tillage practices were studied in an apple orchard located in the Loess Plateau from 2007 to 2009. The objective was to investigate the effects of tillage practices on the soil water-holding capacity in a non-irrigated orchard in China. The results showed that different tillage practices had varied effects on the water-holding properties. Subsoil tillage with straw mulching, plow tillage with straw mulching and no tillage with straw mulching showed a decrease in the soil bulk density and an increase in the soil porosity, soil saturated water content and soil moisture relative to plow tillage in bare soil (i.e., conventional tillage). Among these three tillage practices, the subsoil tillage with straw mulching and no tillage with straw mulching treatments had a significant effect on the soil porosity, soil saturated water content and soil moisture compared to the plow tillage with straw mulching treatment. These results indicate that the subsoil tillage with straw mulching, plow tillage with mulching and no tillage with mulching treatments improved the soil structure and water-holding capacity of the apple orchard. However, the no tillage with bare soil and no tillage with grass treatments increased the soil bulk density and decreased the soil porosity and soil moisture content compared to conventional tillage. This finding demonstrates that no tillage with bare soil and no tillage with grass had adverse effects on the soil structure and water-holding capacity. From the results of this study, we concluded that the subsoil tillage with straw mulching treatment is the optimum practice of the six studied treatments for improving the soil water-holding capacity in this non-irrigated apple orchard in the Loess Plateau of China.

Nitrous oxide emissions under a four-year crop rotation system in northern Japan: impacts of reduced tillage, composted cattle manure application and increased plant residue input

In the context of their role in global warming, nitrous oxide (N2O) emissions from agricultural soil under different management practices were studied in Hokkaido, northern Japan. To assess the impacts of reduced tillage, composted cattle manure-based fertilization and amendments with crop residues and green manure on N2O emissions from soil, a field experiment was conducted under a four-year crop rotation on a well-drained Andisol. The crop rotation included potato (Solanum tuberosum L.) or sweet corn (Zea mays L.), winter wheat (Triticum aestivum L.), sugar beet (Beta vulgaris L. subsp. vulgaris) and soybean (Glycine max (L.) Merr.). The cumulative N2O emissions for the four-year study period differed widely (0.33 to 4.90 kg N ha−1), depending on the treatments imposed, being the greatest for a combination of conventional moldboard plow tillage, composted cattle manure-based fertilization and increased plant residue input, and the lowest for a combination of conventional tillage, chemical fertilizer-based fertilization and normal plant residue input treatments. The cumulative N2O emissions under reduced tillage were all small, irrespective of fertilization and plant residue input treatments. Composted cattle manure-based fertilization (P ≤ 0.01) and increased plant residue input (P ≤ 0.01) significantly increased cumulative N2O emissions. Tillage showed a significant interaction with fertilization and plant residue input, indicating that N2O emissions were enhanced when composted cattle manure, crop residues and green manure were incorporated by conventional tillage. In the present study, the N2O emission factors for chemical fertilizer, composted cattle manure and crop residues were 0.26 ± 0.44, 0.11 ± 0.16 and −0.03 ± 0.52%, respectively, all much lower than the country-specific emission factor for Japan's well-drained soils (0.62%) and the default emission factor used in the IPCC guideline (1%).

The effect of tillage systems on soil seedbank

The research was carried out in 2006–2008 in a static field experiment started in 1993 in the Research Field Station at Lipnik near Stargard Szczeciński, on Eutric Cambisol soil. In soil samples taken from following layers: 0–10, 10–20, 20–30 cm of soil under ploughing, ploughless or direct drilling tillage systems, species composition and number of weed diaspores were evaluated. In the samples, in total there were diaspores of 17 weed species. &lt;em&gt;Chenopodium album &lt;/em&gt;was the dominant weed species in all soil layers and tillage systems. The number of diaspores was significantly dependent on tillage system and soil layer. Irrespective of soil depth, the highest total number of diaspores (12251 pcs × m&lt;sup&gt;-2&lt;/sup&gt;) was in the treatment with the ploughing tillage system, while for the other treatments this number was significantly lower: by 14% for ploughless tillage and by 51% for the direct drilling treatment. Regardless of soil tillage system, the highest total number of diaspores (19936 pcs × m&lt;sup&gt;-2&lt;/sup&gt;) was in the top layer, while in the next layers this number was significantly lower (by 62 and 87%, respectively). The largest number of weed diaspores was in the top layer of soil after long application of the ploughless tillage system.

Effect of tillage systems on soil properties, humus and water conservation

Human action upon soil by tillage determines important morphological, physical-chemical and biological changes, with different intensities and evaluative directions. Nowadays, it is internationally accepted the fact that global climatic changes are the results of human intervention in the bio-geo-chemical water and material cycle, and the sequestration of carbon in soil is considered an important intervention to limit these changes. Carbon sequestration in soil is net advantageous, improving the productivity and sustainability. The more the organic content in soil is higher the better soil aggregation is. The soil without organic content is compact. This reduces its capacity to infiltrate water, nutrients solubility and productivity, and that way it reduces the soil capacity for carbon sequestration. Organic matter is an extremely important constituent of soils and is vital to many of the hydrological, biological and chemical reactions required for sustaining plant life. We present the influence of conventional plough tillage system on soil, water and organic matter conservation in comparison with an alternative minimum tillage system (paraplow, chisel plow and rotary harrow). The application of minimum tillage systems increased the organic matter content 0.8% to 22.1% and water stabile aggregate content from 1.3% to 13.6%, in the 0 - 30 cm depth, as compared to the classical system. For the organic matter content and the wet aggregate stability, the statistical analysis of the data showed, increasing positive significance of minimum systems. While the soil fertility and the wet aggregate stability were initially low, the effect of conservation practices on the soil features resulted in a positive impact on the water permeability of the soil. Availability of soil moisture during the crop growth resulted in better plant water status. Subsequent release of conserved soil water regulated proper plant water status, soil structure, and lowered soil pene-trometer resistance.

Nohut Tariminda Farkli Toprak Isleme Yöntemlerinin Ürün Verimi ve Bazi Verim Unsurlarina Etkilerinin Belirlenmesi

This study was carried out to determine the effects of different soil tillage methods on crop yield and some yield components in chickpea cultivation. For this reason, experimental trials were performed in Caykoy and Guzelpinar in Tokat-Kazova during 2008, 2009 and 2010. In this trials Gokce cultivar of chickpea was used. Six different soil tillage methods were applied which were, mouldboard plough tillage in fall + cultivator in the spring + tooth harrow (Method A), mouldboard plough tillage in spring + cultivator + tooth harrow (Method B), rotary tiller in the spring (Method C), chisel in the spring + disc harrow and slider (Method D), strip tillage with router rotary hoe (Method E) and direct seeding (Method F). Trials were set up in completely randomized block design with three replications. The results indicated that the highest average plant and seed yield per square meter was obtained with method A (470.74 g and 260.63 g) and followed by method B (459.43 g and 254.18 g) and method D (447.82 g and 247.23 g). In terms of factors evaluated; A, B and D methods were superior compared to the other methods.

Depth dependence of chisel plow tillage erosion

Tillage disturbs the soil vertically, and throws soil in the tillage direction. Tillage movement and disruption of soil is not uniform vertically or horizontally. Tracers have been used to document either the vertical or the horizontal disturbance by tillage, but few studies have examined both the vertical and horizontal tracer displacement by tillage. The objective is to document the vertical and the down- or up-slope movement of inert tracers by chisel plow. Colored limestone was applied at the soil surface (yellow) or at 10cm depth (blue) before chisel plowing up or down the slope. Samples were collected vertically close to the tracer application and up or down slope. Tracers were separated from the soil for each vertical and horizontal increment, and bulk densities were determined for each increment. Surface applied tracers declined with depth, and most tracers were above 12cm depth. Tracers applied at 10-cm depth ended up predominately at 4–10cm depth. Surface applied tracers were moved down slope to greater than 3m, and upslope to nearly 2m distance. Tracers applied at 10-cm depth did not move up or down slope much distance, if any, beyond the application zone. The overall erosion flux rate was 104kgm−1, near the low end of published fluxes. The results confirmed the importance of tillage erosion to soil redistribution, and that chisel plow primarily moves soil near the surface rather than the whole tillage depth.

Sistemas de manejo e rotação de culturas no rendimento de grãos e nas características agronômicas de trigo

The adoption of conservation practices can affect the soil properties and, consequently, the yield crop. From 2003 to 2010, the effects of soil managements and crop rotations were assessed in Passo Fundo, Rio Grande do Sul. Four soil management: 1) no-tillage, 2) chisel plow tillage, 3) conventional tillage using disk plow, and 4) conventional tillage using moldboard plow and three crop rotation systems: system I - wheat/soybean; system II - wheat/soybean and common vetch/sorghum; and system III - wheat/soybean, common vetch/sorghum, and white oats/soybean were compared. A random block design with split-plots and three replications was used. The main plot consisted of soil management systems, while the split-plots consisted of crop rotation systems. Wheat yield and final plant population grown under no-tillage was higher than that of wheat grown under conventional soil tillage using either disk plow or moldboard plow and minimum tillage. But tillage systems did not affect significantly severity of rootdiseases and weight of 1,000 kernels. The system III (wheat/soybean, common vetch/sorghum, and white oats/soybean) showed higher yield, higher weight of 1,000 kernels, hectolitre weight and harvest index than the systems I and II (monoculture wheat/soybean) and a winter without wheat (wheat/soybean and vetch/sorghum). The final population the plants was the lowest in the system I in comparison to systems II and III.

Twenty two years of tillage and mulching impacts on soil physical characteristics and carbon sequestration in Central Ohio

Knowledge about the changes in carbon (C) concentration and mechanical and hydrological properties under different tillage and mulch treatments is necessary to assess the feasibility of adoption of conservation practices for sustaining productivity and protecting the environment. It is widely recognized that no-till (NT) farming conserves soil and water, saves energy, improves the environment and enhances soil quality. However, the magnitude and direction of tillage and mulch-induced changes are soil and site specific. Therefore, a field study was conducted on a long-term on-going experiment to evaluate the effects of three tillage {NT, ridge till (RT) and plow till (PT)} and three mulch rates (0, 8 and 16Mgha−1yr−1) on soil physical properties and total C concentrations in macro (250–2000μm) and micro (<250μm) aggregates. The experiment was initiated in 1989 on a Crosby Silt Loam (Stagnic Luvisol) in Central Ohio. The data show positive effects of mulch rate on soil physical attributes and total C concentration under NT. Significant (P<0.05) variations in bulk density (ρb) and penetration resistance (PR) along with their interactions were observed among tillage and mulch treatments. The water infiltration capacity (ic) ranged from 1.2cmh−1 (PT) to 4.6cmh−1 (NT). With increase in mulch rate from 0 to 16Mgha−1, saturated hydraulic conductivity (Ks) for 0–10cm depth increased from 1.78 to 3.37, 1.57 to 2.95 and 1.37 to 2.28 (×10−2cmh−1) under NT, RT and PT, respectively. Analyses of variance indicate significant interaction between tillage, mulch and soil depth for the Ks. Similarly, the mean weight diameter (MWD, mm) increased from 0.36 to 1.21, 0.29 to 0.84, 0.25 to 0.62 under NT, RT and PT, respectively, with increase in mulch rate from 0 to 16Mgha−1. Total C (%) increased from 1.26 to 1.50, 1.20 to 1.47 and 0.95 to 1.10 under NT, RT and PT, respectively, with increase in mulch rate from 0 to 16Mgha−1. Macro-aggregates (250–2000μm) contained 30% more total C and N concentrations than microaggregates (<250μm). Under NT, the soil showed a higher structural stability than PT with significantly lower compaction values. Further, with NT the soil showed a higher capacity to retain C than PT. Thus, long term use of NT along with mulch application enhances soil quality with respect to soil mechanical, hydrological properties along with carbon concentration in the soil.