EFFECT OF ORGANIC MATERIALS ON AVAILABILITY OF BURKINA ROCK PHOSPHATE AND PHOSPHORUS RESIDUAL INFLUENCE IN LOWLAND RICE (ORYZA SATIVA L.) PRODUCTION IN GUINEA SAVANNA ZONE

Abstract

Rock phosphate has a high potential of substituting triple superphosphate for lowland rice production but it has received less attention due to its low level of solubility. The experiment was conducted at Sanga in the Tolon district of Northern Region. The study employed the use of composting with organic materials as a method of improving P solubility/availability in rock phosphate as well as to determine the residual effect of rock phosphate on rice. This was a single factor experiment laid in randomised complete block design with three (3) replications. The ten (10) treatments were ZERO, NK, NK+RP, NK-RP, RS/CD COMPOST+RP+NK, RS/HE COMPOST+RP+NK, NK+TSP, NK-TSP, RS and RS+NK. From the results, it was observed that compost treatments significantly (p < 0.05) enhanced effective tiller counts, plant height, grain yield and straw weight, and had similar performance to TSP plots. TSP plots had the highest grain (3.4 ton/ha) as well as straw yields (7.4 ton/ha). Residual effect from rock phosphate (NK-RP) enhanced most parameters when compared to the control, but had similar performance to NK applications. There was significant positive linear relationship between grain yield and plant height (R2 = 0.6285) as well as effective tiller count (R2 = 0.6245) and straw weight (R2 = 0.6913). From this study, it has shown that rock phosphate solubility could be improved using composting and could be a cheaper method of increasing phosphorus availability. Also, the rock phosphate does not need to be applied in every cropping season since its residual effect could have significant effect on crop growth. Further studies should be done to determine the effect of organic amendments in improving rock phosphate solubility under upland conditions since water could play a significant role in P availability.