Effects Of Agricultural Conservation Practices Research Articles

The Effect of Conservation Agriculture Practices and Two Sampling Seasons on Some Soil Pore Characteristics

The Effect of Conservation Agriculture Practices and Two Sampling Seasons on Some Soil Pore Characteristics

Effect of Conservation Agriculture Practices on Growth Attributes and Yield of Pigeonpea

A two-year field experiment was conducted at Main Agricultural Research Station, Raichur in 2021 and 2022 was laid out in a Split-Split design with four main, two sub and two sub-sub treatments with three replications to evaluate effect of conservation agricultural practices on growth and yield of pigeonpea. The treatments with flat bed, Compartment bund, Ridge and furrow & Broad bed and furrow were takes on main, treatments with mulching and without mulching an sub treatment and FYM and RDF & FYM an sub-sub treatment. Among them ridges and furrow (M3) method along with mulching FYM and RDF was found to have positive influence of growth parameters viz., plant height, number of primary branches and total dry matter production at harvest stage. Adopting the ridge and furrow method can be an effective strategy for optimizing the grain yield (1555 kg ha-1 and 1599 kg ha-1) in 2021 and 2022 in pigeonpea crop respectively.

The role of conservation agriculture practices in mitigating N2O emissions: A meta-analysis

Conservation agriculture is often assumed to reduce soil N2O emissions. Yet, studies analyzing the specific effect of conservation agriculture practices on N2O emissions give contradictory results. Herein, we synthesized a comprehensive database on the three main conservation agriculture practices (cover crops, diversified crop rotations, and no-till and/or reduced tillage (NT/RT)) to elucidate the role of conservation practices on N2O emissions. Further, we used a random meta-forest approach to identify the most important predictors of the effects of these practices on soil N2O emissions. Averaged across all comparisons, NT/RT significantly decreased soil N2O emissions by 11% (95% CI: –19 to –1%) compared to conventional tillage. The reductions due to NT/RT were more commonly observed in humid climates and in soils with an initial carbon content < 20 g kg–1. The implementation of cover crops and diversified crop rotations led to variable effects on soil N2O emissions. Cover crops were more likely to reduce soil N2O emissions at neutral soil pH, and in soils with intermediate carbon (~20 g kg–1) and nitrogen (~3 g kg–1) contents. Diversified crop rotations tended to increase soil N2O emissions in temperate regions and neutral to alkaline soils. Our results provide a comprehensive predictive framework to understand the conditions in which the adoption of various conservation agriculture practices can contribute to climate change mitigation. Combining these results with a similar mechanistic understanding of conservation agriculture impacts on ecosystem services and crop production will pave the way for a wider adoption globally of these management practices.

Effect of Conservation Agriculture Practices on Carbon Pools in a Sandy Loam Soil of Indo-Gangetic Plains

ABSTRACT Conservation agriculture practices have been globally recognized for improving soil quality by enhancing soil organic carbon, mitigating climate change, and boosting resilience, thereby supporting food security. However, declining soil organic carbon (SOC) is reported as a significant issue in Indian soil, particularly in Indo-Gangetic Plain (IGP). In this investigation, the experiment was conducted to assess the impacts of crop residue retention under conservation agriculture practices with green seeker (GS)-based nitrogen (N) application. The finding of this study revealed that passive carbon pools were 25% and 22% higher in Zero Tillage with Residue Retention (ZTWR) than in Zero Tillage without Residue Retention (ZTWoR) during 2018 and 2019, respectively. Active carbon pools were found to increase, 5.47 g kg−1 in ZTWR plots and 4.34 g kg−1 in ZTWoR plots, while passive carbon pools were recorded at 7.46 g kg−1 in ZTWoR plots and 9.23 g kg−1 in ZTWR plots. The passive carbon pool was recorded as highest in ZTWR 50% N+GS treatment (8.61 g kg−1) and lowest in ZTWoR 70%N+GS treatment (8.15 g kg−1). 50%N+GS subplot treatment performed well in precision nitrogen management treatment under conservation agriculture, and it also improved various carbon pools; Overall, ZTWR performed better than ZTWoR plots, and 50%N+GS improved SOC pools in the subplot, it is followed by RDN, 33%N+GS and RDN subplot treatment. The soil organic pools are positively correlated with crop yields. Hence, the present study recommends that residue retention in conservation agriculture and optimized precision nitrogen management improve the soil organic carbon pools, ultimately improving soil fertility and sustainability.

Effects of Conservation Agriculture Practices on Tomato Yield and Economic Performance

Conservation agriculture practices, such as reduced tillage and the incorporation of cover crops, play a crucial role in improving the sustainability of organic farming systems. The aim of this two-year field trial was to evaluate five different organic technical itineraries (ST, IN1, IN2, M1, and M2) which differed on soil management practices adopted before processing tomato transplantation and regarding weed control strategies performed. Soil management practices in comparison consisted of conventional deep tillage (ST and M1) or reduced tillage together with the use of a cover crop mixture composed of common vetch and barley (IN1, IN2, and M2). Weed control strategies involved the use of biodegradable mulch together with mechanical weeding (ST and M2), or false seedbed technique and mechanical weeding (IN1, IN2, and M1). Weed biomass at harvest, tomato yield, and the operational and economic performance of each of the technical itineraries was evaluated. No significant differences emerged in terms of weed biomass at harvest between itineraries. Best yield results were obtained tendentially by ST and M2 when biodegradable mulch was used, with values equal to 42.14 and 41.47 Mg ha−1 in 2020 and 30.68 and 31.19 Mg ha−1 in 2021, respectively. Even though the itineraries where mulch film was used (ST and M2) resulted in significantly onerous processes, they also obtained the highest gross income compared to the other itineraries, with values of 30,998 and 29,900 € ha−1 in 2020, and of 16,060 and 15,186 € ha−1 in 2021, respectively. These results revealed the importance of using mulching to help cope with critical climatic conditions, such as drought seasons. Further studies are needed to evaluate the yield and economic advantages of both the effect of shallower soil tillage over a longer period in this specific context and the creation of ground cover with cover crops managed as dead mulch.

Estimated reduction of nitrogen in streams of the Chesapeake Bay in areas with agricultural conservation practices

Spatial data provided by the U.S. Department of Agriculture National Resource Conservation Service representing implementation at the field-level for a selection of agricultural conservation practices were incorporated within a spatially referenced regression model to estimate their effects on nitrogen loads in streams in the Chesapeake Bay watershed. Conservation practices classified as “high-impact” were estimated to be effective (p = 0.017) at reducing contemporary nitrogen loads to streams of the Chesapeake Bay watershed in areas where groundwater ages are estimated to be less than 14-years old. Watershed-wide, high-impact practices were estimated to reduce nitrogen loads to streams by 1.45%, with up to 60% reductions in areas with shorter groundwater ages and larger amounts of implementation. Effects of “other-impact” practices and practices in areas with groundwater ages of 14 years or more showed less evidence of effectiveness. That the discernable impact of high-impact practices was limited to areas with a median groundwater age of less than 14 years does not imply that conservation practices are not effective in areas with older groundwater ages. A model recalibrated using high-impact agricultural conservation practice data summarized by county suggests effects may also be detectable using implementation data available at such coarser resolution. Despite increasing investment, effects of agricultural conservation practices on regional water quality remain difficult to quantify due to factors such as groundwater travel times, varying modes-of-action, and the general lack of high-quality spatial datasets representing practice implementation.

Conservation Agricultural Practices Impact on Soil Organic Carbon, Soil Aggregation and Greenhouse Gas Emission in a Vertisol

Conservation agriculture (CA), comprising of minimum soil disturbance and crop residue retention (&gt;30%), with a diversified cropping system, has become increasingly popular around the world. It is recognized as a sustainable practice to improve soil health by augmenting key soil properties. However, scanty information exists about the effect of CA practices on soil organic carbon (SOC), aggregation and greenhouse gas emissions (GHG) in a vertisol. Thus, this study investigated the effect of CA practices on SOC, soil aggregation and GHG emission under soybean-wheat and maize-chickpea cropping systems in a vertisol in Central India. Treatment consisted of three different tillage practices, being conventional tillage (CT), reduced tillage (RT), and no tillage (NT) under four cropping systems viz., Soybean–Wheat, Soybean + Pigeon pea (2:1), Maize–Chickpea and Maize + Pigeon pea (1:1). Regardless of cropping system, the soil under NT and RT exhibited better aggregation (20.77 to 25.97% increase), and SOC (12.9 to 19.4% increase) compared to the CT practice in surface layers. The aggregate-associated C concentration increased with aggregate size, and it was highest with large macroaggregates and lowest with silt and clay fractions across different tillage and cropping systems. Higher SOC stock was recorded under NT (4.22 ± 0.133 Mg C/ha) compared to RT (3.84 ± 0.123 Mg C/ha) and CT (3.65 ± 0.04 Mg C/ha) practices at 0 to 5 cm depth. Thus, the adoption of CA practices reduced CO2 emissions, while also contributing to increases in SOC as well as improvement in soil structure.

The Effects of Agricultural Conservation Practices on the Small Water Cycle: From the Farm- to the Management-Scale

Reinforcing the small water cycle is considered to be a holistic approach to both water resource and landscape management. In an agricultural landscape, this can be accomplished by incorporating agricultural conservation practices; their incorporation can reduce surface runoff, increase infiltration, and increase the water holding capacity of a soil. Some typical agricultural conservation practices include: conservation tillage, contour farming, residue incorporation, and reducing field sizes; these efforts aim to keep both water and soil in the landscape. The incorporation of such practices has been extensively studied over the last 40 years. The Soil and Water Assessment Tool (SWAT) was used to model two basins in the Czech Republic (one at the farm-scale and a second at the management-scale) to determine the effects of agriculture conservation practice adoption at each scale. We found that at the farm-scale, contour farming was the most effective practice at reinforcing the small water cycle, followed by residue incorporation. At the management-scale, we found that the widespread incorporation of agricultural conservation practices significantly reinforced the small water cycle, but the relative scale and spatial distribution of their incorporation were not reflected in the SWAT scenario analysis. Individual farmers should be incentivized to adopt agricultural conservation practices, as these practices can have great effects at the farm-scale. At the management-scale, the spatial distribution of agricultural conservation practice adoption was not significant in this study, implying that managers should incentivize any adoption of such practices and that the small water cycle would be reinforced regardless.

Representing soil health practice effects on soil properties and nutrient loss in a watershed-scale hydrologic model.

Watershed-scale hydrologic models are commonly used to assess the water quality effects of agricultural conservation practices that improve soil health (e.g., cover crops and no-till). However, models rarely account for how these practices (i.e., soil health practices) affect soil physical and functional properties such as water holding capacity and soil aggregate stability, which may, in turn, affect water quality. We introduce a method to represent changes in soil physical and functional properties caused by soil health practices in the Soil and Water Assessment Tool (SWAT) model. We used the SWAT model's default representation of winter cover crops and no-till and modified soil descriptive parameters to depict soil health practice effects on soil properties. We assumed that the soil health practices would increase soil organic carbon (SOC), a principal indicator of soil health, by 0.01g C g-1 of soil and then estimated changes in other soil properties (e.g., water holding capacity) using SOC-based predictive equations and preceding literature. Results indicated that our soil property modifications had statistically significant effects on simulated hydrology and nutrient loss, though outputs were more substantially affected by the model's default representation of cover crops and no-till. Results also indicated that soil health practices can reduce nitrogen and total phosphorus loss but may increase dissolved reactive phosphorus loss. Our representation of soil health practices provides a more complete estimate of practice efficacy but underscores a need for additional observational data to verify results and guide further model improvements.

The Effects of Conservation Agriculture Practices on the Population Density of Fungivorous and Free-Living Nematodes in Different Crop Rotation Patterns

The Effects of Conservation Agriculture Practices on the Population Density of Fungivorous and Free-Living Nematodes in Different Crop Rotation Patterns

Effect of conservation agriculture practices on soil quality, productivity, and profitability of peanut‐based system of Saurashtra, India

AbstractMoisture stress and low soil fertility are among the most important factors responsible for low productivity and profitability of peanut (Arachis hypogaea L.) in India. Conservation agriculture (CA) can delay or minimize moisture stress impacts on crop plants and improve the soil fertility. Hence, a field experiment was conducted at Research Farm of ICAR‐Directorate of Groundnut Research, Junagadh, during 2015–2016 and 2016–2017 to evaluate the effects of different CA practices on soil moisture, soil fertility, yield, and profitability of peanut systems. Treatments consisted of four tillage practices in main plots (conventional tillage [CT], minimum tillage [MT], zero tillage [ZT], and rotary tillage [RT]); two residue management practices in sub‐plots (residue removal [NR] and residue retention [RR]), and two intercropping systems in sub‐sub plots using peanut, pigeonpea [Cajanus cajan (L.) Millsp.], and cotton (Gossypium hirsutum L.) (peanut+pigeonpea [PP] and peanut+cotton [PC]) systems and replicated thrice. Minimum tillage and residue management practice RR improved soil moisture content, soil porosity, soil organic C, nutrient status (mainly at 0–15 cm), and soil enzymatic activities and decreased soil temperature variation and soil penetration resistance. Minimum tillage and RR resulted in higher financial returns over CT and NR, respectively. Among the cropping systems, PP was found more productive and profitable as compared to PC. Thus, in the light black soils of Saurashtra, India, MT along with RR seems to be a suitable option particularly during the initial years of shifting to CA to retain soil moisture, improve soil fertility, and provide higher financial returns.

Effect of Conservation Agriculture Practices on Chemical Properties of Soil at Assosa, Western Ethiopia

Conservation agriculture is a crop production system that retains an everlasting soil cover through preservation of crop residues on soil surface with zero and reduced till to enhance natural biological processes. It is also a way of organizing agricultural ecosystems for continued and greater sustainable productivity. Not only sustain agricultural productivity; plants, animals and human health are soil quality dependent. However, conventional agricultural practices have reduced soil productivity at such a scary rate, many agricultural soils are leached-out of nutrients and unable to naturally sustain crops. Determining impact of conservation agriculture on soil chemical properties at Assosa district was chosen to study chemical supplement substances of the soil from CA. This study pointed to assess the impact of distinctive conservation agriculture on soil chemical properties such as pH, %OC, %TN, mg/kg soil of phosphorus, meq/100g of soil exchangeable acidity, meq/100g of soil potassium and CEC at the research site. Chemical parameters analysis were done using AOAC methods. All soil tests collected from the treatment confirmed recognizable difference among the treatment and year. Despite that, in all analysis centrality distinction of soil organic carbon and total nitrogen within the soil showed better result in conservation agriculture and uncovered land than the conventional one. The pH, %TN, mg/kg of P, meq/100g soil K, %OC, CEC and exchangeable acidity were assessed three times in two years interval. The chosen location soil was as well disintegrated and unequivocally acidic.

Effect of conservation agriculture practices on weed management in okra under rice- okra-green manure cropping system

Effect of conservation agriculture practices on weed management in okra under rice- okra-green manure cropping system

Projecting the effects of agricultural conservation practices on stream fish communities in a changing climate

How anticipated climate change might affect long-term outcomes of present-day agricultural conservation practices remains a key uncertainty that could benefit water quality and biodiversity conservation planning. To explore this issue, we forecasted how the stream fish communities in the Western Lake Erie Basin (WLEB) would respond to increasing amounts of agricultural conservation practice (ACP) implementation under two IPCC future greenhouse gas emission scenarios (RCP4.5: moderate reductions; RCP8.5: business-as-usual conditions) during 2020–2065. We used output from 19 General Circulation Models to drive linked agricultural land use (APEX), watershed hydrology (SWAT), and stream fish distribution (boosted regression tree) models, subsequently analyzing how projected changes in habitat would influence fish community composition and functional trait diversity. Our models predicted both positive and negative effects of climate change and ACP implementation on WLEB stream fishes. For most species, climate and ACPs influenced species in the same direction, with climate effects outweighing those of ACP implementation. Functional trait analysis helped clarify the varied responses among species, indicating that more extreme climate change would reduce available habitat for large-bodied, cool-water species with equilibrium life-histories, many of which also are of importance to recreational fishing (e.g., northern pike, smallmouth bass). By contrast, available habitat for warm-water, benthic species with more periodic or opportunistic life-histories (e.g., northern hogsucker, greater redhorse, greenside darter) was predicted to increase. Further, ACP implementation was projected to hasten these shifts, suggesting that efforts to improve water quality could come with costs to other ecosystem services (e.g., recreational fishing opportunities). Collectively, our findings demonstrate the need to consider biological outcomes when developing strategies to mitigate water quality impairment and highlight the value of physical-biological modeling approaches to agricultural and biological conservation planning in a changing climate.

Effects of conservation agriculture practices on soil quality indicators: a case-study in a wheat-based cropping systems of Mediterranean areas

ABSTRACT Conservation Agriculture approach could be strategic for Soil Quality (SQ) conservation under the Mediterranean conditions of Southern Europe’s environments. In this study, we reported the results obtained during a 2-year field experiment (split-plot design) of a 7-year experiment started in 2010–2011, combining two tillage practices (Conventional Tillage (CT) and Zero Tillage (ZT)) with two crop sequences (Wheat monocropping (WW) and Wheat-Faba bean (WF)). SQ was monitored through the selection of some chemical, physical, and biological indicators measured by both visual – Visual Soil Assessment (VSA) – and standard field or laboratory measurements. ZT produced higher values for some VSA indicators, i.e., ‘soil structure and consistence’ and ‘earthworms counts’, as well as for soil organic carbon content (0.84 vs. 0.75% in ZT and CT, respectively). CT+WW and CT+WF treatments released significantly higher CO2 fluxes of 35% and 41% than ZT+WW and ZT+WF, respectively. No clear effect of soil tillage practices on community-level physiological profiles was observed; conversely, WF induced higher values of well-color development, richness (R), and Shannon–Weaver index (H) than WW. Under dry Mediterranean areas, ZT practices, especially when combined with the other conservation principles (i.e., crop rotation), seem to ameliorate several SQ indicators already after 7-year period of adoption, allowing a positive trend for soil preservation.

Nutrient control in water bodies: A systems approach.

Nutrient pollution is considered a wicked problem because of its many significant economic, social, and environmental impacts that are caused by multiple pollutants originating from a variety of sources and pathways that exist across different temporal and spatial scales. Further adding to the difficulty in managing nutrient pollution is that it is a global, rural, and urban problem. A systems approach can improve nutrient management by incorporating technological, environmental, and societal considerations. This approach can consider valuation of monetized and nonmonetized co-benefits and the inherent consequences that make up a nutrient management program. In this introduction to a special collection of papers on nutrient pollution, we describe several systems frameworks that can be used to support nutrient management and evaluation of system performance as it relates to impacts, then highlight several attributes and barriers of nutrient management that point to the need for a systems framework, and conclude with thoughts on implementing systems approaches to nutrient management with effective community engagement and use of new technologies. This special collection presents results from a USEPA Science to Achieve Results (STAR) initiative to advance solutions to nutrient pollution through innovative and sustainable research and demonstration projects for nutrient management based on a systems approach. These studies evaluate several promising nutrient control technologies for stormwater or domestic wastewater, investigate the effects of agricultural conservation practices and stream restoration strategies on nutrient loads, and discuss several challenges and opportunities-social, policy, institutional, and financial considerations-that can accelerate adoption of reliable technologies to achieve system-level outcomes.

Physical and chemical processes determining soil organic matter dynamics in a managed vertisol in a tropical dryland area

Vertisols are soils with a high potential for carbon (C) sequestration. However, these soils undergo swelling and shrinkage cycles, which exert a strong influence on soil organic matter (SOM) dynamics. The long-term effects of agricultural conservation practices on SOM content and stability on a Vertisol located in a tropical dryland area was evaluated.Two tillage systems (conventional tillage [CT], disc ploughing and extraction of 70% harvest residues, and no tillage [NT], incorporating 100% of the harvest residues) in combination with three different crop rotations (sorghum-soyabean [SrSy], maize-maize [MM] or soyabean-maize [SyM]) were tested. All plots were irrigated during dry periods. The effects on soil organic C, N, microbial biomass and aggregate size class distribution were evaluated. Carbon sink capacity were assessed by studying the aggregate-associated SOM content and quality (thermal recalcitrance), as determined by thermo-calorimetry.Relative to the CT system, NT yielded a higher percentage of small macroaggregates (2-0.25 mm). It also promoted the accumulation of aggregate-associated SOM, especially in the small macroaggregates and microaggregates. Thermal analysis revealed that the aggregate-associated SOM was more recalcitrant (higher values of T50 and more energy released at 475 °C) in NT than in CT. Coinciding with these effects, the soil microbial biomass/SOC ratio was lower in NT than in CT. The gain of SOM and the higher recalcitrance of OM in the NT soils may be related to different characteristics of NT Vertisols, such as poor aeration or disruption of the swelling and shrinkage cycles. The findings show that soil conservation practices increase the capacity for long-term C sequestration in Vertisols via organomineral interactions and SOM recalcitrance, which are determined by the formation of large cracks as a result of the swelling and shrinkage cycles that are some of the specific properties and processes of these soils.

Effect of contrasting tillage and cropping systems on soil aggregation, carbon pools and aggregate‐associated carbon in rainfed Vertisols

SummaryWorldwide, conservation agriculture practices involving minimal soil disturbances and retention of crop residue (&gt;30%) have been practised increasingly and recognized to enhance soil health by optimizing key soil attributes. However, little information is available on the short‐term effects of conservation agriculture practices on soil properties under rainfed Vertisols of Central India. Thus, our aim was to study the short‐term effects of contrasting tillage treatments and cropping systems on soil aggregation, aggregate‐associated carbon (C), carbon pools and crop productivity. This study comprised three tillage systems (TS), reduced tillage (RT), no tillage (NT) with retention of crop residue and conventional tillage (CT), together with four cropping systems (CS), namely soya bean (Glycine max L.) + pigeon pea (Cajanus cajan L.) (2:1), soya bean–wheat (Titricum durum L.), maize (Zea mays L.) + pigeon pea (1:1), and maize–chickpea Cicer arietinum L.). The experiment was laid out in a split‐plot design with three replicates. Soil samples were collected at four depths: 0–5, 5–15, 15–30 and 30–45 cm from the experimental field after completion of four crop cycles. Results indicated that at depths 0–5 and 5–15 cm, tillage and cropping system had a significant effect on aggregate mean weight diameter (MWD). The MWDs of 0.97 and 0.94 mm were larger for NT than CT (0.77 and 0.83 mm) at 0–5‐ and 5–15‐cm depths, respectively. Water‐stable aggregates (WSAs) were also larger for NT (70.74%) and RT (70.09%) than CT (59.50%) at 0–5 cm. Tillage practice, cropping system and their interaction had a greater effect (P &lt; 0.05) on the content of aggregate‐associated C for large macroaggregates (LM). There was more aggregate‐associated C for NT and RT at 0–5‐cm depth than for CT. Cropping system also had a significant effect (P &lt; 0.05) on aggregate‐associated C at 0–5‐cm depth. Soil organic C (%) fractions were in the order of non‐labile &gt;very labile &gt;less labile &gt;labile for 0–5‐ and 5–15‐cm depths after four crop cycles. Less labile and non‐labile C fractions contributed &gt;50% of TOC, indicating a more recalcitrant form of carbon present in the soil. Tillage had no significant effect (P &gt; 0.05) on crop yields after four crop cycles. Conservation agriculture can have a positive effect on aggregate stability, aggregate‐associated C and different carbon pools in a Vertisol.Highlights Does conservation agriculture affect soil aggregation, aggregate stability and carbon pools more than conventional tillage? The SOC concentration increases with aggregate size and provides physical protection and stabilization of carbon (C). Aggregate‐associated C content was significantly affected by tillage practices and cropping system. Less labile and non‐labile C fractions contribute &gt;50% TOC in the rainfed Vertisols of central India.

Soil biochemical changes at different wheat growth stages in response to conservation agriculture practices in a rice-wheat system of north-western India

Intensive tillage, removal or burning of crop residues, limited organic manure use, declining irrigation water resources and scarcity of labour are the major causes of soil degradation and unsustainability of rice (Oryza sativa L.)–wheat (Triticum aestivum L.) system (RWS) in South Asia.Resource conservation technologies (RCTs) such as zero tillage (ZT), dry direct seeded rice (DSR) and crop residues retained as mulch have shown promise to increase the productivity and profitability of RWS in South Asia. Effects of RCTs on soil biological parameters are unclear and contradictory. We evaluated the effects of conservation agriculture practices on changes in soil biochemical properties at different growth stages of wheat grown as the fifth crop in RWS. Twelve treatment combinations of tillage, crop establishment and crop residue management included four main plot treatments in rice: (1) conventional tillage (CT)-DSR,(2) ZT-DSR, (3) DTR, ZT machine transplanted rice and (4) PTR, conventional puddled transplanted rice. The three subplot treatments were: (i) CTW-R, CT wheat with both rice and wheat residues removed, (ii) ZTW-R, ZT wheat with residues of both the crops removed and (iii) ZTW+R, ZT wheat with rice residue retained as surface mulch in subsequent wheat. Irrespective of rice establishment methods, mean wheat grain yield under ZTW+R was 6% and 10% greater than CTW-R and ZTW-R respectively. Soil enzyme activities increased (5–18%) under ZTW+R compared with ZTW-R and CTW-R at different growth stages of wheat. The residual effect of rice establishment methods was significant on soil enzyme activities during wheat cropping, which were highest under ZT-DSR followed by CT-DSR, DTR and PTR. Soil organic carbon content in the 0–7.5 cm layer was significantly higher (7–9%) under the ZTW+R treatment compared with all the other treatments. Principal component analysis (PCA) identified three enzyme activities (dehydrogenase, fluorescein diacetate and phosphatase), and soil organic carbon content as the most sensitive indicators for assessing soil quality for RWS based on conservation agriculture. The PCA discriminated rice establishment systems with rice residue as surface mulch from rice establishment systems without rice residue and the maximum tillering stage from the other stages of wheat. The present study provided reliable biochemical indicators to monitor soil biological quality changes in response to conservation agriculture practices in RWS.

Symbiotic Parameters, Growth, Nutrient Uptake as Influenced by Biofertilizers under Conservation Agriculture Practices

A field experiment was conducted during rainy season 2014 and 2015 at Research Farm of the Punjab Agricultural University, Ludhiana, Punjab, India to study the effect of conservation agriculture practices (Happy Seeder sowing, Straw Chopper + Zero Tillage and Conventional tillage) and biofertilizers [Bradyrhizobium and plant growth promoting rhizobacteria (PGPR)] on growth, symbiotic parameters and productivity of soybean. The results showed that Happy Seeder sowing and Straw Chopper + Zero Tillage sowing improved the emergence count, leaf area index, photosynthetic active radiation interception, plant height of soybean and symbiotic traits (number and dry weight of nodules and leghaemoglobin content). Highest pods plant−1 and 100-seed weight were recorded in Happy Seeder sowing, followed by Straw Chopper + Zero Tillage sowing and conventional sowing. Based on the mean of two years, Happy Seeder sowing recorded 14.6 and 17.0% higher seed yield than Straw Chopper + Zero Tillage sowing and conventional sowing, respectively. Total nitrogen, phosphorus and potassium uptake were significantly higher in Happy Seeder sowing than the other planting methods. Single and dual inoculation of Bradyrhizobium and PGPR did not influence the growth parameters, symbiotic traits, yield attributes, biological, straw and seed yields, nutrient uptake and protein content of soybean significantly. Therefore, retention of crop residues with zero tillage (Happy Seeder sowing) proves to be the best planting method for sustainable productivity of soybean.