Dynamic analysis of dry matter and NPK accumulation with time in summer maize

Logistic equation was used to simulate the temporal variation of dry matter and nutrients of the summer maize. The results show that the velocity of maize dry matter and stimulated nutrient contents versus time occur in asymmetry bell-shaped curves which can be divided into the slow (I), quick (II) and declined growth periods (III). The duration for each period is about 1/3 of the total growth period with some fluctuate among different treatments. The cumulative speeds of the plant dry weight and NPK nutrients are very low within the first 30 days after germination (phrase I), which are 1 to 2 orders of magnitude compared to phrase II and Ⅲ. The most quick accumulation is in the period II, then slowdown at the period (Ⅲ). Generally speaking, the cumulative amount of maize plant dry matter and nutrients in different stages depended on the staging time and speed.