Effect of conservation tillage on soil health, crop yield and energy utilization under rice-cotton system in coastal region of India

Abstract

Considering the benefit of conservation tillage in rice based cropping system a field experiment was carried out to evaluate the impact of conservation tillage on soil health in coastal region of West Bengal. The design of experiment was split-split plot with cropping system (rice-rice and rice-cotton) (kharif—rabi) as main plot treatments and tillage type such as zero tillage (ZT), reduced tillage (RT), and conventional tillage (CT) as sub plot treatments. The residue (R) and no residue (NR) were as sub-sub plot treatments. The third year of the study showed that there was 10-13% yield reduction in case of zero tillage than other treatments. The soil salinity (EC) was more in rice-cotton system than rice-rice system in both the seasons whereas organic carbon was slightly more in rice-rice system than rice-cotton system. Exchangeable Mg was slightly more than exchangeable Ca. Exchangeable Na was relatively more in cotton-rice system than rice-rice system. ZT showed marginally high in soil salinity may be due to more capillary rise of salt water in ZT than other treatments. Depth wise soil properties indicated that at surface depth there was reduction in bulk density and increase in organic C in ZT than other treatments. Stratification ratio (defined as a soil property at the soil surface divided by the same soil property at lower depth) of organic C was higher in ZT with residue than other treatments, whereas for bulk density, the trend was reserve. The soil organic C stock was determined up to 45 cm soil depth and it was highest in RT with residue (26.02 Mg/ha) followed by CT with residue (25.62 Mg/ha), RT without residue (25.6 Mg/ha), ZT with residue (25.5 Mg/ha), CT without residue (24.9 Mg/ha) and lowest in ZT without residue (22.9 Mg/ha) treatment. The operation wise energy utilization pattern in each treatment was evaluated. More than 80% of energy was used through application of inorganic fertilizer as indirect energy. Rice-rice system was more efficient in energy utilization than rice-cotton system, and the results showed reduced tillage under rice-rice system was most efficient than other treatments.