Nitrogen Fertilizer Affects Growth,Yield, and N Recovery in Cassava (Manihot esculenta L. Crantz)

Cassava is a very important tuber crop in Asia. As fertilizer application, especially nitrogen (N), is important to sustain yields, the impact of different rates of N fertilizer and their time of application on growth, yield, and N-recovery efficiency was evaluated over two major seasons in Asia. Applying N at planting increased leaf area index (LAI), especially at greater rates. Split application of 90 kg N at planting and 45 days later induced growth of more tubers, resulting in good yields, when compared to single or three split applications at 45 and 90 days after planting. Split application on two occasions also developed the greatest N-recovery efficiency by both shoots and roots. The correlations between N efficiency and yield parameters were significant and negative (P = 0.05). The importance of two split applications of moderate rates of fertilizer to cassava is presented.