Effect of combined application of organic manure and nitrogen fertilizer rates on yield and yield components of potato: A review

Potato (Solanum tuberosum L.) is one of the main tuber crops that contribute to global food security. Fertilizer is an important input for potato production. However, potato productivity is still constrained by soil depletion. Unfortunately, research done on the rate of organic manure and nitrogen fertilizer on potato production are very limited. This review scrutinizes the gaps of organic manure and nitrogen fertilizer rates on the yield and yield components of potato. For the cultivation of potatoes, smallholder farmers use various rates of nitrogen and organic manure fertilizers. Combined application of nitrogen and organic manure fertilizer improved potato growth parameters and yield components (tuber number, average tuber weight). Tuber quality components such as dry matter and starch contents are also influenced by the combined application of nitrogen and organic manure. With the addition of high amount of organic manure with a certain level of nitrogen, fertilizer also gave the highest volume of marketable and total tuber yield. Based on the report of research works done in different parts of the world at different periods, an average of 31 tons/ha of organic manure and 187.5 kg/ha of nitrogen fertilizer are the ideal combinations for the optimum yield of potato. Hence, in order to increase the quality and availability of organic manure, its production should be supported by technologies alike to inorganic fertilizer production. This will boost potato yield, tuber quality, and maintain the soil health. The government should also due attention to the environment and sustainable development.