一、避免重茬由于根对无机离子的吸收有选择性 ,头茬蔬菜从土壤中吸收了其生长发育所需无机离子 ,土壤中这些无机离子大量减少 ,重茬种植土壤中这些无机离子不能满足重茬菜生长发育需要 ,结果导致重茬蔬菜生长发育受到影响。另外重茬种植病虫害严重 ,特别是土壤传播的病害。如 First, to avoid heavy crop As the root of the selective absorption of inorganic ions, the first crop of vegetables from the soil to absorb its growth and development of inorganic ions, soil a large number of these inorganic ions, heavy crop planting soil in the inorganic ions can not meet the heavy crop Growth and development needs, resulting in crop stubble growth and development are affected. In addition crop diseases and insect pests planted serious, especially soil-borne diseases. Such as