Conservation Agriculture Research Updates - April 2026

This study looked at the components of CA individually and in combinations with a control on soil carbon and nitrogen dynamics for a direct rice seeded-green gram system. Reduced tillage alone and in combination with rotation resulted in 10% and 6% lower CO2-C release than the plots with residue retained. The paper has results on the role of rotation and crop residue on various enzymes. They conclude that rotation and residue retention are effective for better C and N cycling in this system. Tillage on the other hand needs a longer time to show beneficial results than the 4 years of this study. The increase in soil enzyme activities improved microbial activity, which can further enhance nutrient availability for plants. and help improve soil health.

This paper looks at the rice-wheat system in Eastern India where smallholder farmers are using excessive water and nitrogen with soil degradation. They used field studies and a crop simulation model to assess resilience, viability, and sustainability of this cropping system under CA with different irrigation methods and nitrogen rates. They had 4 treatments from the puddled transplanted rice (PTR) and zero-tilled wheat (ZTW) with flood irrigation to direct seeded rice (DSR) fb ZTW with sub-surface drip irrigation and 75% and 100% recommended N and a N control plot. The DNDC model accurately predicted soil mineral N. DSR-ZTW with drip irrigation  enhanced sustainability and productivity compared to PTR-ZTW and reduced methane emissions by 70-80%. This system also provided the highest system yield, lowered water losses and improved N use efficiency, and reduced GHG emissions. 

This article is concerned with the impact of climate change (CC) will have on the productivity of the rice-wheat system in the Indo-Gangetic Plains of South Asia and India that is the breadbasket of these countries. This long term research looks at the potential of long term conservation agriculture (CA) management to address this CC issue. The paper describes 6 different production scenarios with one the traditional system and 5 others that have various improvements on the traditional system including just NT wheat, both NT rice and wheat, addition of a mung bean legume, NT maize and wheat, and one with sub-surface drip for irrigation (SSDI). They conclude that overall, soil organic carbon was higher in all CA scenarios compared to the traditional scenario. "By substantially enhancing soil health and crop productivity, as well as boosting resilience, CA emerges as a promising solution for meeting the increasing food demand in Northwest India and beyond and cropping seasons between and across regions."

This two year field study from India looked at various organic weed management practices  for different tillage and residue management strategies on weed dynamics and yields in a rice-maize cropping system. There were 4 main treatments of tillage and residue management and 5 sub-plot weed treatments in a rice-maize cropping system. Total weed density and biomass in rice and maize at 30 days after sowing (DAS) were minimum for Bed planted NT rice and NT maize plus residue. Apart from the weed free treatment, the best weed control was with residue retention treatments. They conclude CA practices (NT + residues) in R-M systems has less weed issues and improves yields. 

The traditional rice-wheat-mung cropping system in North Bihar, India has experienced declining yields and water constraints. This paper looks at alternative tillage and crop establishment (TCE) practices to remedy this problem. Five different TCE practices were evaluated in on-farm experiments. The best yields were found with Zero-tilled direct seeded rice (ZTDSR) followed by Happy Seeder ZT wheat (HSZTW) and HS gram (HSG). This treatment also provided the highest net returns with this CA based system out-performing traditional systems.

I was impressed by this video produced by CIRAD about the agriculture in the Carmague region of Southern France. It uses sub-titles in English since the dialogue is in French. It is a documentary about developing agricultural systems more resilient to climate change based on CIRAD experience with CA in rice and rice systems in France. They want to improve biodiversity and biomass production of crops through double cropping systems that include various crops including forage, cover crops and even market crops like melons and tomato.

This research looked at SOC pools from CA practices in rice-wheat systems in the Eastern Indo Gangetic Plains by collecting soil samples from a 15-year old experiment. There were 8 treatments with combinations of direct seeded rice, zero-till rice and wheat, bed planting, no-puddling TP rice, and use of a Sesbania brown manure. The treatments that had the highest enhanced levels of SOC were the ones with ZT wheat and rice with residue retention. They conclude that this latter set of treatments would be best for enhancing soil C quality and sequestration in Eastern India.

This paper looked at ways to improve the traditional rice-growing techniques to increase productivity, reduce water and fertilizer use, and mitigate climate change. They looked at CT vs NT with 4 rice varieties on GHG emissions in India. The CT plots were transplanted into puddled soil while the NT plots used a NT-Drill to direct sow seed in no-tilled soil. Weeds were controlled by herbicides in both tillage systems. What was not mentioned is the planting dates in the two rice tillage systems although the CT plots were transplanted with 25 day old seedlings. But the paper didn't say if the DSR-NT rice plots were planted the same time as the transplanted rice plants or when the seedbeds for CT rice were sown. After sowing rice straw was placed on the plots. Results showed CT had higher methane and C02 emissions compared to NT, but CT showed lower N20 emissions than NT. Energy use was reduced by 42% in NT compared to CT. Labor use for transplanting and water use in the CT plots were much higher than in the NT plots.

This book chapter reviews the various practices researched and recommended for farmers in eastern IndoGangetic Plains of India for sustainable intensification of rice based cropping systems grown in this part of India. Ca and direct seeded rice, zero-tilled rice, mechanically transplanting improved water use efficiency, soil health and system productivity. Increasing cropping intensity from one crop to 2 or 3 per year was also possible with diversification, using short duration rice varieties, climate resilient other crops  improved management practices and appropriate mechanization. Other practices including infrastructure for irrigation, storage, marketing, value chains, and efficient extension systems also need to be developed. Some important agronomic practices include integrated use of fertilizers, soil mulching, optimal use of irrigation water, robust seed systems, crop rotation, integrated weed management (introducing new molecules and promoting mechanical weeding), using an integrated farming system approach, and policy support for small and marginal households.

This 5-year experiment looked at the best crop establishment-cum-residue management (CERM) practices and suitable crops after rice harvest in rice-fallow systems in Eastern India. Treatments had plus or minus residue Yields of rice were higher (19-32%) in transplanted puddled rice with residue (TPR-R+) over conventional-till direct seeded rice (CTDSR) and zero-till DSR (ZTDSR) treatments. However, TPR adversely impacted the performance of all the post-rainy pulses/oilseed crops. Post-rainy season crop yields under ZTDSR/CTDSR were 15-46% higher leading to higher system productivity as compared to TPR. ZTDSR with residue retention showed higher soil aggregation. The practice of ZTDSR increased the soil dehydrogenase activity, urease activity, soil microbial biomass carbon, and fluorescein diacetate activity in the crop root zone with higher earthworm population and earthworm biomass. More earthworms were found in the rice-pulse system compared to the rice-oilseed system. ZTDSR also had the highest SOC stock. 

This paper addresses issues of transplanted rice, by incorporating conservation agriculture (CA) based crop establishment practices in combination with suitable weed management options to sustain rice productivity. Their experiment had four planting techniques; farmer’s practice (Conventional Transplanting), zero-till direct seeded rice (ZT-DSR), reduced-till direct seeded rice (RT-DSR) (Rotavator single pass) and conventional-till direct seeded rice (CT-DSR) plus five weed management practices using various herbicides, plus hand weeding 20 and 40 DAS and a weedy check. Among various crop establishment methods CT-DSR recorded significantly higher N, P and K uptake by both grain and straw over the rest of the treatments except ZT-DSR during both the years. Based on the results application of pendimethalin pre-emergent followed by chlorimuron + metsulfuron at 20 DAS to the CT-DSR treatment gave the maximum N, P and K uptake by both grain and straw of rice.

This study had four scenarios Sc1. farmers practice transplanted rice (TPR) followed by conventional tilled broadcasted wheat (CT- wheat) with residue removal Sc2. TPR followed by zero tillage (ZT) wheat and mung bean with partial residue retention. Sc3. direct seeded rice (DSR) followed by ZT- wheat and mung bean with full residue retention and Sc4.  ZT-maize followed by ZT-wheat and mung bean.They were used to study the humic acid (HA) content and stability of soil carbon with these scenarios. Sc4 recorded significantly higher HA content at 0–15 and 15–30 cm soil depth. They conclude that CA is efficient in enriching organic carbon but also a more stable complex of HA.

This study looks at the issue of weed control in CA systems that has labor and costs of production problems. This study looked at a CA based rice (direct seeded)-wheat-mungbean cropping pattern over two years of study. The goals were to study the types and distribution of weeds in non-puddled rice and following strip-tilled wheat fields, and to find the most economic way to manage the weeds in both crops. The latter goal included using herbicides. The most most effective treatments involved two herbicides with one applied pre- and one post emergent in wheat and two other herbicides in direct seeded rice also applied pre- and post-emergent.

This paper from India evaluated contrasting tillage and residue management in the rice wheat systems of the Indo-Gangetic Plains to identify sustainable and energy efficient systems. Treatments include various triple cropping patters that include a legume, but also no-till wheat and rice that were compared with conventional  puddled rice and tillage wheat. NT systems had significantly lower operational energy for irrigation (∼40%), sowing (∼26%), and land preparation (100%) compared to a conventional-tillage (CT) system and also resulted in higher system yields, net energy returns, energy ratios, energy productivity and energy intensity. The authors conclude that the conventional system should be replaced with these more efficient and higher yielding NT + legume systems. 

This report used a multilocation and multiyear trials to compare direct seeded (drilled and broadcast) with puddled transplanted (PTR) Aus (spring) rice using three rice varieties and 3 landscape positions (high, high-medium and lowland) in 3 different Districts in Bangladesh. Measurements included yield, profit, energy use efficiency and and productivity, Global warming Potential (GWP), and emissions. They conclude that DSR is more environmentally sound and economically viable and a climate-smart system and more suitable for highland and medium highland landscape positions. The paper did not mention issues of weed control in the abstract. This is probably a major issue when adopting DS rice.

This paper from India looks at the causes of a plateau in rice-wheat yields in South Asia. They used a 2-year on-farm study to look at wheat productivity in a RW system. They introduced various system optimization practices (SOP) that include legume inclusion, NT wheat, Direct seeded rice, and bed planting. Benefits of SOP's were reduced global warming potential, reduces water use, reduced weed density, higher partial factor productivity, wheat yield and net return increases, lower energy use compared to traditional practices. They conclude that wheat production with SOP's of legume inclusion and zero tillage achieve higher productivity and profitability with less environmental footprint in the Indo-Gangetic Plains and similar agroecological regions.

This study looked for the best option for crop establishment, tillage, and rice straw retention over a period of 10 years in a rice-wheat system in the Indian Punjab. Treatments in the main plots included direct seeded rice with ZT (DSRZT), DSR with conventional tillage (DSRCT), DSR with reduced tillage (DSRRT), and puddled transplanted rice (PTR). In sub-plots CT w/o residue (CTW), ZT w/o residue (ZTW), and ZT with residue for wheat. Results showed that bulk density and soil penetration resistance decreased while, plant available water content, infiltration and hydraulic conductivity of the soil increased significantly in DSRZT, DSRRT and ZTW+R compared to PTR and CTW. SOC and aggregation status also increased in DSRZT compared to PTR and CTW. Rice yield was higher in PTR than DSR treatments but wheat yields were higher in ZTW+R than CTW and ZTW..

This paper looks at biological soil health for a long-term rice-wheat system using CA practices in India. The 6 treatments were 1) zero till direct seeded rice (ZTDSR)–zero till wheat (ZTW); 2) ZTDSR + wheat residue (WR) - ZTW + rice residue (RR),  3) ZTDSR + WR + sesbania brown manuring (SBM)–ZTW + RR, 4) ZTDSR–ZTW–zero till mungbean (ZTMB), 5) ZTDSR + mungbean residue (MR)–ZTW + RR-ZTMB + WR, 6)transplanted rice (TPR)-conventional till wheat (CTW)–conventional till mungbean (CTMB). Soil from 0-5 cm depth were analyzed for labile organic carbon pools, soil enzyme activities, and populations of bacteria, fungi and actinomycetes, and two microbial functions using qPCR methods. The results showed that the triple/double ZT plus crop residues caused an increase in the pools of carbon, enzymes, and microbial populations compared to the traditional system. Addition of mungbean and Sesbania improved nifH gene abundance compared to other treatments.

This paper looked at 8 integrated crop management (ICM) practices for 6 years in a direct seeded rice-NT wheat rotation. There were 4 treatments with traditional practices and 4 with CA practices; residue retained and not retained treatments; raised bed and flat treatments. The CA-based treatments outperformed the CT practices for yield, soil quality index, and reduced carbon footprints. They conclude that the CA-based ICM practices proved to be environmentally safer and cleaner and can sustain the food and soil security of the extensive rice-wheat rotation under South Asian ecologies.

This study looks at direct seeded rice (DSR) and NT DSR and the issue of weed control. Field experiments were conducted involving conservation agriculture (CA)-based DSRs compared to puddled transplanted rice (PTR) and weed control/herbicides treatments to appraise weed interference and productivity under an eight-year old CA-based rice-wheat system (RWS). All DSRs encountered more weeds than PTR. A double ZT system without residue had the highest density and dry weight of grassy weeds, but a triple ZT system without residue had the highest density and dry weight of broad-leaved and sedge weeds. However, a triple ZT system adding three crops residues reduced weed interference significantly and led to higher rice yield. The use of various herbicides significantly reduced all weeds. They recommended that the triple ZT system with rice, wheat and mungbean residues (C5) combined with application of herbicides be used in similar agro-ecologies in the IGP.

This study analyzed 84 on-farm trials comparing CA-based practices (CA) with farmers' conventional ones (CT) in rice-wheat systems of the Eastern Tarai region on Nepal. The objectives were to investigate crop and cropping systems productivity, profitability, yield stability, irrigation (WPi) and total water productivity (WP(r+i)), and fertilizer-use efficiencies of three CA- and one CT-based practice in R−W systems. The CT system was puddled transplanted rice (PTR) and tilled wheat (CTW). The three CA based systems were 1) PTR - ZTW; 2) Direct seeded rice (DSR) -ZTW; and 3) unpuddled transplanted rice (UPTR) - ZTW. There were no significant differences in rice or wheat yields between CT and CA treatments, but significant reduction in production cost due to reduced labor use and increased net gain (188−223 USD ha−1) in all CA-based R−W systems. DSR−ZTW showed the highest yield stability and net profit, demonstrating its adaptability in the region. CA based systems reduced production costs and increased farm profits, saved energy and water, increased land and labor productivity, and improved food security.

This paper looks at the rice-wheat system of South Asia (13.5 mha) but within the IGP where there are 10.3 mha. This intensive cropping system that is vital for food security in India has several environmental issues including depleted SOC, declining water tables, decreased soil fertility and reduced factor productivity. The paper describes various resource conserving technologies (RCT's) such as direct seeded rice (DSR), system of rice intensification (SRI), aerobic rice, brown manuring, crop residue incorporation, furrow irrigated raised bed system (FIRBS), zero tillage (ZT) and leaf colour chart (LCC) that not only improved the production and productivity but also maintained soil health. New emerging technologies like system of wheat intensification (SWI), LCC application for nitrogen management, bed transplanting in rice followed by laser levelling in wheat with zero tillage wheat, incorporation of rice residues over conventional transplanting also showed promising results.

This study looks at the impact of long-term CA production systems under rice-based cropping systems on pest status. In this study, direct and indirect effects of tillage (zero, reduced and conventional tillage), residue retention and cropping sequences on abundance and damage by pests were investigated. After 4–5 years of experimentation, populations of oriental armyworm in wheat, mealybug and bandicoot rat in rice were found to increase abnormally in CA-based production systems. Conventionally tilled plots had a significant negative effect while residue load in zero-tilled plots had a significant positive effect on larval population build-up of armyworm. Based on the present study, pest management strategies in CA need to be revisited with respect to tillage, residue retention on soil surface, grassy weeds in the field and cropping sequences to deliver the full benefits of CA in MIGP to achieve the sustainable development goals under the climate change scenarios.

This paper looks at the transition from conventional flooded transplanted rice to direct seeded rice in NW India. The main challenge in these light textured soils is weeds. This study looked at the removal of nutrients by weeds under three different rice treatments as main plots (DSR-ZT; DSR-CT; DSR-RT) and three sub-plots under the following wheat (CTW-R; ZTW-R; ZTW+R using a happy seeder). Overall, the research study concluded that weeds on an average remove 25.65 % macronutrients (N, P, K) and 51.47% of micronutrients (Zn, Cu, Fe and Mn) in DSR under rice-wheat cropping system.