作 者 ：胡宗达,刘世荣,史作民,刘兴良,何飞
期 刊 ：林业科学研究 2012年 25卷 3期 页码：261-268
Keywords:Quercus aquifolioides forest, altitudinal gradient, soil nitrogen, soil microbial biomass,
摘 要 ：川滇高山栎林是川西亚高山地区地带性的灌丛群落,具有重要的生态水文功能。本文在川西巴郎山东南坡沿海拔梯度(2 551、3 091、3 549 m),研究了川滇高山栎林表土层(0~15 cm)和亚表土层(15~30 cm)的土壤微生物量碳氮、有机碳(TOC)和氮素含量的分布特征及其相互关系。结果表明:海拔3 549 m和3 091 m处两土层土壤TOC及其储量、总氮(TN)、水解氮含量无显著性差异,其含量均显著高于海拔2 551 m处;海拔3 091 m处表土层与亚表土层的铵态氮(NH4+-N)含量显著比3 549 m的高,但与2 551 m处的NH4+-N含量差异不显著;在3个海拔梯度,土壤层硝态氮(NO3--N)含量差异不显著;3个海拔梯度的总无机氮含量在表土层差异不显著,而亚表土层无机氮含量在海拔3 091 m和3 549 m处差异显著;表土层微生物量碳含量变化与有机碳含量变化特征一致,亚表土层土壤微生物量碳含量在3个海拔梯度差异显著;表土层土壤微生物量氮含量在海拔3 091 m处最高,但3个海拔梯度的差异不显著,亚表土层土壤微生物量氮含量随海拔梯度降低而减少,但差异不显著。相关分析表明:水解氮、TOC、TN和土壤微生物量氮含量之间极显著相关(P<0.01);土壤微生物量碳与水解氮、TOC和TN显著正相关(P<0.05);pH值与水解氮、TOC和土壤微生物量氮显著正相关;NH4+-N与pH值极显著负相关。
Abstract:Soil microbial biomass and nitrogen play important roles in forest ecosystem as the driving forces for the nutrient transformation. Therefore, the soil microbial biomass and nitrogen are used as important indexes to evaluate the effects of management on quality and function of soil ecosystem in the Quercus aquifolioides forest. However, few studies have been carried out on the spatial variability of soil nitrogen and microbial biomass in the same community in different attitudes. In the current study, the Q.aquifolioides forest in the southeast slope of Balang Mountain in West Sichuan was studied. The experimental design included three 50 m×80 m plots of Q. aquifolioides forest at the attitudes of 3 549 m, 3 091 m and 2 551 m respectively. This vertical variations and correlations of total organic carbon (TOC), nitrogen and soil microbial biomass in the topsoil (0-15 cm) and subsoil (15-30 cm) were studied. The results showed that there was no significant difference in the contents of TOC, TOC stocks, total nitrogen (TN) and hydrolysable nitrogen in two layers (0-15 cm, 15-30 cm) at 3 549m and 3 091 m, but their contents were significantly higher than those in the Q. aquifolioides forest at 2 551 m, there is significant difference in NH4+-N in different soil layers at 3 549 m and 3 091 m compared with that at 2 551 m, and the NH4+-N content at 3 091 m was significantly higher than those in two layers at 3 549 m; the NO3--N content was not significant in two layers in three attitudes; there are no significant differences in soil total inorganic nitrogen content in the topsoil layers among the three attitudes, but with significant difference in the subsoil at 3 549 m and 3 091 m; the variation trend of soil microbial biomass carbon content in the topsoil layers was similar to that of TOC, but there were significant differences in soil microbial biomass carbon content in the subsoil at different attitudes; the soil microbial biomass nitrogen content in the topsoil was the highest at 3 091 m and there were no differences in the three attitudes, but the content of soil microbial biomass nitrogen in the subsoil reduced with the reduce of the attitude, and the differences were not up to significant level. The Pearson correlation analysis showed that the soil microbial biomass nitrogen, hydrolysable nitrogen, TOC and TN were all very significantly positively correlated. The soil microbial biomass carbon was significantly correlated with the hydrolysable nitrogen, TOC and TN. The pH was significantly correlated with the hydrolysable nitrogen, TOC and soil microbial biomass nitrogen. NH4+-N was negatively correlated with pH.