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不同种植年限人工苜蓿地土壤N2O排放通量

谢应忠**,徐坤   

  1. (宁夏大学西北土地退化与生态恢复国家重点实验室培育基地/宁夏大学西部生态与生物资源开发联合研究中心, 银川 750021)
  • 出版日期:2015-05-10 发布日期:2015-05-10

Soil N2O flux from artificial alfalfa in different planting years.

XIE Ying-zhong**, XU Kun   

  1. (Breeding Base of State Key Laboratory for Preventing Land Degradation and Ecological Restoration/The United Research Center for Ecology and Exploitation for Biological Resources in Western China, Ningxia University, Yinchuan 750021, China)
  • Online:2015-05-10 Published:2015-05-10

摘要: 以半干旱区不同种植年限人工苜蓿地(1、3、4、5和8年)为研究对象,利用静态箱-气相色谱法研究不同种植年限人工苜蓿地土壤系统、土壤-植被系统的N2O排放通量规律,探讨影响土壤N2O排放通量的主要因素。结果表明:(1)苜蓿种植年限影响苜蓿地土壤-植被系统、土壤系统的N2O排放通量,不同种植年限苜蓿地N2O排放通量规律为:4年>5年>3年>8年>1年。不同种植年限苜蓿地土壤-植被系统、土壤系统的N2O排放通量季节趋势均呈“春夏季高、秋季低”,在5月和8月中旬各出现了N2O排放峰值,表现出N2O的源效应。土壤-植被系统的N2O排放通量大于土壤系统的N2O排放通量。(2)苜蓿地土壤系统N2O排放通量与土壤有机碳、C∶N、铵态氮、全氮、硝态氮含量及0~5 cm土层的土壤温度呈显著正相关,与0~10 cm土壤含水量呈极显著二次负相关。土壤-植被系统N2O排放通量与地上生物量呈极显著正相关。因此,土壤全氮、硝态氮含量、0~10 cm土壤含水量及地上生物量是制约N2O排放通量的关键因子。

关键词: 水稻, 光合色素, CO2, 温度, 光合日变化

Abstract: In order to clarify factors affecting soil N2O fluxes in artificial alfalfa grasslands in the semiarid region of China, the N2O fluxes from soil and soil-vegetation system of artificial alfalfa in different planting years (1, 3, 4, 5, and 8 years old) were measured by using Static box-Gas Chromatography. The results showed that the N2O fluxes from the soil and soil-vegetation system of artificial alfalfa were affected by planting years, and the N2O fluxes of artificial alfalfa were in order of 4 years >5 years >3 years >8 years >1 year. The N2O fluxes from the soil and the soil-vegetation system exhibited a seasonal variation of higher in spring and summer and lower in autumn, with highest values in midMay and midAugust, and being a source of N2O. The N2O fluxes from the soil-vegetation system were higher than that from the soil in different planting years. N2O fluxes from the soil had significant positive correlations with the soil organic carbon, total nitrogen, C∶N ratio, ammonium nitrogen, nitrate nitrogen, soil temperature of soil layer (0-5 cm), and had a significant quadratic negative correlation with soil water content (0-10 cm). N2O fluxes from the soil-vegetation system had a significant positive relationship with aboveground biomass. Soil total nitrogen, nitrate nitrogen, 0-10 cm soil water content and aboveground biomass were considered as the critical factors controlling N2O fluxes of artificial alfalfa.

Key words: temperature, CO2, diurnal variation of photosynthesis, photosynthetic pigment, rice