Effects of organic and inorganic fertilizers on sweet potato production in Iwo, Nigeria

Sweet potato (Ipomea batatas) is one of the most important horticultural crops for human consumption and livestock feed. All parts of the plant are found useful to human consumption, animal feed, and industrial uses. Fertilizer applications have been shown to improve vegetative and storage parameters could be enhanced, but inorganic fertilizers are not always readily available, or are too expensive for prevalently subsistent farmers in Nigeria. This study aimed to compare the performance characteristics of four potato varieties using two fertilizers from inorganic and organic sources using morphological characteristics of the plants. The experiment was carried out in the field and laid out as randomized complete block design with three replications. Two treatments that is, inorganic and organic fertilizers with three levels for each treatment were used. The yield and other morphological characteristics were measured. The results showed that Iwo 1 (variety 3) produced the highest number of tubers (16.67 and 16.69; 16.67 and 16.33) with both inorganic and organic fertilizers and levels, respectively. Iwo 1 (variety 3) also produced the biggest tuber weight (4.57 and 4.60 kg; 3.97 and 3.88 kg) with both inorganic and organic fertilizers and levels, respectively. The results showed significantly (P≤0.05) similar levels of performance of organic fertilizers when juxtaposed with inorganic fertilizer applications, suggesting that in the absence of inorganic fertilizers either due to cost and or availability, organic fertilizers which are relatively more available to the farmer could be used to obtain similar yield levels. Given the bulky nature of the fertilizers as suggested by the quantity used in this experiment, further research will need to be done to determine the best rate for organic fertilizer application.   Key words:  Fertilizers, improvement, productivity, sweet potato.