滨海盐土肥盐耦合对水稻产量及肥料利用率的影响

采用田间试验，研究上虞涂区低盐和高盐水平下氮磷施用量对水稻产量及肥料利用率的影响。结果表明，水稻成熟期时，田面水排干后0-40 cm土层含盐量显著上升。试验区土壤基础肥力贫瘠，低盐对照区和高盐对照区水稻产量仅为1 260和520 kg·hm-2。稻谷产量随N、P施用量的增加而提高。在产量构成中，有效穗数受N、P的影响最大。其中，最佳经济N、P施用量在低盐水平（1.0～2.0 g·kg-1）下分别为281.8和107.5 kg·hm-2，而高盐水平下（2.0～4.0 g·kg-1）分别为344.9和161.3 kg·hm-2，低盐和高盐区最高产量分别达到6 530和5 030 kg·hm-2。水稻谷草比随N、P施用量的增加而略有下降。N、P肥利用率在低盐水平下分别为33.9%～58.2%和51.2%～61.8%，而高盐水平下分别为25.1%～38.0%和31.0%～43.2%。

Coupling effects of salt stress and fertilizer application on rice yield and fertilizer using efficiency in coastal saline soil

 Field experiments in Shangyu coastal saline soil were carried out to investigate coupling effects of salt stresses and fertilizer application （N and P） on rice yield and fertilizer using efficiency. It was shown that the salt contents in 0-40 cm soil layer increased sharply after drainage during the rice mature stage. Due to the low fertility of saline soil， the rice yields of the control plots with low and high salt content were only 1 260 and 520 kg·hm-2， respectively. The rice yields were significantly increased by N and P application， and the highest yields were obtained as 6 530 and 5 030 kg·hm-2 in either low or high salt stressed soil， respectively. Among yield components， the number of productive ear was the most influenced by N and P application. The economic optimum N and P application rate were 2818 and 107.5 kg·hm-2 in low salt stressed soil （1.0-2.0 g·kg-1）， and 344.9 and 161.3 kg·hm-2 in high salt stressed soil （2.0-4.0 g·kg-1）， respectively. The ratio of grain to straw was slightly decreased with N and P application. The N and P fertilizer using efficiency were 33.9%-58.2% and 51.2%-61.8%， respectively， in low salt stressed soil， and 25.1%-38.0% and 31.0%-43.2%， respectively， in high salt stressed soil.