不同磷钾条件下苗期适度水分亏缺对大豆生长及干物质积累的影响

Effect of moderate water deficit during seedling stage on growth and dry matter accumulation of soybean under different P and K levels

在盆栽条件下研究了不同磷钾肥施用时苗期水分亏缺对大豆生长、干物质积累及产量的影响。结果表明：磷钾肥施用相同时，苗期轻度缺水处理对大豆干物质积累及产量的提高效果最佳，且其水分利用效率接近或超过正常灌水处理，而中度和重度缺水则明显降低大豆干物质积累及产量。当水分亏缺相同时，施用中量磷钾肥有利于豆荚效和籽粒效的提高，从而提高大豆产量及水分利用效率。因此，本试验条件下，苗期轻度缺水（占田间持水量的60％～70％）与施用中量磷钾肥是提高大豆产量的较好组合。

A pot experiment was carried out to study the effects of water deficit during the seedling stage on growth, dry matter accumulation and yield of soybean under different P and K levels. The results showed that, under the same application of P and K fertilizer, slight water deficit during the seedling stage was the best treatment to increase dry matter accumulation and yield of soybean, and its water use efficiency was close to or more than that of conventional irrigation; however, medium water deficit and serious water deficit during the seedling stage reduced dry matter accumulation and yield of soybean markedly. Under the same water deficit, medium P and K fertilizer application was beneficial to increase pod number and seed number, thus improved yield and water use efficiency of soybean. Therefore, moderate water deficit （i. e. , 60 % -70 % of field capacity） during the seedling stage and medium P and K level was an ideal water and fertilizer coupling to improve the output of soybean under the experimental condition.