Minimum tillage unpuddled transplanting: An alternative crop establishment strategy for rice in conservation agriculture cropping systems

摘要

Adoption of conservation agriculture (CA) has been hampered in puddled rice-based cropping systems. In this study, we developed a method for transplanting rice (Oryza sativa L.) with minimal soil disturbance (referred to as minimum tillage unpuddled transplanting) that can expand the range of situations where CA could be practiced in rice-based cropping systems. A field experiment was conducted over three years at two sites with unpuddled and puddled rice comparisons in each monsoon season. In addition, transplanted rice was grown in three seasons on unpuddled or fully puddled soils in a total of 27 farmers' plots in north-west Bangladesh. In each year and season, minimum tillage unpuddled conditions were established by strip tillage and compared with single pass shallow tillage or bed formation, and with the conventional soil puddling and transplanting. Unpuddled transplanting by any of the three single-pass soil disturbance operations had no negative effect on rice yields across seasons and years. The minimum soil disturbance in strip tillage did not impede transplanting of rice or increase the labor costs of transplanting compared to puddled transplanting except in the farmers' plot of the first season. All single-pass and minimum soil disturbance tillage operations reduced cost of production, and increased the gross margin of rice relative to conventional puddling and transplanting. Minimum tillage unpuddled transplanting reduced the time taken for land preparation and crop establishment and decreased the number of irrigation events required to saturate the soil. Minimum tillage unpuddled transplanting appears to be a feasible approach for establishment of wetland rice in CA systems.