丛枝菌根真菌和生物质炭对连作西瓜土壤肥力的影响

Effects of arbuscular mycorrhizal fungi and biochar on the fertility of continuous watermelon cropping soil

摘要:

【背景】作为土壤改良剂生物质炭能够改善土壤条件，促进丛枝菌根(arbuscular mycorrhizal，AM)真菌侵染和植物生长发育。【目的】探究接种AM真菌配合施加生物质炭对连作土壤肥力和西瓜生长的效应。【方法】盆栽‘圆佳’西瓜(Citrullus lanatus)嫁接苗[砧木为‘全能铁甲’南瓜(Cucurbita maxima×C. moschata)]，栽培基质为西瓜连作土壤，试验设接种或不接种AM真菌变形球囊霉(Glomus versiforme)并施加0%、1%、2%和4%的生物质炭，共8个处理，测定土壤理化特性、土壤酶活性、土壤微生物数量和植株生长量。【结果】接种AM真菌并施加生物质炭，可显著促进土壤大颗粒团聚体的形成和有机质的矿化，稳定土壤pH，增加土壤细菌和放线菌数量，降低真菌数量，提高土壤蔗糖酶、过氧化氢酶和脲酶的活性，活化土壤矿质养分，最终促进西瓜植株的生长发育。其中，以接种变形球囊霉并施加2%?4%生物质炭组合的效应最大。两者互作在一定程度上提高了连作土壤的pH、饱和含水量及孔隙度，降低了土壤容重，有利于土壤大颗粒团聚体的形成，提高了土壤酶活性，改善了根围土壤微生物组成。【结论】 AM真菌接种配合施加2%?4%的生物质炭可以显著改善连作土壤的肥力状况。

Abstract:

[Background] As a soil modifier, biochar can improve soil fertility, promote arbuscular mycorrhizal (AM) fungal colonization, plant growth and development. [Objective] To evaluate the effects of AM fungi inoculation with adding biochar on the fertility of continuous cropping soil, and the growth of watermelon plants. [Methods] A pot experiment was conducted with watermelon continuous cropping soil as the substrate for planting ‘Yuanjia’ watermelon (Citrullus lanatus) grafted on the root stock ‘Quannengtiejia’ pumpkin (Cucurbita maxima×C. moschata). A total of 8 treatments were designed with the inoculation with or without AM fungi (Glomus versiforme), being added 0%, 1%, 2% and 4% biochar. The soil physical and chemical properties, soil enzyme activities, soil microbial quantity and the plant growth were measured. [Results] G. versiforme inoculation with biochar addition could significantly promote the formation of large soil aggregates and the mineralization of soil organic matter; stabilize soil pH; increase the number of soil bacteria and actinomycetes, and reduce the number of fungi; increase the activities of soil invertase, hydrogen peroxide enzyme and urease; activate soil mineral nutrients, and ultimately promote the growth and development of watermelon plants. Among them, the effect of inoculating G. versiforme and applying 2%?4% biochar combination is the best. There were interactions between AM fungi and biochar, which improved the continuous cropping soil pH, saturated water content and porosity, reduced the soil bulk density, favorable for the formation of large particles aggregate of soil, increased the soil enzyme activities and improved the rhizosphere soil microbial composition. [Conclusion] The combination of AM fungi and 2%?4% biochar can significantly improve the fertility of continuous cropping soil.