摘要
以水蚀风蚀交错带农地退耕后不同演替阶段的长芒草(Stipa bungeana)和苜蓿—铁杆蒿(Medicago sativa—Artemisia sacrorum)坡地为对象,分析了退耕坡地土壤酶活性与碳氮矿化及其空间分布特征。结果表明:(1)退耕坡地主要土壤养分含量(有机碳、全氮和全磷)不受坡位(除苜蓿—铁杆蒿坡地的全磷含量外)影响,长芒草坡地有机碳(上、中和下坡位)和全氮含量(中和下坡位)高于苜蓿—铁杆蒿坡地。(2)随坡位的降低,长芒草坡地土壤脲酶和淀粉酶活性显著增加,蔗糖酶和碱性磷酸酶活性无显著差异。而苜蓿—铁杆蒿坡地土壤脲酶和淀粉酶活性无显著差异,蔗糖酶活性显著降低。群落类型对碱性磷酸酶活性的影响与坡位无关,对脲酶和蔗糖酶活性的影响则与坡位有关。(3)土壤有机碳矿化量和矿化速率常数在长芒草坡地显著高于苜蓿—铁杆蒿坡地,且不受坡位影响。两种群落土壤氮素矿化均由硝化作用主导,长芒草坡地土壤氮素矿化量和硝化量随坡位降低而显著增加,而苜蓿—铁杆蒿坡地则相反。(4)随苜蓿—铁杆蒿群落向长芒草群落演替,蔗糖酶和碱性磷酸酶活性空间自相关性增强,脲酶和淀粉酶活性空间自相关性减弱,但仍具有强烈空间自相关性,碳氮矿化指标的空间自相关性增强。上述结果表明:在评估退耕草坡地主要土壤过程及其空间分布时,需要考虑草地群落类型或者群落演替阶段的影响。
We analyzed soil enzyme activities, carbon and nitrogen mineralization and their spatial distribution characteristics at different succession stages(Stipa bungeana and Medicago sativa—Artemisia sacrorum) of abandoned slope lands in wind-water erosion crisscross region. The results showed that:(1) soil organic carbon, total nitrogen and phosphorus contents were not affected by slope position(except for total phosphorus in M. sativa—A. sacrorum slope land), and the contents of soil organic carbon(on upper, middle and lower slope) and total nitrogen(on middle and lower slope) were significantly higher in S. bungeana slope land than those in M. sativa—A. sacrorum slope land.(2) Soil urease and amylase activities increased significantly but no significant difference in sucrase and alkaline phosphatase activities in S. bungeana slope land was observed, and no significant difference in activities of soil urease and amylase was found but soil sucrase enzyme activity decreased significantly in M. sativa—A. sacrorum slope land from upper to lower slope position;the effect of grassland type on soil urease and sucrase enzyme activities was related to slope position, but effect of grassland type soil alkaline phosphatase activity was not related to slope position;(3) soil carbon mineralization and the rate constant of mineralization were significantly higher in S. bungeana slope land than those in M. sativa—A. sacrorum slope land and not affected by slope position. Nitrification dominated the mineralization in both slope lands;soil nitrification and mineralization increased significantly from upper to lower slope in S. bungeana slope land, while the opposite trend was observed in M. sativa—A. sacrorum slope land;(4) with the succession from M. sativa—A. sacrorum to S. bungeana stage, the spatial autocorrelation of soil sucrase and alkaline phosphatase activities and soil carbon and nitrogen mineralization index increased, while spatial autocorrelation of soil urease and amylase activities decreased, but a strong spatial autocorrelation still existed. These results indicate that the effects of grassland types or succession stages should be considered in assessing the soil biogeochemical processes and their spatial distribution of abandoned lands.
作者
孔维波
石芸
姚毓菲
邵明安
魏孝荣
KONG Weibo;SHI Yun;YAO Yufei;SHAO Mingan;WEI Xiaorong(Research Center of Soil and Water Conservation and Ecological Environment,Ministry of Education and Chinese Academy of Sciences,Yangling,Shaanxi 712100,China;Agricultural Technology Center,Dingbian,Shaanxi 718600,China;State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Northwest A&F University,Yangling,Shaanxi 712100,China;University of Chinese Academy of Sciences,Beijing100049,China)
出处
《水土保持研究》
CSCD
北大核心
2019年第2期1-8,16,共9页
Research of Soil and Water Conservation
基金
国家自然科学基金(41622105
41571130082
41571296)
中国科学院前沿科学重点研究计划(QYZDB-SSW-DQC039)
关键词
水蚀风蚀交错带
退耕草坡地
土壤酶活性
碳氮矿化特征
空间自相关性
water-wind erosion crisscross region
abandoned grassland
soil enzyme activity
carbon and nitrogen mineralization
spatial autocorrelation
作者简介
第一作者:孔维波(1994—),男,河南信阳人,硕士研究生,研究方向为土壤生态。E-mail:kwb0207@163.com;通信作者:魏孝荣(1978—),男,陕西武功人,研究员,博士生导师,主要从事生物地球化学循环研究。E-mail:xrwei78@163.com
