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两种农田土壤不同组分呼吸及其温度敏感性

蔡金云1,2,孙文娟1,丁凡3,胡洵瑀1,2,陈越1,2,黄耀1**   

  1. (1中国科学院植物研究所植被与环境变化国家重点实验室, 北京 100093;  2中国科学院大学, 北京 100049; 3 沈阳农业大学土地与环境学院, 沈阳 110866)
  • 出版日期:2015-09-18 发布日期:2015-09-18

Respiration from density fractions of two cultivated soils and its temperature sensitivity.

CAI Jin-yun1, 2, SUN Wen-juan1, DING Fan3, HU Xun-yu1,2, CHEN Yue1,2, HUANG Yao1   

  1. (1State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; 2University of Chinese Academy of Sciences, Beijing 100049, China; 3College of Land and Environment, Shenyang Agricultural University, Shenyang 110866, China)
  • Online:2015-09-18 Published:2015-09-18

摘要: 为探讨农田土壤不同组分呼吸及其对温度变化的响应,选取山东平邑旱耕土和湖南桃江水稻土为供试土壤,设置4个温度水平(5、15、25、35 ℃),对两种土壤的轻组、重组及全土进行63 d的培养试验.结果表明: 两种土壤全土的呼吸均高于轻组和重组.旱耕土重组的呼吸高于轻组,水稻土重组和轻组的呼吸在5~25 ℃温度水平下无显著差异,但35 ℃下重组高于轻组.在不同温度水平下,旱耕土轻组、重组和全土累积呼吸量分别占其初始碳的0.3%~2.8%、0.4%~3.7%和0.6%~7.0%,水稻土分别占其初始碳的0.4%~3.0%、0.3%~3.8%和0.7%~5.3%.两种土壤全土及轻、重组呼吸的温度敏感性(Q10)均随温度升高和培养时间延长而降低;水稻土重组的Q10高于轻组,旱耕土重组和轻组Q10的差异无明显规律.在5~25 ℃温度水平下,旱耕土全土Q10显著高于水稻土,但在25~35 ℃下低于水稻土.说明平邑旱耕土有机碳矿化强度高于桃江水稻土,且对温度变化的响应总体比水稻土更敏感.

Abstract: To investigate respiration from density fractions of cultivated soils and its temperature sensitivity, laboratory incubations of upland and paddy soils were carried out for a period of 63 days at four temperature levels of 5, 15, 25 and 35 ℃. The upland and paddy soil samples were taken from Pingyi of Shandong Province and Taojiang of Hunan Province, respectively. CO2 efflux from light fraction (LF), heavy fraction (HF) and bulk soil (BS) was measured during the incubation. The  results indicated that bulk soil respiration was significantly higher than either light or heavy fraction respiration regardless of soil type. Respiration from HF was higher than that from LF in the upland soil. In the temperature range from 5 to 25 ℃, light and heavy fraction respiration in the paddy soil did not show significant difference,  while the HF exhibited higher respiration than the LF at 35 ℃. Over the 63day incubation with various temperatures, cumulative respiration from the LF, the HF and the BS accounted for 0.3%-2.8%, 0.4%-3.7% and 0.6%-7.0% of the original LF, HF and BS carbon in the upland soil, and 0.4%-3.0%, 0.3%-3.8% and 0.7%-5.3% of their original carbon in the paddy soil. The temperature sensitivity of the CO2 efflux from the LF, HF and BS, which was expressed as Q10 value, declined as the incubation proceeded. The Q10 values for the HF were generally higher than the values for the LF in the paddy soil, while the difference of Q10 values between the HF and the LF was divergent in the upland soil. In the temperature range from 5 to 25 ℃, the Q10 values for BS respiration were higher in the upland soil than in the paddy soil, but it was opposite in the temperature range from 25 to 35 ℃. Our results using the sitespecific soils suggested that the decomposition of organic carbon in the upland soil was faster and could be more sensitive to temperature change than in the paddy soil.