Effect of Varying Ratios and Rates of Enriched Cattle Manure on Leaf Nitrogen Content, Yield and Quality of Tea (Camellia sinensis)

Tea (Camelia sinensis) a major cash crop in Kenya is normally grown on highly weathered and strongly acidic soils. Non-judicial use of the recommended inorganic compound fertilizer 25-5-5-5s acidifies the soil and pollutes water masses. Integrated soil fertility management, the combined use of organic and inorganic fertilizer is recommended for higher tea yield and soil health. An experiment was carried out in the Eastern Highlands of Kenya to determine the effect of different ratios and rates of enriched cattle manure on leaf nitrogen content, yield and quality of tea. Inorganic compound fertilizer 25-5-5-5s led to the highest N level in the mature leaf. Enriching organic manures with inorganic fertilizers increased the yield but reduced the quality. Tea quality parameters Theaflavins (TF) and Thearubigins decreased with increase in fertilizer rate irrespective of fertilizer type. Caffeine content however increased with increasing rate fertilizer especially in the case of inorganic compound fertilizer 25-5-5-5. Enriching organic manures with inorganic fertilizers increased the N content in the mature leaf and crop yield but reduced the quality. The study showed the beneficial effect of enriched manures in tea production.