施用无害化污泥影响土壤碳库组分和碳库管理指数的演变

以小麦-玉米轮作体系下的沙质潮土为研究对象,选用经无害化处理后符合国家标准且在推荐量范围内的商业化污泥产品,通过2013~2015年田间定位试验,研究无害化污泥施用对沙质潮土土壤碳库组分和碳库管理指数的影响,为无害化污泥资源化利用提供理论和技术依据.结果表明,与不施无害化污泥处理(CK)相比,土壤总有机碳(TOC)、微生物量碳(SMBC)、易氧化有机碳(LOC)和可溶性有机碳(DOC)施用污泥各处理分别显著增加到了8.40~14.74 g·kg-1、164.45~257.45 mg·kg-1、3.58~4.88 g·kg-1和81.16~101.58 mg·kg-1(P0.05),其中各活性有机碳组分SMBC、LOC和DOC分别显著提高了84.00%~188.07%,26.26%~58.03%和109.58%~185.39%(P0.05),其中45 t·hm~(-2)污泥(W3)处理提升效果最明显;施污泥各处理土壤微生物量熵(SMBC/TOC)和易氧化有机碳有效率(LOC/TOC)均有升高趋势,提高范围分别为8.02%~2.77%和13.75%~46.48%,土壤可溶性有机碳有效率(DOC/TOC)施污泥各处理分别显著降低了17.06%~40.94%(P0.05),并且随污泥施用量的增大,SMBC/TOC、LOC/TOC和DOC/TOC呈下降趋势,说明施用45 t·hm~(-2)污泥增大了土壤中稳定态碳含量,导致其比值降低;施污泥各处理土壤碳库活度(L)和碳库指数(LI)随污泥施用量增大而降低,说明施用45 t·hm~(-2)污泥其土壤稳定态碳含量高,有利于沙质潮土土壤有机碳的积累;施污泥各处理土壤碳库管理指数(CMPI)显著提高了153.45%~195.40%,其中W3处理提升效果最为明显;通过相关性分析及冗余分析得出,用CMPI来表征土壤肥力的变化比用TOC更灵敏、直接,能更好地反映出土壤养分及碳库的动态变化.综上,施用15~45 t·hm~(-2)污泥可以显著提高沙质潮土土壤活性碳库各组分含量和碳库管理指数,尤以施用45 t·hm~(-2)(W3)污泥效果最为显著.

Influence of the Application of Non-Hazardous Sewage Sludge on the Evolution of Soil Carbon Pool and Carbon Pool Management Index

The products of non-hazardous commercial sewage sludge were utilized in the accordance of the national standard in the experiment with sandy fluvo-aquic soil under wheat-maize rotation system during 2013 to 2015. The experiment focused on the effects of the use of non-hazardous sewage sludge on soil carbon pool and carbon pool management index to provide theoretical and technical basis for the resource utilization of non-hazardous sewage sludge. The results showed that compared with CK, soil amended sludge significantly improved soil total organic carbon (TOC), soil microbial biomass carbon (SMBC), labile organic carbon (LOC),and dissolved organic carbon (DOC) to 8.40-14.74 g·kg^-1, 164.45-257.45 mg·kg^-1, 3.58-4.88 g·kg^-1and 81.16-101.58 mg·kg^-1, soil amended sludge significantly enhanced SMBC, LOC and DOC by 84.00%-188.07%, 26.26%-58.03%, and 109.58%-185.39% (P<0.05) respectively, and 45 t·hm^-2 sewage sludge (W3) had the most significant impact on soil carbon pool. The soil microbial entropy (SMBC/TOC), and utilization of labile organic carbon (LOC/TOC) increased by 8.02%-2.77% and 13.75%-46.48% respectively, and the utilization of dissolved organic carbon (DOC/TOC) significantly decreased by 153.45%-195.40% (P<0.05). SMBC/TOC, LOC/TOC, and DOC/TOC declined in treatments of soil amended sludge due to increased application of sewage sludge, which indicated that soil amended with 45 t·hm^-2 of the sewage sludge improved the content of stable carbon resulting in the decease of the ratio. L and LI decreased with the increasing amount of sewage sludge indicating that soil amended with 45 t·hm^-2 of the sewage sludge improved the content of stable carbon and was conducive to the accumulation of organic carbon. Soil amended with sludge significantly increased carbon pool management index (CMPI) by 153.45%-195.40% (P<0.05), and W3 had the most significant effect on CMPI. Compared with TOC, CMPI could be more sensitive and direct to reflect the dynamic changes of soil nutrients and carbon pools through the correlation analysis and redundancy analysis. In summary, the application of 15-45 t·hm^-2 sewage sludge could significantly enhance the soil carbon pool and carbon pool management index, especially 45 t·hm^-2 sewage sludge (W3).