【摘要】 【目的】研究施用益生菌和不同浓度生物炭对桉树幼苗生物量及其林下土壤微生物活性的影响,为调控桉树生长的土壤理化环境提供参考依据。【方法】以桉树幼苗为研究对象,进行2种浓度(20.0和40.0 t/ha)生物炭+5×1010CFU/mL益生菌水平的野外栽培试验,测定分析各处理桉树幼苗的生长量和干生物量、林下土壤微生物数量、土壤氮素含量和土壤酶活性。【结果】单独施用20.0 t/ha生物炭可显著提高桉树幼苗的茎、叶生物量和总生物量(P<0.05,下同),单独施用5×1010CFU/mL益生菌能显著降低桉树幼苗的树高、冠幅、地径、叶生物量和总生物量;单独施用5×1010CFU/mL益生菌或20.0 t/ha生物炭均能显著降低桉树幼苗林下土壤的过氧化氢酶(CAT)活性,而5×1010CFU/mL益生菌与20.0 t/ha生物炭混施可显著增加桉树幼苗林下土壤真菌数量。因子分析及相关性分析结果表明,土壤放线菌数量与土壤因子[硝态氮(NO3--N)、微生物量碳(MBC)和微生物量氮(MBN)]呈显著正相关,即微生物数量可反映桉树幼苗林下土壤营养状况和微生物数量;低浓度生物炭处理在各公因子上的得分和排名最高,表明施用适宜浓度生物炭能提升桉树幼苗林下土壤元素的固持能力和微生物数量。【结论】土壤微生物数量与土壤养分含量、酶活性及微生物量碳氮含量等关系密切,施用20.0 t/ha生物炭可显著提高桉树幼苗的根、茎、叶生物量,同时能提高其对林下土壤营养元素的固持能力和微生物量碳氮含量。更多还原

【Abstract】 【Objective】The objective of this study was to investigate the impact of biochar and eucalyptus probiotics on eucalyptus seedling biomass and soil microbial activity under the forest,and provide a reference for the optimum soil physicochemical environment regulation for eucalyptus growth.【Method】Eucalyptus seedlings were research targets. Two concentrations(20.0 and 40.0 t/ha)of biochar+5×1010 CFU/mL probiotics were used to conduct field cultivation test.Growth,dry biomass,soil microbial activity under the forest,soil nitrogen content and soil enzyme activity were detected and analyzed.【Result】Single application of 20.0 t/ha biochar significantly increased stem and foliar biomass(P<0.05,the same below),and single application of 5×1010 CFU/mL probiotics significantly decreased seedling height,crown diameter,ground diameter,foliage biomassand total biomass. Catalase(CAT)activity in soil under eucalyptus forest was significantly decreased by 5×1010 CFU/mL probiotics and low-level concentration(20.0 t/ha)of biochar.Fungi quantity under eucalyptus forest were significantly increased by mixed application of 5×1010 CFU/mL probiotics and 20.0 t/ha biochar. The factorialanalysis and correlation analysis demonstrated that soil actinomyces quantity was significantly positively correlated to soil factor(NO3--N),microbial biomass carbon(MBC)and microbial biomass nitrogen(MBN),indicating that soil microbial quantity was able to reflect soil nutrient condition and microbial biomass. What was more,low concentration of biochar treatment ranked and scored the highest on all common factors,indicating that a suitable concentration of biochar increased the retention capacity of soil nutrient and soil microbial biomass under eucalyptus forest.【Conclusion】Soil microbial quantity is highly related to soil available nutrient content,enzyme activity,MBC and MBN. The biomass of eucalyptus root,stem and leaf can be significantly increased by 20.0 t/h biochar,meanwhile the capacity of soil nutrient retention,and soil microbial carbon and nitrogen concentrations are improved.更多还原