林窗改造对马尾松人工林土壤有效氮的影响  

Influence of forest gaps on the available nitrogen of soil in a Pinus massoniana plantation

作　　者：韦晴雯 马月伟[1] 肖玖金 党香宁 张亚[4] 涂程伟 WEI Qingwen;MA Yuewei;XIAO Jiujin;DANG Xiangning;ZHANG Ya;TU Chengwei(College of Geography and Ecotourism,Southwest Forestry University,Kunming,Yunnan 650224,China;Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province,Chengdu,Sichuan 611130,China;National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River&Rainy,Chengdu,Sichuan 611130,China;Institute of Ecology and Forestry,Sichuan Agricultural University,Chengdu,Sichuan 611130,China)

机构地区：[1]西南林业大学地理与生态旅游学院,云南昆明650224 [2]长江上游林业生态工程四川省重点实验室,四川成都611130 [3]长江上游森林资源保育与生态安全国家林业和草原局重点实验室,四川成都611130 [4]四川农业大学生态林业研究所,四川成都611130

出　　处：《森林与环境学报》2021年第2期124-131,共8页Journal of Forest and Environment

基　　金：国家自然科学基金青年科学基金项目(31400457);四川省科技计划项目(2019YJ0427;2019YJ0416)。

摘　　要：为探寻适宜的林窗改造面积,提升马尾松人工林的土壤肥力与可持续经营能力,以马尾松人工林7个不同面积林窗和林下土壤为研究对象,利用土壤化学分析的方法,研究林窗边缘和林窗中央土壤团聚体(粒径<0.25 mm,0.25~1.00 mm,1.00~2.00 mm,>2.00 mm)有效氮中铵态氮和硝态氮的分布规律。结果表明:总体上,土壤铵态氮的含量高于硝态氮;林窗面积和粒径大小对土壤铵态氮和硝态氮含量有显著影响,并且在大型林窗中表现更明显;林窗面积越大,土壤铵态氮和硝态氮的含量越高,且均高于对照;土壤硝态氮在中型林窗(G4,625 m^(2))中央和大型林窗(G7,1600 m^(2))边缘含量最高,并且更容易在微团聚体中富集;土壤铵态氮含量在各林窗中随粒径的增大而降低。林窗形成后,林窗中央的土壤酸性减弱,大粒径土壤团聚体比例增大。因此,林窗面积及其对土壤团聚体组成结构的改变是造成土壤铵态氮和硝态氮含量改变的关键因素,大型林窗更有利于氮素的积累和土壤肥力的提升。In order to improve the soil fertility and sustainable management of Pinus massoniana plantations,here seven different area gaps and understory soils were studied in a P.massoniana plantation.Soils from these seven areas were chemically analyzed to characterize soil aggregates at the edges and the centers of the gaps(<0.25 mm,0.25-1.00 mm,1.00-2.00 mm,and>2.00 mm)and to determine the distribution trends of nitrogen in the forms of ammonium and nitrate.Generally,more nitrogen was present as ammonium than as nitrate,which was mainly due to the loss of nitrate through leaching.The gap size and soil aggregates both had significant effects on concentrations of ammonium nitrogen and nitrate nitrogen;these differences were more obvious for larger gaps.Larger forest gap areas corresponded to higher concentrations of ammonium nitrogen and nitrate nitrogen,and both were more concentrated in gap areas than in the understory.Nitrate nitrogen concentrations were highest in the center of a medium-sized gap(G4,625 m^(2))and at the edge of a large gap(G7,1600 m^(2)),suggesting that soil nitrate accumulates easily in micro-aggregates.The ammonium nitrogen concentrations of each gap decreased with increasing soil aggregate size.After a canopy gap was formed,the soil acidity in the center of this canopy gap decreased and the proportion of large aggregates increased.Therefore,the size of a gap and its resulting changes to the composition and structure of soil aggregates are key factors that cause changes in the concentrations of ammonium-and nitrate nitrogen.Furthermore,larger forest gaps are more conducive to nitrogen accumulation and soil fertility improvement than smaller gaps.

关 键 词：马尾松 林窗 土壤团聚体 有效氮 铵态氮 硝态氮 

分 类 号：S154.1[农业科学—土壤学]