不同产地油菜秸秆制备的生物质炭对红壤酸度和土壤pH缓冲容量的影响

Effects of Biochars of Canola Straws from Different Soils on Red Soil Acidity and pH Buffering Capacity

【目的】明确不同产地油菜秸秆制备的生物质炭对红壤酸度的改良和土壤pH缓冲容量的提升效果。【方法】将不同添加量的油菜秸秆炭分别与两种酸性红壤混合,然后进行室内培养试验,测定培养实验前后土壤pH、pH缓冲容量、土壤交换性盐基离子和土壤交换性酸。【结果】添加油菜秸秆炭显著提高了土壤的pH、pH缓冲容量、交换性盐基离子含量,显著降低了土壤交换性酸含量。说明添加油菜秸秆炭不仅可以改良红壤酸度,还能提高红壤的抗酸化能力,因而可以减缓土壤的复酸化。生长在碱性土壤上的油菜秸秆制备的生物质炭对红壤酸度的改良效果和对土壤pH缓冲容量的提升效果均优于生长在酸性土壤上的油菜秸秆制备的生物质炭,在5%添加水平下,前者使湖南红壤pH相比对照提高37.4%,后者使该土壤的p H提高22.4%;相应地,2种生物质炭分别使该土壤的pH缓冲容量分别提高41.4%和37.3%。2种油菜秸秆炭对红壤pH和pH缓冲容量的提升效果与其碱含量和表面官能团多少相一致。【结论】碱性土壤上生长的油菜秸秆制备的生物质炭对红壤具有更好的改良效果。

[Objective] In order to examine the amelioration effects of the biochars generated from canola straws planted in different soils, the acidity and pH buffering capacity(pHBC) were determined in two red soils. [Method] Red soils mixed with different rates of canola straw biochars and then incubated for 30 days. Soil pH, pHBC, exchangeable base cations, and exchangeable acidity before and after incubation experiment were tested. [Result] The addition of canola straw biochars significantly increased soil pH, pHBC, exchangeable base cations and significantly reduced the content of soil exchangeable acidity, which suggested that canola straw biochar cannot only ameliorate soil acidity, but also increase the resistance of red soils to acidification and inhibit soil re-acidification. The biochar generated from canola straw planted in alkaline soil showed a greater amelioration effect on soil acidity and better improvement on soil pHBC than that planted in acidic soil, which was consistent with the fact that the alkalinity and number of functional groups of the biochar generated from canola straw planted in alkaline soil were greater than that in acidic soil. At addition rate of 5%, the pH values of soils in Hunan and Huaian were increased by 37.4% and 22.4%.Correspondingly, the pHBCs of them were increased by 41.4% and 37.3%. [Conclusion] The biochar generated from canola straw planted in alkaline soil was a better amendment for acidic red soils than that planted in acidic soil.