Manures Effectivity to Enhanced the Availability of Phosphorus, Crops Growth and Yield of Rice and Corn in Acid Upland Soil

The research was conducted in Tamanbogo Station Research in the 2007 Rainy Season in upland rice-corn intercropping farming. The research design used Randomized Complete Block Design with 3 replications. The treatments were 1). 15 t ha-1 manures + Residues of rock phosphate (RRP), 2). Without manures + RRP, 3). 15 t ha-1 manures + 150 kg ha-1 SP 36 and 4). Without manures + 150 kg ha-1 SP 36. The upland rice was seeded in planting space of 25 cm x 25 cm, 2-3 seeds/hill. The land was treated with 1 t ha-1 of RP in the last farming year while SP36 was applicated each season. Urea and KCl fertilizers that were used on upland rice were 300 kg ha-1 and 100 kg ha-1, respectively while corns were fertilized with 250 kg ha-1 urea and 100 kg KCl ha-1. The research results showed that the availability of N and K nutrients in the soil at the time of before planting was low but the availability P was high. Application of manures and RRP increased C-organic, availability of P , Ca and Cation Exchangeable Capacity in the soil. Application of 15 t ha-1 of manures with RRP increased dry biomass weight of rice and corn, there were 45.17 % and 49.23 %, respectively. The grain yield of rice and corn on the treatment of manures and RRP were not gave significant different compare to the yield was gained with SP 36 fertilizer