[Effects of different fertilizer applications on citrus rhizosphere soil quality and arbuscular mycorrhizae colonization].

To understand the effects of different fertilizer applications on soil quality and arbuscular mycorrhizal colonization, we examined the changes in soil physical and chemical properties, mycorrhizal colonization and propagules, and their relationships in citrus under inorganic fertilization (IF), organic fertilization (OF), combined organic and inorganic fertilization (CF), and no fertilization (CK) treatments. Results showed that all fertilization treatments improved the content of rhizospheric soil organic carbon (SOC), nutrient contents, and electrical conductivity (EC). Both CF and OF significantly increased soil pH, soil aggregate stability, activities of urease, catalase, and sucrase, and the colonization and reproduction of arbuscular mycorrhizae fungi (AMF) in citrus rhizosphere. However, IF treatment significantly decreased soil pH and the colonization and reproduction of AMF in citrus rhizosphere. The number of mycorrhizal colonization and propagation was positively correlated with soil aggregate stability, SOC content, total nitrogen content, total phosphorus content, urease activity, and soil pH. Combined with the principal component analysis, we concluded that application of inorganic fertilizer alone could cause soil acidification and inhibit AMF colonization in citrus orchards. In contrast, organic fertilizer combined with inorganic fertilizer in citrus could improve the soil quality and AMF colonization.为探究不同施肥处理对柑橘根围土壤质量和丛枝菌根的影响,设置单施无机肥(IF)、单施有机肥(OF)和有机肥与无机肥混施(CF)处理,以不施肥为对照(CK),分析土壤理化性状、丛枝菌根真菌(AMF)侵染与繁殖体数量的变化及其相互关系。结果表明: 与CK相比,施肥均能显著提高土壤有机碳、养分含量和电导率;OF和CF处理显著提高了土壤pH值、团聚体稳定性、脲酶、过氧化氢酶、蔗糖酶活性及柑橘根围AMF侵染率和繁殖体数量;而IF处理显著降低了土壤pH值、柑橘根围AMF侵染率和繁殖体数量。柑橘AMF侵染率和繁殖体数量与土壤团聚体平均重量直径、有机碳、总氮、总磷含量和脲酶活性均呈显著正相关,与pH值呈极显著正相关。结合主成分分析,本研究认为无机肥易造成柑橘园土壤酸化,不利于柑橘菌根的定殖;而有机肥与无机肥混施则可以改善土壤质量,促进柑橘菌根的定殖。.