Effect of Cow Dung, NPK and Their Combinations on Soil Properties and Performance of Sweet Potato (Ipomoea batatas L.) in Sudan Savanna, Nigeria

In Nigeria, one of the major problems confronting agriculture is poor soil fertility replenishment strategy that could allow sustainable production. Two field trials were conducted simultaneously in Sokoto (UDUS, Vegetable Research farm) and Zamfara (Bakalori Irrigation Project) both in Sudan-Savanna agro-ecological zone of Nigeria, with the aim of studying the effect of different rates of cow dung, nitrogen-phosphorus-potassium fertilizer and their combinations on soil properties and performance of sweet potato. The research was conducted during the 2011/2012 dry season using ten treatments: 3, 2, and 1tons per hectare of cow dung, 400, 300, and 200 kilogram per hectare of nitrogen-phosphorus-potassium fertilizer, 2 tons of cow dung + 100 kilogram nitrogen-phosphorus-potassium fertilizer, 1.5 ton of cow dung + 150 kilogram of nitrogen-phosphorus-potassium fertilizer, 1 ton of cow dung + 200 kilogram of nitrogen-phosphorus-potassium fertilizer per hectare and no fertilizer application (control). The result obtained was consistent with regard to locations indicating a numerical increased in soil organic carbon, cation exchange capacity(CEC), total nitrogen, available phosphorus, exchangeable calcium and potassium due to the treatments application as compared to the initial values. However, the effect was not significant (p>0.05) among treatments. While on sweet potato yield the treatments effect was significant (p<0.05) and application of 300 kilogram of nitrogen-phosphorus-potassium fertilizer per hectare gave the highest sweet potato yield at both locations. This research therefore, recommended that treatments used are important materials for soil nutrients replenishment and application of 300 kilogram per hectare of nitrogen-phosphorus-potassium fertilizer is recommended for better sweet potato yield in the study areas.