无害化污泥与钼尾矿配施对沙化潮土土壤质量的影响

以小麦-玉米轮作体系下的沙化潮土为研究对象,通过2012—2015年3年5季田间定位试验,选用经过无害化处理且符合国家相关标准的商业化污泥和钼尾矿产品,研究无害化污泥与钼尾矿施用对我国典型沙化潮土土壤质量指标的影响,为无害化污泥与钼尾矿资源化利用提供理论和技术依据。结果表明:45 t·hm~(-2)污泥(W3)与钼尾矿配施对沙化潮土有机质(SOM)的提升效果最明显,SOM在玉米季W3+75 t·hm~(-2)(M1)处理显著增加了165.10%,在小麦季W3+M2处理显著增加了106.10%(P0.05);相比单施同一水平污泥,污泥与75 t·hm~(-2)钼尾矿配施下土壤0.25 mm水稳性团聚体(WR0.25)含量,平均质量直径(MWD)和几何平均直径(GMD)分别显著升高了38.04%~60.24%,28.45%~45.27%和41.34%~67.77%(P0.05),对促进土壤形成水稳性团聚体以及提高水稳性团聚体稳定性的作用更为突出;45 t·hm~(-2)污泥与75 t·hm~(-2)钼尾矿配施对沙化潮土微生物量碳(SMBC)和微生物量氮(SMBN)提升效果最明显,在玉米季分别显著提高了235.52%和156.79%(P0.05),在小麦季分别显著提高了249.24%和128.32%(P0.05);单施污泥和污泥配施75 t·hm~(-2)钼尾矿处理土壤微生物量熵(q MB)在玉米季和小麦季分别显著提高了21.95%~46.25%和36.38%~71.17%(P0.05)。但污泥与高量钼尾矿配施,SMBC、SMBN和q MB较单施同一水平污泥和与75 t·hm~(-2)钼尾矿配施的处理在玉米季分别下降了3.89%~19.85%、4.31%~17.86%和6.95%~33.47%,在小麦季分别下降了5.34%~23.24%、4.33%~28.08%和3.09%~32.33%,表明钼尾矿高量施用时会降低微生物活性。由灰色关联度分析方法得出,45 t·hm~(-2)无害化污泥与75 t·hm~(-2)钼尾矿配施(W3+M1)能显著提高沙化潮土SOM、SMBC、SMBN和q MB,并提高土壤平均质量直径(MWD)和几何平均直径(GMD),有效改善沙化潮土质量,在3年5季试验期间也未发现土壤和作物籽粒受到重金属污染。同时,W3+M1处理显著提升了土壤肥力等级至Ⅰ级,在此基础上,可以酌情不再施用污泥和钼尾矿。

Effect on the quality of sandy fluvo-aquic soil by application of non-hazardous sewage sludge with molybdenum tailings

The products of non-hazardous commercial sewage sludge and molybdenum tailings were used in the accordance of the national standard in the experiment using sandy fluvo-aquic soil under wheat-maize rotation system during 2013 to 2015. The 5-season of 3-year experiment focused on the effects of soil quality variations of the sandy fluvo-aquic soil by the use of non-hazardous sewage sludge and molybdenum tailings for providing theoretical and technical basis for the resource utilization of non-hazardous sewage sludge and molybdenum tailings. Results showed that the combined application of 45 t·hm^-2 sewage sludge(W3) with molybdenum tailings had the most significant impact on soil organic matter(SOM), which improved significantly by 165.10% for W3+M1 treatment in maize season and 106.1% for W3+M2 in wheat season respectively. In wheat season, compared with that of the single application of the same level of the sewage sludge, >0.25 mm soil water-stable aggregates(WR_0.25), mean weight diameter(MWD), and geometry weight diameter(GWD) enhanced significantly by 38.04%~60.24%, 28.45%~45.27%, and 41.34%~67.77% respectively, in the combined application of sewage sludge with 75 t·hm^-2 molybdenum tailings(M1)(P<0.05). It showed that the combined application of sewage sludge with 75 t·hm^-2 molybdenum tailings were more prominent in improving the formation of soil water-stable aggregates and soil water-stable aggregates formed under the combined application of sewage sludge with 75 t·hm^-2 molybdenum tailings were more stable. The combined application of 45 t·hm^-2 sewage sludge with 75 t·hm^-2 molybdenum tailings had the most significant impact on SMBC and SMBN, which raised significantly by 235.52% and 156.79% in maize season(P<0.05) and significantly improved by 249.24% and 128.32% in wheat season(P<0.05). Microbial biomass entropy(qMB) increased significantly in the single application of sewage sludge and combined application of sewage sludge with 75 t·hm^-2 molybdenum tailings(P<0.05) and in maize and wheat season, respectively improved by 21.95%~46.25% and 36.38%~71.17%. While the combined application of sewage sludge with 150 t·hm^-2 molybdenum tailings, SMBC, SMBN and qMB compared with the single application of the same level sewage sludge and the combined application with 75 t·hm^-2 molybdenum tailings in maize season respectively decreased by 3.89%~19.85%, 4.31%~17.86% and 6.95%~33.47%; in wheat season reduced by 5.34%~23.24%, 4.33%~28.08% and 3.09%~32.33% respectively. It indicated that the higher application of molybdenum tailings inhibited the soil microbial activity. The combined application of 45 t·hm^-2 non-hazardous sewage sludge with 75 t·hm^-2 molybdenum tailings significantly ameliorated SOM, WR_0.25, MWD, GMD, SMBC, SMBN, and qMB, and improved the quality of sandy fluvo-aquic soil effectively by the mean of grey correlation analysis method, and which did not cause the heavy metals pollution to the soil and grain during the experiment. Furthermore, W3+M1 significantly met to first grade of the soil fertilizer and on this basis, it was recommended that the sewage sludge and molybdenum tailings were no more applied.