Effect of raw material and application rate of biogas slurry on Cucumber growth, Fusarium wilt suppression, and soil properties

With the popularization and application of biogas engineering, byproduct biogas slurry has excellent application potential as organic liquid fertilizer, while its source and application rate significantly affect its effect. Irrational application of biogas slurry, can reduce crop yields and cause environmental problems such as soil salinization and diffuse source pollution. In this study, the impact of different types of biogas slurry from various materials (i.e., pig manure, chicken manure, vinasse, and kitchen waste) and their required application rates on the growth and incidence of cucumber were investigated by analyzing the dry weight of cucumber, soil chemical properties, soil extracellular enzyme activity, and the incidence of cucumber wilt disease. The results showed that the effects of the four selected types of biogas slurry on cucumber growth and disease were similar. It was shown that 3% was the most suitable application rate considering the dry weight of cucumber plants and the incidence of wilt disease. At this application rate, it was achievable to increase soil pH, soil AN, AK, Olsen P content, and enzyme activities without increasing the risk of salinization. In summary, despite different sources, biogas slurry showed the best growth promotion and disease suppression ability in 3% (v/w) application, without the risk of soil salinization.