Abstract: A field experiment was conducted to study water use efficiency and agronomic traits in rice cultivated under submerged conditions(SC) and dry cultivation conditions with zero mulching(ZM) and straw mulching (SM). The total amount of water used in rice under SC was 2.42 and 3.31 times as much as that under the ZM and SM treatments, respectively. The average field leakage was 13 560 m³/hm² in the SC plots, 4 750 m³/hm² in the ZM treatment and 4 680 m³/hm² under the SM treatment. Rice straw mulching could decrease water evapotranspiration obviously. The evapotranspiration under the SM treatment was only 38.2% and 63.6% to the SC treatment and ZM treatment, respectively. Compared with the ZM treatment, the SM treatment significantly increased the leaf area per plant, main root length, gross root length and root dry weight per plant of rice. The highest yield under the SM treatment(6 747 kg/hm²) was close to that under the SC treatment(6 8115 kg/hm²) . However, the yield under the ZM treatment (4 716 kg/hm²) was much lower than that under the SC and SM treatments. The order of water use efficiency and irrigation water use efficiency was both as follows: SM> ZM> SC.

Key words: rice, dry cultivation, straw mulching, water saving irrigation, agronomic traits, water use efficiency

摘要： 为减小南方季节性干旱对水稻生长的影响，提高水分利用效率，于2003年在江西省余江县进行了水稻覆盖旱作的田间试验。大田条件下对比研究了裸地旱作、稻草覆盖旱作和常规水作下水稻大田生长期内的水分利用效率和作物主要农艺性状。结果表明，常规水作处理的灌溉水总量分别是裸地旱作和稻草覆盖旱作灌水量的2.42 和3.31倍。旱作处理下水稻的淹水时间明显减少，只有常规淹水处理的1/10左右。由于淹水时间的减少，水分渗漏量和田面蒸发损失也大大降低。旱作条件下，稻草覆盖旱作的水稻分蘖数、叶面积、根系生长明显优于裸地旱作。覆盖旱作产量最高可达6 747 kg/hm2，接近于常规水作对照的6 811.5 kg/hm2，两者无显著差异。而裸地旱作处理的水稻产量仅为4 716 kg/ hm2，显著低于常规水作和稻草覆盖旱作处理。水分利用效率和灌溉水利用效率均为稻草覆盖旱作>裸地旱作>常规水作。

关键词: 水稻, 旱作, 秸秆覆盖, 节水灌溉, 农艺性状, 水分利用效率