Effects of Minjingu Phosphate Rock and Triple Super Phosphate as Phosphorus Sources for Maize and Groundnut in Semi-Arid Lands of Central Tanzania

ABSTRACT

Comparative studies on applications of Minjingu Phosphate Rock (MPR) and Triple Super Phosphate (TSP) as P sources were conducted in acid soils of Hombolo and Gairo located in semi-arid lands of central Tanzania. The objectives were to evaluate the possibilities of using MPR as a direct P source and to assess its residual effects on groundnut and maize grain yields. The experiments were conducted using a Randomised Complete Block Design replicated 4 times for 5 and 6 seasons for maize and groundnut, respectively. In the groundnut experiment 6 P treatments were compared. These included TSP applied at 6.6 kg P/ha, MPR applied at 6.6, 13.2, 26.4 and 52.8 kg P/ha and 0 kg P/ha as the control. TSP was used as a standard P fertiliser. For the maize experiment, the treatments were MPR or TSP at 13.2, 26.4, 39.6 and 52.8 kg P/ha, 2 combinations of MPR and TSP (13.2:13.2 and 26.4:13.2) and 0 kg P/ha as the control. The studies indicated that under adequate rainfall conditions, effectiveness of MPR and TSP were similar for groundnut and maize. Under such conditions MPR can be applied as a direct P source to groundnut and maize and its residual effects can be expected in the 2nd season after application.