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应用生态学报 ›› 2011, Vol. 22 ›› Issue (10): 2533-2538.

• 研究论文 • 上一篇    下一篇

CO2浓度升高和施氮条件下小麦根际呼吸对土壤呼吸的贡献

寇太记1,2 **,徐晓峰1,朱建国2,谢祖彬2,郭大勇1,苗艳芳1   

  1. 1河南科技大学农学院, 河南洛阳 471003;2中国科学院南京土壤研究所土壤与农业可持续发展国家重点实验室, 南京 210008
  • 出版日期:2011-10-18 发布日期:2011-10-18

Contribution of wheat rhizosphere respiration to soil respiration under elevated atmospheric CO2 and nitrogen application.

KOU Tai-ji1,2, XU Xiao-feng1, ZHU Jian-guo2, XIE Zu-bin2, GUO Da-yong1, MIAO Yan-fang1   

  1. 1College of Agronomy, Henan University of Science and Technology, Luoyang 471003, Henan, China; 2State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
  • Online:2011-10-18 Published:2011-10-18

摘要: 依托FACE技术平台, 采用稳定13C同位素技术, 通过将小麦(C3作物)种植于长期单作玉米(C4作物)的土壤上, 研究了大气CO2浓度升高和不同氮肥水平对土壤排放CO2的δ13C值及根际呼吸的影响. 结果表明: 种植小麦后土壤排放CO2的δ13C值随作物生长逐渐降低, CO2浓度升高200 μmol·mol-1显著降低了孕穗、抽穗期(施氮量为250 kg·hm-2, HN)与拔节、孕穗期(施氮量为150 kg·hm-2, LN)土壤排放CO2的δ13C值, 显著提高了孕穗、抽穗期的根际呼吸比例. 拔节至成熟期, 根际呼吸占土壤呼吸的比例在高CO2浓度下为24%~48%(HN)和21%~48%(LN), 在正常CO2浓度下为20%~36% (HN)和19%~32%(LN). 不同CO2浓度下土壤排放CO2的δ13C值和根际呼吸对氮肥增加的响应不同, CO2浓度与氮肥用量在拔节期对根际呼吸的交互效应显著.

Abstract: With the support of free-air carbon dioxide enrichment (FACE) system and by using isotope 13C technique, and through planting wheat (Triticum aestivum L., C3 crop) on a soil having been planted with maize (Zea mays L., C4 crop) for many years, this paper studied the effects of elevated atmospheric CO2 and nitrogen application on the δ13C value of soil emitted CO2 and the wheat rhizosphere respiration. With the growth of wheat, the δ13C value of soil emitted CO2 had a gradual decrease. Elevated atmospheric CO2 concentration (200 μmol·mol-1) decreased the δ13C value of emitted CO2 at booting and heading stages significantly when the nitrogen application rate was 250 kg·hm-2 (HN), and at jointing and booting stages significantly when the nitrogen application rate was 150 kg·hm-2 (LN). Nevertheless, the elevated atmospheric CO2 promoted the proportions of wheat rhizosphere respiration to soil respiration at booting and heading stages significantly. From jointing stage to maturing stage, the proportions of wheat rhizosphere respiration to soil respiration were 24%-48% (HN) and 21%-48% (LN) under elevated atmospheric CO2, and 20%-36% (HN) and 19%-32% (LN) under ambient atmospheric CO2. Under both elevated and ambient atmospheric CO2 concentrations, the δ13C value of emitted CO2 and the rhizosphere respiration had different responses to the increased nitrogen application rate, and there was a significant interactive effect of atmospheric CO2 concentration and nitrogen application rate on the wheat rhizosphere respiration at jointing stage.