Effects of Phosphorus Fertilizer Rates and Its Placement Methods on Residual Soil Phosphorus, Yield, and Phosphorus Uptake of Maize: At Bedele District, Ethiopia

In spitefulness of the increase in land areas under maize production, yield is still low due to declining soil fertility because of un-appropriate use of fertilizer rates and placement methods. Therefore this study was conducted to determine P fertilization rates and the relative effectiveness of different placement methods on the yield, P uptake of maize and concentration of P in the soil. The experiment was carried out at Bedele district. Four level of P fertilizer (0, 23, 46 and 69 P2O5 kgha-1) and three placement methods of P application (broadcasting P and seeds, surface banding P to the side of the seeds, and deep band P fertilizer below the seeds) were implemented as treatments with three replications in randomized complete block design. Dry biomass, grain yield, straw yield, harvest index, residual soil P, and total P in grain were highly significantly (P< 0.01) influenced by effect of P fertilizer rates and placement methods. Total P in the soil significantly (P<0.05) influenced by placement methods. Mean plant height, total N in the grain and total N in the stalks highly significant (P<0.01) influenced by effect of P fertilizer rates and its placement methods. The mean days to maturity highly significantly (P<0.01) influenced only by P fertilizer rates. The highest grain yield (78.40 qt ha-1) and biomass yield (142.11 qt ha-1) were noted from surface banding of P fertilizer to the sides of the seeds at application of 69 P2O5 kg /ha respectively when compared with the no P2O5 application. However, P and N uptakes by Maize ranged from 0.84% with no P2O5 to 1.32% at the rate of 69 kg P2O5 ha-1 and 0.656% with no P2O5 to 1.04% at rate of 69 kg P2O5 ha-1, respectively. Also, the residual soil P after harvest of the maize ranged from 1.312 with no P2O5 to 11.79ppm was recorded at application of 69 kg P2O5 ha-1. Therefore, using surface banding P fertilizer to the sides of the seeds with 69kg P2O5 ha-1 to increase the production of maize over increase the efficiency of P uptake.