Effects of Trichoderma harzianum Fertilizer on Growth and Rhizosphere Microbial Community of Continuous Cropping Lagenaria siceraria

Abstract

This study analyzed the effects of Trichoderma harzianum fertilizer on the growth of continuous cropping Lagenaria siceraria and the physical and chemical properties of rhizosphere soil and microbial community structure, using Illumina Miseq (PE300) high-throughput sequencing technology along with physiological and biochemical detection. The results indicated that after applying T. harzianum fertilizer, the growth of L. siceraria was significantly promoted, with increases in plant height, fresh weight, and dry weight of 21.42%, 24.5%, and 4.5%, respectively. The pH of the rhizosphere soil decreased from 7.78 to 7.51, while the electrical conductivity (EC), the available phosphorus (AP), the available potassium (AK), and the total nitrogen (TN) were markedly higher compared to the CC group and increased by 13.95%, 22.54%, 21.37%, and 16.41%, respectively. The activities of catalase and sucrase in the rhizosphere increased by 18.33% and 61.47%, and the content of Soil Organic Carbon (SOC) elevated by 27.39%, which indicated that T. harzianum fertilizer could enhance soil enzyme activity and promotes the transformation of organic matter. Among them, the relative abundance of beneficial bacteria such as Pseudomonas increased, while the relative abundance of harmful fungi such as Fusarium and Podosphaera decreased significantly. This study clarified that T. harzianum fertilizer promoted the growth of continuously planted L. siceraria plants by improving soil physical and chemical properties and microbial community structure and was an effective microbial agent to alleviate the adverse effects of continuous cropping of L. siceraria.