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水蚀风蚀交错带不同退耕模式对土壤有机碳及全氮的影响

刘学彤1,2,魏艳春1,2,杨宪龙1,2,郝明德1,3*,魏孝荣1,2   

  1. (1西北农林科技大学资源环境学院, 陕西杨凌 712100; 2西北农林科技大学黄土高原土壤侵蚀与旱地农业国家重点实验室, 陕西杨凌 712100; 3西北农林科技大学水土保持研究所, 陕西杨凌 712100)
  • 出版日期:2016-01-18 发布日期:2016-01-18

Effects of different re-vegetation patterns on soil organic carbon and total nitrogen in the windwater erosion crisscross region,  China.

LIU Xue-tong1,2, WEI Yan-chun1,2, YANG Xian-long1,2, HAO Ming-de1,3*, WEI Xiao-rong1,2   

  1. (1College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, Shaanxi, China; 2State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, Shaanxi, China; 3Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China).
  • Online:2016-01-18 Published:2016-01-18

摘要: 以黄土高原水蚀风蚀交错带不同退耕模式为研究对象,分析了不同模式退耕地(农地退耕后自然恢复草地、退耕后种植苜蓿和退耕后种植柠条)和相邻未退耕农地土壤有机碳和全氮含量的差异以及它们随退耕年限的动态变化.结果表明: 不同退耕模式均能提高0~10 cm土层土壤有机碳和全氮含量,但效果受退耕年限的影响.与相邻未退耕农地相比,退耕后自然恢复草地在演替10年时0~10 cm土层土壤有机碳和全氮含量不受影响,而在演替20年时均显著增加;退耕种植苜蓿后0~10 cm土层土壤有机碳和全氮含量分别增加51.6%~82.9%和43.4%~67.0%,其储量的增加速率分别为0.17~0.46和0.015~0.043 t·hm-2·a-1,但不同退耕年限间差异不显著;退耕后种植柠条前20年土壤有机碳和全氮含量增加较多,退耕40年时增加量有所降低.农田退耕后种植柠条40年、苜蓿20年,其固存碳、氮的能力优于退耕后自然恢复草地,然而由于受土壤水分条件的限制和自身高耗水的特性,这2种退耕模式可能不具备长期的增碳、增氮能力.

Abstract: This study was conducted to analyze the responses of soil organic carbon (SOC) and total nitrogen (TN) to three typical revegetation patterns, i.e., grassland, alfalfa land and peashrub land on the Loess Plateau of China, and also to assess the dynamics of SOC and TN with revegetation age. The results showed that all the three revegetation practices increased the concentrations of SOC and TN in the 0-10 cm soil layer, but their effects differed with re-vegetation age. Compared with adjacent croplands, the concentrations of SOC and TN in the 0-10 cm soil layer in grassland did not change within 10 years of succession, but increased after 20 years of succession. In alfalfa land, the concentrations of SOC and TN increased by 51.6%-82.9% and 43.4%-67.0% in the 0-10 cm soil layer, with the increasing rates of stocks of SOC and TN being 0.17-0.46 and 0.015-0.043 t·hm-2·a-1, respectively. However, SOC and TN were not affected by re-vegetation age in alfalfa land. The increases of concentrations of SOC and TN remained high in the first 20 years after conversion of cropland to peashrub land, but decreased after 40 years of conversion. In conclusion, the conversion of croplands to peashrub or alfalfa land could be better in contributing to high stocks of SOC and TN than natural succession of grassland. However, their positive effects on the enrichment of SOC and TN may not be sustainable due to the scarcity of soil moisture and high water consumption of these two re-vegetation plants.