1 Department of Agroindustrial Technology, Faculty of Agricultural Technology, Universitas Brawijaya, Malang, Indonesia 65145
2 Department of Agricultural and Biosystem Engineering, Faculty of Agricultural Technology, Universitas Brawijaya, Malang, Indonesia 65145
* corresponding author: hendrix[at]ub.ac.id
Abstract
Biochar Phosphate Fertilizer (BPF) is a biofertilizer impregnated with phosphate and using biomass as the carrier materials. Phosphate is an inorganic form of phosphorus that available for plant uptake. The optimum pH of 6-7 was needed to optimize the availability of phosphorus and help plant growth. At lower pH level, phosphate tends to bind with aluminium or iron compounds in the soil and decreasing its availability for plant uptake. BPF was made from three different phosphate sources (MAP, DAP and SP36) and one control phosphate source (P2O5) and found to have an acid characteristic. The aim of this research is to optimize the pH characteristics of BPF into neutral. This research uses an experimental method to neutralize BPF using some alkaline solutions to reach neutral pH. BPF from 3 different biochar (rice husk, bagasse, and corncobs) was impregnated with phosphate fertilizer (MAP, DAP, SP36, and P2O5) with ratio of phosphate fertilizer:biochar:distilled water 1:1:3 (w/w/v), then neutralized using 3 alkaline solutions (calcium hydroxide (Ca(OH)2)- potassium hydroxide (KOH)- sodium Hydroxide (NaOH)) with 5 levels of concentrations (0%- 1%- 2%- 3%- 4%- 5%). This research shows that there was no significant different neutralization performance between analytical and technical alkaline solution. The use of technical alkaline solution in the range of 2%-4% can neutralize all samples exclude the samples with P2O5 as the phosphate source.
