生石灰对林下酸化土壤的调控作用及三七生长的影响

土壤酸化是导致林下三七生长不良和根腐病发生的重要因素。本试验利用不同量(0、500、1000、1500和2000 kg·hm^-2)的生石灰改良林下酸化土壤,评价生石灰对土壤理化性质、酚类物质、根际微生物和三七生长的影响。结果表明: 适量的生石灰(500～1000 kg·hm^-2)可显著提高土壤pH值,降低酚类物质(羟基苯甲酸、香草醛、丁香酸、阿魏酸和香草酸)含量,促进三七的生长,并降低根腐病的发生。适量的生石灰(500～1000 kg·hm^-2)能显著降低土壤的真菌/细菌,提高细菌多样性,提高门水平上子囊菌门、变形菌门和属水平上马赛菌属和鞘脂单胞菌属的相对丰度。但是过量的生石灰(1500～2000 kg·hm^-2)会降低土壤碱解氮和有机质含量,抑制三七的生长。因此,500～1000 kg·hm^-2生石灰可显著改善林下土壤的化学性质和微生物群落,从而促进三七生长,降低根腐病的发生。

Modification of quicklime on acid soil under forest and their effect on the growth of Panax notoginseng

Soil acidification is an important factor leading to poor growth and root rot disease of Panax notoginseng in the understorey of forests. In this study, different amounts of quicklime (0, 500, 1000, 1500 and 2000 kg·hm^-2) were amended into acid soil under forest. We evaluated the effect of quikelime addition on soil chemical properties, phenols, rhizosphere microorganisms and growth of P. notoginseng. The results showed that an appro-priate amount of quicklime addition (500-1000 kg·hm^-2) could significantly increase soil pH, decrease the content of phenols (p-hydroxybenzoic acid, vanillin, syringic acid, ferulic acid and vanillic acid), promote P. notoginseng growth, and reduce the incidence of root rot disease. An appropriate amount of quicklime (500-1000 kg·hm^-2) could significantly reduce the fungi:bacteria ratio, increase bacteria diversity, and increase the relative abundance of Ascomycota and Proteobacteria as well as Massilia and Sphingomonas. However, excessive quicklime addition (1500-2000 kg·hm^-2) could reduce the content of available nitrogen and organic matter, and inhibit P. notoginseng growth. Therefore, 500-1000 kg·hm^-2 of quicklime amendment could improve the chemical properties and microbial community of acid soil under forest, thereby promoting P. notoginseng growth, and reducing the incidence of root rot disease.