土壤水分对免耕水稻生长与产量的影响

The influence of soil moisture on plant growth and grain yield in no-tillage rice

【目的】研究土壤水分对免耕水稻生长和产量的影响，以期为免耕水稻节水栽培土壤水分调控指标的优选提供依据．【方法】2013年早季和晚季，以吉优716为试验材料进行盆栽试验．设3种土壤水分条件：水稻全生育期土壤水分含量保持田问最大持水量的95％～100％、80％～85％、65％～70％（分别用W100、W85、W70表示）．【结果和结论】W70处理免耕水稻产量、生物量和收获指数均显著低于W100与W85处理．W70处理产量降低的直接原因是穗变小和结实率下降．W70处理土壤水分显著抑制了生物量积累和物质转运．水稻分蘖数随土壤水分下降而下降，分蘖盛期各处理问差异达显著水平，最终分蘖数各处理问差异不显著．水稻株高均随着土壤水分的降低而降低，差异达显著水平．拔节期水稻上部3片完整叶（上三叶）的叶面积、叶长和叶宽均随着土壤含水量的降低而降低，水分亏缺首先影响叶宽，其次为叶长，进而使叶面积降低．免耕水稻抽穗期W70处理上三叶叶面积、叶长和叶宽均显著降低．因此，免耕水稻节水栽培中，土壤水分应不低于最大田问持水量的70％为宜．

【Objective】The effect of soil moisture on plant growth characteristic and grain yield of no-tillage rice was investigated to identify the optimal soil moisture for no-tillage rice production. 【Method】Pot experiments were conducted in the early and late seasons of 2013. In each season,a hybrid rice cultivar Jiyou716 was cultivated under the saturated soil moistures of 95%- 100%( W100),80%- 85%( W85) and 65%- 70%( W70). 【Result and conclusion】The grain yield,biomass and harvest index of no-tillage rice under W70 were significantly lower than those under W100 and W85. The reason why the grain yield decreased under W70 was that panicle became small and seed set decreased. The biomass and transportation under W70 were significantly inhibited. The tiller dynamic of no-tillage rice was divided into two stages,and the tiller number first increased and then decreased. The tiller number decreased when soil moisture reduced,and there were significant differences among the three treatments at peak tillering stage,but no significant differences in the end. The plant height decreased when soil moisture reduced,and there were significant differences among the three treatments. The area,length and width of three leaves from top decreased when soil moisture reduced at the elongation stage. The soil water deficiency first influence the leaf width,then the leaf length,and lead to the leaf area decrease in the end atthe elongation stage. The area,length and width of three leaves from top under W70 significantly reduced at the heading stage. Therefore,the soil moisture should be not less than 70% of saturated soil moisture in no-tillage rice cultivation.