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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]

Monotonous rice-wheat cropping system with conventional management practices have resulted in declining soil quality and biota in addition to low input factor productivity and farmer’s profitability in western Indo-Gangetic plains (IGP) of India. Conservation agriculture (CA) based sustainable intensification (SI) is required to improve the soil quality while improving the productivity and profitability. A field experiment was conducted to evaluate the effects of CA based management practices such as zero tillage (ZT), direct seeding of rice (DSR), crop diversification, residue recycling and legume integration for SI in comparison to conventional management on soil quality and biota in cereal (rice and maize) based cropping systems. Fourteen treatments were included in which four treatments (T 1 –T 4 ) with rice–wheat and two treatments (T 11 –T 12 ) with maize-wheat system were based on conventional management, while six treatments (T 5 –T 10 ) with rice–wheat and two (T 13 –T 14 ) with maize-wheat were based on CA management practices. Conservation agriculture based SI of maize-wheat-mungbean (T 14 ) recorded lower soil bulk density (1.33 Mg m −3 ). Soil organic carbon (OC) was increased by 83% and 72% with CA based rice-wheat-mungbean (T 10 ) and maize-wheat-mungbean (T 14 ) system, respectively and it was at par with T 9 and T 12 compared to farmer’s practice (T 1 ) (4.6 g kg −1 ). Mean microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) were 213% and 293% higher with T 14 over T 1 (646 and 201 µg g −1 dry soil), respectively. However, T 10 recorded 117% and 171% higher MBC and MBN, respectively compared to T 1 . Dehydrogenase activity (DHA) and alkaline phosphatase activity (APA) were improved by 210% and 49% under T 14 ; 140% and 42% under T 10 compared to T 1 (180 µg TPF g −1 soil 24 h −1 and 144 µg p-nitrophenol g −1 h −1 ), respectively. Mean number of bacteria, fungi and actinomycetes were increased by 28%, 68%, 98% respectively, under T 14 relative to T 1 , and at par with T 12 and T 10 . Most abundant micro-arthropod group belonged to Collembola followed by Acari and Protura , irrespective of treatments. Higher soil quality index (SQI) was observed in T 10 (0.82), followed by T 14 and T 6 treatment (0.76). Sustainable intensification of rice and maize based systems (T 10 and T 14 ) recorded 39% higher system yield compared to T 1 (11.12 Mg ha −1 ). CA-based sustainable intensification of rice/maize systems improved soil quality and biota, hence resulted higher system yield in alluvial soils of IGP. Conservation agriculture based SI of maize-wheat-mungbean system was found to be the best alternative option than rice–wheat system to achieve sustainable productivity while improving the soil quality index (35%) and conservation of natural resources. [ABSTRACT FROM AUTHOR]

In agriculture production system, soil enzymes are important indicators of soil quality. Measurements of soil quality parameter changes are essential for assessing the impact of soil and crop management practices. Keeping this in view, an experiment was conducted to evaluate the enzyme activities namely dehydrogenase (DHA), β-glucosidase, acid and alkaline phosphatase (AcP & AlP), fluorescein diacetate hydrolases (FDH), cellulase, urease and aryl sulphatase in rhizosphere and bulk soil after 8 years of different management regimes. Soil organic carbon (SOC), moisture content and few enzyme indices such as enzymatic pH indicator (AcP/AlP), alteration index three (Al3) and geometric mean (GMea) were also measured. The treatments were conventional rice-wheat system (termed as scenario (Sc1), CT system), partial conservation agriculture (CA)-based rice-wheat-mungbean system (Sc2, PCA-RW), partial climate smart agriculture (CSA)-based rice-wheat-mungbean system (Sc3), partial CSA-based maize-wheat-mungbean system (Sc4), full CSA-based rice-wheat-mungbean system (Sc5), and full CSA-based maize-wheat-mungbean system (Sc6). Soil samples were collected from rhizosphere and away from roots (bulk soil) at 0–15 cm soil depth before sowing (from rhizosphere of previous crops), at maximum tillering, flowering, and after harvesting of wheat crop. Results showed that DHA activity was higher before sowing (59.8%), at maximum tillering (48.4%), flowering (8.6%) and after harvesting (19.1%) in rice based CSA systems (mean of Sc3 and Sc5) over maize based CSA systems (mean of Sc4 and Sc6) in rhizospheric soil. On average, β-glucosidase activity was significantly higher in rhizospheric soils of rice based system over maize based CSA system. Before sowing of wheat, significantly higher (21.4%) acid phosphatase activity was observed in rhizosphere over bulk soils of maize based CSA system. Significantly higher alkaline phosphatase activity was observed before sowing of wheat in bulk soils of rice (25.3%) and maize (38.5%) based CSA systems over rhizospheric soils. Rice based CSA systems showed 27% higher FDH activity than maize based systems. Significant interaction effect was observed between the managements and enzymes. SOC played an important role in regulating the enzymes activity both in rhizosphere and bulk soil. Significant variation in AcP/AlP , Al3 and GMea was observed among the managements. Therefore, CSA managements are beneficial in improving enzyme activities not only in rhizosphere but also in bulk soil where residues are retained thereby may help in improving nutrient cycling. • Soil enzyme activities in rhizosphere and bulk soil were carried out with climate smart agriculture practices. • Residue retention and zero tillage improves enzyme activities in bulk soil. • Dehydrogenase and β-glucosidase activities were higher in rhizospheric soils of rice based system. • Urease activity was not affected by growth stages and climate smart agriculture practices. • SOC played an important role in regulating the enzymes activity in soil. [ABSTRACT FROM AUTHOR]

Intensive tillage coupled with crop residue burning in rice-wheat (RW) system is a serious issue that causes soil degradation and environmental pollution. Soil organic carbon (SOC) is one of the main indicators of soil health and system's sustainability. Zero-tillage has been widely recommended as an alternative for improving carbon sequestration in soil under different ecologies. But the SOC sequestration is very inconsistent and varied as it depends on the crop management practices. This study was performed in the western Indo-Gangetic plains (IGP) of India where RW system contributes 40% to the total country's food grain basket; however there exists issue of its sustainability because of declining SOC coupled with open field crop residue burning. Therefore, we evaluated the effects of different management scenarios (Sc) namely Sc1 (conventional till rice-wheat cropping system; business as usual), Sc2 (partial climate smart agriculture (CSA)-based rice-wheat-mungbean system), Sc3 (CSA-based rice-wheat-mungbean system), and Sc4 (CSA-based maize-wheat-mungbean system) on SOC pools and biological properties after 4 crop cycles (year 2009–2013). Soil samples were collected from surface and sub surface layers (0–15 and 15–30 cm soil depth) after rice harvesting in 2013. Results showed that the SOC stock at surface layer was higher by 70% with Sc4 than Sc1 (16.2 Mg C ha−1) (P < 0.05). All the forms of carbon in different pools were higher (P < 0.05) with Sc4 and Sc2 over Sc1 at 0–15 and 15–30 cm soil depths, respectively. At surface soil SOC pools were found in order of Sc4 > Sc3 > Sc2 > Sc1 (P < 0.05). Higher lability index (LI) (2.1) and stratification ratio (SR) (2.5) of organic carbon were observed in CSA-based systems (Sc2 and Sc4). At surface layer (0–15 cm) the CSA- based scenarios (mean of Sc2, Sc3 and Sc4) showed higher (P < 0.05) enzyme activities viz. dehydrogenase (641 μgTPF g−1 24 h−1) and alkaline phosphatase (158 μg p-nitrophenol g−1), and microbial biomass carbon (MBC) (787 μg g−1) and microbial biomass nitrogen (MBN)(98 μg g−1) compared with Sc1. Higher value of the basal soil respiration (34%) was also observed with CSA-based scenarios (Sc2, Sc3, Sc4). Surface soil layer showed maximum counts of fungi, bacteria and actinomycetes in Sc4. MBC, fungal population and SOC were the most sensitive biological soil parameters identified through principal component analysis (PCA) which can be used for soil quality assessment. Therefore, medium term adoption of climate smart agricultural practices involving zero-tillage, crop establishment, residue management and crop diversification in rice-wheat system can significantly improve the systems productivity by improving SOC and soil biological quality. • Organic carbon stock was improved under climate smart agriculture (CSA) based cereal systems. • MBC, MBN, microbial population and soil enzymes were improved in CSA. • CSA practices enhanced the systems productivity. • MBC, fungal population and SOC were the most sensitive indicators identified. [ABSTRACT FROM AUTHOR]

Disposal of paddy residue has turn out to be a huge problem in north-west Indian states, resulting farmers prefer to burn the residues in-situ. Paddy residue management is of utmost important as it contains plant nutrients and improves the soil-plant-atmospheric continuum. Burning biomass not only pollutes environment and results in loss of appreciable amount of plant essential nutrients. The objectives of the review paper is to access the amount of residue generation, its utilization in-situ and ex-situ, emphasize harmful effects of residue burning on human health, soil health and environment of north-west states of India specially in Punjab and Haryana. This paper also discusses the possible strategies, financial and socio-economic evaluation of the paddy residue management technologies and accentuates the assessment of range of potential policy instruments which would offer avenues for sustainable agriculture and environment. Timely availability of conservation agriculture (CA) machinery is of utmost significance to manage the paddy residues in-situ. Collection and transportation of voluminous mass of paddy residue is cumbersome, therefore, ex-situ residue management is still not an economically viable option. The agricultural waste opens vivid options for its versatile usage and is possible if residue is collected and managed properly. It is a prerequisite for surplus residues to be used for CA. There is an urge to create awareness among farming communities to incline them to understand importance of crop residues in CA for sustainability and resilience of Indian agriculture. [ABSTRACT FROM AUTHOR]