Effects of types and rates of nitrogen fertilizer on soil. 1. pH, exchangeable calcium, magnesium and extractable manganese contents on seedling tea field in Nandi Hills, Kenya
1995
Wanyoko, J.K. | Othieno, C.O. | Mwakha, E. | Cheruiyot, D. (Moi Univ., Eldoret (Kenya))
Three types of nitrogenous fertilizers, sulphate (S/A) and two compound formulation: NPKS 25:5:5 and NPK 20:10:10 applied annually at 0, 50, 100, 150, 200 and 250 kg N/ha were compared in a field experiment which lasted nine years. Soil pH, and soil exchangeable calcium and magnesium content were lowered by application of the nitrogen fertilizer with S/A showing the strongest effects. Increasing the nitrogen fertilizer rates linearly lowered the soil pH end the levels of the two exchangeable bases. The content of the extractable manganese was on the other hand increased more by S/A than by the other fertilizers while increasing the nitrogen fertilizer rates also increased its content linearly
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