Physicochemical properties and efficiencies of biochar and biochar-based nitrogenous fertilizer

【Objective】 The research was conducted to investigate the physicochemical properties of biochar and biochar-based nitrogenous fertilizers and their fertilizer efficiencies.【Method】 With bamboo charcoal,wood charcoal and ammonium nitrate as raw materials,we respectively prepared a bamboo charcoal-based nitrogen fertilizer and a wood charcoal-based nitrogen fertilizer.We systematically investigated and evaluated the physicochemical properties,morphology and biological fertilizer efficiencies of the two biochars and biochar-based nitrogenous fertilizers through elemental analysis,ash determination,environmental scanning electronic microscope(ESM) and infrared microscopy(IR).A pot experiment was conducted to investigate the effects of the two biochars and biochar-based nitrogenous fertilizers on the growth and yield of wheat and pearl millet,and nitrogen use efficiency on sandy loam and sand soil.【Result】 The carbon contents of bamboo charcoal and wood charcoal were more than 60%.The ash and less ammonium nitrate(AN)-loaded contents of bamboo charcoal were about 8% and 18% respectively,much higher than that of wood charcoal.The bamboo charcoal-based nitrogenous fertilizer and wood charcoal based nitrogenous fertilizer exhibited amorphous and porous structure,and kept the morphology characteristics of original bamboo charcoal and wood charcoal basically.Physical adsorption was the only process that dominated the mixing of biochar and AN in the adsorption process.The bamboo charcoal and wood charcoal were alkaline.However,the pH of the AN-loaded biochar declined.Application of bamboo charcoal-based nitrogenous fertilizer and wood charcoal-based nitrogenous fertilizer to the sandy loam and sand soil can dramatically improve the growth and yield of wheat and millet,improve nitrogen use efficiency,delay fertilizer nutrient remaining period in the soil and reduce leaching and other losses.【Conclusion】 Combining biochar and fertilizer to produce biochar-based fertilizer can not only promote crop growth and increase crop yield,but also enhance the agronomic use of biochar.