Evaluation of Compost and Manure Amendments for Suppressing Heterodera glycines

Soybean cyst nematode (SCN) is a major pest of soybean crops, causing significant yield losses and economic impact. Current management strategies primarily rely on resistant varieties, cover crops, and seed treatments. In addition, there is a growing interest in developing sustainable, ecologically based approaches to integrate SCN risk reduction into soybean production systems. This study aimed to evaluate the efficacy of various compost and manure amendments in suppressing SCN populations and promoting soybean productivity. An in vitro egg hatching assay was conducted to screen the inhibitory effects of different compost and manure extracts on SCN egg hatching. Results indicated that poultry manure, Layer Ash Blend, and swine manure extracts significantly inhibited SCN hatching compared with other treatments across multiple time points. Greenhouse trials further validated the effectiveness of Layer Manure, poultry manure, High Carbon Dairy Doo, and Seed Starter 101 in suppressing SCN cysts, eggs, and juveniles. A field microplot trial confirmed the potential of Layer Ash Blend and poultry manure in SCN management, with significant reductions in SCN populations and increased soybean yields. The study also investigated the impact of these amendments on promoting the population of bacterivorous and frugivorous nematodes, contributing to a biological diverse soil ecosystem. Overall, the results indicate that amending SCN-infested soil with specific compost or manure formulations can effectively suppress nematode populations while improving soybean productivity. These findings contribute to the development of sustainable strategies for SCN management in soybean production systems.