Search

Highlights: [•] Various nutrient management strategies were evaluated under NT and CT based wheat production. [•] SSNM based on Nutrient expert® increased yield and economic profitability than state recommended and farmers’ practice of nutrient management. [•] SSNM and NT system had lower GWP than CT system and farmer's fertilization practice, respectively. [ABSTRACT FROM AUTHOR]

• Enrichment in soil organic carbon was observed under ZT diversified cropping system. • Conservation agriculture improved aggregate indices. • ZT and crop diversification improved particulate and aggregate associated carbon. • Conservation agriculture showed higher system productivity. Intensive tillage based management practices are threatening soil quality and systems sustainability in the rice-wheat belt of Northwest India. Furthermore, it is accentuated with puddling of soil, which disrupts soil aggregates. Conservation agriculture (CA) practices involving zero tillage, crop residue management and suitable crop rotation can serve as better alternative to conventional agriculture for maintaining soil quality. Soil organic carbon is an important determinant of soil quality, playing critical role in food production, mitigation and adaptation to climate change as well as performs many ecosystem functions. To understand the turnover of soil carbon in different forms (Total organic carbon-TOC; aggregate associated carbon-AAC; particulate organic carbon- POC), soil aggregation and crop productivity with different management practices, one conventional agriculture based scenario and three CA based crop management scenarios namely conventional rice-wheat system (Sc1), partial CA based rice-wheat-mungbean system (Sc2), full CA-based rice-wheat-mungbean system (Sc3) and maize-wheat-mungbean system (Sc4) were evaluated. TOC was increased by 71%, 68% and 25% after 4 years of the experiment and 75%, 80% and 38% after 6 years of the experiment in Sc4, Sc3 and Sc2, respectively, over Sc1 at 0–15 cm soil depth. After 4 years of the experiment, 38.5% and 5.0% and after 6 years 50.8% and 24.4% improvement in total water stable aggregates at 0–15 and 15–30 cm soil depth, respectively was observed in CA-based scenarios over Sc1. Higher aggregate indices were associated with Sc3 at 0–15 cm soil depth than others. Among the size classes of aggregates, highest aggregate associated C (8.94 g kg−1) was retained in the 1-0.5 mm size class under CA-based scenarios. After 6 years, higher POC was associated with Sc4 (116%). CA-based rice/maize system (Sc3 and Sc4) showed higher productivity than Sc1. Therefore, CA could be a potential management practice in rice-wheat cropping system of Northwest India to improve the soil carbon pools through maintaining soil aggregation and productivity. [ABSTRACT FROM AUTHOR]

• Surface drip irrigation in maize-wheat system on permanent raised bed was evaluated. • Drip irrigation with residue retention increased maize yield by 14% and wheat yield by 23% compared to furrow irrigation. • Drip irrigation with residue retention increased irrigation water productivity by 259% in maize and 66% in wheat compared to furrow irrigation. • Fertigation increased the N recovery efficiency by 17% in maize and 29% in wheat compared to furrow irrigation. The traditional flood irrigation system has led to overexploitation of ground water and low nitrogen (N) use efficiency. In north-western India, maize-based systems with lower irrigation requirement are being advocated as an alternate to rice-based systems to address the issues of declining water table. Bed planting of crops, straw mulching and drip irrigation are known to save precious irrigation water, and improve N use efficiency and grain yields. To this effect a two-year field experiment was conducted with annual wheat-maize rotation on permanent bed system to evaluate the effect of surface drip irrigation, residue management, and N application on crop and water productivity. Maize and wheat under drip irrigation with residue retention system showed significant grain yield increase of 13.7% and 23.1% compared to furrow irrigation with no residue, respectively. Surface drip irrigation with residue retention saved 88 mm and 168 mm of water and increased water productivity by 66% and 259% in wheat and maize on permanent beds compared to the conventional furrow irrigation system with residue removal, respectively. Similarly, fertigation at 10-day interval with five splits in wheat and seven splits in maize under drip irrigation system increased the mean N recovery efficiency by 16.5% and 29% compared to furrow irrigation in wheat and maize, respectively. [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]

In intensive rice–wheat systems of north-west (NW) India, surface retention of rice residues in wheat has been recommended instead of burning. Optimum nitrogen (N) management for zero till (ZT) wheat sown into rice residues may to differ from that of conventional practice ( in-situ burning of residues followed by intensive tillage prior to sowing). Therefore, we conducted several on-farm and on-station field experiments in 2007–2008 to 2012–2013 to evaluate N management practices for ZT wheat sown into rice residues using the Happy Seeder. The optimum N rate for wheat planted into rice residues in fields with no or only a short history of rice residue retention was 120 kg N ha −1 , the current recommendation for conventional practice. Short-term (up to 20 d) soil N mineralization was lower in undisturbed soil than disturbed soil, while the total amount of N mineralization was similar after 40 d, suggesting that over the crop season, total soil N mineralization may be similar in tilled and non-tilled soil. Ammonia volatilization loss from urea broadcast over the residue covered surface, followed by irrigation, was low (<2 kg ha −1 ) regardless of time of urea application. Band placement of 20% of the fertilizer N as diammonium phosphate at seeding, and topdressing of the remaining 80% as urea in two equal doses before first and second irrigations produced higher grain yield and N use efficiency than other treatments. However, surface residue retention reduces the rate of soil drying and in some situations this delays the time of the second irrigation and thus N fertilizer application beyond the optimum time. Therefore, the effect of banding various proportions of the urea N between the rows at sowing was investigated. The results showed that, on a loam soil, up to 75% of the recommended N fertilizer can be applied at sowing, 24 kg N ha −1 as DAP with the seed and 66 kg N ha −1 as urea drilled between every second wheat row, without loss of yield. In conclusion, a better applied N management strategy for ZT wheat than currently practiced is drilling of 24 kg N ha −1 as diammonimum phosphate into the soil at seeding followed by two top-dressings of 48 kg N ha −1 each just prior to first and second irrigations. [ABSTRACT FROM AUTHOR]

Abstract: Conservation agriculture (CA) based crop management technologies specially zero- or minimum-tillage are being rapidly adopted by the farmers in intensively cultivated wheat (Triticum aestivum L.) production systems of South Asia. Farmers use these tillage options considering them best as per their wisdom. However, scanty information is available on relative energy and economic efficacy of different tillage and seeding implements being used by the farmers for wheat production in the Indo-Gangetic Plains (IGP) of South Asia. We investigated the effect of five wheat establishment methods (i) conventional tillage; (ii) reduced-tillage; (iii) rotavator tillage; (iv) raised bed planting; and (v) zero-tillage for their energy and economic efficiency in a Typic Ustochrept alluvial sandy loam soil in the IGP during 2005–2008. We hypothesized that (1) zero- or minimum-tillage implements would lead to improved operational field capacity; (2) the CA based technologies would enhance energy efficiency; and (3) overall these tillage and seeding methods would enhance net income and crop productivity. We measured implement efficiency, energy inputs and outputs, tillage and seeding efficiency as well as wheat productivity and economics. The results of the study showed that zero-tillage improved the operational field capacity by 81%, specific energy by 17% and the energy usage efficiency by 13% as compared to the conventional tillage. But, higher total effective field capacity (9.93hha−1) on raised beds is in contrast with our second hypothesis. The enhanced net income in zero-tillage (33%) and reduced-tillage (20%) compared to CT support the third hypothesis. The overall results of the study revealed that CA-based crop establishment practices are a viable options for the farmers not only in terms of energy and time efficiency but also for attaining higher productivity and profitability. There exists a large potential of CA based crop establishment practices in South Asia not only in terms of crop productivity and profitability but also their energy efficiency, global warming potential and soil health. The study also emphasizes for long-term strategic research in systems perspective for better understanding CA based technologies in different efficiency and soil health aspects. [Copyright &y& Elsevier]

The rising economic and environmental costs of mineral fertilizers associated with lower nutrient use efficiency, and the need to respond the limitations of N fertilization under residue retained condition of conservation agriculture (CA) motivate the research for alternative N placement methods. The third principle of CA, i.e., residue retention on the soil surface hinders the right placement of split applied nitrogen (N). To address this issue, we assessed the impact of three N placement methods, i.e., NPM 1 : both the N splits were surface band placed, NPM 2 : the first split of N was sub-surface point placed and second N split (late vegetative stage) was surface band applied, and NPM 3 : both the N splits were sub-surface point placed, under 4-long-term tillage and residue management (+R) options, i.e. , permanent raised bed (PB+R), zero-till flat (ZT+R) conventional till flat (CT+R) and first time zero till flat sowing of the crop on last 10-year fallow land (FZT+R), in an on-going long-term study (since 2008) in maize for three consecutive years (2018–2020). Results showed that sub-surface point placement of both the N splits (NPM 3) increased maize grain yield by 4.7, 7.0 and 6.0% (3-years mean basis) compared to NPM 2 , under CA-based PB, ZT, and FZT plots, respectively. The peak growth rate in the CA-based PB+R plot was advanced by 4-days with a 9.2% higher growth rate compared to CT+R. Similarly, the peak growth rate in NPM 3 was 20% higher than NPM 1 plots. The changes in soil properties under CA altered the crop growth behavior, while sub-surface point placement of split applied nitrogen (N) increased the grain N content and altered the peak growth rate of maize. The variability in maize grain yield was best described by cob length and number of cobs in long-term tillage and by cob length in N management plots. The cob length and grains per cob were increased by 4.8–8.7 and 8.6–12.8% under CA-based plots compared to CT+R, respectively. The amount of vegetative stage accumulated N remobilized to maize grain was 21.2% higher under PB+R compared to CT+R plots, while the N remobilization in NPM 3 was 22.9% higher compared to NPM 1 plots. Similarly, the contribution of reproductive stage N uptake to grain was 9–12% higher in CA-NPM 3 compared to CT-NPM 1 plots. Further, the early and vigorous growth of maize resulted in a higher accumulation of N and its remobilization to the grains in CA-based and N point placed plots. The sub-surface point placement of N (NPM 3) resulted in a 12.8, 14.5 and 9.2% higher benefit-cost ratio compared to NPM 1 plots in 11th (2018), 12th (2019) and 13th (2020) years of experimentation, respectively. Therefore, the present study visualizes the impact of a decade-long CA and efficient N management on crop growth behavior, N uptake and remobilization and crop productivity and water use efficiency. This study provides evidence to popularize this technology in the CA-systems of Indo-Gangetic Plains and other similar agro-ecologies. • Long-term tillage alters maize growth behavior, while N placement increases the growth rate. • Both N remobilization and reproductive stage N uptake were higher under CA and NPM3. • Point placement of third N split under CT could not increase maize yield significantly. • Cob length and cob number described most of the yield variability in CA. [ABSTRACT FROM AUTHOR]

Recently conservation agriculture (CA) using the principles of zero tillage, crop residue management and suitable crop rotation has gained the momentum and quite popular among the farmers. Researchers throughout the globe have shown the potential of CA in enriching soil organic carbon storage in various soil types and cropping systems. But there is very limited study on the effect of CA on soil humic acid content and their stability and abundance of functional groups. An experiment was conducted in an Alfisols with four scenarios (designated as Sc) namely conventional farmers practice (Sc1) of transplanted rice (TPR) followed by conventional tilled broadcasted wheat (CT- wheat) with residue removal, transplanted rice (TPR) followed by zero tillage (ZT) wheat and mung bean with partial residue retention (Sc2), direct seeded rice (DSR) followed by ZT- wheat and mung bean with full residue retention (Sc3), ZT-maize followed by ZT-wheat and mung bean (Sc4) at the research farm of ICAR-Central Soil Salinity Research Institute, Karnal, Haryana, India. The objectives of this study were to assess the humic acid (HA) content and stability of soil carbon through desorption study and to characterize the functional groups of HA by Fourier Transform Infrared (FTIR) spectroscopy under different scenarios. HA was extracted from soil samples collected from 0 to 15 and 15–30 cm depth after rice harvesting in 2018 after nine years of the experiment. Results showed that Sc4 recorded significantly highest HA content at 0–15 depth (4.23 g/kg) and 15–30 cm soil depth (2.08 g/kg). Lower E4/E6 ratio revealed higher stability and humification of humic acid carbon under CA based scenarios. Lowest desorption rate constant (0.20/day) was observed under Sc4 indicating higher organic carbon stability in soil. Higher labile carbon and nitrogen was observed in soils under Sc3 as revealed through desorption study. FTIR spectroscopy results confirmed the prevalence of higher number of functional groups (O C O, C O or CHO) in HA under CA based scenarios with an order of Sc4 >Sc3 >Sc2 >Sc1. Therefore, CA is not only efficient in enriching the organic carbon in soil but also in more stable complex of HA with soil particles having long term implications in soil carbon sequestration for future posterity. • Conservation agriculture (CA) effects on humic acid (HA) content and behaviour was studied. • CA based maize-wheat-mungbean showed highest HA content. • Desorption study reflected higher stable carbon under CA based maize system. • FTIR spectroscopy reveals complex functional groups in HA under CA based systems. • CA has potential to store more carbon in stable forms compared to conventional agriculture. [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]