Direct wet seeding in rice – A review

Transplanting is the most popular method of rice cultivation in south and south-east Asia. In India transplanted rice covers 19.0 m.ha. which is 44% of the total rice area. In recent years, transplanting is becoming increasingly difficult option due to shortage and high cost of labour, scarcity of water and the reduced profit. Wet seeding on puddled soil either through broadcasting or in lines is gaining popularity due to lower labour requirement, shorter crop period and efficient water use. Wet seeding of rice differs with respect to varietal choice, seed rate, weed, water and fertilizer management. Genotypes with less tillering ability, limited leaf area production during the reproductive stage coupled with high initial vigour, submergence resistance and lodging resistance were suitable for direct wet seedling. Direct wet seeded rice was efficient in nitrogen uptake in the initial stages due to absence of transplanting shock, however, the yields were low at lower levels of N in comparison to transplanted rice. Fertilizer N loss was lower with broadcast surface flooded rice (BSFR) because of more lateral root development. Agronomic efficiency was low in direct wet seeded rice (DWSR) due to lodging in the iater stages. Infestation of weeds in general, grassy and broad weeds in particular was more in DWSR compared to transplanting. Pre-emergence application of butachlor+Safener @ 1.0 kg a.i./ha controlled weeds effectively. DWSR saved 18% water over transplanting. Higher WUE was obtained with continuous submergence at 2.5 cm depth in DWSR and was at par with 5 cm depth of irrigation. Effects of DWSR were more promising due to lesser man hour requirement (16 h) in comparison to transplanting (347 h) per ha of land. Higher net returns and B:C ratio were obtained in DWSR. DWSR will be inevitable in the near future. To make this into a successful reality identifying of suitable genotypes, better water, weed, green manuring and fertilizer management practices are essential. DWSR may be adopted under sufficient water availability and weed control measures.