Biochar-ammonium phosphate as an uncoated-slow release fertilizer in sandy soil

The objective of this study was to manufacture of a granular biochar-ammonium phosphate (BAP) as an uncoated-slow release fertilizer by using the reaction among biochar (derived from rice husk), phosphoric acid and ammonia gas for fertilization of sandy soil. In this study we assessed the influence of two types of BAP {1.5 mol NH3 + (0.76 molH(3)PO(4) + 150 g biochar) BAP1 and 1.5 mol NH3 + (0.76 mol H3PO4 + 220 g biochar) BAP2} on nitrogen (N) use efficiency (NUE) and N losses in leachate water and compared them to a conventional mineral N fertilizer (ammonium phosphate, AP). Additionally the surface morphology of biochar, BAP1 and BAP2 was examined by scanning electron microscopy (SEM) and Fourier transfer infra-red (FT-IR). SEM and FT-IR confirmed the formation of ammonium phosphate inside the biochar's pores. Release of the available nitrogen (NH+4-H and NO-3- H) from both BAP1 and BAP2 fertilizers was detected to be slow and low compared with AP fertilizer. pots treated with either BAP1 or BAP2 demonstrated fundamentally higher (p < 0.05) N content and vegetative improvement compared with AP, however no critical difference (p > 0.05) were found among BAP1 and BAP2 fertilizers. Correspondingly, the synthesis of this new fertilizer using this technology provided a unique organic matter in the manufacture of uncoated-slow release fertilizer. Subsequently, BAP could be used as an uncoated-slow release fertilizer to maximize the functions of the nitrogen fertilizer when added to a sandy soil and minimize its environmental impact.