Browsing by Author "Foster, H.L."
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Item Comparison of the yield, response of groundnuts to single and triple superphosphate in Uganda(1972) Foster, H.L.; Kawanda Research Station, UgandaSince 1963 more than a thousand fertilizer trials on small private farms in Uganda have been carried out to test the effect of single superphosphate on groundnuts. Many significant yield responses have been recorded [1, 2] and recommendations for the application of single superphosphate to groundnuts have been made for specific areas in Uganda [3]. It was generally assumed that the yield response was almost entirely due to the phosphate content of the fertilizer. However, analysis of soils from responsive trials in Ankole district revealed that some contained a high level of extractable phosphate, suggesting that yield response in these trials may infact have been due to the calcium or sulphur content of the fertilizer. To obtain a quick indication of which constituents of single superphosphate were indeed responsible for crop response in Ankole and also other districts of Uganda, pot tests on soil collected from different response areas were carried out. The results, which have been published [4], indicated that crop response to single superphosphate in all districts was mainly or entirely due to the phosphate content of the fertilizer. However, on very acid soils or low organic matter soils, calcium probably produced an extra response. The pot test results indicated that the sulphur content of single superphosphate had little or no effect on crop yields.Item Fertilizer Recommendations for Cereals Crown on Soils Derived from Volcanic Rocks in Uganda(1973) Foster, H.L.; Kawanda Research StationEighty-five fertilizer trials on whe.1t and 132 fertilizer trials on maize were carried out. Over a period of several years on small private farms situated on soils derived from the volcanic rocks of Mount Elgon in Eastern Uganda. Although soil test figures were exceptionally high, large and profitable responses to fertilizer were obtained with both crops. This unexpected result can be accounted for by either the special nature of these soils or the fact of their intense almost ;continuous cultivation, and emphasizes that the interpretation of soil analysis results depends considerably on soil type and history.Item The Identification of Potentiality Potassium Deficient Soils in Uganda(1972) Foster, H.L.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.
