What are the influencing factors of rational close planting of sorghum?

(1) Variety characteristics. Botanical characters and biological characteristics of varieties are one of the main basis for determining reasonable density. The general principle is that varieties or hybrids with short stems, narrow leaves, few capsules and tough stems are suitable for close planting. Varieties with tall plants, thin stems and loose leaves are prone to lodging in the field, resulting in canopy, so they should be planted thinly, early-maturing varieties can be planted densely, and late-maturing varieties can be planted thinly. High-yield varieties with poor adaptability, like fertilizer and water should be planted thinly, and varieties with wide adaptability and strong stress resistance should be planted densely. 2) Fertile soil, fertile soil, sufficient water and fertilizer, and high planting density; However, in the plots with poor soil and low fertilization level, the planting density is smaller. Sandy soil or sandy loam has poor water and fertilizer conservation ability, small seedlings in the early stage, no strength in the later stage, and high density is not good for growth; Clay land has high nutrients and water content, strong fertilizer and water retention, and is suitable for close planting. The land is flat, thick and fertile, and it is suitable for close planting. The mountainous area has thin soil layer and low fertility, which is suitable for sparse planting. Pay attention to the thick soil layer, but it has high water content and poor air permeability, so it should be planted thin. (3) Planting method. Reasonable arrangement of plant distribution and plant spacing in the field can not only make full use of land and sunshine, but also facilitate field management operations, such as reducing base and increasing rows, reducing plant spacing, and planting in large ridges and double rows.