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The future of South Asia’s major production system (rice–wheat rotation) is at stake due to continuously aggravating pressure on groundwater aquifers and other natural resources which will further intensify with climate change. Traditional practices, conventional tillage (CT) residue burning, and indiscriminate use of groundwater with flood irrigation are the major drivers of the non-sustainability of rice–wheat (RW) system in northwest (NW) India. For designing sustainable practices in intensive cereal systems, we conducted a study on bundled practices (zero tillage, residue mulch, precise irrigation, and mung bean integration) based on multi-indicator (system productivity, profitability, and efficiency of water, nitrogen, and energy) analysis in RW system. The study showed that bundling conservation agriculture (CA) practices with subsurface drip irrigation (SDI) saved ~70 and 45% (3-year mean) of irrigation water in rice and wheat, respectively, compared to farmers’ practice/CT practice (pooled data of Sc1 and Sc2; 1,035 and 318  mm  ha−1 ). On a 3-year system basis, CA with SDI scenarios (mean of Sc5–Sc8) saved 35.4% irrigation water under RW systems compared to their respective CA with flood irrigation (FI) scenarios (mean of Sc3 and Sc4) during the investigation irrespective of residue management. CA with FI system increased the water productivity (WPi) and its use efficiency (WUE) by ~52 and 12.3% (3-year mean), whereas SDI improved by 221.2 and 39.2% compared to farmers practice (Sc1; 0.69  kg grain m−3 and 21.39  kg grain ha−1 cm−1 ), respectively. Based on the 3-year mean, CA with SDI (mean of Sc5–Sc8) recorded −2.5% rice yield, whereas wheat yield was +25% compared to farmers practice (Sc1; 5.44 and 3.79  Mg  ha−1 ) and rice and wheat yield under CA with flood irrigation were increased by +7 and  +  11%, compared to their respective CT practices. Mung bean integration in Sc7 and Sc8 contributed to ~26% in crop productivity and profitability compared to farmers’ practice (Sc1) as SDI facilitated advancing the sowing time by 1  week. On a system basis, CA with SDI improved energy use efficiency (EUE) by ~70% and partial factor productivity of N by 18.4% compared to CT practices. In the RW system of NW India, CA with SDI for precise water and N management proved to be a profitable solution to address the problems of groundwater, residue burning, sustainable intensification, and input (water and energy) use with the potential for replication in large areas in NW India. [ABSTRACT FROM AUTHOR]

A three-year field study was conducted to explore the use of Conservation Agriculture (CA) as a cost-effective alternative to conventional tillage (CT) in rice-wheat (RW) systems. Therefore, to minimize the weed menace while sustaining the system productivity, a three-year field study was undertaken with different CA-based practices layered with flooded (FI) and subsurface drip irrigation (SDI). In rice, weed density (WD) in Sc8 {Zero tillage direct seeded rice with residue (+R) and SDI} recorded 72.9% lowered then Sc1 (CT-Puddled transplanted rice) after three years. However, maximum WD (162 m−2) and dry matter (WDM; 772.8 g m−2) were recorded in ZTDSR without residue (-R) with FI (Sc3) during third year which reduced rice yield by ∼37%. In wheat, the WD and WDM of Phalaris minor, Coronopus didymus, Melilotus indica and other species lowered in CA with SDI system (Sc5-Sc8) than CTRW system (Sc1 and Sc2). Lowest weed index (WI) observed with Sc8 during third year, while diversity indices (H', R, E) increased by 10, 57 and 10% under SDI system than CTW-R scenario (Sc1). CA-system improved productivity by 7.40–37.11% over CTRW systems in weed free (WF) conditions, regardless of residue and irrigation management. Under weedy check (WC), Sc8 was top yielder with yield of 8.32 Mg ha−1. Moreover, sustainable intensification (Sc7-Sc8) improved productivity by 35.2 and ∼52% than CTRW systems in WF and WC plots, respectively. In conclusion, CA+SDI scenarios may be recommended for RW system owing to their system yield enhancement, resource savings and weed reduction advantages. [Display omitted] • CA based sustainable intensification options ensures food security in IGP. • CA with SDI reduced the weed density (∼73% in rice) then CT system. • CA with SDI increased the diversity indices (H′, R, E) then CT wheat. • In weedy check, CA with SDI get higher system yield then CT rice-wheat system. • Mungbean integration in CA based RW system with SDI owing yield enhancement, resource savings and weed reduction advantages. [ABSTRACT FROM AUTHOR]

Climate-smart agriculture (CSA)-based management practices are getting popular across South-Asia as an alternative to the conventional system for particular weed suppression, resources conservation and environmental quality. An 8-year study (2012–2013 to 2019–2020) was conducted to understand the shift in weed density and diversity under different CSA-based management practices called scenarios (Sc). These Sc involved: Sc1, conventional tillage (CT)-based rice–wheat system with flood irrigation (farmers' practice); Sc2, CT-rice, zero tillage (ZT)-wheat–mungbean with flood irrigation (partial CA-based); Sc3, ZT rice–wheat–mungbean with flood irrigation (partial CSA-based rice); Sc4, ZT maize–wheat–mungbean with flood irrigation (partial CSA-based maize); Sc5, ZT rice–wheat–mungbean with subsurface drip irrigation (full CSA-based rice); and Sc6, ZT maize–wheat–mungbean with subsurface drip irrigation (full CSA-based maize). The most abundant weed species were P. minor > A. arvensis > M. indicus > C. album and were favored by farmers' practice. However, CSA-based management practices suppressed these species and favored S. nigrum and R. dentatus and the effect of CSAPs was more evident in the long-term. Maximum total weed density was observed for Sc1, while minimum value was recorded under full CSA-based maize systems, where seven weed-species vanished, and P. minor density declined to 0.33 instead of 25.93 plant m−2 after 8-years of continuous cultivation. Full CSA-based maize–wheat system could be a promising alternative for the conveniently managed rice–wheat system in weed suppression in north-west India. [ABSTRACT FROM AUTHOR]

Conventional- till (CT) agriculture is known to be ecologically indiscreet, economically and environmentally unsustainable, and leads to degradation of soil and environment in Indo-Gangetic Plains (IGP). Conservation Agriculture (CA) approach was introduced to manage agro-ecosystems for improved and sustained productivity, and increased farmers' profits while maintaining the natural resources. This comprises the management of natural resources at the farm, village, and landscape scales to increase synergies between food production and ecosystem conservation. CA-based rice-wheat (RW) system integrated with mungbean improved the system productivity by ∼10%, profitability by 20–30% using 15–30% less irrigation water, and 20–25% less energy input compared to conventional RW system in the IGP. However, the replacement of rice with maize improved the productivity by 10-15% and profitability by 40–50% using ∼70% less irrigation water. CA layered with subsurface drip irrigation (SDI) in CA-based rice/maize systems recorded ∼5% higher system productivity and saved ∼50% of irrigation water compared to flood irrigation in CT-based systems. CA-based systems are found more adapted to extreme climatic conditions and can mitigate the negative effects of climatic stresses like terminal heat, water stress and thereby helps in increasing crop yields to the tune of 0.4–0.8 t ha−1 per season over the conventional system. [ABSTRACT FROM AUTHOR]

Earthworms (EWs) could be a viable indicator of soil biology and agri-food system management. The influence of climate-smart agriculture (CSA)-based sustainable intensification practices (zero tillage, crop rotations, crop residue retention, and precision water and nutrients application) on earthworms' (EWs) populations and soil physico-biochemical properties of rice-wheat cropping system in the Indo-Gangetic plains of South Asia was investigated. This study investigates the effect of 10-years adoption of various CSA practices on the abundance of earthworms and physical and biochemical properties of the soil and EWs' casts (EWC). Five scenarios (Sc) were included: conventionally managed rice-wheat system (farmers' practices, Sc1), CSA-based rice-wheat-mungbean system with flood irrigation (FI) (Sc2) and subsurface drip irrigation (SDI) (Sc3), CSA-based maize-wheat-mungbean system with FI (Sc4), and SDI (Sc5). Results revealed that EWs were absent under Sc1, while the 10-year adoption of CSA-based scenarios (mean of Sc2–5) increased EWs' density and biomass to be 257.7 no. m−2 and 36.05 g m−2, respectively. CSA-based maize scenarios (Sc4 and Sc5) attained higher EWs' density and biomass over rice-based CSA scenarios (Sc2 and Sc4). Also, SDI-based scenarios (Sc3 and Sc5) recorded higher EWs' density and biomass over FI (Sc2 and Sc4). Maize-based CSA with SDI recorded the highest EWs' density and EWs' biomass. The higher total organic carbon in EWC (1.91%) than in the bulk soil of CSA-based scenarios (0.98%) and farmers' practices (0.65%) suggests the shift of crop residue to a stable SOC (in EWC). EWC contained significant amounts of C and available NPK under CSA practices, which were nil under Sc1. All CSA-based scenarios attained higher enzymes activities over Sc1. CSA-based scenarios, in particular, maize-based scenarios using SDI, improved EWs' proliferation, SOC, and nutrients storage (in soil and EWC) and showed a better choice for the IGP farmers with respect to C sequestration, soil quality, and nutrient availability. [ABSTRACT FROM AUTHOR]

Soil sodicity is a growing concern for crop growth and development in arid and semi-arid regions of the world. Conservation agriculture (CA) provides an effective solution towards reclamation of degraded sodic lands and enhance the crop productivity. A field experiment was carried out to assess the sodic soil reclamation potential of CA based management practices including zero tillage, legume (mungbean; Mb) rotation, residue (+R) mulch, and subsurface drip irrigation (SDI) for three years under rice-wheat (RW) system. The system scenarios (Sc) comprised of multiple indicators to measure their impact on soil properties as well as system productivity, profitability, water and nitrogen use efficiency. The results indicated that soil pH s under Sc5-Sc8 (CA-based SDI scenarios) was significantly (p < 0.05) lowered by 2.16, 2.16 and 1.33% compare with mean of Sc1 and Sc2 (CT-based system; 9.10, 8.29 and 8.14) at all three soil layers (0-5, 5-15 and 15-30 cm), respectively. Similarly, the exchangeable sodium percentage (ESP) was lowered by 2.9, 11.2 and 14.9% under CA-based scenarios with residue management compared with CT-based system (mean of Sc1 and Sc2; 15.2, 17.2 and 28.6%) during the study. The concentration of extractable anions (CO З 2‾, HCO З ‾, Cl‾) decreased notably whereas, soil organic carbon and soil solution cations (Na+, Ca2+, Mg2+) concentration were increased under CA based management SDI plots. In addition, CA with SDI scenarios (mean of Sc5-Sc8) proved to be more productive and water-efficient than CA-based flood irrigation (FI; mean of Sc3 and Sc4). Moreover, CA-based FI and SDI scenarios saved 29.5 and 60.7% irrigation water, and improved the partial factor productivity of nitrogen (PFP N) by 6.8 and 24.4%, respectively compared to CT-R (conventional tillage without residue) based Sc1. Therefore, CA practices can potentially reduce sodicity and improve soil chemical properties for profitable crop cultivation. [Display omitted] • Conservation agriculture (CA) practices demonstrated a significant reduction in soil sodicity. • CA in rice-wheat system significantly improved energy productivity (EP) and use efficiency (EUE). • CA with subsurface drip irrigation (SDI) system outperformed farmer's practices with 22% higher productivity, 41% higher profitability, and 46% irrigation water saving. • CA practices coupled with SDI hold great potential to reclaim sodic soil and achieve land degradation neutrality in India. [ABSTRACT FROM AUTHOR]

Potassium fertilization is often neglected and /or ignored leading to imbalanced fertilization under intensive cultivation especially in the Indo Gangetic Plains (IGP) in North-West India. Recently conservation agriculture (CA) with crop residue retention has become quite popular among the farmers and land practitioners in India and globally. Crop residues are generally rich in potassium (K) content and its continuous addition under CA may impact K dynamics and supply to crops to some extent. Keeping this in view, a field experiment was conducted to assess the effect of long-term cereal-based CA on K supplying capacity in soil of North-West India. Both routine method (neutral normal ammonium acetate extractable) and quantity-intensity (Q/I) approach were adopted to predict K supply under CA vis-à-vis conventional agriculture. Available K and Q/I parameters were analyzed after 11 years of an experimental setup consisting of six scenarios i.e. Scenario 1 (Sc1): conventional till rice-wheat cropping system; Scenario 2 (Sc2): partial CA based rice-wheat-mungbean system; Scenario 3 (Sc3): full CA based rice-wheat-mungbean system; Scenario 4 (Sc4): full CA based maize-wheat-mungbean system; Scenario 5 (Sc5) and 6 (Sc6): same as Sc3 and Sc4 but with sub surface drip irrigation system. Results revealed that full CA based scenarios maintained significantly higher (p < 0.05) available K (145 mg kg−1) than Sc1 (86 mg kg−1). However, it was observed that Q/I approach helped in better understanding of K supply under long term CA soils than routine method. Regarding K availability, Sc6 was the best scenario with high values of planar K (0.147 cmol kg−1), labile K (0.325 cmol kg−1) and potential buffering capacity (PBCK) while Sc1 (without K fertilization or residue addition) presented lowest values of Q/I parameters. Partial CA (Sc2) maintained higher labile K (0.368 cmol kg−1) and equilibrium concentration ratio (CR e 0K) (1.93(mol L−1) 1/2 × 10−3) but very low PBCK (36.4 cmol kg−1 (mol L−1) −1/2) suggesting that K intensity shall not be sustained for long period of time and lead to soil K depletion over time. However, on an average, all full CA based scenarios maintained higher Q/I parameters over the conventional practice (Sc1), representing better ability to supply K both immediately and over a long period of time to meet crop requirement. The impact of maize-wheat-mungbean cropping system was prominently observed with respect to CR e 0Kover rice-wheat-mungbean system; whereas the effect of irrigation method was not significantly distinguishable. The study thus highlights the potential of long term crop residue retention under CA for improving and maintaining K supply to crops. [Display omitted] • Q/I approach was better than 1 N NH 4 OAC method for understanding K dynamics under long term CA. • Intensity and quantity parameters were higher in CA than conventional agriculture. • Partial CA maintained higher immediately available K but poor supplying capacity over long term. • Long term residue retention significantly impacts K dynamics under CA. [ABSTRACT FROM AUTHOR]

• Conservation agriculture enhances SOC, nutrient availability and enzyme activity. • Infiltration improved under conservation agriculture practices. • Soil pH, SOC stock, available zinc and iron were the key soil quality indicators. • Higher soil quality index in CA based treatments over conventional one. • Maize-wheat cropping system showed higher soil quality over rice–wheat system. Soil quality is of utmost essential for yield sustainability of intensive cereal based cropping system in North West Indo Gangetic plains of India. Hence, we evaluated long-term (10 years) effect of conservation agriculture (CA) practices on soil quality improvement under six different cropping scenarios (Sc), i.e. Sc1-represented by transplanted puddled rice (TPR) followed by conventional tilled broadcasted wheat (CT-wheat) with residue removal, Sc2-TPR rice followed by zero tillage (ZT) wheat and ZT-mung bean with partial residue retention, Sc3-direct seeded rice (DSR) followed by ZT-wheat and ZT-mung bean with full residue retention, Sc4-DSR is replaced by ZT-maize followed by ZT-wheat and ZT-mung bean, Sc5 and Sc6 were – Sc3 integrated with sub surface drip irrigation (SDI) and Sc4 + SDI, respectively. Soil samples were collected from 0 to 5, 5–15 and 15–30 cm soil depth from each scenario after harvesting of wheat in 2019. Results showed that, reduction in bulk density (BD), soil penetration resistance (SPR) and enhancement of water holding capacity and infiltration were associated with CA based scenarios (Sc3–Sc6). Scenario 3 recorded lowest BD of 1.39 and 1.58 g cm−3 at 0–5 and 5–15 cm soil depth, respectively. CA based Sc6 recorded highest infiltration rate (1.48 cm hr−1) and lowest was associated with Sc1 (0.5 cm hr−1). The enrichment of soil organic carbon (SOC) content, stock, available nitrogen and potassium was mainly confined to upper surface soil layer (0–5 cm). The SOC content and stock in CA based scenarios (average of Sc3 to Sc6) was 41–57 and 69–94% higher than Sc1 at 0–5 cm soil layer. Available nitrogen was increased by 23–50 and 64–98% and available potassium increased by 13–28 and 42–71% in 0–5 and 5–15 cm soil depth, respectively in CA based scenarios over Sc1. Similarly, microbial biomass carbon (MBC) and dehydrogenase (DHA) activity in top soil layer under CA based scenarios was increased by 177–195 and 67–107% over Sc1, respectively. The maximum SQI was registered with Sc6 (0.91) followed by Sc4 (0.89) and least was recorded in Sc1 (0.65) at 0–5 cm soil depth. Maize-wheat based cropping system recorded higher SQI over rice–wheat based cropping system. Sustainable yield index was strongly related with key soil quality indicators and also positively correlated with SQI. Thus our study suggests that CA based maize-wheat-mung bean cropping system should be recommended for better soil quality and yield sustainability in North West India. [ABSTRACT FROM AUTHOR]