Rice-maize System Research Articles

Soil carbon-nutrient cycling, energetics, and carbon footprint in calcareous soils with adoption of long-term conservation tillage practices and cropping systems diversification

Calcareous soils, comprising vast areas in northern and eastern parts of India, are characterized by low soil organic carbon (SOC) with high free CaCO3 that results in low nutrient bioavailability with poor soil structure. Improvement of this soil can be achieved with conservation tillage with residue retention coupled with diversification of cropping system including legumes, and oilseeds in the system. Concerning all these, a long-term experiment was carried out in the calcareous soils having low organic carbon and high free CaCO3 (∼33 %) with varied tillage practices, viz. permanent bed with residue (PB), zero tillage with residue (ZT), and conventional tillage without residue (CT); and cropping systems viz. maize-wheat-greengram (MWGg), rice-maize (RM), and maize-mustard-greengram (MMuGg) during 2015–2021. From this study, it was observed that PB and ZT resulted in ∼25–30 % increment in SOC compared to the initial SOC, while CT showed a 4 % decrease in the SOC. Conservation tillage practices also resulted in better soil aggregation and favourable bulk density of the soil. Furthermore, PB and ZT practice exhibited 10–13 %; 15–18 %; 11–15 %; 40–60 %, 20–36 %, and 23–45 % increments in the soil available N, P, K, soil microbial biomass carbon, dehydrogenase activity, and urease activity, respectively over those under CT. Crop diversification with the inclusion of legume and oilseed crops (MMuGg, and MWGg) over cereal-dominated RM systems resulted in better soil health. Maize equivalent yield and energy use efficiency (%) were also found to be the maximum under PB, and ZT, in combination with the MMuGg system. ZT and PB also reduced the carbon footprint by 465 and 822 %, respectively over CT by elevating SOC sequestration. Hence, conservation tillage practices with residue retention coupled with diversification in maize-based cropping systems with mustard and greengram can improve soil health, system productivity, and energetics, and reduce the carbon footprint in calcareous soils.

Grain nitrogen content and productivity of rice and maize under variable doses of fertilizer nitrogen

The rice-maize system is a dominant cropping system of south Asia and consumes a considerable amount of fertilizer. The indiscriminate use of fertilizer particularly nitrogen (N) is degrading the soil health and polluting the environment. Lower N-use efficiency is a major problem and needs to be improved for higher yield, lower cost of cultivation and better environment. The grain quality is also altered by the N-application as N is a major constituent of protein. Studies on the effect of N-application on grain N-content is still lacking. We hypothesised that optimization of N application would result in economising N dose, improving yield and NUE and improving grain quality. Under that context, a field experiment was conducted with different doses of fertilizer N for rice and maize. Fertilizer N was applied at the rate of 0, 40, 80, 120, 160, 200 and 240 kg ha−1 (N0–N240). An increase in grain yield was observed up to 80 and 160 kg ha−1 for rice and maize, respectively. The N content of grain increased with N rates and a significant increase was noted in N200 (1.42%) being at par with N240 (1.49%) but significantly higher than others by 13–32%. With an increase of each kilogram of N, the grain N content increased by 14 and 20 μg (microgram) for rice and maize, respectively. The leaf N content registered a decreasing trend with the progress of the crop growth for both rice and maize. The agronomic efficiency (AE) of N initially increased with an increase in the rate of fertilizer N followed by a decrease with higher doses of N. Unlike the AE, the partial factor productivity (PFP) of N decreased gradually with an increase in the rate of fertilizer N. The chlorophyll content of flag leaves also registered an increasing trend with an increasing rate of fertilizer N. On the surface soil (0–15 cm), the treatments which received lower (N0, N40) and higher (N240) fertilizer N recorded a comparatively higher total soil N than other treatments. The mean NUE was 0.42 and 0.75 for rice and maize, respectively. The study suggests an economic fertilizer N rate of 165 and 167 kg N ha−1, for rice and maize, respectively. It also concludes that the grain N content can be altered by N-application rates though more research is needed.

Influence of residual maize crop residue management techniques and fertilizer levels on growth and productivity of zero till maize in rice-maize sequence

A field trial was conducted on a sandy clay loam soil during rabi seasons of 2020-21 and 2021-22 at the Agricultural College Farm, Bapatla to investigate the residual effect of maize crop residue management techniques and fertilizer levels on growth and productivity of zerotill maize in rice-maize sequence. The experiment was laid out in split-split plot design with four maize crop residue management practices (M1 : Exportation of maize stover, M2 : In-situ burning of maize stover (farmers practice), M3 : Mulching maize stover with rotary mulcher and M4 : Incorporation of maize stover with rotovator) as main plot treatments and three fertility levels (100% RDF, 75% RDF and 50% RDF) as sub plot treatments applied to kharif preceded rice and three fertility levels (100% RDF, 75% RDF and 50% RDF) as sub-sub plot levels applied to succeeding maize. Results revealed that incorporation of maize stover with rotovator (M4 ) applied to preceding rice significantly improved plant height (cm), days to 50% tasseling and 50% silking, cob length (cm), cob girth (cm), test weight (g) and grain yield of maize. Mean values for fertiliser levels revealed that plant height (cm), days to 50% tasseling and 50% silking, cob length (cm), cob girth (cm), test weight (g) and grain yield were registered with application of 100% RDF (S1 ) applied to preceding rice and application of 100% RDF applied to succeeding maize. Thus, incorporation of maize stover with rotovator (M4 ) along with application of 100 % RDF applied to preceding rice and application of 100% RDF (S1 ) to succeeding maize is an optimum and sustainable approach to enhance the growth and productivity of zero till maize in rice-maize system.

Conservation tillage and residue management improve soil health and crop productivity—Evidence from a rice-maize cropping system in Bangladesh

The rice-maize (R-M) system is rapidly expanding in Bangladesh due to its greater suitability for diverse soil types and environments. The present conventional method of cultivating puddled transplanted rice and maize is input-intensive, decreases soil health through intense ploughing, and ultimately reduces farm profitability. There is a need to investigate alternatives. Accordingly, we conducted a replicated 2-year (2020–2021) field study to investigate the effects of conservation agriculture (CA) based tillage and crop establishment (TCE) techniques and residue management practices on the physical, chemical, and biological properties of soil along with crop productivity and the profitability of rice-maize systems in the sandy loam soil of Northwest Bangladesh. Two TCE techniques Puddled transplanted rice (PTR) followed by Conventional tillage maize (CTM) and strip tillage direct-seeded rice (STDSR) followed by strip-tilled maize (STM) were assigned to the main plots and different percentages of crop residue retention (0, 25, and 50% by height) were allocated to the subplots. Results showed that a reduction in bulk density (BD), soil penetration resistance (SPR), and increased soil porosity were associated with STDSR/STM-based scenarios (strip tillage coupled with 25 and 50% residue retention). The soil organic carbon (SOC) fractions, such as dissolved organic C (DOC), light and heavy particulate organic matter C (POM-C), MAOM, and microbial biomass C (MBC) levels in the 0–10 cm layer under ST based treatments were 95, 8, 6, 2 and 45% greater, respectively, compared to CT with no residue treatment. When compared to the CT treatment, the DOC, light POM-C, heavy POM-C, and MAOM in the 10–20 cm layer with ST treatment were 8, 34, 25, 4 and 37% higher, respectively. Residue retention in ST increased average rice, maize, and system yields by 9.2, 14.0, and 14.12%, respectively, when compared to CT. The system gross margin and benefit-cost ratio (BCR) were $1,515 ha−1 and 1.90 under conventional tillage to $1,696 ha−1 and 2.15 under strip-tillage practices. Thus, our study suggests that CA could be an appropriate practice for sustaining soil fertility and crop yield under R-M systems in light-textured soils or other similar soils in Bangladesh.

Indigenous Nutrient Supplying Capacity of Young Alluvial Calcareous Soils Favours the Sustainable Productivity of Hybrid Rice and Maize Crops

The crop productivity in calcareous soils is low due to their low organic matter content, high pH levels and improper nutrient management without considering the indigenous nutrient supplying capacity and crop yield potential; therefore, this study was conducted for a quantitative assessment of the nutrient supplying capacity of a calcareous soil on the productivity of hybrid and conventional rice and maize crops using an omission plot technique. The treatments included the ample application of Nitrogen (N), Phosphorus (P), Potassium (K), Sulphur (S) and Zinc (Zn), and an unfertilized check and omissions of N, P, K, S and Zn in rice and maize for six cropping seasons. The impact of the nutrient omission towards crop productivity was highest for nitrogen followed by phosphorous, potassium, zinc and sulphur. The total grain yield (3 yr average) in the hybrid rice–maize system was highest (16.32 t ha−1) for the optimum fertilized plot and lowest (6.34 t ha−1) for the unfertilized check. The sustainable yield index indicated that hybrid and conventional rice-maize cropping systems were more sustainable in the amply fertilized plot than in the nutrient-limited and unfertilized treatment plots. The average percent contributions of nitrogen, phosphorous, and potassium from the soil towards total nutrient removal were 36, 80 and 137 kg ha−1, in the hybrid system and 24, 54 and 104 kg ha−1 in the conventional system, respectively. The return on investment (ROI) of the N, P, K, S and Zn for the hybrid rice was 21.2, 7.1, 6.7, 4.1, and 0.3 USD, respectively, while for the maize it was 28.8, 7.6, 4.9, 6.5, and 0.7 USD, respectively. The results suggest that there is a direct link between the soil nutrient supplying capacity and the nutrient requirements by different types of crops in calcareous soil; therefore, the omission plot technique used for the assessment of the indigenous nutrient supplying capacity could be used in the larger domain for improved nutrient management, through synchronization with a targeted crop yield for improved productivity, soil fertility, nutrient use efficiency and farm income.

Nutrient Management Practice for Conservation and Conventional Agriculture Practices on Rice Based System at Central Terai of Nepal

A field experiment was conducted to evaluate the effect of inventive nutrient management practices on the system productivity and profitability of rice-wheat and maize in the rice-based cropping system under conservation agriculture and conventional tillage at Agriculture and Forestry University (AFU), Rampur, Chitwan, Nepal during 2018 - 2019.The experiment was executed in the field in split-split design (for rice), and split plot design (both for wheat and maize) with three replications which included two cropping system (rice-wheat and rice-maize) as main plot treatments, two establishment methods (conservation agriculture and conventional agriculture) as sub plots and four nutrient management practices (100% Recommended dose of fertilizer (RDF), Residue (5 t ha-1) + 75% RDF, Nutrient Expert (NE) dose, brown/green manuring (BM/GM) + 75% RDF) as sub-sub plot treatments. The data on yield and economics were recorded and analyzed by R studio. The yield of wheat and maize were converted into rice equivalent yield (REY) from which system yield was calculated. The research revealed that the rice-maize system had significantly higher REY (12.21 t ha-1), net returns (163.10 thousand NRs. ha-1) over rice-wheat system (8.61 t ha-1 and 68.09 thousand NRs. ha-1, respectively) whereas the crop establishment methods and nutrient management practices have no influence on the REY of the system. NE dose, Residue +75% RDF and 100% RDF produced similar REY. The rice grain yield was found higher (5.28 t ha-1) for conventional tillage than under CA (4.52 t ha-1) however the maize and wheat yield was not affected by the crop establishment methods. Under both establishment methods, NE dose performed better for all crops but NE dose and green manuring produced higher yields under conventional tillage for rice. The residue +75% RDF performed better than 100% RDF for maize and wheat. Rice-maize cropping system was more productive and eventually more profitable than rice-maize cropping system and the under both establishment methods, better yield can be obtained using NE dose, green manuring and residues in the fields with the saving of 25% RDF applied for each crops.

Sustainable Intensification of a Rice-Maize System through Conservation Agriculture to Enhance System Productivity in Southern India.

Integrated management of rice–maize systems is an emerging challenge in southern India due to improper rice residues and tillage management in maize crops. Conservation agriculture (CA) practices such as a reduced tillage and maintaining stubble mulch may hold the potential to increase yields, reduce crop establishment costs and increase farm incomes. A five-year trial was performed to study the effect of different CA and establishment methods in rice on system productivity, profitability, and soil carbon status in a rice–maize system. In the rainy season, the trial consisted of two main treatments: (i) normal manual transplanting and (ii) direct-wet seeding, and three sub-main treatments at different sowing dates with fifteen day intervals. In addition, in the winter season, two tillage treatments (conventional and minimum tillage) were imposed over the rainy season treatments. Both rice and maize were grown under irrigated conditions. The results showed that sowing times at 15 day intervals did not impact the yield significantly. Transplanted rice obtained a significantly higher grain yield during the first four years, but in the last year, the yield was similar in both of the establishment methods. In the winter season, conventional tilled maize recorded a higher cob yield than under the minimum tilled treatment, except for the last year, where both the tillage treatment effects were the same. System productivity of CA-based minimum tilled rice–maize was inferior during the first three years but was superior to the conventionally tilled method in the fourth and fifth year. Pooled analysis revealed that the conventionally tilled rice–maize system resulted in a similar system productivity as that of the CA during the study period. The cost–benefit analysis revealed that transplanted rice and conventionally tilled maize fetched higher net returns of INR 111,074 and INR 101,658/ha, respectively, over the direct-wet seeded rice and CA. In addition, the 15 July rice sown followed by the maize system led to an increase in irrigation water productivity by 15.7%, and the total water (irrigation + rainfall) productivity by 27.1% in the maize crop compared with the 30 July sown system. The CA-based rice–maize system resulted in a significantly higher very labile (0.194%) and labile (0.196%) carbon concentration at a 0–5 cm depth of soil compared to those under the conventional system. Thus, CA can be recommended for southern India and similar agro-ecological tropic and sub-tropic conditions. This system can be followed with appropriate location-specific modification in South-Asian countries, where crop yields and soil health are declining as a result of continuous cereal–cereal crop rotation.

Soil organic carbon and labile and recalcitrant carbon fractions attributed by contrasting tillage and cropping systems in old and recent alluvial soils of subtropical eastern India.

Conservation agriculture-based sustainable intensification (CASI) technologies comprising zero-tillage with crop residue retention (>30%) on the soil surface, diversified cropping systems, and balanced nutrient management are recognized as operative and efficacious strategies to ensure food security in the parts of South Asia. The present investigation was a component of CASI technologies undertaken in the farmers’ field of Malda (old alluvial Inceptisol) Coochbehar (recent alluvial Entisol) district, West Bengal (subtropical eastern India). This study was conducted to evaluate the short-term impact of contrasting tillage (zero and conventional) and cropping systems (rice–wheat and rice–maize) on total organic carbon (TOC) and its fractions, viz., labile pool-1 (LP1), labile pool-2 (LP2) and recalcitrant carbon (RC) fractions after 4-year trial of conservation agriculture (CA) in the old and recent alluvial soils. Soil samples were collected from three depths (0–5, 5–10, and 10–20 cm), and thus, our study was focused on two factors, viz., cropping system and tillage. Results pointed that TOC along with LP1, LP2, and RC fractions under rice–maize (RM) cropping system were significantly (p<0.05) greater (15–35%) over rice–wheat (RW) system as a result of higher residue biomass addition. Zero-tillage (ZT) improved the C fractions by 10–20% over conventional tillage (CT) in all aspects. TOC and its fractions were observed to be greater under the ZT system in the topmost soil depths (0–5 and 5–10 cm), but the same system failed to improve these at 10–20 cm. Interestingly, the CT increased all the fractions at 10–20 cm depth due to the incorporation of crop residues. The concentration of TOC along with its fractions decreased with increasing soil depth was evident. Comparatively, all the C fractions, including TOC were maximum in soils from Malda sites as compared to Coochbehar sites because of a higher amount of residue biomass application, higher clay content, and greater background content of C in these soils. All the studied C fractions showed a significant correlation (r = >0.635; p<0.01) with TOC among all the soil depths in both the districts but the relationship with soil texture showed some interesting results. TOC fractions were significantly correlated (p<0.01) with clay particles indicating that its higher stabilization with clay in old alluvial Inceptisol (Malda); while in recent alluvial Entisol (Coochbehar), sand particle showed its strong relation with TOC fractions. Higher stratification ratio (SR) in the ZT system suggested that the concentration of TOC and its fractions are confined to the upper soil layers whereas in the case of CT, by and large, the distribution of these was comparatively high in subsequent soil depths due to residue incorporation effect. The concentration of C fractions in soils followed the order: TOC > RC > LP2 > LP1. The present investigation concluded that ZT under the RM system increases the turnover rates of C in both soil types but the amount of clay influences the stabilization/storage of C.

Identifying existing management practices in the control of Striga asiatica within rice-maize systems in mid-west Madagascar.

Infestations by the parasitic weed genus Striga result in significant losses to cereal crop yields across sub‐Saharan Africa. The problem disproportionately affects subsistence farmers who frequently lack access to novel technologies. Effective Striga management therefore requires the development of strategies utilizing existing cultural management practices. We report a multiyear, landscape‐scale monitoring project for Striga asiatica in the mid‐west of Madagascar, undertaken over 2019–2020 with the aims of examining cultural, climatic, and edaphic factors currently driving abundance and distribution. Long‐distance transects were established across the middle‐west region of Madagascar, over which S. asiatica abundance in fields was estimated. Analysis of the data highlights the importance of crop variety and legumes in driving Striga density. Moreover, the dataset revealed significant effect of precipitation seasonality, mean temperature, and altitude in determining abundance. A composite management index indicated the effect of a range of cultural practices on changes in Striga abundance. The findings support the assertion that single measures are not sufficient for the effective, long‐term management of Striga. Furthermore, the composite score has potential as a significant guide of integrated Striga management beyond the geographic range of this study.

Adoption of conservation agriculture-based tillage practices in the rice-maize systems in Bangladesh

In this study, conservation agriculture-based tillage (CA-T) practices (zero tillage, minimum tillage and strip tillage) in rice-maize production systems were implemented through on-farm participatory research trials for five years in Bangladesh to evaluate them under farmers’ field conditions, build awareness among farmers about such practices, and diffuse them in the farming communities. This study examines the adoption of those practices using farm level data from participating and non-participating farmers from and surrounding the field trial areas. For this, a farm household survey was conducted with 606 farmers, who earlier either participated or didn’t participate in the trials. A double hurdle model was employed to determine the factors influencing CA-T adoption and intensity of its adoption. During five years of the trial period, participatory and non-participatory farmers respectively adopted CA-Ts in 12% and 3% of annual cropped areas with overall adoption of 6.6%. Several factors contributed to the probability and intensity of adoption. Variations in adoption existed between locations, cropping systems, and seasons. Contrary to conventional wisdom, the propensity score matching analysis showed that yields either remained unchanged or were higher in the CA-T practices compared to farmers’ practices. Access to critical inputs, knowledge dissemination, capacity building and cropping season influenced the diffusion of CA-T practices.

Sustainable farming systems for hill areas of north coastal Andhra Pradesh

An on-station farming system experiment was carried for two years during 2012-13 and 2013-14, at Agricultural Research Station, Seethampeta, Andhra Prtadesh, India to arrive a profitable farming system module for hilly and agency area of north coastal districts in Andhra Pradesh , where major population is scheduled tribes. Rice-Maize system,Paddy - Dairy - cum poultry system, Paddy- Fish – Banana-Vegetable system and Paddy-Dairy cum apiary system were the test modules, where rice- maize is the traditional system considered as check. Among different integrated farming system modules evaluated for two years for hilly areas of north coastal Andhra Pradesh showed that, Paddy -Dairy - poultry system recorded 202 per cent higher rice equivalent yield, 97 per cent higher gross returns, 191 per cent higher net returns and 134 per cent additional man days over sole crop component, while B:C ratio was higher with Paddy-Dairy cum apiary system.

Nutrient management in calcareous soil improves rice–maize sustainable yield index, performance indicators

Rice-maize is an emerging cropping system in South Asia that plays significant role in terms of achieving food security in the region. However, achievement of attainable yield in these two crops is often a constrain due to imbalanced and inadequate use of essential plant nutrients. Understanding the contribution of different nutrients (N, P, K, S and Zn) toward yields of hybrid rice—hybrid maize cropping system in calcareous soil is a need for large number of smallholder farming systems. A four seasons study was conducted with an objective to develop further knowledge on crop productivity and nutrient performance indicators in this newly adapted emerging farming system. Replicated nutrient omission trials were conducted at Bihar, India. At the calcareous soil, omission of the nutrients reduced yields, and N was the most limiting nutrient followed by P and K. Omission of Zn impacted crop yields more than S omission, effect was more prominent in hybrid maize. Nutrient uptake in the cropping system was declined by 58%, 37%, 34%, 31% and 25% for N, P, K, S, and Zn, respectively, when these nutrients were systematically removed from fertilization schedule. Sustainable Yield Index (SYI) for cropping system was highest in the ample balanced fertilizer treatment. Post-harvest soil nutrient availability declined in the nutrient omission plots as compared to the initial soil status. We included additional treatments of ample balanced nutrient application and unfertilized check where hybrid cultivars were replaced by inbred varieties of rice and maize. Cropping system productivity highlighted the synergistic effect of seed and nutrients. The unfertilized checks reduced yield by 9 t/ha and 5 t/ha for the hybrid and inbred cropping systems, respectively. Results from present study conclude that adoption of hybrids in rice-maize system and balanced nutrient management are the best management practices for sustainable food production.

Crop and Residue Management Improves Productivity and Profitability of Rice–Maize System in Salt-Affected Rainfed Lowlands of East India

This study was conducted over 3 years in a salt-affected coastal rainfed lowland ecosystem. Farmers most commonly grow tall rice varieties in the wet season to cope with flash and/or stagnant floods, leading to large amounts of rice residue production. Most of the land remains fallow during the dry season because of increased salinity and scarcity of freshwater for irrigation. The study aims to provide options for increasing cropping intensity through management of crop residues (CR) and soil salinity, conservation of soil moisture, and reduction in production cost. The rice–maize rotation was assessed with rice as the main plot as (1) puddled transplanted rice (PTR) with CR of both rice and maize removed, (2) PTR and 40% CR of both crops retained, (3) dry direct-seeded rice (DSR) with CR of both crops removed, and (4) DSR with 40% CR of both crops retained. Maize in the dry season was supplied with different N levels as sub-plots—control (0 kg N ha−1), 80, 120, and 160 kg N ha−1. DSR, when combined with CR retention (DSR + R), reduced soil salinity. The increase in rice grain yield with CR retention (observed in second and third years) and crop establishment (higher in DSR versus PTR in the third year) was 16 and 24%, respectively. The cost of production increased by 17% (USD 605 ha−1) in PTR compared with DSR (USD 518 ha−1). CR retention reduced irrigation water requirement by 37% and N requirement by 40 kg ha−1 for hybrid maize. When CR was removed (−R), the N requirement for hybrid maize increased to 160 kg N ha−1 compared to when it was partially (40%) retained, where the requirement was 120 kg ha−1 with similar yields. Available N was highest under DSR + R (314 kg ha−1) and lowest under PTR − R (169 kg ha−1), and it also increased with increasing N application up to 120 kg ha−1 (+R) and 160 kg ha−1 (−R). The results of the study hold promise for increasing cropping intensity and farmers’ incomes, with broader implications for increasing productivity on about 2.95 million hectares currently under a rice–fallow system in eastern India, and in coastal areas affected by similar conditions in South and Southeast Asia.

Integrated Weed and Nutrient Management Improve Yield, Nutrient Uptake and Economics of Maize in the Rice-Maize Cropping System of Eastern India

Increasing productivity of maize while decreasing production costs and maintaining soil health are emerging challenges for the rice–maize system in South Asia. A range of integrated nutrient and weed management practices were tested in winter maize for their effects on yield, profitability, and soil health. The nutrient management treatments were a partial substitution of nitrogen with bulky (Farmyard manure; vermicompost) and concentrated organic manures (Brassicaceous seed meal, BSM; neem cake), whereas weed management practices compared chemical controls only versus an integrated approach. The N supplementation through BSM diminished the weed growth by reducing weed N uptake, and enhanced the maize crop uptake of nutrients. As compared to the sole chemical approach, atrazine-applied pre-emergence followed by hoeing reduced weed density by 58 and 67% in years 1 and 2, respectively. The N supplementation through BSM resulted in the maximum yield of maize grain (6.13 and 6.50 t ha−1 in year 1 and year 2, respectively) and this treatment increased yield in year 2 compared to N application through synthetic fertilizer. Hoeing in conjugation with herbicide enhanced the maize grain yield by 9% over herbicide alone. The maximum net return and economic efficiency were achieved with the application of BSM for N supplementation, together with the integrated weed management practice.

Improved water management practices improve cropping system profitability and smallholder farmers’ incomes

In the Eastern Gangetic Plain of South Asia, cropping systems under conventional crop management are frequently unprofitable due to the inefficient use of resources, particularly irrigation water and energy. Across the Eastern Gangetic Plain, farmers generally produce a wet-season rice crop followed by an irrigated dry season crop: maize has been recently introduced as the dry-season crop and is rapidly growing in popularity. Irrigation water is commonly applied using diesel-powered pumps and fluctuating fuel prices are a major factor affecting cropping system profitability. We hypothesised that the adoption of zero tillage crop establishment in a rice-maize system would reduce irrigation requirements compared to a conventionally-established rice-maize system, while maintaining comparable crop yields. Thus, higher water use efficiency and economic profitability would be achieved under the improved crop management compared to conventional practice. Field experiments over two years in Sabour, Bihar, demonstrated that early sowing of maize resulted in 8% higher maize grain yields, while zero tillage establishment produced 7% higher maize grain yields than conventionally established maize. Using the APSIM cropping systems model we tested our hypothesis over 49 years, from 1969 to 2018. Over the longer-term, zero-till maize grain yields were 9% higher than those of conventionally established crops. Under these improved management practices fuel savings of 8–15 % and labor savings of 34–43 % were achieved compared to conventionally managed crops, leading to higher water use efficiency in all treatments under improved management. Overall, gross margins in rice-maize systems under improved management practices were 20–39 % higher than rice-maize systems under conventional management. In rice-maize cropping systems in the Eastern Gangetic Plain, improved crop management practices can improve the efficiency of water use and thus increase farming households’ profitability and incomes.

Viable weed seed density and diversity in soil and crop productivity under conservation agriculture practices in rice-based cropping systems

Viable weed seed density and diversity in soil were assessed in an experiment that comprised two types of crop rotation [rice-wheat and rice-maize], two crop residue management (without residue and with residue), and four tillage techniques: conventional tillage (CT) transplanted puddled rice (TPR) – CT wheat/maize (CTTPR-CT), unpuddled transplanted rice – zero tillage (ZT) wheat/maize (UPTPR-ZT), ZT transplanted rice (ZTTPR) – ZT wheat/maize (ZTTPR-ZT), and ZT dry seeded rice (ZTDSR) - ZT wheat/maize (ZTDSR-ZT). The aim was to investigate the density and community composition of viable weed seed in soil in UPTPR-ZT, ZTTPR-ZT, and ZTDSR-ZT systems with and without crop residue, using the seedling germination method. The soil seed density was assessed in 2013-14 and 2014-15 after 4th and 5th year crop cycles established on a sandy loam soil of Patna, India. Total viable seed density was the highest for Cyperus iria L. irrespective of the treatment in both years. Rice-wheat system recorded 4% higher (mean of two years) seed density over the rice-maize system. Residue management practices did not differ for total viable seed density in both years. The ZTDSR-ZT, UPTPR-ZT, and ZTDSR-ZT systems resulted in significantly higher Shannon-Wiener, Simpson, and evenness indices compared to the CTTPR-CT system. Total viable seed density was the lowest for ZTDSR-ZT compared to the remaining tillage practices in both years. The sequence for Leptochloa chinensis (L.) Nees emergence was ZTTPR-ZT > ZTDSR-ZT > UPTPR-ZT > CTTPR-CT in 2014-15 (P < 0.05), signifying the more dominance of monocotyledons in ZT systems. The density of total aboveground weed density (no. m−2) was higher in ZTDSR-ZT in 2013-14 and lower in 2014-15 compared with remaining tillage techniques at 65 days after sowing. Thus, higher aboveground weed density in ZTDSR-ZT system minimized the soil seed density over time. Complete ZT-based practices (ZTDSR–ZT, ZTTPR–ZT) with crop residue significantly enhanced the grain yield of component crops over the CTTPR–CT. Thus, it implies that exhaustion of soil seedbank in ZTDSR-ZT system after 5 years can reduce the aboveground weed infestation and attain the higher grain yield compared to the CTTPR-CT system.

Key soil attributes as influenced by cropping systems in an entisol of West Bengal, India

This study aims to assess the effect of cropping systems on depth-wise distribution of important soil properties like bulk density (BD), pH, porosity, total organic carbon (TOC), total nitrogen (TN), C:N ratio, and texture. Purposeful random sampling was carried in the farmer’s fields under two cropping systems, viz., rice-maize (RM) and rice-jute (RJ) on Entisol of Durganagar (26°09’62.7N, 89°53’51.7E) village under Dinhata district of West Bengal (India). Soil samples were collected at four soil depths (0- 0.15, 0.15-0.30, 0.30-0.45, and 0.45-0.60 m). Results suggested that cropping systems and soil depths significantly influenced the physicochemical properties of soil. The RJ system showed significantly (p < 0.05) higher TOC and TN contents as compared to the RM system. Increased TOC in the RJ system lowered the BD and enhanced the porosity percentage of the soil. The loamy texture in the RJ system resulted in more nutrient accretion capacity than the RM system which was sandy loam in texture. The TOC and TN contents were in positive correlation with clay and silt particles but showed a negative relationship with sand. High sand content in the RM system recorded lower values of soil pH due to leaching losses of basic cations or salts. Soil pH and BD increased with depth but a reverse trend was noted in porosity percentage, TOC, TN, and C:N ratio.

Energy and carbon budgeting of tillage for environmentally clean and resilient soil health of rice-maize cropping system

Human interventions in the environment leading to higher green house gas emissions which are degrading the soil and environment quality. Traditional/conventional tillage systems following since inception and residue burning are accelerating the degradation of soil and environment leading to food insecurity. The present study was executed to evaluate energy budgeting, carbon foot prints, gaseous emission and soil health under conservation tillage with residue retention for identifying cleaner production technology in rice-maize system. The novelty of the study is that it examines the integrated effect of tillage, residue retention through mulching on GHG emission along with soil health, energy consumption and carbon footprints together as conservation effective measure for sustainable and clean agricultural production. Zero tillage reduced the energy consumption by 56% and carbon footprints by 39% and besides that N2O emission was 20% lower than conventional tillage. Apart from clean environment, soil health was also improved by adoption of zero tillage in terms of NPK status, labile pool of carbon and enzymatic activities; the population of all the microbiota was increased, which was around 21.3, 51.2 and 27.6% higher in bacteria, fungi and actinomycetes. Crop residue retention as residue mulching (rice straw) significantly improved the crop productivity, microbial biota and enzymatic activities of soil, but it increased the energy consumption and carbon footprints by around 10%. N2O emission was also enhanced by residue mulching, and higher the quantity of residue used as mulch, more was emission. Although in initial years some yield penalty (10–15%) was recorded but in long run zero tillage can be a step towards sustainability as it can be a valuable approach for resilient soil health and cleaner production of maize in rice–maize system.

Trends in key soil parameters under conservation agriculture-based sustainable intensification farming practices in the Eastern Ganga Alluvial Plains

Key soil parameters, organic matter, soil pH and plant nutrients determine the capacity of a soil to sustain plant and animal productivity. Conservation agriculture (CA) and crop diversification or intensification may change these soil parameters positively or negatively, which eventually affect long-term sustainability. We monitored these key soil properties (at depths of 0–15 and 15–30 cm) under CA-based sustainable intensification practices: zero-till (ZT), and crop residue retention, and crop rotations on Inceptisols and Entisols in the Eastern Ganga Alluvial Plains from 2014 to 2017. The rainfall of this sub-tropical region is 1273–3201 mm. Soil organic carbon (C) ranged within 0.46–1.13% and generally followed (positive) rainfall gradients. At all sites, the soil under ZT tended to have higher organic C than conventional tillage (CT). Soil pHH2O ranged within 5.7–7.8 across the region. At all sites, soil pH generally decreased under ZT compared to CT. This was most marked at some acidic soil sites where pH decreased by up to 0.4 units; the lower the initial soil pH, the higher was the decrease in pH under ZT practice. In contrast, the reverse trend was observed for soil organic C. Partial nutrient balances for N, P and K in rice–wheat and rice–maize systems were positive for N and P (&amp;lt;50 kg ha–1) but negative for K (up to 90 kg ha–1) under both tillage practices; more so under ZT practice even though crop residues were retained. Changes under ZT provide an opportunity to maintain soil organic C. However, remediation measures such as liming and efficient use of fertilisers are required for long-term sustainability of the farming systems in this agriculturally important region of South Asia.

Ten years of conservation agriculture in a rice–maize rotation of Eastern Gangetic Plains of India: Yield trends, water productivity and economic profitability

In recent years, scarcity of water, energy and labour, increasing production cost, decreasing farm profitability and climate-change-induced variability are major challenges faced by the farmers in the Indo-Gangetic Plains (IGP) of South Asia. Conservation agriculture (CA) based best-bet crop management practices may increase crop productivity and profitability, while conserving natural resources. In a 10-year (2007–2017) field study, we assessed the effects of four combinations of tillage and, crop establishment (TCE), and residue (R) management options for the crop and water productivity and profitability of rice-maize (RM) system in Eastern IGP of India. The treatments consisted of zero-till direct seeded rice followed by zero tilled maize (ZTDSR/ZTM); ZTDSR followed by maize both on permanent raised beds with residue (PBDSR/PBM (+R)); PBDSR followed by PBM without residue (PBDSR/PBM (-R)) and conventional till puddled transplanted rice followed by conventional till maize (PTR/CTM). Overall, mean rice grain yield was similar under ZTDSR/ZTM, PBDSR/PBM (+R) and PTR/CTM, but 5.0–7.9% higher than PBDSR/PBM (-R). However, the maize yield was significantly (P < 0.05) higher by 6–82% in CA-based PBDSR/PBM (+R) RM system compared to PTR/CTM and PBDSR/PBM (-R) right from first year onwards. The RM system productivity (rice equivalent yield, REY) was higher by 1.5–38% in CA-based systems [ZTDSR/ZTM; PBDSR/PBM (+R)] than in the PTR/CTM and PBDSR/PBM (-R) systems. APSIM model predicted yield of rice and maize under different TCE and residue management practices with cumulative probability distribution plots was higher and consistent in PBDSR/PBM (+R) and ZTDSR/ZTM compared to PBDSR/PBM (-R) and PTR/CTM, suggesting that CA plots has lower probability of low yield than CT. CA-based ZTDSR/ZTM and PBDSR/PBM (+R) practices reduced the total system water use by 151–341 mm and 212–423 mm, and resulted enhanced system water productivity (WP) by 27–57% and 39–68%, respectively compared to CT (PTR/CTM) system. Economic profit for RM system was always significantly (P < 0.05) higher (225–1028 US$/ha/year) in CA-based systems than in CT system. Our study shows that CA-based system under RM rotation is one of the ways for improving crop and water productivity and farm income, as well as sustaining the natural resources in smallholder production systems of Eastern IGP in India and other similar agro-ecologies of South Asia.