| 生物炭输入对城郊农业区农田地表反照率及土壤呼吸的影响 |
| 摘要点击 2772 全文点击 812 投稿时间：2016-09-19 修订日期：2016-10-25 |
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| 中文关键词 生物炭 地表反照率 土壤呼吸作用 土壤有机碳组分 土壤呼吸温度敏感性 |
| 英文关键词 biochar surface albedo soil respiration soil organic carbon fractions temperature sensitivity of soil respiration |
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| 中文摘要 |
| 为了探究生物炭输入对地表反照率及土壤呼吸的影响，通过田间小区试验的方法，在不同生物炭用量[0（CK）、0.5 kg·（m2·a）-1（BC0.5）、4.5 kg·（m2·a）-1（BC4.5）]不同地表条件下[种植作物（以+表示）、裸地（以-表示）]，对农田地表反照率、土壤温湿度、土壤CO2排放通量、土壤有机碳组分等指标进行了测定分析.结果表明，在作物生长前期（玉米的苗期至拔节期、小麦苗期至越冬期），BC4.5+、BC0.5+的地表反照率相较CK+处理均有显著下降（P<0.05），小麦季最大降幅分别为23.7%、17.9%，玉米季最大降幅分别为44.5%、44.9%.随叶面积指数增加，地表反照率在3个处理间的差异随之逐渐消失，作物覆盖可有效缓解生物炭输入导致的地表反照率的降低效应；裸地条件下，生物炭处理的地表反照率较对照处理在全部的观测中均有显著下降（P<0.05）；生物炭在输入初期可显著增加土壤CO2释放量（P<0.05），但其增幅随时间逐渐减小，其中BC4.5+较CK+的增幅从276.7%逐步降低至36.1%，BC4.5-较CK-的增幅从163.5%明显减弱至39.8%.生物炭处理较对照处理增加的CO2释放量主要来自生物炭-土壤共存体系中的易分解碳组分，其土壤CO2释放通量与土壤水溶性有机碳含量呈显著相关（P<0.05）；生物炭输入导致的地表反照率变化未对土壤呼吸产生直接的影响，而且生物炭输入可降低土壤呼吸温度敏感性Q10值，表明生物炭具有一定的化学和生物学稳定性. |
| 英文摘要 |
| Biochar application to soils is currently considered as a means of mitigating climate change by sequestering C, which withdraws CO2 from the atmosphere and consequently influences the trend of global climate change. However, only a few studies have been done on surface albedo variations on farmland, it might be true that the application of biochar to soil could induce a radiative forcing by changing the surface albedo. Based on this background, this study aiming at the characterization of seasonal changes in albedo on the farmland both with plants and without plants, and its effect on soil temperature, soil moisture, soil respiration and soil organic carbon fractions. There were 3 major treatments in the experiment with 3 repetition of each major treatment, namely, CK (the control treatment), BC0.5 (biochar applied at 0.5 kg·(m2·a)-1) and BC4.5 (biochar applied at 4.5 kg·(m2·a)-1). Each major treatment contained 2 sub-treatments, which were crop cultivation (+) and non-cultivation (-). The experiment results showed that in the early stage of crop growth (maize seedling stage to jointing stage, wheat seedling stage to winter period), the surface albedo of BC4.5+and BC0.5+significantly decreased compared with CK +(P<0.05). The biggest surface albedo decline rates of BC4.5 + and BC0.5 + in winter wheat season were 23.7%, 17.9% and 44.5%, 44.9% in summer maize season. The leaf area index of each treatment was remarkably correlated with the surface albedo. The shadow produced by the development of crop canopy structure would cover the change of surface color induced by the input of biochar. Under the condition of bare land, the surface albedo of biochar treatment was significantly decreased compared with the control treatment(P<0.05). Compared with the control treatments, the soil CO2 flux of the biochar treatments was significantly increased(P<0.05). With the extension of time, the growth rate of soil CO2 flux of biochar treatment was decreased gradually. The increase from BC4.5 + to CK + was gradually reduced from 276.7% to 36.1%, and the increase of BC4.5-from to CK-was significantly reduced from 163.5% to 39.8%. The increase of soil CO2 flux could be derived from the mineralization of the readily decomposed carbon fractions in the biochar-soil system. The decrease of surface albedo caused by the input of biochar had no direct effect on soil respiration, and the input of biochar could reduce the temperature sensitivity of soil respiration. This result could provide a foundation for the verification of the chemical and biological stability of biochar. |
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