干旱处理对土壤水分变化及大豆产量的影响

Effect of Drought Treatments on Soil Moisture and Yield in Soybean

采用框栽方式,研究不同阶段干旱处理对土壤水分、大豆植株干物质积累及产量的影响。结果表明,土壤含水率随干旱历时的增加而递减,长时间干旱后稳定在20%～24%;对于短期干旱处理,灌溉量较大时,土壤含水率会迅速恢复到稳定值32%～34%,但是对于18d以上的干旱历时,较少的灌溉量并不能保证土壤含水率在1～2次灌溉后得到恢复,表明较少的灌溉量对土壤含水率的提升能力有限。各干旱处理结束时期,大豆植株干物质积累均随干旱历时增加呈下降趋势,长期干旱会使全株干物质积累下降13%～30%;苗期和花荚期的短期干旱处理产生激发补偿效应,不会使大豆减产,结荚鼓粒期对水分供应较为敏感,干旱导致大豆减产。

Severe drought limits the enhancement of soybean yield.Frame experiment（pot without bottom）was conducted to investigate the effect of different drought treatments on soil moisture,dry matter accumulation in soybean plant and yield.The results showed that soil moisture declined as the days of drought increased and it stabilized at 20%~24% after long-term drought.For short-term drought treatments,soil moisture recovered to 32%~34% when irrigation was heavy.However,for 18 or more days of drought,less irrigation cannot guarantee recovery of soil moisture after one or two irrigations,which showed that the ability of less irrigation to improve soil moisture was limited.When the different drought treatments ended,dry matter accumulation in soybean plant declined as the days of drought increased and it dropped to 13%~30% after long-term drought.Short-term drought treatment during seedling and flowering-podding stages exhibited a compensatory effect and did not lead to yield reduction.However,podding-seed filling stage was more sensitive to the supply of water and drought resulted in yield reduction.