Dynamic varieties of dry matter and nutrient accumulation in maize plants under different water and N、P、K supply condition

The effects of different water and N、P、K supply on the dynamics of N,P and K uptake and accumulation were studied by pot experiment with the design of orthogonal.The results showed that the dry matter and nutrient accumulation were continuously increased with plant growth,and their accumulation in different plant-growing periods were shaped in S curves that could be described by the exponential regression equations.The momentary rate of the dry matter and nutrient uptake was obtained by the regression equations for the first derivatives.At the same time,the time for the maximum absorptive rate was obtained by the regression equations for the second derivatives.The time for accumulation of maximum dry matter is 33.56～68.06 d after the maize emergence,the times for accumulation of N,P,K are 14.73～64.19,45.23～80.64,18.80～53.91 d respectively.