Abstract:

Organic fertilizer and biochar play an important role in improving soil quality and soil fertility in medium and low yield fields. Five treatments (CK: no fertilization, NPK: chemical fertilizer only, NPK+M: chemical fertilizer+sheep manure, NPK+B: chemical fertilizer+corn straw biochar, and NPK+M+B: combined application of sheep manure and corn straw biochar) were applied to a corn field once at the first crop growing season in a 5-year field experiment. High-throughput sequencing was used for exploring the impact of adding sheep manure and corn straw biochar on soil microorganism community diversity and function in saline-alkali sandy soil of Xinjiang. The results showed that sheep manure and corn straw biochar could improve the physical and chemical properties of saline-alkali sandy soil, reduce soil pH, and increase the cation exchange capacity and nutrient content. NPK+M+B treatment had stronger effects on the organic matter, available phosphorus and available potassium, which were significantly increased by 87.80%, 125.15% and 59.52%, respectively. Fertilization increased soil EC, but NPK+B treatment and NPK+M+B treatment could alleviate the increase. The analysis of microorganism α diversity showed that fertilization increased Shannon diversity index and Chao and Ace abundance index of the bacterial community in saline-alkali sandy soil. NPK+M+B treatment had the best effect, which led to increases by 6.31%, 57.98% and 57.25%, respectively. The application of chemical fertilizer increased the soil fungal diversity, but sheep manure and corn straw biochar decreased the diversity. NPK+M+B treatment could increase the abundance of Actinomycetes which tolerated saline-alkali, drought, antibacterial and oligotrophic, and reduce the community composition and abundance of potential pathogenic fungi significantly. So, NPK+M+B treatment alleviated the risk of soil-borne fungal diseases and improved the microenvironment of saline-alkali sandy soil. A redundancy analysis identified AK, OM, TP, TK and TN, TK, CEC, AN as the major factors that affected the bacterial and fungal community structure and functional groups. PICRUSt functional analysis showed that fertilization could improve the bacterial metabolic function related to stress resistance, such as salt alkali and drought, etc. FUNGuild function prediction showed that NPK+M+B treatment significantly reduced the proportion of pathotroph fungi. Overall, sheep manure and corn straw biochar changes soil physiochemical properties, optimizes the niches of beneficial soil microbiome and suppresses the number of harmful fungi, and thus helps create a stable and healthy soil microecosystem.

Key words: fertilization measures, saline-alkali sandy soil, bacteria, fungi, high-throughput sequencing

摘要：

有机肥和生物炭在改善中低产田土壤质量，提升土壤肥力方面具有重要意义。设置不施肥CK、单施化肥NPK、增施羊粪有机肥NPK+M、增施生物炭NPK+B和增施羊粪有机肥-生物炭NPK+M+B等5个处理，进行5年田间定位试验，采用高通量测序技术，探讨有机肥和生物炭对改善新疆盐碱沙化土壤微生物群落多样性和功能的施肥策略。结果表明，有机肥和生物炭改善了盐碱沙化土壤理化性质，降低pH，增加阳离子交换量和养分含量，其中NPK+M+B处理对土壤中有机质、速效磷和速效钾有显著提升作用，分别提高了87.80%、125.15%和59.52%。施肥增加了土壤电导率，但NPK+B和NPK+M+B处理可缓解其升高。微生物α多样性分析发现，施肥增加了盐碱沙化土壤细菌群落Shannon多样性指数及Chao和Ace丰度指数，以NPK+M+B处理效果最好，分别提高了6.31%、57.98%和57.25%。施用化肥增加了土壤真菌多样性，增施羊粪有机肥和生物炭则降低。NPK+M+B处理使细菌群落组成朝更有利于增加耐受盐碱、干旱、抗菌和寡营养能力的放线菌门方向发展，显著减少了潜在病原真菌群落丰度，降低了土传真菌性病害风险，改善了土壤微环境。冗余分析表明，AK、OM、TP、TK和TN、TK、CEC、AN是影响土壤细菌和真菌群落结构和功能类群的主要环境驱动因子。PICRUSt功能分析表明，施肥能提高与盐碱、干旱等抗逆相关的细菌代谢功能；FUNGuild功能预测表明，NPK+M+B处理显著降低了土壤病理营养型真菌比例。由此可以看出，有机肥和生物炭改变了盐碱沙化土壤理化性质，有助于优化土壤有益微生物组、抑制有害真菌数量，从而使土壤微生态系统朝稳定健康方向发展。

关键词: 施肥措施, 盐碱化沙土, 细菌, 真菌, 高通量测序