(1) The seedling stage is from sowing to jointing stage. This stage is characterized by vegetative growth, rooting and differentiation of stems and leaves. During this period, stems and leaves grow slowly, while roots grow rapidly. By the jointing stage, strong roots had basically formed, which laid the foundation for the future growth and development of aboveground parts. Seedling management center is carried out around promoting root growth.
(2) Heading stage refers to jointing stage to heading stage. During this period, a large number of leaves spread out, the stems stretched rapidly, and the male and female ears differentiated and formed one after another, which was the stage of vegetative growth and reproductive growth. Therefore, the management center at this stage is to promote leaves, strengthen stems, and strive for more ears and big ears.
(3) The flowering and filling period refers to the period from tasseling to grain maturity. During this period, it experienced the growth process of flowering and pollen spread, spinning and fertilization, grain formation and maturity. The characteristics of this period are that the vegetative growth of roots, stems and leaves basically stops, and plants enter a reproductive growth stage dominated by flowering, pollination, fertilization and seed growth. Corn ear is the main organ to accumulate dry matter during flowering and fruiting. During this period, 85-90% of grain dry matter is the synthetic product of green leaves. Therefore, the management center of flowering and filling stage is to ensure adequate fertilization of corn, increase grain volume, enhance photosynthesis, extend filling time, achieve more grains, larger grains and heavier grains, and achieve the goal of high yield.