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为掌握华北平原麦田总土壤呼吸、异养呼吸和自养呼吸的日内变化规律及其控制因素,该文于2011年4月—6月开展了土壤呼吸实验,采用根系排除法,测得总土壤呼吸及其2个分量异养呼吸和自养呼吸。结果表明:总土壤呼吸和异养呼吸呈现单峰变化规律,峰值出现在午后14:00附近,自养呼吸无明显日内变化特征。自养呼吸对总土壤呼吸的贡献率在日时间尺度上变化较小,但不同生育期的量值有微小差异。相关关系分析结果表明:异养呼吸与空气温度具有很好相关性,好于与土壤温度的相关性,异养呼吸与空气相对湿度具有较好的负相关性。自养呼吸主要受光合作用速率控制,但在时间上滞后于光合作用速率。因此控制该地区麦田土壤呼吸日内变化的主要因素为空气温度、空气湿度和光合作用速率。
In order to understand the law of day-to-day variation of total soil respiration, heterotrophic respiration and autotrophic respiration in the North China Plain and its controlling factors, a soil respiration experiment was conducted from April to June 2011. Root exudation method was used to determine total soil Breathing and its 2 components heterotrophic and autotrophic breathing. The results showed that the total soil respiration and heterotrophic respiration showed single peak changes, the peak appeared around 14:00 in the afternoon, and there was no obvious intraday variation of autotrophic respiration. The contribution rate of autotrophic respiration to total soil respiration was less on the diurnal time scale but slightly different in different growth stages. Correlation analysis showed that heterotrophic respiration had a good correlation with air temperature, better than soil temperature, heterotrophic respiration with air relative humidity had a good negative correlation. Autotrophic respiration is dominated by photosynthesis rates, but lags behind photosynthesis rates in time. Therefore, the main factors controlling the diurnal variation of soil respiration in wheat field in this area are air temperature, air humidity and photosynthesis rate.