添加氮素对沙质草地土壤氮素有效性的影响  

Effects of nitrogen addition on soil nitrogen availability in sandy grassland

作　　者：于占源[1] 曾德慧[1] 艾桂艳[1] 姜凤岐[1] 

机构地区：[1]中国科学院沈阳应用生态研究所大青沟沙地生态实验验站,沈阳110016

出　　处：《生态学杂志》2007年第11期1894-1897,共4页Chinese Journal of Ecology

基　　金：国家重点基础研究发展计划(2007CB106803);辽宁省陆地生态过程与区域生态安全重点实验室开放基金项目(06ZDS212SS);中国科学院知识创新工程青年人才领域前沿项目(07SBS115S3)资助

摘　　要：通过氮素添加(20g.m-2.a-1)试验,研究了科尔沁沙地东南部沙质草地生态系统土壤氮矿化及有效氮的季节变化。对2006年生长季的观测发现,添加氮素显著提高了沙质草地生长季土壤铵态氮、硝态氮、矿质氮的含量以及9月1日至10月15日的净氮矿化速率与硝化速率;添加氮素导致土壤有效氮的季节变异增大,净氮矿化(1.29～11.60mg.kg-1.30d-1)与硝化(-4.15～11.20mg.kg-1.30d-1)速率随时间呈上升趋势,铵态氮含量逐渐降低,硝态氮与矿质氮(6.49～20.66mg.kg-1)含量的变化呈"V"型,最小值出现在生物量生长高峰期的7月中旬。该沙质草地土壤氮的有效性较低,施氮肥可明显提高土壤供氮能力。By the method of top-closed core insertion, a field experiment of nitrogen addition （20 g · m-^2 · ^-1 ） was conducted in Daqinggou Ecological Station in 2006 to investigate the seasonal dynamics of soil nitrogen mineralization and available nitrogen in a sandy grassland of southeastern Keerqin sandy land. The results showed that nitrogen addition increased significantly the contents of soil ammonium nitrogen, nitrate nitrogen, and inorganic nitrogen from June 1 to October 15, and the rates of net nitrogen mineralization and nitrification from September 1 to October 15. The seasonal fluctuation of soil available nitrogen was increased, with the ranges of 1.29-11.60 mg · kg^-1 · 30 d^-1 in net nitrogen mineralization rate, -4. 15-11. 20 mg · kg^-1 · 30 d^-1 in ni- trification rate, and 6.49-20.66 mg · kg^-1 in inorganic nitrogen content. The net nitrogen mineralization and nitrification rates increased but ammonium nitrogen content decreased with time, while nitrate nitrogen and inorganic nitrogen contents varied in ＂V＂ shape, with the lowest contents observed on July 15, the peak time of biomass production. It was concluded that the soil nitrogen availability in test sandy grassland was lower, and nitrogen addition could significantly increase the capability of its soil nitrogen supply.

关 键 词：沙质草地 科尔沁沙地 氮矿化 顶盖埋管法 矿质氯 

分 类 号：S812.2[农业科学—草业科学]