Conservation Tillage Systems Research Articles

Factors governing soil hydrological function under long‐term tillage practices: Insight into soil water repellency

AbstractDrought is increasingly common due to frequent occurrences of extreme weather events, which further increases soil water repellency (SWR). It could reinforce the effect of SWR on soil functions under conservation tillage systems. However, the relationship between SWR and soil hydrological function is still unclear. We studied the impacts of SWR and soil structure on soil hydrological function. Three treatments were conducted in a long‐term tillage experiment: conventional tillage (CT), reduced tillage (RT), and no‐tillage (NT). Tillage, soil depth, and growth period had significant influences on SWR, soil structure (i.e., penetration resistance [PR], total porosity [TP], and mean weight diameter [MWD]), and soil hydrological functions (i.e., water storage, least limiting water range [LLWR], and plant available water). Compared to CT, NT and RT increased the water repellency index (RI) in 0–20 cm by 13.8%–40.1% and 6.5%–18.2% during the growth period. RI played a prominent role in increasing soil water storage compared to soil TP, PR, MWD, and SOC. PR was the most critical influence on LLWR compared to other variables. A structural equation model revealed that SWR directly affected soil hydrological function, whereas the effect of SWR (0.24) was smaller than that of soil structure (0.67). In addition, soil structure had a direct influence on SWR, indicating that the effect of SWR could be regulated by soil structure. Overall, this study showed a link between SWR and soil hydrological function and provides deeper fundamental insights into the role of SWR on the sustainability of conservation tillage.

Use of life cycle assessment and modeling techniques for prediction of energy-environmental indicators in different wheat production systems

This study was conducted to analyze and model the energy consumption and environmental indicators for different wheat production systems in Qazvin province. Information needed for this study, related to 2021–2022, data was collected by monitoring machinery, and inputs during wheat production were interviewed by farmers and filled out questionnaires. The purpose of this study includes: (1) estimating the fuel consumption and energy of inputs in different wheat production systems, (2) estimating the environmental impact associated with input consumption using life cycle assessment (LCA), and (3) providing suggestions for optimization. The results showed wheat production in irrigated conservation tillage system has energy ratio (2.12) and energy productivity (0.18 kg MJ−1) suitable compared to conventional irrigated and rainfed tillage, and conservation rainfed tillage. Nitrogen fertilizer (55%–68%) and fuel consumption (15%–31%) of affect the energy consumption of four wheat cultivation systems. Three categories of damage to human health, ecosystem and resources in LCA were using the ReCiPe2016 method. Resource damage category for conventional tillage irrigation (76.05 USD2013) has significant pollution. The share of seed emissions, On-Farm emissions and nitrogen emissions affect the categories of damage to human health, ecosystems and resources, respectively. The results of the Cobb-Douglas model showed that T3 (fertilization and weed control) was significant at the level of 1% among other inputs. T1 (chisel packer roller), T2 (planting) and T4 (harvest and straw packaging) were significant at 5% level. The results of artificial neural network (ANN) of conventional rainfed cultivation showed that 6 input layers, 7 hidden layers with 10 hidden neurons and 1 output parameter were selected as the best structure. R2 and RMSE for fuel consumption were 0.95 and 43.65, respectively. As a result, the ANN results show higher accuracy than the Cobb-Douglas model.

The role of land use, management, and microbial diversity depletion on glyphosate biodegradation in tropical soils

Land use and management changes affect the composition and diversity of soil bacteria and fungi, which in turn may alter soil health and the provision of key ecological functions, such as pesticide degradation and soil detoxification. However, the extent to which these changes affect such services is still poorly understood in tropical agroecosystems. Our main goal was to evaluate how land-use (tilled versus no-tilled soil), soil management (N-fertilization), and microbial diversity depletion [tenfold (D1 = 10−1) and thousandfold (D3 = 10−3) dilutions] impacted soil enzyme activities (β-glycosidase and acid phosphatase) involved in nutrient cycles and glyphosate mineralization. Soils were collected from a long-term experimental area (35 years) and compared to its native forest soil (NF). Glyphosate was selected due to its intensive use in agriculture worldwide and in the study area, as well as its recalcitrance in the environment by forming inner sphere complexes. Bacterial communities played a more important role than the fungi in glyphosate degradation. For this function, the role of microbial diversity was more critical than land use and soil management. Our study also revealed that conservation tillage systems, such as no-tillage, regardless of nitrogen fertilizer use, mitigates the negative effects of microbial diversity depletion, being more efficient and resilient regarding glyphosate degradation than conventional tillage systems. No-tilled soils also presented much higher β-glycosidase and acid phosphatase activities as well as higher bacterial diversity indexes than those under conventional tillage. Consequently, conservation tillage is a key component for sustaining soil health and its functionality, providing critical ecosystem functions, such as soil detoxification in tropical agroecosystems.

Innovative soil-crop management systems for climate smart sustainable agriculture

Innovative soil-crop management systems for climate smart sustainable agriculture

ESTIMATION OF MAIZE GENETIC COEFFICIENTS FOR THE CERES-MAIZE MODEL USING NON-DESTRUCTIVE METHODS

The Crop Environment Resource Synthesis-Maize (CERES-Maize) mechanistic model, included in the Decision Support System for Agrotechnology Transfer (DSSAT), is a useful and powerful tool that simulates the growth and yield of maize in different environments. The qualitative and quantitative information provided to the CERES-Maize model guarantees reliability in the simulations obtained. However, it requires a lot of information such as soil characteristics, daily climate, crop characteristics and management, as well as six genetic coefficients. This research assessed a non-destructive methodology for estimating the six required parameters (genetic coefficients): P1, P2, P5, G2, G3 and PHINT, based on the maize physiology, measured from the Growing Degree Days (GDD) base 10. An experiment was established at the experimental station of the International Maize and Wheat Improvement Center (CIMMYT) in Tlaltizapan, Morelos, Mexico, where 27 white maize hybrids and 14 yellow maize hybrids were manually sown in an irrigation conservation tillage system. Once the simulations of maize growth and yield were obtained with CERES-Maize model, the genetic coefficients were calibrated using the Generalized Likelihood Uncertainty Estimation (GLUE). After calibration of the six genetic coefficients for all hybrids, an average values of P1, G2 and G3 were within the typical range, while P2 and P5 were greater than the typical range, and PHINT was below typical range. However, the simulation model showed good performance after calibration, according to the average R2 of 0.9809 and 0.9730 between measured and simulated yields for white and yellow hybrids respectively. The coefficients estimated in this study can be used in the CERES-Maize model to simulate maize yields in different regions of the country for the hybrids used here.

COMPARATIVE EFFECT OF INTEGRATED FERTILIZATION APPROACHES ON SOIL HEALTH AND CROP PRODUCTIVITY OF WHEAT (TRITICUM AESTIVUM L.) UNDER DIFFERENT TILLAGE SYSTEMS

The study was conducted at Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, Pakistan to monitor the impact assessment of tillage systems on soil health indicators by integrating organic and inorganic resources to sustain wheat production in arid and semi-arid conditions i.e. high temperature and low rainfall. The field experiment was conducted in 2019-20 and carried out in alkaline soil (pH 8.2) with low organic matter (0.45%) to grow wheat after rice and treatments were arranged in randomized complete block design. Farmyard manure (FYM 20.5 Mg/ha), rice crop residues application (CRA 100%) and chemical fertilizers (CF) N-P-K 100-80-60 kg/ha, respectively were used under conventional and conservation tillage systems. During this research different growth and yield parameters were noted and evaluated the level of N, P, K and organic matter contents from soil and plant at the harvest. The results indicated that the combined application of FYM and CRA with CF improved the chlorophyll contents (20% in conventional tillage and 39% in conservation tillage) which helped in nutrient translocation (N, P, K) and increased growth, biological and grain yield by improving soil organic carbon (SOC) and organic matter contents in soil. Growth parameter i.e. germination percentage upto 64%, plant height 27% and spike length upto 35% were increased by T7 . The conservation tillage method was the best where we used T7 i.e. CF + 25% FYM + 50% CRA, and CF + 50% FYM + 25% CRA by conserving moisture and built OM (0.90%), soil organic carbon (0.49%) and mineral nutrition in soil as well as in wheat leaves. It is concluded that the integrated use of organic and inorganic resources are helpful for sustainable wheat production by enhancing fertilizer use efficiency (FUE) to improve soil health especially in arid to semi-arid climate conditions in alkaline soil.

Could conservation tillage increase the resistance to drought in Mediterranean faba bean crops?

Climate change, especially in Mediterranean countries, might have a detrimental effect on agro‑ecosystems and agricultural production, as well as on the price, quantity and quality of the products. This study assesses the potential impact of drought predictions on a faba bean crop, and evaluates the adoption of conservation tillage practices to reduce this effect. For this purpose, a rainfall exclusion experiment was carried out in a Mediterranean rotation in Southwest Spain, where a long-term tillage experiment was running since 2008. Soil water storage (SWS), crop productivity and mineral nutrition, plant ecophysiology and biomass quality, as well as the colonization of roots by arbuscular mycorrhizal fungi (AMF) and symbiotic Rhizobium bacteria were evaluated over one growth cycle to study the combined effect of different tillage systems - non-tillage (NT), reduced tillage (RT) and traditional tillage (TT)- and rainfall reduction. Rainfall reduction had a negative impact on faba bean germination on the TT system, and on its aboveground biomass across the three tillage systems, but did not affect grain production. The percentage of biomass yield reduction by rainfall exclusion was 30% for NT, 50% for RT and 20% for TT. In the case of RT, low yields were influenced by a high incidence of weeds under rainfall reduction. The negative effect of water exclusion was especially evident on photosynthesis rates and stomatal conductance across all tillage types, while leaf water potential was affected by drought only in the TT system. These ecophysiological indicators were positively associated to some variables of arbuscular mycorrhizal colonization and Rhizobium nodulation in roots. Changes in the patterns of symbiotic interactions in response to drought depended on the tillage type. We conclude that, despite no effect on soil water storage, in the conservation tillage systems the increase in the mycorrhizal colonization in roots, particularly under NT, could be beneficial for plants to face drought stress. However, in a scenario of reduced rainfall it will be necessary to invest more resources in weed control under RT.

The Impact of Conservational Tillage Systems on Some Physical Properties of Silty Clay Loam Saline Soil

The Impact of Conservational Tillage Systems on Some Physical Properties of Silty Clay Loam Saline Soil

Durum Wheat Production as Affected by Soil Tillage and Fertilization Management in a Mediterranean Environment

Several strategies have been proposed recently to reduce the accumulated harmful circumstances of intensive conventional farming practices. The adoption of conservation soil tillage and organic fertilization techniques could contribute to achieving this goal. The study was conducted over a three-year trial to assess the effects of soil tillage practices (plough; subsoil; spading) and fertilization management (inorganic vs. organic) on durum wheat growth dynamics and productivity in a Mediterranean environment. The chlorophyll concentration (CC) was evaluated using an MC-100 chlorophyll meter, and Green Area (GA) was extracted from red-green-blue (RGB) digital images acquired with a commercially available digital camera. These non-destructive low-cost methods were used to examine crop status and its reactions to climate conditions over three consecutive growing seasons in the field. A positive strong linear relationship between both CC and GA against grain yield in each growing season was identified. The study highlights that CC and GA methods are valuable tools to assess crop development under Mediterranean conditions. The results indicated that the applied conservation tillage systems, such as subsoil tillage and using the spading machine, along with organic fertilization with compost, are valuable choices in the Mediterranean basin for sustainable and higher crop production (13%) compared to the conventional traditional system.

Soil organic carbon, aggregation and fungi community after 44years of no-till and cropping systems in the Central Great Plains, USA.

Implementing sustainable agricultural land management practices such as no-till (NT) and diversified crops are important for maintaining soil health properties. This study focuses on the soil health of three long-term (44years) tillage systems, NT, reduced tillage (RT), and conventional tillage (CT), in monoculture winter wheat-fallow (W-F) (Triticum aestivum L.) and wheat-soybean (W-S) (Glycine max (L.) Merrill) rotation. Soil organic carbon (C) was higher in NT than CT in the surface 0-5cm, but not different in the 5-15cm, demonstrating SOC stratification on the soil profile. The soil water content was higher in NT followed by RT and CT in the top 0-5cm. We found an association between increased carbon, aggregation, and AMF biomass. Greater soil aggregation, carbon and AMF were observed in NT at 0-5cm soil depth. The W-S cropping system had greater soil microbial community composition based on fungi biomass, AMF and fungal to bacteria ratio from phospholipid fatty acid analysis (PLFA). Large macroaggregates were positively correlated with total C and N, microbial biomass, Gram + , and AMF. Soil water content was positively correlated with macroaggregates, total C and N, and AC. No-till increased soil carbon content even after 44years of cultivation. By implementing conservation tillage systems and diversified crop rotation, soil quality can be improved through greater soil organic C, water content, greater soil structure, and higher AMF biomass than CT practice in the Central Great Plains.

Soil nitrogen and carbon storages and carbon pool management index under sustainable conservation tillage strategy

Agricultural practices are significant to increase the soil nitrogen and organic carbon sequestration to adapt and mitigate the climate change in a recent climate change scenario. With this background, we carried out research in the Longzhong Loess Plateau region of China. This research was conducted under a randomized complete block design, with three replicates. Adopt the method of combining outdoor positioning field test with indoor index measurement to explore the soil bulk density (BD), nitrogen components (viz., nitrate nitrogen (NO3−-N), ammonia nitrogen (NH4+-N), total nitrogen (TN), microbial biomass nitrogen (MBN) and nitrogen storage (NS), and carbon components [viz., soil organic carbon (SOC), easily oxidized organic carbon (EOC), microbial biomass carbon (MBC) and carbon storage (CS), carbon pool index (CPI), carbon pool activity (A) and carbon pool activity index (AI) and carbon pool management index (CPMI)] and C/N, ratio under different tillage practices [namely., conventional tillage (CT), no tillage (NT), straw mulch with conventional tillage (CTS) and straw mulch with no tillage (NTS)]. Our results depicted that different conservation tillage systems significantly increased soil BD over conventional tillage. Compared with CT, the NTS, CTS and NT reduced soil NO3−-N, increased the soil NH4+-N, TN, MBN and NS, among them, NS under NTS, CTS and NT treatment was 25.0, 14.8 and 13.1% higher than that under CT treatment, respectively. Additionally, conservation tillage significantly increased SOC, EOC, MBC, CS, CPI, AI, CPMI and C/N, ratio than CT. Inside, CS under NTS, CTS and NT treatment was 19.4, 12.1 and 13.4% higher than that under CT treatment, respectively. Moreover, during the 3-year study period, the CPMI under NTS treatment was the largest (139.26, 140.97, and 166.17). Consequently, we suggest that NTS treatment was more sustainable strategy over other investigated conservation tillage practices and should be recommended as climate mitigation technique under climate change context.

Influence of a cereal rye cover crop on the critical period for weed control in soybean

AbstractSoybean is the world’s most widely grown leguminous crop and is an important source of oil and protein for food and feed in addition to other industrial uses. However, herbicide-resistant and troublesome weed control challenges limit yield potential and threaten conservation tillage (CT) systems. Cover crops have been widely adopted as an integrated pest management component in CT systems to suppress weeds and maintain soybean yield potential. A 3-yr field experiment was conducted to estimate the influence of a cereal rye cover crop following CT on the critical period for weed control (CPWC) in soybean. The experiment was implemented in a split-plot design in which main plots as CT following cover crop (CT + CC), CT following winter fallow (CT + WF), and conventional tillage (CVT), and subplots were multiple durations of weed-free and weed interference. Results showed that the estimated CPWC of CT + CC and CT + WF treatments was 0 wk and >7 wk, respectively, in 2018. In 2019, the estimated CPWC was 0 wk, 5.0 wk, and 1.3 wk under CT + CC, CT + WF, and CVT treatments, respectively. In 2020, the estimated CPWC was 3.5 wk, >6.2 wk, and 0 wk under CT + CC, CT + WF, and CVT treatments, respectively. The presence of a cover crop delayed the CTWR and caused an early beginning of the CWFP compared with CT + WF treatment, and hence shortened the CPWC in 2018 and 2019. In conclusion, the CT + WF system did not reduce the weed competition and subsequent yield loss in soybean compared to the CT + CC system.

РЕАКЦІЯ ГІБРИДІВ КУКУРУДЗИ НА СИСТЕМИ ОБРОБІТКУ ГРУНТУ В УМОВАХ ЗАХОДУ УКРАЇНИ

Summary The purpose of research: Evaluation of the impact of soil tillage systems on grain productivity and efficiency of growing new corn hybrids in the soil and climatic conditions of western Ukraine. Research methods: Field trials were conducted in Western Ukraine on fields with sod-podzolic carbonate-gley soils. The total experimental field area of 6 ha was divided into 15 experimental plots with three tillage systems (conventional, conservation, mulching) and five maize hybrids of different indices and maturity groups («Ajax» (FAO 210), «Amaros» (FAO 230), «Danubio» (FAO 260),» DSK 3730» (FAO 280) and «Artenio» (FAO 340)). The indicators were determined in three replications at each experimental site. Research results: The research has established that the highest yields of corn grain were obtained in plots with hybrids «Amaros» (FAO 230) and «DCS 3730» (FAO 280), which amounted to 11.59 and 11.37 t/ha, respectively. It should be noted that the «Amaros» hybrid responds well to shelf loosening of the soil, with a grain yield of 12.34 t/ha on the background of ploughing, and the «DCS 3730» hybrid formed the highest grain yield (12.18 t/ha) in the variant with mulching tillage. The grain productivity of hybrids «Ajax» (FAO 210) and «Danubio» (FAO 260) is approximately the same and was at the level of 10.24 and 10.65 t/ha, respectively. The lowest average grain yield (9.72 t/ha) for all tillage options was obtained in the mid-season hybrid «Artenio» (FAO 340). Grain yields of the studied hybrids in plots with conventional tillage ranged from 10.34 to 12.34 t/ha, with conservation tillage - from 9.03 to 11.42 t/ha, and with mulching tillage - from 9.57 to 12.18 t/ha. On average, all plots with conventional tillage had a profit of 43518 UAH/ha, which is 10.0% and 6.9% higher than in the variants with conservation tillage and mulching systems. Conclusions. It was found that medium-early maize hybrids Ajax, Amaros, Danubio respond positively to the depth of cultivation and intensity of soil crumbling (traditional and conservation systems). The hybrid DKS 3730 produced the highest grain yield in the area with mulch tillage. The highest economic efficiency of growing corn for grain was obtained in variants with traditional tillage, with the exception of the DSK 3730 hybrid, for which mulch tillage was the most effective. In terms of economic effect, the conservation tillage system was the worst. Key words: corn, tillage systems, corn hybrids, yield, efficiency.

Вплив систем обробітку ґрунту на ефективність вирощування соняшника в умовах заходу України

The purpose of research: сomparative assessment of the effectiveness of sunflower cultivation with the introduction of traditional and resource-saving tillage systems in the soil and climatic conditions of Western Ukraine. Research methods: hypothesis, experiment, field observation, laboratory, visual and comparative calculation method. Research results: Field research was carried out in the soil and climatic conditions of Western Ukraine on a field with sod and deep clayey sandy soils. Plots with different tillage systems were laid out for research: plot 1 – traditional tillage (plowing to a depth of 25 cm); plot 2 – conservation tillage of the soil (chiseling to a depth of 35 cm); plot 3 – mulching of the soil (disking to a depth of 10 cm). According to the results of the research, a positive effect of the intensity and depth of the main tillage on plant height and elements of the structure of the sunflower crop was noted. With traditional tillage, the highest yield of sunflower seeds was noted - 1.81 t/ha. On the plot with conservation tillage, the yield is 1.75 t/ha, and on the plot with mulch tillage – 1.72 t/ha. The yield difference between the best and worst indicators was only 0.09 t/ha. Plowing requires significant energy and labor costs, which exceed similar indicators for the implementation of tillage systems. Direct operating costs for plowing were the largest and amounted to 1,661 UAH /ha, which is 618 and 986 UAH /ha more than the costs of deep plowing and disking, respectively. The introduction of traditional tillage contributes to the formation of the highest yield and an increase in profit by 192-229 UAH /ha. However, despite the lowest profit, the highest profitability of 52.2% was obtained due to the lowest costs on the plot with mulching, which is 1.0-1.8% more than on the plots with conservation and traditional tillage systems. Conclusions. The results of the conducted research and calculations indicate that the investigated tillage systems (traditional, conservation and mulching) are at the same level in terms of yield and economic efficiency of sunflower cultivation in the conditions of Western Ukraine. Keywords: research: sunflower, tillage systems, yield, efficiency.

Discrete element modeling and shear properties of the maize stubble-soil complex

Stubble-soil complex (SSC) after crop harvest affects subsequent operations of agricultural equipment under conservation tillage system. It is necessary to identify the mechanical properties of SSC and its interaction with soil-engaging tools to develop efficient agricultural equipment. Direct shear tests of SSC samples were carried out to ascertain shear properties of soil and SSC. A discrete element model of maize SSC based on structure measurements was developed using EDEM software. The results showed that internal friction angles of soil and SSC ranged from 21.8 to 25.7° and from 20.8 to 27.9°, respectively; cohesions of soil and SSC ranged from 7.4 to 32.2 kPa and from 9.8 to 41.2 kPa respectively. Model parameters of soil, single root (SR), and SSC were calibrated by angle of repose test, shear test, and direct shear test, respectively. The calibrated surface energies of soil and soil-root ranged from 0.20 to 0.34 and from 1.72 to 3.83 J·m−2, respectively. The SR's calibrated stiffnesses and critical stress ranged from 2.5e9 to 6.51e9 N·m−3 and 6e9 to 7e9 Pa, respectively. The variations of shear stresses and cutting forces with displacement were basically consistent in DEM simulations and measurements; moreover, both simulated internal friction angle and cohesion had relative errors of less than 5%. These results indicated that the calibrated discrete element models of direct shear and cutting tests could accurately simulate the shearing and cutting processes of SSC. The current study results are beneficial to improve the reliability of numerical simulations for crop SSC and optimize tillage components.

Effect of Conservation Tillage on Soil and Water Quality

Soil erosion from cropland has been recognized as a major problem in agricultural production. Conservation tillage is one of many conservation practices developed to reduce soil erosion. Meanwhile, many benefits from conservation tillage system beyond controlling soil loss have been reported. The objective of this work is to briefly review effect of conservation tillage on soil erosion and runoff, soil organic matter, selected soil physical properties, and water quality. Conservation tillage has inconsistent effects on surface runoff and soil loss due to differences in surface roughness and the rate of crop residue left on the soil surface. Increased soil organic carbon (SOC), mainly concentrated near soil surface, has been widely reported in the literature. However, SOC under conservation tillage is labile in topsoil and more recalcitrant in subsoil. Increased SOC leads to improved soil physical properties such as reduced bulk density, increased hydraulic conductivity and infiltration, and improved water retention capacity. Conservation tillage could improve water quality by reducing the total sediment, nitrate, ammonium, and phosphate in the runoff. However, conservation tillage may also facilitate nitrate leaching due to the increase of macropores in soil body.

First report of glyphosate-resistant downy brome (Bromus tectorum L.) in Canada

Glyphosate is the most used herbicide worldwide, and is an important source of economical weed control in glyphosate-resistant crops, and conservation tillage systems, among other uses. Downy brome (Bromus tectorum L.), otherwise known as cheatgrass, is a highly invasive winter-annual grass weed in cropping systems, pastureland, and naturalized or ruderal areas in western North America. In 2021, a downy brome population remained uncontrolled following four applications of glyphosate in a glyphosate-resistant canola (Brassica napus L.) field located in Taber County, Alberta, Canada. All individuals from the subsequent generation of the population survived glyphosate treatment at the typical field rate (900 g ae ha−1). In dose-response bioassays, the putative glyphosate-resistant population exhibited 10.6- to 11.9-fold, 7.7- to 8.7-fold, 7.8- to 8.8-fold, and 8.3- to 9.5-fold resistance to glyphosate based on plant survival, visible control, and biomass fresh weight and dry weight, respectively, compared with two susceptible populations 21 days after treatment. Estimated glyphosate rates for 80% control of this population ranged from 2795 to 4511 g ae ha−1; well above common usage rates. This downy brome population represents the first glyphosate-resistant grass weed confirmed in Canada, and the second weed species exhibiting glyphosate resistance in the Canadian prairie region.

Advancing Sowing Time and Conservation Tillage - The Climate-Resilient Approach to Enhance the Productivity and Profitability of Wheat.

Field experiments consisting of two sowing time (early and timely), two tillage options (conventional tillage and conservation tillage) and ten genotypes were conducted with the aim to maximize the wheat productivity and profitability. The early sowing (second fortnight of October) produced 16.0% higher grain yield compared to timely sowing (mid-November) in northern Indian Plains. However, no significant yield differences were observed between conventional tillage (CT) and conservation tillage (CST) practices. Among genotypes, the better yielders were PBW 723, BISA 927 and HD 2967. The interaction of sowing time and genotype had a significant (p < 0.05) effect on wheat yield. However, the interaction of genotype and tillage did not produce any significant response on wheat yield. The experiments conducted at farmer's fields also demonstrated similar performance of wheat under CT and CST systems but CST offered the savings of more than Rs. 3500 (US $ 47) along with 125kg ha- 1 lesser CO2 emissions over CT due to reduction in fuel consumption associated with tillage and seed bed operations. At farmers field also, early sown wheat yielded 5.5% higher over wheat sown in November. The results of present studies show that early sowing of high yielding wheat genotypes under CST practice enhanced the productivity and profitability of wheat under rice-wheat cropping system along with lesser noxious impact on the environment. Amidst climate vagary and its menace on the agriculture, the adoption of climate-resilient management practices such as advancing the sowing time and conservation tillage can improve the productivity of long duration wheat cultivars in sub-tropical humid conditions besides lesser deleterious consequences on the environment.

Effects of long-term no-tillage and maize straw mulching on gross nitrogen transformations in Mollisols of Northeast China

Conservation tillage practices are widely proposed as an effective management approach to guarantee soil productivity and sustainability by manipulating nutrient status, especially nitrogen (N) cycling. However, little is known about the interactive response of individual gross N transformation processes and their regulation of N availability in soil. Therefore, a 15N tracing study was carried out to investigate the effect of 12 years of no-tillage with different amounts of maize straw mulching on gross N transformation rates in Mollisols of Northeast China. Four treatments were arranged, including conventional ridge tillage (RT) and no-tillage treatments with 0 % (NT0), 33 % (NT33, 2500 kg ha−1 y-1) and 100 % (NT100, 7500 kg ha−1 y-1) harvested maize straw mulching. The results explicitly indicated that field management practices intensively controlled the dynamic N transformation between inorganic and organic forms and thus manipulated the retention and supply of soil N pool. Specifically, relative to the conventional ridge tillage, no-tillage reduced the rate of gross organic N mineralization (MNorg, from 2.47 to 1.56 mg N kg−1 d−1) but increased NH4+-N immobilization (INH4, from 3.47 to 4.83 mg N kg−1 d−1) due to reduced soil disturbances. Increased maize residue input in no-till systems stimulated both MNorg and INH4, denoting an improved supply of available N with the enhanced retention of soil organic N in conservation tillage systems. In addition, no-tillage with maize straw mulching synchronically stimulated NH4+-N adsorption/fixation (ANH4, from 2.38 to 4.11 mg N kg−1 d−1) and subsequent release (RNH4ads, from 1.80 to 3.64 mg N kg−1 d−1) processes, and such accelerated abiotic N turnover could react as an effective buffer for the supply and retention of available NH4+-N. Moreover, no-tillage with maize straw mulching considerably reduced autotrophic nitrification (from 6.39 to 3.70 mg N kg−1 d−1) while simultaneously promoted dissimilatory NO3−-N reduction to NH4+-N (DNRA, from 0.35 to 0.85 mg N kg−1 d−1), thus improving soil N retention capacity and reducing N loss risk. Taken together, considering the internal transformation of different soil N components, effective N cycling was gained in conservational cultivation by enhancing the retention and availability of soil N.

Tillage and pesticide seed treatments have distinct effects on soil microbial diversity and function

Conservation tillage practices can benefit soil health relative to conventional tillage; however, conservation tillage systems are often coupled with the use of pesticide seed treatments (PST; fungicides and insecticides, including neonicotinoids), which may undermine these benefits by disrupting microbial communities and processes. We examined the effects of tillage system (conventional moldboard plowing versus two conservation tillage practices: no tillage and strip tillage) and PST on microbial diversity and microbial function in a field experiment with a soybean–corn rotation. Enzyme activities and the microbial functional capacity to degrade a variety of substrates was intermediate in strip tillage compared with conventional and no tillage. Microbial community composition under strip tillage was similar to those under no tillage but distinct from conventional tillage, and community differences were associated with soil C/N and pH. However, tillage system had no effect on alpha diversity. Communities under strip tillage and no tillage had different substrate preferences to those under conventional tillage, which could be explained by the major C sources under each management practice. Pesticide seed treatment affected microbial substrate preference and altered the relative abundance of various fungal taxa, indicating a direct (i.e., toxic) effect. Despite this, PST had no effect on enzyme activities or alpha diversity of the microbial community. There were limited interactions between tillage and PST on microbial properties. Our results support that microbial communities are valuable indicators of soil health and show that strip tillage maintains soil microbial health better than conventional tillage but not as well as no tillage, and that PST may negatively affect soil microbial health.