氮素营养与水分胁迫对大豆产量补偿效应的影响

在大豆营养生长期,对大豆进行不同程度的干旱锻炼,同时改变土壤中的施氮水平,研究大豆产量及其构成因子对干旱胁迫复水的反应机制,为大豆节水增产及抗旱机制的实践探索提供理论依据。水分胁迫强度、历时和氮素营养都对大豆产量及其构成因子的补偿效应产生明显影响,水分胁迫抑制了大豆单株粒数的增长,但可以显著提高百粒重;氮素营养会抑制大豆百粒重的增加,但在一定水分条件下可以显著提高单株籽粒的数量,然而随着水分胁迫程度的加重,单株粒数的增加幅度也会相应减少。虽然氮素营养和水分胁迫使大豆产量构成因子产生补偿效应的阈值范围不同,但二者具有一定的耦合区域,在耦合区域内(水分胁迫时间14d左右、土壤含水量为田间持水量的50%—55%、施氮量在97.5—225kg/hm2之间)单株粒数和百粒重都产生较强的补偿效应,二者的协同作用显著提高了大豆的经济产量,使大豆产量表现出较强的补偿效应。结果表明:氮素营养和适度水分胁迫可以通过不同途径提高大豆植株的生长能力,当二者结合后大豆的补偿生长机制更为复杂,最终表现为水分胁迫提高了大豆的百粒重,而氮素增加了大豆单株粒数,二者协同作用使大豆经济产量显著增加。

Effects of nitrogen nutrition and water stress on compensation effect of the yield of soybean

Through the experiment of drought training at different degrees in vegetative growth stage and levels of nitrogen in the soil, mechanisms of soybean yield and its components to drought stress and re-watering were studied, which will provide a theoretical basis for practice and exploration of soybean water-saving, yield-increasing and drought resisting mechanisms. The intensity of water stress, time and nitrogen nutrition have a clear effect on the compensation effect of soybean yield and its components. Water stress could inhibit the increase of soybean grains per plant, but improve the100-seed weight significantly; nitrogen nutrition could limit the increase of 100-seed weight in soybean, but significantly improve the numbers of grain per plant under certain water conditions, and with the increase of the degree of water stress, the increase extent of the grains per plant would be reduced accordingly. Although the threshold ranges of compensation effects of soybean yield components produced by the nitrogen nutrition and water stress were different, but they had a certain area of coupling. In the area (the water stress durations were about 14d, soil water contents were 50%-55% of field moisture capacity, nitrogen amount were 97.5-225 kg/hm2), the compensation effects on the grains per plant and 100-seed weight were considerable intensive, the synergy of the water stress and nitrogen nutrition made the economic yield of soybean increase significantly and the soybean yield showed the strong compensation effect. Nitrogen nutrition and moderate water stress can enhance the growth capacity of soybean plant through the different approaches, the compensatory growth mechanism of the soybean is more complicated after the coupling of the two, and ultimately presents that water stress and the nitrogen can make the 100-seed weight and the grains per plant increase respectively, the synergy of the two can significantly increase the economic yield of soybean.