Effects of and rates of rock phosphate and triple super phosphate fertilizers on soil and leaf nutrient contents and yields of clonal replanted tea in Kericho, Kenya
1997
Othieno, C.O. | Wanyoko, J.K. | Owuor, P.O. | Langat, J.K.
Rock phosphate (RP) and Triple Super phosphate (TSP) were applied at 0, 25, 50, 75, 100 and 125 kg P2O5/ha/year on clone S 15/10 tea which had been replanted after uprooting old tea in a field trial lasting seven years. TSP application significantly increased the soil pH values towards the end of the trial compared to RP. RP significantly increased extractable phosphorus in the soil especially at high rates compared to TSP. Soil extractable potassium and calcium were not significantly affected by the phosphorus sources. Mature leaf phosphorus content was significantly higher in the TSP treatment compared to RP while mature leaf nitrogen, potassium, calcium, magnesium and aluminium contents were not significantly affected by the fertilizer rate or sources. The mean annual yield for the trial duration were not significantly affected by the fertilizer source, but increasing the rate increased the yield in a significantly quadratic manner
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