苏北沿海不同土地利用方式冬季土壤氮矿化速率比较  

Effect of different land uses on soil nitrogen mineralization in a coastal area of northern Jiangsu province,China,in winter

作　　者：陈书信 王国兵[1] 阮宏华[1] 岳臻[1] 徐长柏 徐亚明 

机构地区：[1]南京林业大学,江苏省林业生态工程重点实验室,江苏南京210037 [2]江苏省东台市国有林场,江苏东台224200

出　　处：《南京林业大学学报（自然科学版）》2014年第1期41-46,共6页Journal of Nanjing Forestry University：Natural Sciences Edition

基　　金：国家林业公益性行业科研专项项目(201104006)

摘　　要：土壤氮矿化速率常被作为生态系统中氮有效性和氮损失的指标。不同的土地利用方式可能影响土壤氮素的矿化、运输和植物的吸收与利用，因而造成土壤氮素循环过程的差异。该研究以苏北沿海地区杨树纯林、杨农复合、草地和农田等4种不同土地利用模式为研究对象，采用原位封顶法测定了土壤矿质氮含量的变化，分析了不同土地利用方式土壤氮净矿化速率的特征，以及土壤矿质氮与土壤微生物量氮（SMBN）、土壤水溶性有机氮（WSON）与土壤主要理化性质的相关关系。结果表明：不同土地利用方式土壤净矿化速率从大到小表现为杨树纯林〉杨农复合〉农田〉草地；土壤铵态氮（NH﹢4-N）与N矿化速率、SMBN、全氮有显著的正相关（p〈0．05）；土壤硝态氮（N03一N）与SMBN、WSON、有机碳有极显著的正相关（p〈0．01）；NH。’一N、矿质总氮（TMN）与土壤C／N有极显著的负相关（p〈0．01）。土壤矿质氮含量随土层的加深而显著减少；在〉10～25cm土层，杨树纯林与杨农复合之间的土壤矿质氮含量差异显著（p〈0．05）。研究结果表明土地利用方式的改变将影响土壤氮净矿化速率，森林转变为农田或农林复合结构后．氮在土壤中的储量和循环遗率瞳著降低。In order to study the effect of different land use patterns on soil N mineralization, transportation, absorption and utilization of plant, and which lead to difference of soil nitrogen cycle, we selected four different land use patterns （i.e. poplar plantation, crop-poplar integrated system, meadow and cropland） in a coastal area of northern Jiangsu as the experimental sites. The variations of soil mineral N were determined by close-top incubation method. The soil net N mineralization rate, soil microbial biomass nitrogen （ SMBN）, water-soluble organic nitrogen （WSON） and soil physical and chemical properties were analyzed. The resuhs showed that the net N mineralization rate decreased in order of poplar plantation, crop-poplar integrated system, cropland and meadow. Ammonium N was significantly positive correlated with microbial biomass nitrogen and total nitrogen, the nitrate N was significantly positive correlated with microbial biomass nitrogen, WSON and organic carbon, but the soil C/N was significantly negative correlated with ammonium N and total mineral nitrogen. The soil mineral nitrogen decreased with soil depth increasing. In 25-40 cm soil layers, the soil miner- al nitrogen had significant difference with poplar plantation and crop-poplar integrated system. The results indicated that different land use patterns would affect soil net N mineralization rate, and the conversion of forest into cropland or crop- forest system could also alter the cycle rate of nitrogen significantly.

关 键 词：矿质氮 微生物量氮 水溶性氮 土地利用方式 苏北沿海地区 

分 类 号：S718[农业科学—林学]