The Change of Phosphorus Form in Vermicompost Using Cassava Pulp

Abstract

The aim of this study was to investigate the change of phosphorus form in vermicompost using cassava pulp. The ratio of cassava pulps: soil mix (sandy soil and cow manure) were applied at 75%:25% (W/W) in compost (CP: without earthworm) and vermicompost (VCP: with earthworm). The qualities of vermicompost and the form of phosphorus after 60 days incubation were analyzed. The results showed that the pH and EC (Electrical conductivity) were increased in CP and VCP. The water-soluble P in VCP was increased by 21.55% from initial and higher than CP 16.07%. The exchangeable P in VCP was increased by 39.57% from initial and higher than CP 24.25%. Total P in VCP was increased by 21.55% from initial and higher than CP 16.07%. The total N in VCP was increased by 87.61% from initial and higher than CP 85.14%. Moreover, the decrease of %OC (organic carbon), C/N ratio, C/P ratio were found in VCP more than CP, the percentage of decreasing from initial was 76.93%, 97.27%, 82.15%, respectively. The humic acid (%) content in VCP was higher than CP and the percentage of changing after 60 days of VCP was 56.41% and of CP was 32.83%. The growth and reproduction of earthworm showed that the growth rates of earthworm were 10.75 worm^-1 day^-1 (mg) and the numbers of cocoons produced in vermicompost were 6.8 earthworm^-1. Therefore, the activity of earthworm and microbial was helpful to phosphorus available form and nutrient fertilizer content in vermicomposting. These data suggest that vermicompost helps to enhance phosphorus availability in compost.