The Impact of Nitrogen Levels on the Growth, Development, and Yield of Orange-fleshed Sweet Potatoes ( Ipomoea batatas L.)

Nitrogen (N) is one of the most important fertilizers in agriculture because it promotes the growth of plants and the uptake of other plant nutrients. This nutrient plays a significant role in determining the yield and nutrient composition of sweet potato root tubers. Therefore, this study aimed to determine the optimum application rate of N in sweet potatoes to maximize yields and increase growth efficiency. Four levels of N (50, 100, 150, and 200 kg/ha) were applied as treatments. A randomized complete block design was used, and each treatment was replicated five times. Vine length, leaf length, stem thickness, and chlorophyll content were measured weekly, and the storage root yield was determined at the end of the experiment. The results showed a significant effect of the N treatments on plant growth, chlorophyll content, vine length, leaf area index and storage root yield. The chlorophyll content and vine length increased with an increase in the N rate. However, an inverse relationship was observed between storage root yield and N rates; the highest yield was recorded for the 50 kg/ha N treatment and the lowest yield was recorded for the 200 kg/ha N applied. Therefore, a rate of 50 to 100 kg/ha N is recommended for the production of orange-fleshed sweet potatoes.