黄土丘陵区退耕植被细根生物量及其碳氮磷库动态变化

摘要

In order to investigate the trends of biomass and C,N,P storages of fine root under typical revegetation lands in hilly loess region,Robinia pseudoacacia,Caragana korshinskii and abandoned land were selected as study objects.Seasonal dynamic changes of biomass and C,N,P storages of fine root in 0～50 cm soil layer were studied during the growth period (from April to October).The results showed that biomass,C,N,P contents and storages of fine root in three selected lands changed significantly during the growth period.Biomass and C,N,P storages of fine root decreased firstly and then increased during the growth period,while C,N,P contents of fine root showed the opposite tendency;biomass,C,N,P contents and storages of fine root in Robinia pseudoacacia and Caragana korshinskii were significantly higher than that in abandoned land;relevant analysis results showed that correlations between C storages in soil and fine root,N storages in soil and fine root,P storages in soil and fine root,were significantly positive,especially for the correlation between N storages of soil and fine root,which reached an extremely significant level.In conclusion,biomass and C,N,P storages of fine root in the 3 selected vegetation types in Hilly Loess Region changed significantly,and the changes of fine root C,N,P storages significantly increased storages of soil C,N,P,especially storages of soil N.Moreover,the increase was more significant in Robinia pseudoacacia and Caragana korshinskii than that in abandoned land.%为揭示黄土丘陵区不同退耕植被细根季节动态,选取刺槐(Robinia pseudoacacia)、柠条(Caragana korshinskii)以及撂荒3种退耕模式为研究对象,采集0～50 cm土层细根,分析其生物量及C(碳)、N(氮)、P(磷)库的生长期变化.结果显示:刺槐、柠条及撂荒地细根生物量,C,N,P含量及储量在生长期内变化显著(P＜0.05),其中细根生物量与C,N,P储量先减小后增加,而细根C,N,P含量先增加后减少;刺槐与柠条细根生物量,C,N,P含量及储量在生长期内均显著大于撂荒地;相关性分析结果表明,细根C储量与土壤C储量、细根N储量与土壤N储量、细根P储量与土壤P储量均显著正相关,尤其是细根N储量与土壤N储量相关性达到极显著水平.综上,黄土丘陵区刺槐、柠条与撂荒3种退耕模式细根生物量及其碳氮磷库存在显著季节变化,细根碳氮磷库通过季节变化显著提高土壤C,N,P储量尤其是土壤N储量,且刺槐与柠条提高效果优于撂荒草地.