Effect Of Integrated Nutrient Management On Lodging Resistance And Yield Of Rice In Cold Area

The lodging of rice has become the main limiting factor for high yield, how to improve lodging resistance ability is the key to high yield of rice. To solve this problem, field experiment was conducted with 4 nutrition managements and the physical shape and properties, mechanical features, carbon-nitrogen ratio, as well as indicators of the stems of rice analyzed. The relationship between the nutrient management and the lodging resistance ability of rice were studied to proven the main reason that lodging resistance ability under the conditions of the strong in high yield and find the mechanism of improving lodging resistance ability in cold area to provide a theoretical basis for fertilization. The main results are as follows:There were significantly positive correlations (P<0.05) between the snapping resistance and the length of the second internode of the basal stem, the snapping resistance and the steam diameter, the snapping resistance and the leaf sheath weight, the snapping resistance and the area of cross section. Compared to Farmers Fertilization Practice(FFP), Optimal Fertilization Practice(OPT) increased the plant height by 3.2%(P<5%), the length of the first and second internode of the basal stem were separately reduced by 13% and 6%(P<5%), the length of panicles was increased by 3.7%(P<5%). Compared to Farmers Fertilization Practice for High yield(FFP-H), the length of the first and second internode of the basal stem of Optimal Fertilization Practice fo High yield(OPT-H) were separately reduced by 12% and 4%(P<5%). In the high density conditions, Compared to FFP, OPT-H increased plant height by 3.3%, the length of the second internode was decreased by 6%(P<5%).There were significantly positive correlations (P<0.01) between the snapping resistance and great vascular bundle area, the snapping resistance and number of mechanical tissue cell layers. In the same densities, compared to FFP and FFP-H, OPT and OPT-H great vascular bundle area is separately increased by 31% and 6%(P<0.05), great vascular bundle cell wall thickness is separately increased by 27% and 38%(P<0.05). In the high density conditions, compared with FFP, FFP-H and OPT-H great vascular bundle area was separately increased 37% and 45%,OPT-H great vascular bundle cell wall thickness increased by 46%(P<0.05).There were significantly negative correlations (P<0.01) between the lodging index and the soluble sugar content of the second internode of the basal stem, the lodging index and carbon-nitrogen ratio of the second internode, and significantly negative correlations (P<0.05)between the lodging index and amylum content, and significantly curve correlation (P< 0.05) between the lodging index and k content. Compared with FFP, OPT increased soluble sugar content by 156%, increased carbon-nitrogen ratio by 170%, increased amylum content by 150%, and increased k content by 14.3%. Compared with FFP-H, OPT-H increased soluble sugar by 16.5%, increased carbon-nitrogen ratio by 18.5%, and increased k content by 14.7%,and differences were significant(P<0.01).There were significantly negative correlations(P<0.01) between the lodging index and the snapping resistance. Compared OPT with FFP at the stage of 10 days and 30 days after heading, the snapping resistance separately increased by 32.8%-41.3%(P<0.01), the lodging index separately decreased by 12.3%-14.185%(P<0.05), Compared OPT-H with FFP-H at the stage of 10 days and 30 days after heading, the lodging index separately decreased by 8.14%-6.19%(p<0.05). Compared with FFP, the lodging index of FFP-H and OPT-H separately reduced 3.03% and 9.42% in the high density conditions. Compared with OPT, OPT-H increased the lodging index, but the difference was not significan.In the same density conditions, compared with the FFP, OPT increaded yield of rice by 11.6% by the integrated nutrition management and to achieve the intended output target. Compared with FFP, FFP-H increased yield of rice by 15.2% by increasing crop density and the nutrition optimal management, and also increase production to achieve the intended goal. Through the nutrition optimal management of FFP-H—reduced the amount of the fertilizer for basic and tiller and N application at later stage, yield of OPT-H up to 10.58t·hm-1.Compared with FFP and FFP-H, OPT-H separately increased yield of rice by 23.5% and 7.2%, reaching the high yield of rice objectives.The results of this experiment showed that integrated nutrient management(INM) reduced the length of the first and second intemode of the basal stem, enhanced the second internode of the basal stem's stem diameter, wall thickness, increased the second internode of the basal the leaf sheath weight and significantly increase the great vascular bundle area, wall thickness, thereby enhancing the microstructure the internode of the basal stem; increased carbon-nitrogen ratio, enhanced the material of the second internode of the basal stem, increased the output rate of assimilation of material and promote the formation of a thick stem; Increased the height of gravity center and plant height, but significantly decreased the lodging index and improved snapping resistance of rice plant. In the high density conditions, the nutrient integrated management may significantly reduced lodging index, resulting in high grain yield and lodging resistance ability of rice plant.