Browsing by Author "Gama, Benjamin Michael"

Now showing 1 - 1 of 1

Studies on phosphate sorption in Tanzania haplustox and vitrandept soils
(Sokoine University of Agriculture, 1979) Gama, Benjamin Michael
Two virgin soils, a Haplustox with appreciable amounts of kaolinite, amorphous ferrialunino silicate (ATAS), and oxides and liydrous oxides of iron, and a Vitrandept dominant in ADAS with very little crystalline minerals, were chosen for this project. Phosphate sorption in these soils were investigated with respect to length of equilibration, initial solution concentration and pH, organic natter content, and amount and nature of extractants. It was also attempted to assess the equilibrium-? required for near maximum growth of maize (Zea nays L. vor. Ilonga composite) end bean (Phaseplus vulgaris L, var Canadian wonder) in the greenhouse. With respect to the length of equili' ration, rapid P sorption was observed initially in both the soils but near equilibrium condition was obtained only after 24 hours. The magnitude of sorbed-? increased with increasing initial P concentration in the equilibrating solution. The initial solution pH had no effect on P sorption. Destruction of organic natter led to over threefold increase in P sorption in both the soils. Studios in into greenhouse showed that dry matter yield} percent P in plant tissues and total P uptake for both the crops grown on either soil increased with increasing equilibrium -P up to certain concentration beyond which these parameters tended to reach a plateau. On the Haplustox soil. 95 percent of the maximum rinse yield was obtained are on adjusted P concentration of 9.7 P/ml while 2.6 jpg P/ml was odocuate on the Vitrondept soil, 95 percent of the maximum maize yield was obtained at 9.5 and 5 kg, 1/ml adjusted P concentration in the Vitrandept haplustox soils, respectively. From economic considerations, however an adjusted P concentration lower than that required for 95 percent of the maximum yield is suggested