不同火烧时间对杉木人工林土壤性质的影响

分析不同强度火烧对福建将乐林场杉木人工林土壤理化性质的影响，对林火管理和火后植被恢复提供参考依据。在福建将乐林场选择3块人工杉木林标准样地，每间隔60 d实施一次计划烧除，每次燃烧试验共设置10、30 min与60 min和对照（CK）4个处理，试验结束后统一进行土样采集和室内分析。火烧10 min和30 min钟后1 d杉木林土壤的容重降低，之后逐渐增加；火烧60 min的土壤容重呈现出先增大后降低再增大的变化趋势，火烧60 d和120 d时的土壤容重均低于火烧前。与火烧前相比，火烧10、30 min和60 min后土壤总孔隙度和非毛管孔隙度先增加后降低，且120 d后均降低到火烧前水平以下。火烧10、30 min和60 min后土壤pH值和碱解氮含量均持续增加。火烧10 min和60 min后的土壤有机碳呈持续增加趋势；火烧30 min后土壤有机碳含量呈先增加后减少再增加的变化趋势，但均高于火烧前水平。火烧10、30 min和60 min后1 d土壤全氮含量均增加，之后开始降低。火烧10 min后土壤有效磷含量持续递增；火烧30 min和60 min的土壤有效磷含量先降低后增加的趋势，但火烧后120 d仍未恢复到火烧前水平。火烧10 min后1 d的土壤速效钾含量升高，之后开始下降，120 d后下降到火烧前水平以下；火烧30 min后60 d天的土壤速效钾含量增加，之后逐渐降低，到120 d几乎降低到火烧前水平；火烧60 min的杉木林土壤速效钾含量持续增加。不超过60 min的低强度计划火烧有利于改善土壤养分。

The Effects of Burning with Different Intensities on Soil Property in Chinese Fir Plantations

The effects of burning with different intensities on soil physicochemical properties in Chinese fir plantations at Jiangle Forest Farm,Fujian,were investigated to provide references for forest fire management and post-fire vegetation restoration.In 3 standard sampling plots,prescribed burning was conducted for every two months with four treatments: 10 min,30 min and 60 min,and control．Soil sample collection and laboratory analysis were carried out after the final burning test．The results showed that soil bulk density decreased firstly and then increased after the burning lasted 10 and 30 min.The soil bulk density increased firstly and then decreased after 60 mins burning,but the values were lower than the burning before in 60 and 120 days.The total and capillary porosity increased firstly and then decreased after burning,and the values in 120 days were lower than the control.The soil pH value and alkali-hydrolyzable nitrogen increased constantly after three burning durations.The soil organic carbon content increased constantly after the burning lasting 10 min and 60 min.The carbon content increased firstly and then decreased and increased finally,but the value was higher than before burning.The total nitrogen content increased in 1 day after the burning lasted 10,30 and 60 min,and then decreased.The soil available phosphorus content increased continuously after 10 mins burning,while the content increased firstly and then decreased after the burning lasted 30 min and 60 min.The soil available potassium content in 1 day increased at first,and then quickly declined after 60 mins burning,and the value in 120 days was lower than before burning.The content increased in 60 days and then decreased gradually after 30 mins burning,and the value in 120 days almost reduced to the level before the burning.The potassium content increased continuously after 60 mins burning.It was suggested to conduct prescribed burning with low intensity within 60 min to improve soil nutrients.