覆盖材料对云贵高原柑橘园土壤理化性质和细菌群落特征以及柑橘品质的影响

采用田间试验,研究了玉米秸秆覆盖(JF)、白色地膜覆盖(BF)、黑色地膜覆盖(HM)和园艺地布覆盖(YD),以及清耕作为对照(CK)对云贵高原柑橘园土壤理化性质、细菌群落特征及柑橘品质的影响。结果表明,与CK相比,不同覆盖处理下柑橘产量、单果重、果汁率、可食率、维生素C含量和可溶性固形物等指标均提高,可滴定酸含量则有所降低,进而提高了固酸比,其中以JF处理效果最显著。BF、HM和YD处理降低了土壤pH值,JF处理则相反,不同覆盖处理均能提高土壤温度、含水量、有机质和养分含量,JF处理对土壤有机质、全氮、全磷、全钾、有效磷和速效钾含量的提升作用最明显,BF处理下土壤温度最高。JF、HM和YD处理均能显著提高Chao1指数和Observed species指数,而BF处理则相反。在门水平上,覆盖提高了有益菌放线菌门的相对丰度,降低了致病菌拟杆菌门的相对丰度;在属水平上,覆盖提高了有益菌热酸菌属、朱氏杆菌属、Babeliales、红杆菌属和脱氯单胞菌属的相对丰度,降低了致病菌Saccharimonadales、成对杆菌属、金黄色杆菌属、芽孢八叠球菌属和丛毛单胞菌属的相对丰度。此外,覆盖还使土壤细菌共生网络变得简单而稳定。冗余分析结果表明,土壤全氮和细菌群落红杆菌属是提升柑橘产量和品质的关键因子,其解释率分别为45.67%和39.40%。方差分解分析结果表明,土壤理化性质和细菌群落的共同作用对柑橘产量和品质提升的贡献最大,其解释率为45.0%。综上所述,覆盖能有效改善土壤理化性质,提升土壤养分供应水平,优化细菌群落结构,提高柑橘产量和品质,其中,玉米秸秆覆盖可优先作为云贵高原柑橘园土壤的地表覆盖措施。

Effects of mulching materials on soil physio-chemical properties, bacterial community characteristics, and citrus quality in orange orchards on the Yunnan-Guizhou Plateau

A field experiment was carried out to study the effects of corn straw mulching (JF), white film mulching (BF), black film mulching (HM), horticultural mulching (YD), and clean cultivation as the control (CK) on soil physio-chemical properties, soil bacterial community characteristics, and citrus quality of the citrus orchards on the Yunnan-Guizhou Plateau. The results showed that compared with CK treatment, the yield, single fruit weight, juice rate, edible rate, vitamin C content, and soluble solids of citrus increased under different mulching treatments. In contrast, the titratable acid content of citrus decreased, resulting in increasing the solid-acid ratio of citrus. Among different types of mulching, the most significant effective treatment was JF. BF, HM, and YD decreased soil pH, while mulching treatments could increase soil temperature, water content, organic matter, and nutrient content. JF treatment exhibited the most obvious effect on the contents of soil organic matter, total nitrogen, total phosphorus, total potassium, available phosphorus, and available potassium. BF treatment significantly increased soil temperature. JF, HM, and YD treatments significantly increased Chao1 index and Observed species index. At the phylum level, the mulching increased the relative abundance of Actinobacteria and decreased the relative abundance of Bacteroidetes. At the genus level, the relative abundance of Acidothermus, Chujaibacter, Babeliales, Rhodobacter, and Dechloromonas were increased, but the relative abundance of Saccharimonadales, Dyadobacter, Chryseobacterium, Sporosarcina and Comamonas were decreased. In addition, the mulching treatments made a simple and stable soil bacterial symbiosis network. Redundancy analysis showed that soil total nitrogen and Rhodobacter were key factors in improving the yield and quality of citrus, explaining 45.67% and 39.40% variations in the yield and quality of citrus, respectively. Variance decomposition analysis showed that the combined effect of soil physio-chemical properties and bacterial community contributed most to the improvement of citrus yield and quality, with an explanation rate of 45.0%. In conclusion, the mulching treatments can effectively improve soil physio-chemical properties and the level of soil nutrient supply, optimize bacterial community structure, and improve citrus yield and quality. Of these, the corn straw mulching can be preferentially used as a surface mulching measure for citrus orchard soil on the Yunnan-Guizhou Plateau.