Abstract:

【Objective】 The relationship between integrated nutrient management and the lodging resistance of rice was studied to elucidate the mechanism underlying the lodging resistance of rice plant in cold area. 【Method】 A field experiment was conducted with 4 nutrition managements and the physical properties, mechanical features and carbon-nitrogen ratio of the stems of rice were analyzed. 【Result】 The yield of the farmers fertilization practice (FFP) was 8.55 t?hm-2. Optimal fertilization practice (OPT) increased the yield, reduced the length of the first and second internode of the basal stem by 11.6% (P＜5%), 13% and 6% (P＜5%), respectively, significantly increased carbon-nitrogen ratio, stem diameter, stem wall thickness, leaf sheath weight and area of cross section 30 d after heading, and reduced the index of lodging resistance by 14.18% (P＜5%). Compared to FFP, the yield of the farmers fertilization practice for high yield (FFP -H) was increased by 15.2% and achieved high-yield rice. Compared to FFP-H, the optimal fertilization practice for high yield (OPT-H) increased rice yield by 7.4%, the length of the first and second internode of the basal stem is reduced by 12% and 4% (P＜5%), separately, at the same time, carbon-nitrogen ratio, stem diameter, stem wall thickness, leaf sheath weight and area of cross section were significantly increased, and the index of lodging resistance was reduced by 6.19% (P＜5%) 30 d after heading. Compared to OPT, the harvest panicles of OPT-H was increased by 15.1% (P＜5%), yield was increased by 10.9% (P＜5%), but the index of lodging resistance between the two treatments was not significanty different. 【Conclusion】 OPT and OPT-H increased the height of gravity center and plant height, but reduced the distance of basal internode due to optimization of internode collocation of rice, and increased carbon-nitrogen ratio of rice stems and stem diameter, promoted stem substantiality, resulting in high grain yield and lodging resistance of rice plant.

Key words: rice in cold area')">rice in cold area, integrated nutrient management, lodging index, grain yield