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在紫色土丘陵区连续6年进行秸秆覆盖试验的“旱三熟”农田系统中,于2012年12月—2013年4月小麦生长季内对土壤呼吸进行测定,并对小麦根系生物量、土壤温度、土壤水分和土壤有机碳含量等指标进行监测,以分析土壤呼吸动态变化的影响因素.结果表明,秸秆覆盖措施显著提高了土壤呼吸速率,秸秆覆盖(S)和秸秆覆盖+腐熟剂(SD)处理分别比对照(CK)增加了45.0%和29.4%.曲线估计表明,土壤呼吸作用与根系生物量呈显著线性关系,通过建立二者的线性回归方程,采用生物量外推法估算小麦根系呼吸作用占土壤呼吸作用的比例,在分蘖期(2012年12月)、拔节期(2013年1月)、抽穗期(2012年3月)和灌浆期(2013年4月),根系呼吸分别占土壤呼吸的28.2%、44.0%、56.9%、56.2%,平均贡献为46.3%,并呈先增加再降低的趋势,在抽穗期达到最大,与根系生物量的变化同步.按照不同处理建立根系生物量与土壤呼吸间的线性回归方程,经计算得出CK、S和SD 3个处理中,根系呼吸作用占土壤呼吸作用的比例分别为42.9%、43.8%和43.7%,秸秆覆盖对根系呼吸作用比例无显著影响.
Soil respiration was measured during the wheat growing season from December 2012 to April 2013 in a “three-year-old” farmland system with straw mulching test conducted in the hilly area of purple soil for 6 consecutive years. The effects of wheat root biomass , Soil temperature, soil moisture and soil organic carbon content were measured to analyze the influencing factors of soil respiration dynamic changes.The results showed that straw mulching significantly increased soil respiration rate, straw mulching (S) and straw mulching + straw mulching (SD) increased by 45.0% and 29.4%, respectively, compared with the control (CK) .Calculation estimates showed that there was a significant linear relationship between soil respiration and root biomass. By establishing a linear regression equation between them, biomass extrapolation Root respiration rate of wheat as a proportion of soil respiration, root respiration at the tillering stage (December 2012), jointing stage (January 2013), heading stage (March 2012) and filling stage (April 2013) Accounting for 28.2%, 44.0%, 56.9% and 56.2% of the total soil respiration, respectively, with an average contribution of 46.3% and increasing first and then decreasing, reaching the maximum at heading stage and synchronizing with changes of root biomass. Root biomass and soil According to the linear regression equation of soil respiration, the root respiration rate accounted for 42.9%, 43.8% and 43.7% of CK, S and SD treatments, respectively. The proportion of straw respiration to root respiration Significantly affected.