Characteristics of dry matter and nutrients accumulation and transformation of super-high yield spring maize Effect of waterlogging on nutrient uptake and transport of summer maize Study on N and K concentration and N and K balance in tobacco leaves Characteristics of nitrogen, phosphorus and potassium uptake and accumulation of potato in Ningxia Effects of Varied Fertilization Strategy with N,P,K Nutrients on the Growth of Acacia mangium Saplings Characteristics of dry matter, accumulation and distribution of N, P and K of superhighyield summer maize