摘要
Inorganic fertilizer NPK （nitrogen, phosphorus and potassium） （S） 25：5：5：5 is generally recommended for optimum yield and quality of tea （Camellia sinensis）. Non-judicious use of this inorganic fertilizer however acidifies the soils and pollutes the environment. Integrated soil fertility management （ISFM） which involves the combined use of organic and inorganic fertilizer is recommended for improved crop yield and soil health. An experiment was carried out to determine the effect of enriching cattle manure with different ratios of inorganic fertilizers （OM： NPKS at ratios 1：2 and 1：4）, and rates on soil nutrient status, nitrogen uptake and yield of tea in the east of Rift Valley, Kenya. Enriching manures and organic manure up to a rate of 150 kg N/ha increased the level of P mature leaf. A higher N and K level in the mature leaf was observed when NPKS was applied at higher rates. In the soil, fertilizer rate up to 150 kg N/ha showed higher pH and K where organic manure and enriched manures were applied while NPKS treatment showed higher P content throughout the soil depths. Enriching organic manures with inorganic fertilizers increased yield significantly.
