Water, energy and labour scarcity, increasing cost of production, diminishing farm profits and uncertain
weather events are major challenges faced by the farmers under intensive tillage based conventional
rice–wheat (RW) production system of Indo-Gangetic Plains (IGP) in South Asia. To address these
challenges, conservation agriculture (CA) based crop management practices are being developed,
adapted and promoted in the region. We evaluated agronomical productivity and economical
profitability of various combinations of tillage, crop establishment and residue management practices
in rice–wheat rotation of Eastern IGP of India: a smallholder, poorly resourced and most vulnerable
regions for the climatic variability. The long-term trial was initiated in 2006 having 7 combinations of
tillage, crop establishment and residue management in rice–wheat rotation. These consisted of
conventional till puddled transplanted rice followed by conventional tilled wheat (CTR–CTW); CTR
followed by zero tilled wheat (CTR–ZTW); direct seeded rice followed by wheat both on permanent
raised beds (PBDSR–PBW); zero-till direct seeded rice followed by CTW (ZTDSR–CTW); ZTDSR followed
by ZTW without residues (ZTDSR–ZTW); ZTDSR followed by ZTW with residues (ZTDSR–ZTW + R) and
unpuddled transplanted rice followed by ZTW (UpTPR–ZTW). All these treatments were completely
randomized and replicated thrice within a block.
During the initial three years of experimentation, we recorded higher rice grain yield in conventional
tillage based rice systems (i.e. CTR–CTW and CTR–ZTW) than in CA based systems (i.e. ZTDSR–ZTW,
UpTPR–ZTW). During the fourth and
fifth years, the rice yields under CT and CA were comparable
whereas sixth year onwards, higher yields were recorded under CA based system than in CT based
systems. However, the wheat yield was higher in CA based system right from second year onwards. We
observed the lowest wheat yield in the system where preceding rice crop was grown with intensive
tillage operations (CTR). RW system productivity was higher in almost all the CA based systems than in
the CT based and mixture of CT and CA based systems from the second year onwards. The net returns
were always higher in CA based systems than in CT based system although the significant differences
were obvious only from fourth year onwards in rice and second year onwards in wheat as well as at the
system level. The higher grain yields and economical advantage of CA was realized after 2–3 years as the
adaptation of CA based component technologies evolved over the time. In medium term, we found CA
based systems to be agronomically and economically superior to CT based systems for rice–wheat
rotation in a smallholder production system of Eastern IGP of South Asia. Hence, CA based RW production
system is one of the pathways for improving productivity, income and food security while sustaining the
natural resources in smallholder production systems of Eastern IGP.