The vegetative growth period of rice refers to the growth stage of roots, stems and leaves of plant vegetative organs, generally from seed germination to young panicle differentiation. This stage includes seedling stage, tillering stage and jointing stage. Seedling stage refers to the period from seed emergence to transplanting. Tillering period can be divided into initial tillering period, effective tillering period, highest tillering period and final tillering period according to different tillering time and speed. The number of tillers increases slowly at the beginning, and the number is small, which is called the initial tillering stage; With the increase of rice plant assimilation, rice plants grow vigorously, tillering speed is accelerated, and the number of tillering stems increases rapidly, reaching the highest tillering number, which is called the highest tillering stage; After the highest tillering stage, the number of tillers increased slowly, so that the number of tillers stopped and some tillers died, and finally reached a stable value. This period is the end of tillering. Before the arrival of the highest tillering stage, not all tillers can ear at the end of tillering stage, but only effective tillers can ear, and the number and size of tillers determine the yield level per unit area. Therefore, in rice production, it is necessary to rationally use the measures of promoting control, strive for more effective tillers and avoid ineffective tillers. Generally, before the termination of effective tillers, measures should be taken to promote growth, strengthen water and fertilizer management, and promote early growth and rapid development, so as to increase the number of effective tillers. After the termination of effective tillers, measures should be taken to control water and dry land to inhibit the occurrence of ineffective tillers, so that effective tillers can grow sturdily and lay the foundation for the formation of large ears.