Research on the Different Ratio of N,P and K-Fertilization for the Potato in Qaidam Region and its Photosynthetic Characteristics

[Objective] The relationship between photosynthetic characteristics and potato yield was explored through the experiment in the different ratio of N,P and K-fertilization.[Method] The relationship between the amount of N,P and K-fertilization and the tuber yield,the content of chlorophyll,the photosynthetic rate of leaf of the potato variety-Qingshu-6 planted in Qaidam Area was experimented with the three-factor quadratic universal rotary combination design.[Results] The results showed that there was a significant regression relationship between the amount of N,P and K-Fertilization and the tuber yield,the content of chlorophyll,the photosynthetic rate of leaf of the variety.In the range of low N-fertilization,the tuber yield,the content of chlorophyll,the photosynthetic rate of leaf were increased with the increment of N,P and K-fertilization.The tuber yield,the content of chlorophyll and the photosynthetic rate of leaf would not be raised with the increment of N,P and K-fertilization when they reached its highest point.The content of chlorophyll in potato was closely related to the photosynthetic efficiency,which relevance was closer than that between the content of chlorophyll and the tuber yield,and that between the photosynthetic rate of leaf and the tuber yield.[Conclusion] The optimal combination of fertilization for the highest yield of potato tuber was N,239.2 kg/hm2,P2O5,240.0 kg/hm2 and K2O,119.6 kg/hm2.The optimal combination of fertilization for the highest content of chlorophyll and the largest photosynthetic rate of leaf was N,239.2 kg/hm2;P2O5,191.3 kg/hm2 and K2O,119.6 kg/hm2.