Biochar bound urea boosts plant growth and reduces nitrogen leaching

作者：Wei Shi, Yanyan Ju, Rongjun Bian, Lianqing Li, Stephen Joseph, David R. G. Mitchell, Paul Munroe, Sarasadat Taherymoosavi, Genxing Pan · 发表于：The Science of The Total Environment · 年份：2019 · DOI：10.1016/j.scitotenv.2019.134424 · 被引用次数：284 · 研究领域：Clay minerals and soil interactions、Soil Carbon and Nitrogen Dynamics、Phosphorus and nutrient management

Over use of N fertilizers, most commonly as urea, had been seriously concerned as a major source of radiative N (Nr) for severe environment impacts through leaching, volatilization, and N2O emission from fertilized croplands. It had been well known that biochar could enhance N retention and use efficiency by crops in amended croplands. In this study, a granular biochar-mineral urea composite (Bio-MUC) was obtained by blending urea with green waste biochar supplemented with clay minerals of bentonite and sepiolite. This Bio-MUC material was firstly characterized by microscopic analyses with FTIR, SEM-EDS and STEM, subsequently tested for N leaching in water in column experiment and for N supply for maize in pot culture, compared to conventional urea fertilizer (UF). Microscopic analyses indicated binding of urea N to particle surfaces of biochar and clay minerals in the Bio-MUC composite. In the leaching experiment over 30 days, cumulative N release as NH4+-N and of dissolved organic carbon (DOC) was significantly smaller by >70% and by 8% from the Bio-MUC than from UF. In pot culture with maize growing for 50 days, total fresh shoot was enhanced by 14% but fresh root by 25% under Bio-MUC compared to UF. This study suggested that N in the Bio-MUC was shown slow releasing in water but maize growth promoting in soil, relative to conventional urea. Such effect could be related mainly to N retention by binding to biochar/mineral surfaces and partly by carbon bonds of urea to bioch...