营林用火对针叶林地土壤化学性质的影响研究

摘要

营林用火对维护林地土壤生态平衡和林地养分管理有重要指导意义。在针叶林地每两个月燃烧一次，每次用火时间30 min、60 min、90 min、120 min和CK 5个处理，3次重复。1 a后统一采样，采样深度设置0～5 cm、5～10 cm、10～20 cm 3个层次。结果表明：用火1年后，①土壤pH值变化不大，土壤有机质含量、土壤速效氮、土壤速效磷和土壤速效钾均有不同程度的增加。最大增幅分别为：燃烧30 min，5～10 cm土壤有机质含量增加50.2%，0～5 cm土壤速效氮增加34.9%，5～10 cm速效磷增加53.3%，10～20 cm土壤速效钾增加57.2%。②用火1 a后，燃烧60 min，0～5 cm有机质含量加39.4%，10～20 cm土壤速效氮增加20.6%，5～10 cm土壤速效磷增加38.2%，0～5 cm土壤速效钾增加51.5%。③燃烧90 min，0～5 cm土壤有机质含量增加38.5%，土壤速效氮变化不大，5～10 cm土壤速效磷增加38.4%，5～10 cm土壤速效钾增加51.7%。④燃烧120 min，10～20 cm土壤有机质含量增加38.5%，0～5 cm有效氮增加23.2%，5～10 cm的土壤速效磷增加42.9%，5～10 cm速效钾增加51.7%。土壤化学成分与用火时间没有关系，与燃烧时间长度关系很大。%Prescribed burning has important guiding significance for maintain the ecological balance and nutrient management of forest land. There was once prescribed burning every two months in plot. The burning time was set to 30 min, 60 min, 90 min, 120 min and CK 5 treatments, repeated three times each burning. And a year later, unified sampling. The sampling depth is set to 0~5 cm, 5~10 cm, 10~20 cm three levels. A year later, the results were as follows: (1) the soil pH did not change significantly, but organic matter, available N, available P and available K in soil increase to different levels. In processing of 30 min combustion, organic matter in depth between 5 cm to 10 cm increases 50.2%, available N in depth between 0 cm to 5 cm increases 34.9%, available P in depth between 5 cm to 10 cm increases 53.3% and available K in depth between 10 cm to 20 cm 57.2%. (2) A year later, with fire burn 60 min, the content of organic matter increased 39.4%between 0 cm to 5 cm, the content of soil available N increased 20.6%between 10 cm to 20 cm, the content of soil available P increased 38.2% between 5 cm to 10 cm, the content of soil available K increased 51.5% between 0 cm to 5 cm. (3) In processing of 90 min combustion, the content of organic matter increased 38.5% between 0 cm to 5 cm, and there is little change of soil available nitrogen, the content of soil available P increased 38.4% between 5 cm to 10 cm, the content of rapidly-available K increased 51.7%between 5 cm to 10 cm. (4) By burnning 120 min, the content of organic matter content increased 38.5% between 10 cm to 20 cm, the content of soil available N increased 23.2% between 0 cm to 5 cm, the content of soil available P increased 42.9% between 5 cm to 10 cm, the content of rapidly-available K increased 51.7%between 5 cm to 10 cm. Soil chemical composition has nothing to do with fire time, but has a relationship with the length of burning time.