Study On Agronomic Performance Of Direct Seeding In Double-season Rice In Hubei Province

Rice(Oryza sativa L.) is one of the most important food crops in China. Increasing rice production in a sustainable manner is vital for ensuring food security. It is essential to promote the development of double-season rice through simplified and mechanized management practices under the situation of lacking arable land and labor force. Direct seeded rice is popular in rice production of southern China and the Yangtze River regions due to labor-saving and low production cost. Compared with transplanted rice of double-season, direct seeded rice of double-season is more efficient by reducing labor and economic input in crop establishment. Furthermore, the planting area of double-season rice could be resumed to the historical level by adopting direct seeding practice in both seasons. The main objectives of this study were to(1) screen the varieties which adapted to direct seeded rice of double-season in Hubei Province;(2) determine the suitable variety and optimal sowing date for each season in direct seeded rice of double-season;(3) evaluate the yield differences between direct seeded rice and transplanted rice. Field experiments with eight varieties under different sowing dates were conducted in Zhougan and Zhangbang Villages, Dajin Town, Wuxue County, Hubei Province, China in 2014 and 2015. The major conclusions of this study are as follows:1. This study suggested that Xiangzaoxian6 was suitable for direct seeded rice of double-season in Hubei Province due to its higher grain yield and shorter total growth duration compared with the others. The growth duration of Xiangzaoxian6 was 90 to100 d and 88 to 102 d in early and late seasons, respectively; grain yield of Xiangzaoxian6 was 7.37 to 8.25 t ha-1 and 7.67 to 8.65 t ha-1 in early and late seasons, respectively.2. The optimal sowing date of direct seeded rice in early season in Hubei Province ranged from 8 April to 13 April. The recommended sowing data in late season should be as soon as possible after the harvest of early rice, and can not be late than 23 July. In this case, the yield of direct seeded rice of double-season can reach 15.51-16.11 t ha-1.3. The total biomass accumulation at maturity of Xiangzaoxian6 was lower than other vatieties, but the harvest index was much higher. The productive panicle number per unit area was greater, but spikelets numbers per panicle was lower than the others. This study indicated that grain yield of Xiangzaoxian6 could be improved byincreasing the spikelets numbers per unit and total biomass accumulation.4. The grain yield of direct seeded rice was comparable to that of trasnsplanted rice. The results indicated that the crop productivity of direct seeded rice of double-season would not be reduced with optimal crop management practices.