不同耕作措施下土壤有机碳含量的模拟研究

doi:10.11849/zrzyxb.2011.09.010

摘要/Abstract

摘要： 应用甘肃农业大学定西旱农综合试验站的2001—2008年长期定位实验数据对DNDC模型进行验证,4个处理的相对误差均小于±10%,均方根误差在6.41%~12.96%之间,模型模拟值与实测值表现出较强的一致性,证明DNDC在模拟预测该地区土壤有机碳储量上是可行的。对定位试验的4个处理的长期(100 a)模拟表明,免耕覆盖秸秆(NTS)和传统耕作+秸秆还田(TS)能够较大幅度地提高土壤有机碳含量,其土壤有机碳含量分别较初始值增加了74.76%和71.13%,免耕(NT)处理下土壤有机碳含量增加了39.18%,趋势较为平缓。而传统耕作不覆盖(T)处理下土壤有机碳呈下降趋势,较初始值减少了35.54%。土壤有机碳含量对土壤性状以及耕作管理措施变化的响应模拟研究表明,秸秆还田和施用有机肥是最有效的提高土壤有机碳含量的耕作措施,而土壤性状,尤其是初始有机碳含量是影响土壤有机碳变化的最主要敏感因素。DNDC模型模拟得出,实行秸秆覆盖或还田及免耕等耕作措施将有效持续地增加土壤有机碳含量,提高土壤的可持续利用能力。

关键词: 土壤, 土壤有机碳, DNDC模型, 耕作方式

Abstract: During the past century decreases in soil organic carbon content and soil fertility have been widely observed in many agricultural regions. Maintaining farmland soil organic carbon content is essential for the sustainable development of Chinese agriculture. Dingxi County with typical inland agro-ecosystems was selected as a geographic domain for a modeling study reported in this paper. A process-based biogeochemical model DNDC (Denitrification Decomposition) was linked to a Geographic Information System (GIS) database holding spatially differentiated information of climate, soil, vegetation and management for Dingxi to quantify impacts of farming management alternatives on C sequestration in farmland of this region. DNDC was first validated against a long-term SOC dataset observed in Dingxi County in Gansu Province. Based on the feasibility of DNDC model in the hilly areas of the Loess Plateau, which was validated using database of a long-term experiments on different tillage practices in Dingxi experimental station of Gansu Agricultural University, continuous SOC changes and carbon cycle features under different tillage patterns were studied by using DNDC model. The results derived from four tested simulations for long-term periods (100 years) showed that SOC increased greatly in the treatments of no-tillage with straw cover and conventional tillage with straw incorporated, by 74.76% and 71.13% respectively; but in-creased gently in the treatments of no tillage with no strew cover by 39.18%. Sensitivity tests indicated that soil property especially initial SOC content was the major source of uncertainty generated from up scale modeling. The simulation of soil organic carbon content under different tillage modes showed that SOC can be increased depending on higher manure, higher proportions of straw returning. According to the simulating results of DNDC model on the hilly areas of the Loess Plateau, straw addition, fertilizer application or no-tillage will be an effective measure for maintaining improved soil fertility, increasing the amount of storage of the organic carbon pools in soil.

Key words: soil, soil organic carbon, DNDC model, tillage

中图分类号:

S181

马玉芳, 蔡立群, 张仁陟. 不同耕作措施下土壤有机碳含量的模拟研究[J]. 自然资源学报, 2011, 26(9): 1546-1554.

MA Yu-fang, CAI Li-qun, ZHANG Ren-zhi. Study on the Simulation of Soil Organic Carbon Content under Different Tillage Modes[J]. JOURNAL OF NATURAL RESOURCES, 2011, 26(9): 1546-1554.

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