Contribution of rice straw compost-biochar to the increase of p-available in lowland soil

Organic matter has been shown to play an effective role in restoring soil fertility. These soil fertility indicators include, among others, the soil C-organic content, the population of bacteria, the nutrient availability and plant yield. This study conducted with the purpose of assessing the impact of rice straw compost-Biochar and NPK chemical fertilizer application on soil C-organic content, phosphate solubiliser bacteria (PSB) population, P availability and crop production. The objective of this research is to get treatment interaction which is able to improve soil fertility, increase soil nutrient availability to encourage more optimal crop production, and provide better efficiency of NPK fertilizer. The experiment conducted from April to August 2014 in SPLPP experimental station of Agriculture Faculty UNPAD, located in Ciparay-Bandung regency West Java. Treatment applied is rice straw compost -Biochar in 5 degree of doses (0; 1; 2; 3; 4 t ha-1) and NPK fertilizer in 4 levels of doses decreasing from recommendation dose (100 %, 80 %; 60 %; 40 %), by applying the Complete Randomized Block design in the factorial pattern. The experimental results showed that 2 tons ha-1 of rice straw compost-Biochar was able to induce significant different responses and the highest achievement of soil C-organic content, number of PSB population, P availability, and dry weight of grain. Interaction of 2 tons ha-1 rice straw compost -Biochar with NPK fertilizer is able to reduce the use of fertilizers by 40 %, with the highest grain dry weight results. (author)