水氮耦合对滴灌复播大豆干物质积累氮素吸收及产量的影响

为探明不同水氮组合对复播大豆干物质积累、氮素吸收及产量的影响,于2013年7—10月在新疆伊宁县进行了不同滴灌量与施氮量的裂区田间试验。滴灌量为主因子,分设3 000 m3·hm-2(W1)、3 600 m3·hm-2(W2)、4 200 m3·hm-2(W3)、4 800 m3·hm-2(W4)四个灌水梯度;施氮量为副因子,设0 kg·hm-2(N0)、150 kg·hm-2(N1)、300 kg·hm-2(N2)三个水平。结果表明:同一施氮量条件下,随着滴灌量的增加各施氮处理干物质积累平均速率、干物质积累持续时间及氮素吸收量基本表现为"先增后降"的趋势,且均在W3处理(4 200 m3·hm-2)达到最大;在低水量(W1)条件下增加氮肥的投入,有利于增加复播大豆干物质积累,提高复播大豆氮素吸收量,进而提高复播大豆产量,但降低了氮素籽粒生产效率;水分充足时适量增施氮肥能促进大豆干物质的积累,增加植株氮素的吸收量,增加氮素籽粒生产效率,而过量追施氮肥,阻碍根系吸收氮素进入植株体内,降低氮素的利用效率,且W3N1组合条件下,干物质积累量、植株氮素吸收量、产量均达到最大,产量达到3 741.23 kg·hm-2,分别比低水低肥处理(W1N0)、高水高肥处理(W4N2)增加了54.30%、17.02%。

Effects of different water nitrogen couplings on dry matter accumulation, nitrogen uptake and yield of summer soybean

In order to study the effects of different water-nitrogen couplings on dry matter accumulation ,nitrogen uptake and yield of summer soybean ,a field experiment was conducted based on a two factors split plot experiment in Yining County from the July to October .For the split plot design ,the irrigation factor was assigned to the main plot with 4 irrigation levels as 3 000 m3·hm - 2 (W1) ,3 600 m3·hm - 2 (W2) ,4 200 m3·hm - 2 (W3) and 4 800 m3·hm - 2 (W4) , and the nitrogen factor to the subplot with 3 nitrogen levels as 0 kg·hm - 2 (N0) ,150 kg·hm - 2 (N1) and 300 kg·hm - 2 (N2) .The results showed that with the increase of irrigation quantity ,the average increase rate of dry matter (Va) ,the continued days of dry matter accumulation (T) and nitrogen uptake were all presented a trend of being increased first then becoming decreased ,reaching the maximum by W3 .Under the condition of the nitrogen input increased at low water (W1) ,the dry matter accumulation ,nitrogen uptake and yield were also increased while the nitrogen use efficiency be-came reduced .Under sufficient soil water condition ,increasing the application of nitrogen elevated dry matter accumula-tion ,nitrogen uptake and nitrogen use efficiency ,and excessive nitrogen was not favorable to root absorption of nitrogen , which adversely decreased the nitrogen use efficiency .In a word ,the treatment of W3N1 had the highest dry matter ac-cumulation ,nitrogen uptake and yield (3 741 .23 kg·hm - 2 ) ,54 .30% and 17 .02% in yield higher than those of W1N0 and W4N2 ,respectively .