The Identification of Potentiality Potassium Deficient Soils in Uganda

Abstract

Fertilizer trials have been carried out at 12 different sites on agricultural station, mostly in the south and west of Uganda, on a sequence of different annual crops grown on the same land over an eight-year period. During the first four years, few significant yield increases due to the application per season of 65 kg of muriate of potash per hectare were recorded, even though several sites had low extractable potassium value. Only at the one site where soil pH was below 5.2 was the average crop response to potassium fertilizer over this period greater than 10 per cent. During the second four-year period, when 260 kg of muriate of potash per hectare was applied in alternate seasons. Significant yield increases due to the potassium treatment were much more frequent and an average crop response to this fertilizer of more than 10 per cent was recorded at all the sites where soil-extractable potassium was less than 18 mg. / 100 g. An average crop response of more than 35 per cent was recorded at five sites which had an average soil-extractable potassium level of 10 mg. /100g.