Effects of fermented biogas slurry returning of tail vegetables on soil enzyme activity and fertility

Abstract

Objective The objective of this study is to study the effects of fermented biogas slurry derived from tail vegetables on soil physicochemical properties and enzyme activities, and to evaluate soil fertility. Method Baby cabbage cultivated in the field, five treatments with iso-nitrogen fertilization were set up: CK (no biogas liquid nitrogen), T1 (25% biogas liquid nitrogen), T2 (50% biogas liquid nitrogen), T3 (75% biogas liquid nitrogen) and T4 (100% biogas liquid nitrogen). Results It was found that returning biogas slurry from the fermentation of tail vegetables to the field significantly increased soil organic matter, total nitrogen, alkaline dissolved nitrogen, available phosphorus, available potassium, and microbial carbon (nitrogen) content, improved soil porosity and decreased soil bulk density, with little effect on soil water content; Fermentation of biogas slurry from tail cabbage significantly increased the activities of urease, sucrase and alkaline phosphatase, but had little effect on catalase activity, and the increases of urease, sucrase and phosphatase activities were 3.49%~21.83%, 8.71%~22.29% and 1.95%~10.38%, respectively. Through principal component cluster analysis, the weighted comprehensive score was used as a new index, and soil fertility was comprehensively evaluated as T3>T2> T4>T1>CK. Conclusion Considering the comprehensive effects of fermented biogas slurry fertilization on soil physicochemical properties and soil enzyme activities, the fertilization effect T3 (246m3·hm-2 tail vegetable fermentation biogas slurry + 44kg·hm-2 pure chemical nitrogen) was the best and the comprehensive fertility was the best.