Synthesis modified biochar-based slow-release nitrogen fertilizer increases nitrogen use efficiency and corn (Zea mays L.) growth

Nitrogen use efficiency enhancement is an important approach to obtain sustainable agriculture. Engineered biochar is considered as a super carrier to produce high-quality slow-release fertilizer. The purpose of this study was to compare nitrate and ammonium release using three treatments (i.e., MgCl2-modified biochar-based slow-release fertilizer (MBSRF), enriched modified biochar (EMBC), and chemical fertilizer (ammonium nitrate: AN)) and to analyze their effects on water retention, nitrogen use efficiency, and Zea mays L. growth. The treatments were prepared, and nitrate and ammonium release were determined. A pot experiment was performed with four treatments (control, MBSRF, EMBC, and AN), and the treatments’ impacts on selected parameters were investigated. Soils treated with EMBC and MBSRF retained more water than those treated with AN and the control treatment. The nitrate and ammonium release of MBSRF was slower and about 2.5 and 1.5 times lower than that of AN. MBSRF effectively increased plant height (20.1, 11.7, 37.1 %), shoot dry weight (24.2, 23.3, 44.0 %), root dry weight (29.9, 24.1, 48.8 %), chlorophyll content (9.43, 8.01, 13.6 %), and leaf area (24.8, 21.0, 30.4 %) in comparison to the AN, EMBC, and control treatments, respectively. Furthermore, the highest soil and plant nitrogen content and nitrogen use efficiency were associated with the MBSRF treatment. In conclusion, the use of MgCl2-modified biochar is promising in the synthesis of nitrogen slow-release fertilizer, and MBSRF can be used as a novel nitrogen slow-release fertilizer for increasing nitrogen use efficiency and improving corn growth.