连续多年种植蔬菜的老菜区,土壤环境恶比,会造成蔬菜病虫害日趋严重,大片死亡。土壤恶化的表现一是线虫、病菌、残留毒素增多:蔬菜连作造成病菌及毒素在土壤中积累,根系因受害而腐烂,甚至全株死亡。同时,线虫危害也加重;二是土壤板结,有机质匮乏:由干大量施用二铵、复合肥等化肥,忽视有机肥的施用,造成土壤板结,透气性降低,需 For many years planting vegetables in the old vegetable area, the soil environment worse than the ratio will cause vegetable pest and disease more serious, large-scale death. First, the performance of soil deterioration nematodes, germs, residual toxins increased: continuous crop vegetables and toxins caused by the accumulation of bacteria in the soil, root rot due to damage, and even the whole plant died. At the same time, nematodes also aggravate the harm; the second is the soil compaction, lack of organic matter: a large number of dry application of diammonium, fertilizer and other chemical fertilizers, ignoring the application of organic fertilizer, resulting in soil compaction, reduce air permeability, required