火烧对草原土壤养分状况的影响

The Effects of Fire on the Nutriem States of Steppe Soil

根据野外的实地调查资料，同时参阅国内外的有关文献，就火烧对草原土壤养分状况的影响进行了初步探讨，结果表明：火烧会减少表层土壤的有机质含量，其中以连年重复火烧最为明显，而火烧当年表层土壤的有机质含量减少较少。根据草原植物的自然分解速率，表层土壤有机质含量的恢复约需２～３年，另外，土壤中、下层中的有机质含量在火烧后略有增加．在矿质养分中，火烧会增加土壤中交换性钙的含量，而交换性镁和速效磷的含量则无规律性的变化，因此，本项工作对探讨火烧对草原土壤的影响效应，以及在草原管理和草场改良等生产活动中制定合理的用火措施都有一定的参考价值和指导意义。

ccording to the data of field survey ,and refering to the references on this subject,this arti-cle preliminarily discussed the effects of fire on the nutrient states of steppe soil. The resultsshowed,firing can reduce the content of organic matter of surface layer,among firing treatments,repeat firing year by year had the most obvious effect,but the content in the same year after firingreduced a little. According to the natural decomposition ratio of died steppe plants ,the recoveringof the content of organic matter of surface soil needs about 2～3 years. Otherwise,the content oforganic matter of mid-layer and deep-layer increased slightly. For the mineral elements,firing canincrease the content of exchangeable calcium in the soil,but the content of exchangeable magne-sium and rapid available phosphorus had no regular changes.