沼液对河西绿洲葡萄园土壤微生物功能多样性的影响

为探明使用沼液对土壤质量的影响，明确土壤微生物功能多样性对沼液使用量和使用年限的响应，在甘肃祁连葡萄观光园进行等氮量替代和增施沼液处理，采用Biolog方法测定土壤微生物功能多样性。结果表明：（1）100%等氮量沼液处理的土壤微生物群落代谢活性最小，替代33%氮量处理的土壤微生物群落代谢活性最高，连续两年使用沼液的处理间差异大于一年。（2）试验地土壤微生物利用的主要碳源为碳水化合物类，使用沼液能够显著提高土壤微生物对氨基酸类和羧酸类碳源的利用率。连续两年使用沼液条件下，增施沼液处理（133%和167%）效果优于等氮量替代处理。（3）与单施化肥对照相比，使用沼液处理仅在提高土壤微生物均一度指数方面存在优势，且增施沼液处理（133%和167%）效果优于等氮量替代处理。（4）主成分分析表明，沼液使用量和使用年限对土壤微生物碳源利用水平以及代谢多样性的影响有差异，且使用年限增加能使各处理间变异程度增大。（5）碳水化合物类和氨基酸类碳源是引起不同沼液用量处理土壤微生物功能群分异的主要碳源，其中碳水化合物类是使用年限增加后土壤微生物群落变化的敏感碳源。（6）Pearson相关性分析表明，该试验地土壤微生物功能多样性与土壤有机质、碱解氮呈正相关关系，与速效磷、速效钾呈负相关关系。综上，长期使用沼液（尤其是沼液与化肥配施）有利于提高土壤微生物代谢活性和土壤微生物群落功能多样性，且当沼液使用量较大时能达到完全取代化肥的效果。

Effects of Biogas Slurry on Soil Microbial Functional Diversity of Vineyard in Hexi Oasis

A 2a field experiment was conducted in Qilian Grape Sightseeing Garden of Gansu Province in order to investigate the effects of biogas slurry application amount and year on soil quality and soil microbial functional diversity. The designed treatments included CK treatment (pure chemical fertilizer, N 180 kg/hm², P₂O₅ 150 kg/hm², K₂O 22.5 kg/hm²), biogas slurry replacing chemical fertilizer treatments (biogas slurry nitrogen replaced 33%, 67% and 100% of chemical fertilizer nitrogen), and increasing biogas slurry treatments (biogas slurry nitrogen were 133%, 167% and 200% of chemical fertilizer nitrogen). Soil microbial functional diversity was determined by Biolog method. The results showed that metabolic activity of soil microbial community was the lowest in 100% biogas slurry treatment but the highest in 33% biogas slurry treatment. Meanwhile the differences in metabolic activity between the treatments with 2a application biogas slurry were greater than those of 1a. The main carbon sources used by soil microbes were carbohydrates, biogas slurry application significantly increased the utilization rates of amino acids and carboxylic acids. Under the condition of applying biogas slurry for 2a, the effects of 133% and 167% biogas slurry treatments were better than those of other treatments. Compared with CK, biogas slurry application only had obvious advantage in promoting the McIntosh index, and the effects of 133% and 167% biogas slurry treatments were better than those of other treatments. Principal component analysis (PCA) showed that biogas slurry applying amount and year had different effects on soil microbial carbon source utilization rate and metabolic diversity, and the variation degree among treatments increased with increasing applying year of biogas slurry. Carbohydrates and amino acids were the main carbon sources that caused the differentiation of soil microbial functional groups treated with different amounts of biogas slurry, and carbohydrates were the sensitive carbon sources for soil microbial community changes after the increase of applying year of biogas slurry. Pearson correlation analysis showed that soil microbial community functional diversity had positive correlation with soil organic matter and available N, and negative correlation with available P and K. In conclusion, biogas slurry application (particularly combined with chemical fertilizer) is beneficial to improve soil microbial metabolic activity and soil microbial community functional diversity, and it can completely replace chemical fertilizer when enough amount is applied.