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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)、0.5kg·(m~2·a)~(-1)(BC0.5)、4.5 kg·(m~2·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CO_2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CO_2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CO_2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CO_2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.
In order to explore the effects of biochar input on surface albedo and soil respiration, the effects of different biochar treatments [0 (CK), 0.5 kg · (m ~ 2 · a) -1 (BC0 4.5 kg · m -2 · a -1 BC 4.5]. Compared with the surface condition of cultivated land (indicated by +, bare land (-)) under different surface conditions Albedo, soil temperature and humidity, soil CO2 flux and soil organic carbon fraction were measured and analyzed.The results showed that during the early crop growth stage (corn seedling stage to jointing stage, wheat seedling stage to wintering stage), BC4 (P <0.05). The maximum decrease of wheat season was 23.7% and 17.9% respectively, and the maximum drop of corn season was 44.5% and 44.9% respectively. With the increase of leaf area index, the difference of surface albedo in three treatments gradually disappeared. Crop cover can effectively reduce the effect of surface albedo reduction caused by biochar input. Under bare land conditions, the surface albedo of biochar treatment Compared with the control, all the treatments showed a significant decrease (P <0.05). In the initial stage of biosynthesis, biochar could significantly increase the CO 2 release (P <0.05), but the increase The time of BC4.5 + CK + decreased gradually from 276.7% to 36.1%, and the increase of BC4.5- over CK- was significantly reduced from 163.5% to 39.8%. Compared with the control, the increase of CO_2 The released amount was mainly from the components of biodegradable carbon in biochar-soil coexistence system, and the soil CO 2 fluxes were significantly correlated with soil water-soluble organic carbon content (P <0.05). The change of surface albedo caused by biochar input was not significant Which has a direct impact on soil respiration. Moreover, biochar input can reduce Q10 values of soil respiration temperature sensitivity, indicating that biochar has certain chemical and biological stability.