杨树人工林沼液和生物炭混施对表层土壤活性有机碳的影响

人工林施肥是一种重要的经营管理措施,而近年来沼液的处理与生物炭肥的使用也引起了人们广泛关注。在苏北杨树人工林集中分布区开展了沼液(施用量为0、125、250、375 m³/hm²)和生物炭(施用量为0、40、80、120 t/hm²)交互肥效实验,结果表明:①在所有沼液施肥水平中,生物炭的施用增加了表层土壤的活性有机碳,并提高了土壤微生物生物量碳氮比,使得微生物群落向真菌主导类型发展; ②在所有沼液施肥水平中,生物炭的添加显著提高了表层土壤(0～10 cm)的pH,促进了土壤的氮矿化和硝化作用; ③沼液和生物炭对土壤活性有机碳和pH具有显著的交互效应。因此,沼液和生物炭混施能进一步促进土壤活性有机碳的含量,改良土壤肥力,提高人工林生态系统生产力。

Effects of biogas slurry and biochar application on active organic carbon in the topsoil of poplar plantation

Fertilization is an important measure in the management of plantation, and the disposal of biogas slurry and application of biochar attracted widespread attention recently. Interactive fertilizer efficiency experiment was carried out in the poplar plantation in northern Jiangsu. The content of nitrate & ammonium nitrogen in the concentration of biogas slurry were 0, 125, 250, 375 m³/hm² and biochar were 0, 40, 80, 120 t/hm². The results showed that: ① application of biochar improved topsoil(0-10 cm)pH and promoted the nitrogen mineralization and nitrification in all concentrations of biogas slurry addition; ② Application of biochar could increase soil active organic carbon, dissolved organic nitrogen and soil microbial biomass carbon and nitrogen ratios, which indicated that the microbial community had shift to fungi dominated; ③ Significant interactive effects on soil active organic carbon and pH were observed between the applications of biogas slurry and biochar. Therefore mixed fertilizer of biogas slurry and biochar could promote the content of soil active organic carbon, improve soil fertility and enhance the productivity of plantation ecosystem.