Kitchen Waste Digestate and Digestate Biochar Fertilizer for Turfgrass Management and Nutrient Leaching

Abstract

Slow-release fertilizer is generally used in turfgrass management to maintain quality turf without inducing excess vertical growth, to avoid frequent mowing. This study was designed to verify whether kitchen waste digestate and digestate biochar could serve as slow-release fertilizers to promote turf quality and reduce nutrient leaching risk in two turfgrass species over two years in controlled pot experiments. The results showed that the nutrient release of granular fertilizers made from kitchen waste digestate and digestate biochar was a two-phase process (an initial rapid phase, followed by a slow-release phase). The kitchen waste digestate showed higher nitrogen and phosphorus release ratios than the biochar and sheep manure. Compared to the reference sheep manure, fertilization with kitchen waste digestate and biochar increased the leaf chlorophyll content by 48.6% and 27.9%, and reduced senescent leaves by 15.6% and 11.1%, respectively, at 23 d after fertilization, leading to higher turf quality. Fertilization with kitchen waste digestate biochar significantly reduced the nutrient leaching risk compared to fertilization with kitchen waste digestate and sheep manure. Our results demonstrated the potential of reusing kitchen waste digestate and digestate biochar as slow-release fertilizers for promoting turf quality in turfgrass management.