Conventional Tillage Treatments Research Articles

Soil Macrofauna Abundance and Taxonomic Richness under Long-Term No-Till Conservation Agriculture in a Semi-Arid Environment of South Africa

Soil macrofauna are a critical component for ecosystem function and strongly affect production sustainability. The effect of fertiliser management practices, in different cropping systems, on soil macrofauna communities remains poorly understood in semi-arid to arid regions. The objective of this study was to investigate the effect of tillage practices i.e., no-till (NT), rotational tillage (RT) and conventional tillage (CT) and nitrogen fertiliser application rates (0, 100 and 200 kg/ha N) (urea) on abundance and order diversity of soil macrofauna in a maize continuous monocropping system. The sampling of macrofauna in the trial was conducted in April 2019, August 2019 and March 2020 using 25 cm × 25 cm × 25 cm steel monoliths in randomly selected positions, and this was replicated four times. The study found a significant (p < 0.05) increase in the abundance of soil macrofauna in NT (127 ind/m2) and RT (110 ind/m2) compared to CT (51 ind/m2) treatment. The abundance of macrofauna was also negatively affected by increasing the rate of fertiliser, with 0, 100 and 200 kg/ha resulting in 133, 94 and 62 ind/m2. Orders Haplotaxida and Diplopoda were found to be sensitive to increases in the fertiliser application rate. Haplotaxida (48.4%) was the most abundant order, followed by Coleoptera (18.2%). Other orders included Diplopoda (9.2%), Gastropoda (6.3%), Isoptera (4.7%), Chilopoda (4.7%), Araneae (4%), Hymenoptera (3.2%), Orthoptera (0.9%) and Dermaptera (0.3%). No-till (NT) and rotational tillage (RT) with mulch favoured the establishment of various macrofauna communities in the studied cropping system.

Phosphorus fertilizer application and tillage practices influence bacterial community composition: implication for soil health

ABSTRACT Microorganisms are important in maintaining soil quality and contribute to plant nutrient uptake and pathogen resistance. However, intensive tillage and inappropriate fertilizer management distorts these important functions. This study therefore investigates the influence of tillage practices and P-fertilizer management on plant beneficial bacteria. The bacterial communities were profiled using DNA metabarcoding. Actinobacteria (40%) and Proteobacteria (21%) were the most abundant phyla in both the No-tillage (NT) and Conventional-tillage (CT) treatments. Alpha diversity analysis revealed that differences in P application influenced diversity. The bacterial community structure was significantly impacted by tillage practices. Plant beneficial bacteria including Lysobacter, Dyella, Sphingomonas and Dactylosporangium were among biomarkers in the NT treatment. Pathways for energy metabolism and the biosynthesis of siderophores were significantly influenced by both P-fertilizer application and tillage practices. Co-occurrence analysis revealed that the CT treatment reduced the efficiency of the bacterial communities while keystone species with potential for plant pathogen suppression were more in the NT treatment. Overall, this study demonstrates that tillage practices induce bacterial compositional changes, with the NT treatment exhibiting greater potential in promoting the stability and proliferation of plant beneficial bacteria, while P fertilizer influences diversity and community putative functions, regardless of tillage practice.

Conservation agriculture for increasing productivity, profitability and water productivity in rice-wheat system of the Eastern Gangetic Plain

There are increasing concerns about the negative effects of conventional tillage (CT), extreme climate events, increased weed incidence, and reduced availability of farm inputs on crop yield and yield stability, profitability, and water productivity in rice-wheat (R−W) systems of the Eastern Gangetic Plains (EGP) in South Asia. Conservation agriculture (CA)-based tillage practices have been proposed in the region to address these concerns. We analysed 84 on-farm trials’ data comparing CA-based practices with farmers’ CT practices in R−W systems of eastern Terai region of Nepal in the EGP. The objectives were to investigate crop and cropping systems productivity, profitability, yield stability, irrigation (WPi) and total water productivity (WP(r+i)), and fertilizer-use efficiencies of three CA- and one CT-based practices in R−W systems. Treatments included: (i) CT-based: puddled transplanted rice - conventional tillage wheat (PTR−CTW); (ii) CA-based: PTR − zero tillage wheat (PTR−ZTW); (iii) CA-based: direct-seeded rice − ZTW (DSR−ZTW); and (iv) CA-based: un-puddled transplanted rice − ZTW (UPTR−ZTW). Results showed that although there were no significant differences in yield of either rice or wheat or R−W system between CA-based and CT treatments, there was a significant reduction in production cost (by 245−369 USD ha−1) mainly due to reduced labor use and increased net gain (188−223 USD ha−1) in all CA-based R−W system. DSR−ZTW showed the highest yield stability and net profit, demonstrating its adaptability in the region. Among the irrigation applicators (35%) in rice, DSR used 107 mm (67 mm higher than PTR) irrigation water with WPi of 70% and 96% of PTR and UPTR, respectively due to the need of additional irrigation for crop establishment. In contrast, among the irrigation applicators (75%) in wheat, due to earlier sowing of ZTW, it required 18% less irrigation water resulting in 9% higher WPi compared to CTW. However, a follow-up study two years after completion of field trials revealed that no local farmers had continued CA-based practices mainly due to high weed pressure, lack of land leveling, inaccessibility of zero-till (ZT) drill machines, and lack of ZT service providers. Effective support systems incentivizing in land leveling, ZT machines, technical knowledge dissemination, and the development of integrated weed management practices for scaling-out strategies are essential to adopt CA-based practices. As the results have great implications to reduce production costs and increase farm profits, save energy and water, increase land and labor productivity, and improve food security of millions of smallholder farmers in the EGP, strong policy support to incentivize farmers to avoid the adoption barriers of CA-based practices is required.

Is it Sustainable to Cultivate a Monoculture of Durum Wheat with Prolonged No-Tillage Management?

The prolonged effect of no-tillage (NT) and conventional tillage (CT) treatment on durum wheat (Triticum durum Desf.), continuously grown in Southern Italy, has been evaluated in experimental fields for sixteen years (1994/95-2009/10) to ascertain whether the yields and quality of the grain as well as some soil characteristics had changed. The average grain yield in CT (2.70 ± 0.96 t ha-1) and NT (2.63 ± 0.74 t ha-1) treatment was not significant. CT treatment showed higher values of plant height and grain weight (74.2 cm and 43.2 g) than NT (71.0 cm and 41.8 g). Regarding to the semolina quality, the values of the gluten index and the dough strength (W parameter) as well as the protein content and the yellow index were not significantly different for the NT and CT treatments. As for soil moisture, the NT treatment stored in the soil profile, and over time, about 13% more water than the CT one. In the upper soil layer of the NT treatment the SOC value (16.0 ± 2.2 g kg-1) was 13.2% higher than CT one (14.2 ± 1.2 g kg-1) while the CT treatment (13.7 ± 0.5 g kg-1) showed in the lower soil layer a SOC value of 30.2% higher than the NT one (9.6 ± 1.9 g kg-1). Hence the prolonged no-tillage adoption in conditions of continuous durum wheat cultivation, even with slight losses in yield but not in the quality of grain or semolina, would seem sustainable.

Evaluation of conservation tillage practices in the production of organic flue‐cured tobacco

AbstractIntensive tillage in flue‐cured tobacco (Nicotiana tabacum L.) contributes to soil erosion and reduced water‐holding capacity of soils. Conservation tillage minimizes soil disturbance by planting a crop directly into the residue of overwintered cover crop. Reducing tillage has been shown to improve soil health (increased rainwater infiltration, improved water‐holding capacity, reduced erosion) and to reduce production costs (fuel and labor). The objective of this study was to compare the effects of conservation and conventional tillage on weed management in organically grown flue‐cured tobacco. Field studies were conducted in Kinston, NC, in 2019 and 2020 and in Rocky Mount, NC, in 2020, comparing the impacts of conventional tillage and conservation tillage on weed emergence and tobacco production. An overwintered cereal rye (Secale cereal L.) cover crop was conventionally tilled or terminated via roller‐crimper and left in place as a mulch prior to transplant of flue‐cured tobacco. Cover crop biomass, weed emergence and biomass, soil resistance, crop yield and quality, and cured leaf chemistry were evaluated. In all environments, conservation tillage with cover crop residue reduced weed density and biomass when compared with conventional tillage treatments. In 2019, cured leaf yield was higher under conservation tillage practices than under conventional tillage. In 2020, environmental conditions in both locations resulted in crop loss. These results indicate that conservation tillage practices may be an effective weed management strategy while improving yields in an organic production system. However, organic flue‐cured tobacco grown under conservation tillage is vulnerable to extreme rain events due to the exclusion of in‐season cultivation.

Simulation of maize and soybean yield using DSSAT under long-term conventional and no-till systems

Context No-tillage (NT) has been gaining popularity over the conventional tillage (CT) for agricultural sustainability. Field experiments conducted worldwide to compare crop production under NT vs CT systems are generally site specific and expensive to maintain over longer duration. To overcome this gap, process-based models have been used to simulate the potential impact and benefits of various management practices on crop yield and soil properties under different environmental conditions. Aims (1) We evaluated the Cropping System Model (CSM)-CERES-Maize and CSM-CROPGRO-Soybean model for NT and CT systems; and (2) compared the long-term impacts of NT and CT on crop yield and soil organic carbon (SOC). Methods Two crop models, available in the Decision Support System for Agrotechnology Transfer (DSSAT), were calibrated and evaluated using maize (Zea mays L.) and soybean (Glycine max L.) yield data from 2006 through 2011 under CT and NT treatments. Key results For crop yield, we showed that the coefficient of determination (R2) for the calibration and evaluation phases of CERES-Maize model were 0.94 and 0.94, respectively, while the index of agreement (d) for these phases were 0.93 and 0.86. Similarly, the R2 values for the calibration and evaluation phases of CROPGRO-Soybean model were 1.00 and 0.65, respectively, with d-values of 0.99 and 0.85. Conclusions The results from these long-term (30-year) simulations suggest that compared to CT, the NT system enhanced SOC over time and, hence, crop yield and biomass production. Implications Application of NT can be beneficial for enhancing the soils and crop production in the long-term as compared to the CT system.

Evaluation of Tillage Systems on Wheat Crop Production Under Surface and Sprinkler Irrigation Methods: Application for Rural Areas Close to Baghdad, Iraq

This study investigated the effect of soil conservation tillage systems on the growth and productivity of wheat crops under surface and sprinkler irrigation. Field trials were conducted in 2016–2017 and 2017–2018 using three tillage systems under a split-plot design by a systematic arrangement with three replicates. Experimental plots included two irrigation methods (surface and sprinkler), within which were sub-plots for conventional tillage (CT), minimum tillage (MT), and zero tillage (ZT). The results show that surface irrigation treatment produced the greatest wheat crop growth (plant height, length of spike and biomass) in both seasons compared to sprinkler irrigation. The CT treatments resulted in better growth than ZT and MT. However, ZT recorded a decrease in biomass and grain yield of less than 10% compared to CT during both seasons, although superior plant height resulted from CT during the second season. Even so, ZT reduced the water use to 17% and 16% for the first and second seasons, respectively. These results indicate that ZT or MT may slightly reduce wheat yield under sprinkler and surface irrigation, but will consume less irrigation water, providing a sustainable strategy in water-deficient conditions.

Cotton Weed Management Systems in Conventional and Conservation Tillage

Weed management trials were established near Lubbock, TX in 2017 and 2018 to compare systems in both conventional and conservation tillage. Four herbicide systems were included for both the conventional and conservation tillage. Conventional tillage treatments included trifluralin preplant incorporated (PPI) followed by (fb) no preemergence (PRE) fb dicamba + glyphosate + acetochlor early postemergence (EPOST) fb dicamba + glyphosate midpostemergence (MPOST), trifluralin PPI fb prometryn PRE fb dicamba + glyphosate EPOST fb dicamba + glyphosate + acetochlor MPOST, no PPI fb prometryn PRE fb dicamba + glyphosate EPOST fb dicamba + glyphosate + acetochlor MPOST, trifluralin PPI fb prometryn PRE fb glyphosate EPOST fb glyphosate + acetochlor MPOST. Conservation tillage treatments included dicamba + glyphosate early preplant (EPP) fb paraquat + prometryn PRE fb dicamba + glyphosate EPOST fb dicamba + glyphosate MPOST, dicamba + glyphosate + flumioxazin EPP fb paraquat + prometryn PRE fb dicamba + glyphosate EPOST fb dicamba + glyphosate MPOST, glyphosate EPP fb dicamba + prometryn fb dicamba + glyphosate EPOST fb dicamba + glyphosate MPOST, no EPP fb dicamba + prometryn fb dicamba + glyphosate EPOST fb dicamba + glyphosate MPOST. Visual weed control for Russian thistle, kochia, and Palmer amaranth was recorded at cotton planting and 14 days after planting. Palmer amaranth control was recorded at 14 and 28 days after the EPOST and MPOST treatments. Effective season-long control of Palmer amaranth (>98%) was achieved using various dicamba-based herbicide systems in both conventional and conservation tillage. Glyphosate-based herbicide systems controlled Palmer amaranth <53% in 2017 and <84% in 2018 due to the number of glyphosate-resistant weeds present. All dicamba treatments controlled Palmer amaranth >83% in 2017 and >98% in 2018.

Potential mechanisms of maize yield reduction under short-term no-tillage combined with residue coverage in the semi-humid region of Northeast China

No-tillage with residue coverage has been proven for protection of agricultural soils worldwide. However, in Northeast China, inconsistent maize yields under no-tillage system have hindered the broad adoption of this practice and its mechanisms in yield reduction remain unclear. This study therefore aimed to determine key factors affecting growth and yield of maize under no-tillage with residue coverage in the semi-humid region of Northeast China. The experiment included conventional tillage (CT), no-tillage with 100% residue coverage (RC), and no-tillage with 30% residue removal (RR) in maize fields in Jilin, Northeast China. From 2017 to 2019, we measured soil physical and chemical properties, phenological period (PP), dry matter accumulation (DMA), and maize yield in field experiments. The results showed that the RC and RR treatments increased soil organic C and nutrients in the 0–5 cm soil layer, and soil water content in 0–30 cm soil layers, compared with the CT treatment. However, residue coverage, especially in the RC treatment, decreased soil temperature during the early stages of maize growth and delayed the time of emergence and PP and decreased DMA and yield in maize. The maize yield of the RC treatment was 10.35% less than that of CT, whereas there was no difference between the RR and the CT treatments. Structural equation modeling (SEM) demonstrated that the reduction in soil temperature from the time of sowing to emergence under no-tillage is a primary reason for the observed reduction in maize yield. Our results indicate that no-tillage systems with partial residue cover may maintain maize yield and protect black soils in the semi-humid region of Northeast China.

Soil carbon sequestration and soil quality change between no-tillage and conventional tillage soil management after 3 and 11 years of organic farming

ABSTRACT The aim of this study was to evaluate the long-term effect of no-tillage systems in organic farming on soil carbon sequestration and soil quality, which is associated with nutrient availability. The experiment was conducted on a low-input organic farm since 2009, using a randomized complete block design with four replications. Two treatments, conventional tillage (CT) and no-tillage (NT), were tested. Soil samples were obtained after crops were harvested in 2012 and 2020 from four different soil depth layers between 0‒30 cm, and the physical and chemical properties of soil samples were measured. Data were analyzed using ANOVA with Tukey tests (α = 0.05), while the correlation was analyzed based on Pearson correlation. At 0–2.5 cm and 2.5–7.5 cm depths, soil bulk density (BD) in the NT treatment was 30% and 8% lower, respectively, in 2012, and 25% and 14% lower, respectively, in 2020 compared with the CT treatment. The NT treatment could enhance the soil organic carbon (SOC) better than CT treatment at the same depth, sequestering a greater amount of carbon in the soil. Compared with the CT treatment, SOC concentration in the NT treatment was 76% and 12% higher, respectively, in 2012, and 103% and 38% higher, respectively, in 2020. In 2012, the SOC stock showed a significant difference between NT and CT treatments only at the 0–2.5 cm soil depth, with the value being 24% higher in the NT treatment than in the CT treatment. However, in 2020, the SOC stock was 50% and 19% higher in the NT treatment than in the CT treatment at 0–2.5 cm and 2.5–7.5 cm depths, respectively. The SOC also could significantly expand cation exchange capacity (CEC) and the availability of some nutrients in the soil. However, the relationship between was weak in 2020. Moreover, the NT treatment showed better progression of humification than CT. Finally, long-term NT systems in low-input organic farming could reduce soil bulk density and enhance soil carbon sequestration and soil quality. However, this system must be complemented with the conventional approach to maintain nutrient balance for long-term management.

Mulch and no-till impacts on nitrogen and phosphorus leaching in a maize field under sub-tropic monsoon climate

Mulching and no-till are recommended practices to conserve soil water and soil health, but their effects on nutrient leaching in maize fields under monsoon rainfall need to be assessed. Soil water, soil temperature, and root and shoot growth of maize under plastic mulch, straw mulch, and no-till treatments were observed. Nitrogen (N) and phosphorus (P) leaching below a 110-cm deep lysimeter after heavy rainfall events were determined. The mulching and no-till treatments increased soil water content by 0.022–0.025 cm3/cm3 and reduced daytime soil temperature by 0.5–2.6 °C. Average leaching concentrations of total N and available P at 63 and 93 DAS (days after sowing) were 2.4 and 4.9 mg N/L and 0.12 and 0.08 mg P/L, respectively. For the control condition, the leaching concentrations of N and P decreased between 63 and 93 DAS. The mulching treatments did not influence nutrient leaching load at 63 DAS, but at 93 DAS the N leaching load increased by 181–248 g/ha and P load by 3.1–4.9 g/ha compared with the control treatment. The mulch treatments had taller shoots (5.1–18.3 cm) and a higher root-shoot ratio. The higher soil water content in the mulched treatments facilitated nutrient redistribution, plant growth, nutrient transport, and leaching. No-till increased N leaching by 103 g N/ha per leaching event but not P leaching. The no-till treatment had shorter shoots but longer roots than the conventional tillage treatment due to poor nutrient redistribution in the no-till soil. A modification in the nutrient management plan is needed to better control nutrient redistribution and minimize leaching.

Interactive Effects of Residue and Tillage Methods on Growth, Yield and Yield Components of Melon

Field experiments were conducted to investigate the effects of residue and tillage on growth and yield of melon. Tillage treatments included conventional tillage (using a moldboard plough and two passes with a disk harrow), minimum tillage (one pass with a disk harrow), and no tillage (NT). Residue treatments included the application of 0%, 30% and 60% residue. Yield and yield components were obtained for all treatments. Tillage significantly affected yield and its components (P ≤ 0.05). The maximum FWPP (2.678 kg), NFPP (6.799), D (18.49 cm), L (45.93 cm), S (12.51%) and RUE (2.470) and yield (16.17 t/ha) were recorded in the conventional tillage treatment. Also, maximum FWPP (2.192 kg), NFPP (5.353), D (16.66 cm), L (39.52 cm) and yield (12.83 t/ha) were observed in the 30% residue treatment. In terms of the interaction effects, maximum FWPP (2.850 kg), NFPP (6.790), D (20.71 cm), L (53.53 cm) and yield (17.09 t/ha) were obtained in the conventional tillage + 30% residue treatment. Therefore, the use of a moldboard plough followed by two passes with a disk harrow, in concert with 30% residue treatment, were maximizing the yield Almost all growth indicators had the optimum values in the conservation tillage treatments.

Influence of Tillage and Weed Management Practices on Yield and Nutrient Uptake of Maize

A field experiment entitled ‘Influence of tillage and weed management practices on yield and nutrient uptake of maize’ was conducted during Rabi-2018 at all India coordinated research project on Weed Management, College of Agriculture, Rajendranagar, Professor Jayashankar Telangana State Agricultural University, Hyderabad to study the effect of different tillage and weed management practices on nutrient uptake of maize. The soil of the experimental field was sandy clay loam in texture with moderately alkaline pH, low in available nitrogen, medium in available P and high in available K. The field experiment was laid out in split plot design with (five tillage practices) in main plots and (three weed management practices) in sub plots. The results revealed that highest total nitrogen uptake was recorded with conventional tillage (Transplanted rice) – zero tillage (maize) and it is on par with conventional tillage (transplanted rice) – conventional tillage (maize) treatments. The highest total phosphorus and total potassium uptake was recorded with conventional tillage (transplanted) – conventional tillage (maize) and it was on par with conventional tillage (Transplanted) – zero tillage (maize). Integrated weed management was found to be significantly superior with nutrient uptake followed by chemical weed management.

Soil nutrients and crop yield response to conservation-effective management practices in the sub-humid highlands agro-ecologies of Kenya

Crop productivity in most smallholder farming systems in Sub-Saharan Africa experience low use of soil amendment resources, low and erratic rainfall, frequent dry spells, and droughts. Rain-fed agriculture has a high crop yield potential if rainfall and soil nutrient input resources are utilized effectively. Thus, in 2011, we set up an on-farm experiment in Meru South (sub-humid) and Mbeere South (marginal sub-humid) sub-counties in upper Eastern Kenya to assess conservation-effective management (CEM) practices effects on maize (Zea Mays L.) yields response and soil nutrients. The CEM practices were; tied ridging (TR), mulching (MC), and minimum tillage (MT), with conventional tillage (CT) as a control. There were frequent dry spells and droughts during the experimental period. The experiment ran for four seasons, from the long rains season of 2011 (LR11), short rains seasons of 2011 (SR11), long rains season of 2012 (LR12), short rains 2012 (SR12), and long rains season of 2013 (LR13). In Meru South, TR and MT treatments had significantly higher phosphorus content (100% and 66%, respectively) than the control. Also, in the same site, Cu and Zn were high in MT than in CT treatments. In the Mbeere South site, the aboveground biomass yield was significantly higher in TR treatment (by 71%) than CT during SR11, while in LR12 season, it significantly increased by 72% and 46% under MC and TR treatments, respectively, than the control. The TR treatment had significantly higher aboveground biomass than the control (84% and 115%) in the SR12 and LR13 seasons. In Meru South, MC treatment had significantly higher aboveground biomass, which was significantly higher, by 39%, during the SR11 season and 46% in TR treatment in SR12 season than the control. This study highlighted tied ridging as the best-fit practice for enhancing maize crop aboveground biomass production in rain-fed farming systems of marginal lands and sub-humid regions receiving unreliable rainfall. Further, we recommend longer-term experimentation to explore CEM effects on soil nutrients.

Effects of tillage and straw mulching on the crop productivity and hydrothermal resource utilization in a winter wheat-summer maize rotation system

Tillage combined with straw mulching is an effective water-saving agricultural strategy in eastern Central China. A two-year field experiment with four treatments, including conventional tillage (CT), conventional tillage with straw mulching (CT+S), no-tillage (NT) and no-tillage with straw mulching (NT+S), was conducted on semihydromorphic soil. The objective was to investigate how tillage with straw mulching affected the soil temperature, water consumption, photosynthetic rate (Pn), grain yield, soil temperature use efficiency (TUE) and water productivity (WP) in a winter wheat-summer maize rotation system. The results indicated that straw mulching tended to increase the soil temperature before the wheat regreening stage and decrease the soil temperature during the following wheat growing season and throughout the maize growing season. Compared with CT, the soil effective accumulated temperature (EAT) under the NT+S treatment significantly decreased by 4.8% but the annual ET increased by 4.3% in the winter wheat–summer maize rotation system. The Pn and transpiration rate (Tr) at the anthesis stage of wheat under the NT+S treatment increased by 15.2% and 15.6%, respectively, and the leaf water use efficiency (LWUE) during the growing season of maize increased by 11.3% as compared with that under CT treatment. Wheat yields decreased in the order of NT+S, NT, CT and CT+S during both experimental years, and the average yield of maize under the NT+S treatment increased by 27.2% compared with that under CT. Additionally, WP values under the NT+S treatment during both the wheat and maize seasons were 7.0% and 21.8% higher than those of the CT treatment (p < 0.05), respectively. The annual yield, TUE and WP values under the NT+S treatment were much higher than those under the other treatments. Therefore, NT+S treatment has a positive effect on yield and hydrothermal resource utilization in semihydromorphic soil in eastern Central China.

The effect of tillage management on microbial functions in a maize crop at different slope positions

Determining whether agricultural soils act as sinks or sources of greenhouse gases (GHGs) requires the quantification of variations in the pools and fluxes of soil organic carbon (SOC) and nutrients, e.g. nitrogen (N), as well as the associated soil microbial responses. In this study, soil was collected from experimental plots of maize (Zea mays) under conventional, minimum or strip tillage treatments established in a sloping field (~10%) of loamy soil in SW England, UK, where maize had been cultivated conventionally for 12 years. Topsoil (0–10 cm) cores were collected from the top, mid, bottom and foot slope positions to investigate soil C, N and microbial properties. The impact of conventional management on potential GHG emissions was assessed by incubating soils collected from the top, mid and bottom slope positions from the conventional treatment. Contents of SOC and total N were greatest at the top slope position and soil mineral N (NO3−-N and NH4+-N) concentrations were greater at the bottom and foot slope positions in all treatments. Biomarker phospholipid fatty acids (PLFA) for Gram positive bacteria and fungi were relatively 13C-enriched at each slope position regardless of treatment, indicating preferential utilization of organic matter from maize (C4) rather than SOC (C3). Around 70% of carbon incorporated into total PLFA was derived from C3-SOC at the slope foot, indicating that more SOC older than 12 years was being mineralized at the depositional position. Effluxes of N2O and CO2, and total GHG emission were greatest from the incubated soils sampled from the bottom slope position, suggesting that conditions in depositional positions of regularly ploughed sloping arable fields may have increased the potential for mineralization and denitrification. We conclude that the C sink potential of the depositional positions of slopes may be diminished by coincidental GHG emissions.

Evaluating the effects of different sowing dates and tillage methods on dry-land wheat grain dry matter accumulation based on the APSIM model.

Accurate simulation of dry matter accumulation in wheat grains can provide important technical support for regulating wheat production in hilly areas of Loess Plateau. Using the APSIM model, we analyzed dryland wheat grain dry matter accumulation and distribution using the meteorological data from 1971 to 2017 in Anding District, and the field test data from 2016 to 2017 in Anjiagou Village, Fengxiang Town, Anding District, Dingxi City, Gansu Province. Furthermore, the influence of sowing date and tillage method on dry matter accumulation of wheat grain was quantitatively analyzed on the basis of model validation. The results showed that the root mean square error (RMSE) between the simulated and measured values of grain dry matter was 57.5-143.1 kg·hm-2 and the normalized root mean square error (NRMSE) was 1.4%-9.9% under the three sowing dates and four tillage methods, respectively. The precision of the APSIM model was satisfactory. Under different sowing dates, the order for beneficial degree of tillage treatment to dry matter accumulation in wheat grains was no tillage with straw cover &gt; conventional tillage with straw cover &gt; no tillage &gt; conventional tillage. The treatment of no tillage with straw covered was the most favora-ble to dry matter accumulation in wheat grains, with no significant difference between no tillage and conventional tillage treatments. Under different farming methods, early sowing was better than normal sowing and late sowing for the dry matter accumulation process of wheat. Late sowing had stronger impacts on dry matter accumulation, with the least ideal accumulation process.

Water use efficiency, grain yield, and economic benefits of common beans (Phaseolus vulgaris L.) under four soil tillage systems in Mukono District, Uganda

With the increasing climate change impacts and variabilities, water is becoming a limiting factor for rainfed crop production in Uganda. Conservation tillage practices could improve soil and water conservation in croplands. Field experiments were conducted for three consecutive seasons from April 2019 to June 2020. The experiments evaluated the effect of soil tillage treatments on soil water storage, water use efficiency, grain yield, and economic benefits of the common beans (Phaseolus vulgaris L.) in two sub-counties of Mukono District, central Uganda. The soil tillage treatments were: no-tillage, stubble-mulching, deep tillage, and conventional tillage. The no-tillage and stubble-mulching improved soil water storage by 46 and 45%, respectively, compared with the conventional tillage in the 0–100 cm soil depth over the 14 months. Soil tillage treatments significantly (p < 0.05) affected the water use efficiency, with water use efficiency values generally higher under no-tillage and stubble-mulching than under deep tillage and conventional tillage treatments. The grain yield was highest under no-tillage and stubble-mulching than deep tillage and conventional tillage treatments, with over 5, 38, and 43% higher grain yield under no-tillage than under stubble-mulching, deep tillage, and conventional tillage treatments, respectively. Although no-tillage and stubble-mulching improved soil water storage and grain yield, seasonal precipitation distribution had a greater influence on the final grain yield, soil water storage, and water use efficiency. The net profit was 3 and 5 times higher under no-tillage than under conventional tillage and deep tillage treatments, respectively. The overall results showed that no-tillage and stubble-mulching were the optimum tillage treatments for increasing soil water storage and common bean yield, enhancing water use efficiency, and improving economic returns in central Uganda.

Long term impact of different tillage systems on carbon pools and stocks, soil bulk density, aggregation and nutrients: A field meta-analysis

Intensive tillage frequently has adverse impact on soil physical quality and soil organic carbon stocks in temperate regions. A consequence of this has been a reduction in crop production over the years demonstrating the necessity of effective and sustainable agriculture. This study aimed to evaluate soil organic carbon (SOC) storage and pools, soil bulk density, aggregation and nutrient availability under different tillage systems (no-tillage, chisel and conventional tillage), based on a long field experiment. After 10 years of crop rotation, in 0–30 cm soil depth, no-tillage system had higher total organic carbon over conventional tillage treatment. Plots under no-till and chisel treatments in 0–10 cm depth, had 7–13%, 34–35% and 9–15% higher non-labile fraction (Cfrac4), very-labile fraction (Cfrac1) and total organic carbon (TOC), respectively compared to that of conventional ones. Also, no-till system had higher passive carbon pool and carbon management index than conventional system. In addition, the conservative tillage, reduced soil bulk density compared with conventional tillage in the surface layer. The stability of slow-wetting and room storage aggregates from conservative tillage were significantly higher (p < 0.05) than conventional tillage. Overall, stability of soil aggregates is improved under conservative tillage. Tillage system, crop rotation and residues, increased soil available nutrients N, P and K in the 0–10 cm depth, with the highest values in no-tillage system. Therefore, conservation tillage could be recommended as a tillage practices that improve fertility soil characteristics and production sustainability.

Effect of tillage systems and tillage direction on soil hydrological properties and soil suspended particle concentration in arable land in Uganda

The 2030 Agenda for Sustainable Development addressing the issues of environmental degradation has been challenged by human developments and activities. Crop production systems and technologies (e.g. soil tillage) are among the leading factors causing environmental degradation. In this study, the effect of soil tillage systems (i.e. no-tillage (NT); stubble-mulching (SM); deep tillage (DT); and conventional tillage (CT)) on surface runoff volume (SRV), suspended sediment concentration (SSC), infiltration rate (IR), and soil moisture content (SMC) in the common bean (Phaseolus vulgaris L.) farms, Mukono District, Uganda was evaluated. The effect of soil tillage direction on SRV was also assessed. The SRV, SSC, IR, and SMC were monitored under Complete Randomized Block Design (CRBD) experiments with four soil tillage systems in Goma and Kimenyedde experimental sites during two wet seasons. The results showed that SRV, SSC, IR, and SMC were significantly (p < 0.05) influenced by the soil tillage system, season, and site. The highest total SRV was observed during the first season in Goma experimental site under CT with soil tillage along the slope (1071.3 mm). The lowest SRV was observed during the second season in Kimenyedde experimental site under NT (165.0 mm). The highest and lowest mean SSC was observed in the CT (2.41 ± 0.3 g L−1) in Goma experimental site during the first season and NT (0.43 ± 0.1 g L−1) in Kimenyedde experimental site during the second season, respectively. The SSL was highest under CT in both Goma (147.17 kg ha−1season−1) and Kimenyedde (114.93 kg ha−1season−1), and lowest under NT with the means of 11.25 and 9.19 kg ha−1season−1 in Goma and Kimenyedde experimental sites, respectively. Both SRV and SSC increased linearly with both rainfall amount (RF) and rainfall intensity at 10 min (RI10). The highest and lowest IR and SMC were observed in the NT and CT treatments, respectively. No significant (p > 0.05) variations were observed in the SMC under the NT and SM treatments. Overall, soil tillage systems, soil type, and rainfall characteristics are among the key factors influencing the magnitudes of SRV and SSC in both time and space. This particular study suggests that NT and SM would help reduce the magnitudes of SRV and SSC, in agricultural fields.