模拟氮沉降对西藏高山栎林地土壤理化性质的影响

摘要

To investigate the effects of different degrees of nitrogen deposition on soil nutrient and soil soluble organic carbon content,a field experiment was conductedin Zhuqudeng Village Bujiu Linzhi County Tibet Quercus forest,fom July 2014 to August 2015 of simulated nitrogen deposition in situ (CK,0,25,50,and 150 kg · hm-2 · a-1).The effects of nitrogen deposition on the organic matter,total N,total P,total K,available N,available P,available K,exchangeable Ca,exchangeable Mg and pH value and soluble (P＜0.05).With the increase of simulated nitrogen deposition,the exchangeable Mg and soluble organic carbon fractions of 0-20 cm soil were inhibited,and the total K content and pH value were increased.The contents of organic matter,total N and available K were increased under low nitrogen treatment and decreased under medium and high nitrogen treatment.All P,available N and available P were increased under LN and HN treatment and decreased in MN treatment.While the exchangeable Ca content was increased after high nitrogen treatment,and then decreased under high nitrogen treatment.%以西藏林芝县布久乡朱曲登村高山栎林地为研究对象,于2014年7月份到2015年8月份原位模拟氮沉降(CK(对照)、LN低氮(25 kg·hm-2·a-1)、MN中氮(50kg· hm-2·a-1)、HN高氮(150 kg·hm-2·a-1),探讨不同程度的氮沉降量对林地土壤养分和土壤可溶性有机碳质量分数的影响.结果表明:不同程度模拟氮沉降对林地有机质、全N、全P、全K、速效N、速效P、速效K、交换性Ca、交换性Mg质量分数和pH值以及可溶性有机碳质量分数都有显著影响(P＜0.05).随着模拟氮沉降增加,0～20 cm林地土壤的交换性Mg和可溶性有机碳质量分数受到抑制;全K质量分数和pH值升高;有机质、全N和速效K质量分数在低氮处理下升高,在中高氮处理下降低;全P、速效N和速效P质量分数则在LN和HN处理下升高,在MN处理下降低;而交换性Ca质量分数在中高氮处理下升高后又在高氮处理下降低.