秸秆覆盖条件下玉米不同生育期间的干旱阈值研究

Drought Threshold of Maize during Different Growth Periods under Straw Mulching Conditions

2018~2019年在人工遮雨棚内进行不同梯度的干旱胁迫试验,研究秸秆覆盖免耕条件下玉米不同生育时期的干旱阈值。结果表明,以减产5%为临界点,拔节至抽雄期间,覆盖免耕条件下的干旱阈值为0.609,明显高于裸地旋耕条件下的0.551;在抽雄至乳熟期间分别是0.524和0.512,相差不大。干旱阈值出现的时间,拔节至抽雄期间,覆盖比裸地晚6.1 d;在抽雄至乳熟期间,二者差距缩小为3.7 d。结果说明,秸秆覆盖能明显提高玉米的抗旱性,延长必须补水的间隔,拔节期至抽雄期间效果更显著,从而在产量不变的前提下,减少玉米全生育期的补水次数。

To find out the drought threshold of maize in different growth periods under the condition of no till⁃age under straw mulching,so as to scientifically guide supplementary irrigation and avoid water resource waste.Our team conducted drought experiments with different gradients in the artificial awning from 2018 to 2019.The results showed that,with 5%reduction as the critical point,the drought threshold under no-tillage coverage was 0.609 dur⁃ing the period from jointing to tasseling,which was significantly higher than 0.551 under the condition of open rota⁃ry tillage,but there was no significant difference between tasseling and milk ripening(0.524 and 0.512,respective⁃ly).In terms of the time of occurrence of drought threshold,the coverage was 6.1 days later than that of bare land during jointing to tasseling,but the difference was reduced to 3.7 days between tasseling and milk ripening.These results indicated that straw mulching could significantly improve the drought resistance of maize and extend the in⁃terval of necessary water replenishment(especially from jointing to tasseling),so as to reduce the number of water re⁃plenishment during the whole growth period of maize with the same yield.