No abstract

HighlightsConservation agriculture (CA) practice meaningfully stabilized organic carbon (OC) upto lower depth of soil.Crop intensification with nutrient exhaustive crops lowers OC stabilization in soil even after adoption of CA practice.Farmers practice of growing rice and wheat produce less yield with less storage of carbon in soil.Rice-wheat-legume crop with CA proved as most efficient in terms of crop yield, soil health and carbon sequestration.

Presently, rice-fallows are targeted for cropping intensification in South Asia. Rice-fallows a rainfed mono-cropping system remain fallow after rice due to lack of irrigation facilities and poor socioeconomic condition of the farmers. Nevertheless, there is the scope of including ecologically adaptable winter crops in water-limited rice-fallow conditions with effective moisture conservation practices. The study aimed to identify the winter-crops that are adaptable and productive in rice-fallow conditions and to evaluate the different tillage-based crop establishment practices for soil moisture conservation, grain yield, economics, and sustainability parameters. Six different crop establishment and residue management (CERM) practices viz., zero-tillage direct seeded rice (ZTDSR), zero-tillage transplanted rice (ZTTPR), puddled transplanted rice (PTR), ZTDSR with rice residue retention (ZTDSR R+), ZTTPR with rice residue retention (ZTTPR R+), PTR with rice residue retention (PTR R+) as main-plot treatment and five winter crops (chickpea, lentil, safflower, linseed, and mustard) as sub-plot treatment were evaluated in a split-plot design. The productivity of grain legumes (chickpea and lentil) was higher over oilseed crops in rice-fallow conditions with an order of chickpea > lentil > safflower > mustard > linseed. Among the CERM practices, ZTDSR R+ and ZTDSR treatments increased the grain yield of all the winter crops over PTR treatment, which was primarily attributed to higher soil moisture retention for an extended period. Grain yield increment with conservation tillage practices was highly prominent in safflower (190%) followed by lentil (93%) and chickpea (70%). Rice grain yield was higher (7-35%) under PTR treatment followed by ZTDSR treatment. Conservation tillage practices (ZTDSR, ZTTPR) reduced energy use (11-20%) and increased the energy ratio over conventional tillage practice (PTR), higher in rice-safflower, rice-lentil and rice-chickpea rotations. Higher net return was attained in rice-safflower and rice-chickpea rotations with ZTDSR R+ treatment. Predicted emission of greenhouse gases was markedly reduced in ZTDSR treatment (30%) compared to ZTTPR and PTR treatments. Hence, the study suggests that cropping intensification of rice-fallows with the inclusion of winter crops like chickpea, lentil, and safflower following conservation tillage practices (ZTDSR R+ in particular) could be the strategic options for achieving the higher system productivity, economic returns, and energy use efficiency with the reduced emission of greenhouse gases. Rice-fallows, the rainfed mono-crop production system, nowadays are gaining greater attention for cropping intensification in South Asia 1. Rice-fallow areas extended over 22.3 M ha in South Asia, having maximum acreage in India (88.3%) and remaining in Bangladesh (8.7%), Pakistan (0.5%), Sri Lanka (1.1%), Nepal (1.4%), and Bhutan (0.02%) 2. The major challenges of cropping intensification in rice-fallow areas includes lack of irrigation

No abstract

Short-term (5 years) impact of tillage and residue management practices on physical properties and organic carbon (OC) of a silty clay soil was evaluated in a rice-wheat rotation in the Indo-Gangetic Plains of Bihar. The experiment had three conservation agriculture (CA) practices: one full (direct-seeded rice (DSR)-no-tilled wheat (NTW)-no-tilled mung bean (NTMB); fCA) and two partial (puddled transplanted rice (PTR)-NTW-conventionally tilled mung bean (CTMB); pCA1 and unpuddled transplanted rice (UPTPR)-conventionally tilled potato+maize (CTP + M)-NTMB; pCA2), which were evaluated against full conventional practice (puddled transplanted rice (PTR)-conventionally tilled wheat (CTW); TA). Subsurface compaction reduced and soil aggregation improved under both full and partial CA. Macro-and water-stable aggregates increased to a large extent (26 and 11%, respectively) in full CA and to a lesser extent in partial CA, mostly due to increase in coarse macroaggregate (2-8 mm) contents in the 0-10 and 10-20-cm depth soil layers. Steady-state infiltration rate nearly doubled under full CA, with larger pore volume recorded in 10-20 and 20-30-cm depth soil layers. The CA increased OC associated with all size fractions of aggregates in the surface soil layer (0-10 cm), but a higher amount of C was associated with macroaggregates, indicating relative stabilization of OC in the soil under CA. Change in bulk soil OC was larger in the 0-10-cm depth soil layer in favour of CA, which also had an 11% increase in OC stock in the 0-30-cm depth soil layer. Improvement in soil physical condition did not effectively translate into increased rice or wheat yields, but the system productivity increased largely. Highlights • Conservation agriculture (CA) resulted in 11-12% higher macro-aggregation compared to conventional practice (CT). • Macro-and total pores reduced in the 0-10 cm depth soil layer but increased in the 10-20 cm depth soil layer under CA. • CA resulted in 27-35% higher aggregate-associated OC content and 11% increase in OC stock at 0-30 cm.