火烧对杨树人工林土壤有机碳及速效养分的影响

Effect of Planned Fire on Soil Organic Carbon and Available Nutrients of Poplar Plantation

2014年5月4日对江苏省南京市一杨树人工林进行不同火强度点烧试验，5月3日和4日在试验前后分别采取土样，研究火烧后样地土壤有机碳与速效养分含量的即时变异。结果表明：火烧后24h，土壤pH、速效磷和速效钾含量随着土壤深度的增加而减少，却随着火强度的增强而增加；土壤有机碳含量则降低，且随着土壤深度的增加其降幅减小，随着火强度的增加其降幅增大；土壤水解氮含量在高强度火烧下的0~5、5~10cm 土层以及中强度火烧下的0~5cm 土层是降低的，其他土层的水解氮含量是增加的；林火强度与土壤pH、速效磷和速效钾含量呈正相关，而与土壤有机碳含量则呈负相关。

Planned fire was implemented on May 4, 2014 at poplar plantation in Nanjing, Jiangsu province. On May 3 and May 5 of the same year,soil samples were collected in the same place to analyze instant variation of soil organic carbon and available nutrients before and after planned fire.The result showed that 24 hours later of planned fire, soil pH value, available phosphorus and potassium contents decreased with the deepness of soillayer, but increased with the intensity of fire. Soil organic carbon content decreased with deepness of soil layer. Soil hydrolysable nitrogen contentdecreased at 0-5cm and 5-10cm layers under the high-intensity fire, as well as at 0-5cm layer under the moderate-intensity fire. The experimentdemonstrated that fire intensity had positive relation with pH value, available phosphorus and potassium, and negative one with organic carboncontent.