肥力水平对水稻苗期生长及氮素吸收同化的影响

Effects of Soil Fertility Levels on Rice Growth,Nitrogen Accumulation and Assimilation at Seedling Stage

通过盆栽试验研究了不同肥力水平红壤水稻土种植条件下,水稻苗期生长及其N素吸收同化的差异。结果表明,在高肥力土壤中水稻的苗期生物量均显著高于低肥力土壤,主要表现为根生物量的差异,而且高肥力显著增加了水稻根数,但对水稻根冠比无显著影响。高土壤肥力对水稻N素吸收有显著促进作用,在一定程度上提高了水稻N素利用率,但并无显著影响。与低肥力红壤水稻土相比,水稻在高肥条件下叶片和根硝酸还原酶活性(NRA)和谷氨酰胺合成酶活性(GSA)均显著提高,显著促进水稻对N素的吸收同化。因此,适当提高和改善红壤水稻土肥力对红壤区水稻生长及N素营养具有重要意义。

A pot experiment was conducted to study the differences in rice plant biomass, N accumulation, N use efficiency, glutamine synthetase activity （GSA） and nitrate reductase activity （NRA） of paddy soil derived from red soil under different fertility levels at 40, 50 and 60 days after sowing. The results showed that the fresh and dry weights of rice plant under high fertility condition were significantly higher than those under low fertility condition, especially for the root biomass. High soil fertility increased rice root numbers significantly, but showed no significant effect on the root/shoot ratio. The rice N accumulation, NRA and GSA were significantly improved under high fertility soil conditions, which showed that high soil fertility increased rice N accumulation and assimilation significantly. High soil fertility increased the rice N use efficiencies but resulted in no statistically significant difference. In summary, appropriate amelioration for the paddy soil fertility was of important strategic significance for rice growth and nitrogen nutrition in tropical and subtropical China.