南方季节性干旱区再生稻降水资源高效利用研究

Improving rainfall use efficiency of ratoon rice in seasonal drought areas of South China

以四川、湖北、江西、广西和重庆季节性干旱危害严重的69个县为研究对象,依高产栽培的水分管理要求,基于作物需水量和自然降水量的时空分布特点,提出不同稻区再生稻水分管理策略:(1)四川、重庆大部分地区的降水量大于或等于该地区的作物需水量,可以采用水稻生长前期适当露田、中期烤田和后期干湿交替的高产水分管理策略;(2)湖北省大多数地区降水仅能满足作物需求,达不到高产栽培的水分管理要求;(3)广西大部分地区可在水稻生长前期适当露田,但头季稻后期及再生季秋旱严重,不宜中期烤田;(4)江西多数地区在水稻生长前期可以烤田,头季稻后期及再生季秋旱严重,降水不足,较难实现干湿交替。

This study is to investigate the strategies for high rainfall use efficiency of ratoon rice in seasonal drought areas of southern China. Crop e vapotranspiration（ETc） was calculated by means of the Penman- Monteith equation using meteorological and crop data from 69 counties of five provinces （Sichuan, Hubei, Jiangxi, Chongqing and Guangxi ） According to the spatial and temporal distribution and its congruence between rainfall and ETc, strategies for rainfall management of different areas are outlined as follows ： （ 1 ） In most counties of Sichuan and Chongqing, amount of rainfall match to that of Eric during rice growing season. Drying paddy field in sunshine at early stage and alternate drying and wetting at middle and late stage are suggested as the rainfall management practices for these areas; （2） Most counties, except three in Hubei, are not suitable for ratoon rice production; And （3） Guangxi and Jiangxi are similar in rainfall temporal distribution, with the majority of rainfall occurring in the early rice growing season. Therefore, drying paddy field in sunshine at early stage is strongly recommended, while ahemate drying and wetting at middle and late stage are not suitable for these areas. At the end of this paper, the importance of high rainfall use efficiency for reducing methane emission in ratoon rice field is highlighted according to our experiences of field experiments.