Effect of Bio-phosphate on Increasing the Phosphorus Availability, the Growth and the Yield of Lowland Rice in Ultisol

Ultisol soil is low of macro and micro nutrient, pH and base saturation aswell as high toxicity of Al and Fe. To increase productivity of ultisols soils, especially availability of P nutrients, theuse of bio-phosphate can increase P solubilizing in the soils. The research was conducted in the green house ofAgriculture Faculty, the University of Lampung from January to March 2005. A factorial experiment using twofactors in a randomized completely block design with five replications was conducted. The first factor was dosagesof bio-phosphate (0; 10; 20 g L-1), the second factor was lowland rice cultivar (Ciherang, Sintanur, Cilosari and IR64).The results showed that the availability of N, K and P nutrients in the soil before planting was low. Application of biophosphateincreased availability of N, K and P in the soil. Application of 10 g L-1 and 20 g L-1 of bio-phosphateincreased root length of lowland rice, there were 13.3% and 36.8%, respectively. Application of 20 g L-1 of biophosphateincreased 100 grain weight of lowland rice which were higher 11.4% compared to without any bio-phosphate