Conservation agriculture effects on yield and profitability of rice-based systems in the Eastern Indo-Gangetic Plain

Abstract

Sustaining productivity of the rice-based cropping systems in the Eastern Indo-Gangetic Plain (EIGP) requires practices to reverse declining soil fertility resulting from excessive tillage and crop residue removal, while decreasing production costs and increasing farm profits. We hypothesize that the adoption of conservation agriculture (CA), involving minimum tillage, crop residue retention and crop rotation, can address most of these challenges. Therefore, the effects of crop establishment methods – strip planting (SP), bed planting (BP) and conventional tillage (CT); and levels of crop residue retention – high residue (HR) and low residue (LR) on individual crop yield, system yield and profitability were evaluated in a split-plot design over three cropping seasons in two field experiments (Alipur and Digram sites) with contrasting crops and soil types in the EIGP. The SP and BP of non-rice crops were rotated with non-puddled rice establishment; CT of non-rice crops was rotated with puddled transplanted rice. In the legume-dominated system (rice-lentil-mung bean), lentil yields were similar in SP and CT, while lower in BP in crop season 1. A positive effect of high residue over low residue was apparent by crop season 2 and persisted in crop season 3. In crop season 3, the lentil yield increased by 18–23% in SP and BP compared to CT. In the cereal-dominated system (rice-wheat-mung bean), significant yield increases of wheat in SP and BP (7–10%) over CT, and of HR (1–3%) over LR, were detected by crop season 3 but not before. Rice yields under CA practices (non-puddled and HR) were comparable with CT (puddled and LR) in both systems. Improved yield of lentil and wheat with CA was correlated with higher soil water content. The net income of SP increased by 25–28% for dry season crops as compared to CT and was equal with CT for rice cropping systems. Conservation agriculture practices provide opportunities for enhancing crop yield and profitability in intensive rice-based systems of the EIGP of Bangladesh.

Conservation agriculture for regenerating soil health and climate change mitigation in smallholder systems of South Asia

“…Adopting CA practices will help to reduce the risk of soil N depletion and ultimately conserving more total N in soil supplied by the crop residues in comparison to CT. Significantly more (7-63%) total N was observed under CA in surface layers (0-15 cm) in comparison to CT after 3-12 cropping cycles in many studies from India (Choudhary et al, 2018c(Choudhary et al, , 2020Das et al, 2021;Jat et al, 2018;Kushwa et al, 2016;Patra et al, 2019;Rashid et al, 2019;Sinha et al, 2019;Zahid et al, 2020), which might be due to microbial immobilization of N from the soil and increased residue retention with slow decomposition rate compared to CT. Several other researchers from South Asia (Alam et al, 2014(Alam et al, , 2018a(Alam et al, , 2020Dey et al, 2016;Haque et al, 2016;Islam et al, 2016;Sadiq et al, 2021;Salahin et al, 2021) have also reported higher total N content in soil in the different rice-based cropping systems. Alam et al (2020) stated that adoption of partial CA (non-puddled transplanted rice and strip tillage along with high residue load) increased total N content in soil by 62% relative to CT at 0-10 cm depth in Jute-mustard-rice triple cropping system.…”

Conservation agriculture’s impact on total and labile organic carbon pools in calcareous and non-calcareous floodplain soils under a sub-tropical rice-based system

“…Several studies reported that addition of organic materials such as crop residues significantly increased the SOC content by 29.6 to 119.8% and 10.3 to 36.3% at 0-15 and 15-30 cm, respectively, when compared to N fertilizer application by farmers. Organic amendments also improved soil labile carbon fractions, especially the MBC and POC [10].…”

“…The prolongation of farmers' practices of intensive tillage without residue retention has accelerated SOC decline over time. Higher amounts of crop residue return in strip tillage (ST) can be an effective strategy in slowing the loss of SOC and enhancing C sequestrations in the intensive rice-based production systems of the Eastern Indo-Gangetic Plain of Bangladesh [10]. SOC, especially labile C fractions, can be increased by crop residue management that is characterized by a rapid turnover, and thus, recommended as early and sensitive indicators of the effects of conservation management practices on soil fertility [11].…”

“…Conservation agriculture (CA) is an eco-friendly farming system composed of reduced soil disturbance, residue retention, and crop rotation, which has been reported to enhance soil health and reduce the cost of production [10,12,13]. Worldwide crop production area under CA is around 180 M ha, which was equal to 12.5% of the total global cropland in 2015-16 [14].…”

“…SOC is not only an important source of C for soil processes, but also a sink for SOC sequestration [19]. While conventional agricultural practices can reduce SOC content, lead to soil deterioration, and reduce soil productivity, by contrast, the adaptation of a CA system can minimize the adverse effects of crop production via climate change mitigation and adaptation [10,20]. By changing plowing to NT systems, or by improved management practices, SOC sequestration can be increased with a new equilibrium within several decades.…”