Direct seeded rice: research strategies and opportunities for water and weed management

Anticipated water crisis, traditional rice cultivation having standing water for most of the growth stages and mounting labour shortage necessitates the search for alternative water management methods to increase the water productivity in rice cultivation. The major benefit of direct seeded rice (DSR) is its low-input demand. DSR with non-puddled and non-flooded conditions has the potential to maximize the water productivity under deficit soil moisture conditions. The major constraint for DSR is water and weed management for sustaining the yield. Exposure of rice plants to water deficit stress leads to the nutrient deficiency and panicle sterility, which ultimately leads to reduction in yield. One of the prominent reasons for yield penalty under DSR is weed infestation, which accounts for enormous losses in economic terms and sometimes crop failures. High weed density not only compete with the rice plant but often provides a shelter for growth of various harmful insect, pest and pathogens, which adversely affect the rice production. Compared to manual weeding, weed control by herbicides are considered to be more efficient and economical in wet direct seeded rice. Hence, the identification and selection of cultivars based on their competitive ability with weeds coupled with drought tolerance is of paramount importance. In order to achieve long term sustainable and economic weed control in DSR, an integration of different weed management strategies involving cultural, mechanical, biological and chemical methods are very much essential. In this review, we discuss the experiences, potential benefits and major challenges associated with DSR, and suggest sustainable management practices for direct seeded rice cultivation.