Effects Of Different Ratio Of Nitrogen And Potassium On Grownth And Lodging Resistance Of Early Direct Seeding Rice

The rice variety Lulianyou996was used as the experimental material to study the effect of different ratio of nitrogen and potassium on grownth, absorption of N,P,K and lodging resistance in early direct seeding rice in this work.3different nitrogen and potassium levels were set as follows, Nitrogen (N) for using120kg/hm2(N1),165kg/hm2(N2),210kg/hm2(N3). Potassium (K2O) for using90kg/hm2(K1),150kg/hm2(K2),210kg/hm2(K3). The results show that:(1) In the conditions of this experiment, the rice yield to N2K3combination is the highest, about9045.33kg/hm2. In the same level of nitrogen fertilizer, the yield increase with the increase in the amount of potassium. The growth rates for yield with increasing the amount of nitrogen and potassium decreased. In certain range of nitrogen application, with nitrogen application increased, the milled rice rate, head rice rate increased, but decreased until nitrogen application reached165kg/hm2.The chalky grain rateand and protein content increased with nitrogen application increasing, the amylose content gave the minimum under medium N deposition. Brown rice rate, head rice rate and protein content increased with the potassium application increased, chalky grain rate showed the opposite pattern.(2)In this experiment conditions, the tiller number increased with the increase of the amount of nitrogen and potassium, decreased with increasing of nitrogen fertilizer when nitrogen application reached165kg/hm2, Effective panicles increased with the increase of the amount of potassium. leaf area index, leaf area, SPAD value of rice increased with the growing of the amount of nitrogen and potassium. After heading, flag leaf stomatal conductance, net photosynthetic rate increased with the increase of the application of nitrogen and potassium. Bleeding sap amount of root was N2>N3>N1, K3>K2>K1. The dry matter accumulation in the different treatment conditions appeared as N2>N3>N1, K3>K2>K1, The main organs in rice transitioning into spike were the leaf and sheath, the weight of dry matter transport into grain was N2>N3>N1, K3>K2>K1.(3) In this experiment conditions, the NR, GS, GOGAT activity and soluble protein content of top leaves were largest in medium nitrogen treatment at the heading stage. In the panicle initiation,milk and mature stages, the activity increased with the increases of nitrogen and potassium application. At young panicle differentiation and heading stages, the yield significantly and positively correlated with the activeness of nitrogen metabolism enzymes and nitrogen accumulation, translocation and utilization. Uptake of nitrogen, phosphorus and potassium increased with the increase of the amount of nitrogen, decreased with nitrogen fertilizer increasing when nitrogen fertilizer reached165kg/hm2. Uptake of nitrogen, phosphorus and potassium increased with application of potassium increased. Nitrogen translocation of rice increased with the increase of the nitrogen and potassium application. Potassium translocation of rice was increased and then decreased in the nitrogen fertilizer range of120-210kg/hm2, the amount of potassium translocation got highest in N2, and it increased with the increase of the potassium application. The utilization efficiency and agronomic efficiency of nitrogen and the accumulation of N, P and K in spike expressed as N2>N3>N1, K3>K2>K1. The dry matter production efficiency of NPK and nitrogen harvest index decreased with the increase of application of nitrogen and potassium. The amount of Nitrogen and phosphorus produced100kg grains increased with the increase of the amount of nitrogen and potassium. At different fertilization level of nitrogen and potassium, production of100kg rice for potassium content were N2>N3>N1, K3>K2>K1.(4) The lodging index in different treatments had significantly differences as follow, N3>N1>N2, K1>K2>K3, and the N2K3treatment got the maximum of lodging capacity. The quantity of rice roots, root weight, stem diameter, wall thickness,dry weight of per unit length stalk, resistant press, content of cellulose, hemicellulose and lignin were aslo had significantly differences in different treatments, N2>N3>N1, K3>K2>K1. The retentive force of root decreases with the increase of amount of nitrogen, increases with the increased of potassium application. The content of N,P,K in stalk increased with the increase of the amount of nitrogen and potassium. The stem diameter, wall thickness, dry weight of section â…  and section â…¡, dry weight of unit length stalk, resistant press, culm type index, root retention power, lodging resistance force per plant,accumulation of soluble sugar and starch, content of nitrogen and potassium in sheath, hemicellulose and lignin were negative correlated to the lodging index at the1%or5%level of significance.