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    施用农肥对岩溶溶蚀作用的影响及其生态环境意义

    The effect of farm manure on the dissolution of carbonate rocks and its eco-environmental impact

    • 摘要: 提要:土壤下伏碳酸盐岩溶蚀作用研究对岩溶区成土作用及大气中CO2影响意义重大。施肥改变了土壤的生物地球化学场,进而会影响岩溶区的岩溶动力学过程及碳循环。本文在贵州贵阳碳酸盐岩土壤剖面不同深度,埋设白云石、石灰石试片,进行了野外溶蚀试验,观测了试片溶蚀量、土壤CO2、土壤pH及其他如土壤含水量、土壤矿物与化学成分、土壤水化学成分等影响因素。结果表明: (1)施用农家肥降低了碳酸盐岩的溶蚀速率:石灰石的溶蚀速率降低了10.48%~53.90%,平均25.51%;白云石的溶蚀速率降低了25.0%~65.69%,平均39.45%。同样条件下土壤中石灰石溶蚀量比白云石大。(2)施用农家肥降低了当地的碳酸盐岩成土速度,降低了35.77%~37.27%。 (3)施肥土壤更利于CO2的产生:施肥剖面土壤中CO2浓度比空白剖面CO2浓度高22.52%~198.87%,平均高93.94%;施肥剖面地面CO2通量比空白剖面地面CO2通量高67.64%。(4)施用农家肥减少了土壤对大气CO2的沉降量,在贵州贵阳地区,减少的大气CO2沉降量为25.50%~39.45%;间接地对岩溶水CO2汇的作用产生了抵消作用,在贵州贵阳地区,抵消作用为59.41%~62.73%。

       

      Abstract: Abstract:Research on the effect of farm manure on carbonate rock dissolution is important for pedogenesis of carbonate rocks and source/sink of atmospheric CO2. In this study, dolomite and limestone tablets were buried in different depths of the soil profile in the karst area of Guiyang City, Guizhou Province and, at the same time, the dissolution amounts of tablets, soil CO2, soil pH, soil water content, soil minerals and chemical composition and soil water chemistry were monitored. The results show that manure application decreases the dissolution rate of carbonate rocks, with the dissolution amount of limestone and dolomite decreasing by 11.7%-116.9% (averagely 34.2%) and 25.0%-65.69% (averagely 39.45%), respectively, and the dissolution rate of limestone higher than that of dolomite under the same condition. Using these values, the decrease of the pedogenesis rate of carbonate rocks was estimated to be up to 35.77%-37.23% due to the application of manure. The results also suggest that manure accelerates the generation of soil CO2, and that soil CO2 concentration in the manure profile increases by 22.52%-198.87% (averagely 93.94%) and the CO2 flux increases by 67.64% as compared with the control profile. The data also indicate that manure decreases CO2 uptake by 25.50%-39.45% due to the dissolution of carbonate rocks in Guiyang City, and that it brings indirectly a 59.41%-62.72% counteraction to CO2 uptake in karst water of Guiyang area.

       

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