Investigations on Nigerian root and tuber crops. Influence of nitrogen fertilization on the yield and chemical composition of two cassava cultivars (Manihot esculenta)

Abstract

The results of field experiments on the influence of nitrogen fertilization on the yield components, starch and prussic acid content of two of the cassava cultivars recommended for cultivation in Nigeria are presented. The two cultivars 53101 (local) and 60506 (improved) were harvested at 9, 12 and 15 months. In general, the improved cultivars appeared to respond better to N fertilization, but high rates of N (150 kg N/ha) tended to reduce the yield performance of the two cultivars. The local cultivar produced maximum yields of 31-5, 37-5 and 55-7 fresh tuber t/ha with 60 kg N/ha at 9, 12 and 15 months, respectively, while the improved cultivar gave maximum yields of 31-5 and 48-4 t/ha with 120 kg N/ha at 9 and 12 months, respectively, and 64-1 t/ha with 90 kg N/ha at 15 months. By allowing the crop to grow up to 15 months, the starch yield was more than doubled and about three times the yield obtained at 9 months. The 53101 strain seemed to produce maximum starch yields with 60 kg N/ha while the 60506 type tended to give maximum starch yields with 90 kg N/ha. Influence of N treatments was significant up to 12 months of age but not at 15 months.The HCN content of both cultivars diminished considerably with the age of the plant, dropping at 15 months to about half the level at 9 months. While the HCN concentration of the local cultivar tended to increase with higher N-fertilization, that of the improved cultivar diminished, particularly at 12 months after planting. At 15 months however, the HCN content of both cultivars rose with increasing Nfertilization.

Cassava mineral nutrition and fertilization.

“…As the latter cultivar is extremely vigorous, high N levels produced too much top growth at the expense of root production. Similar negative responses to high N applications have been reported by Acosta and Perez (1954), Vijayan and Aiyer (1969), Fox et al (1975) and Obigbesan and Fayemi (1976). Krochmal and Samuels (1970) reported a root yield reduction of 41% and top growth increase of 11% due to high N applications.…”

Investigations on Nigerian root and tuber crops: effect of potassium on starch yields, HCN content and nutrient uptake of cassava cultivars (Manihot esculenta)

“…A recent paper (Obigbesan & Fayemi, 1976) indicated the nitrogen needs of two of the cultivars; their response to potash was described in a subsequent report (Obigbesan, 1977). This paper presents the results of starch yields, cyanide (HCN) content and nutrient uptake of the cultivars as influenced by potassium fertilizer.…”

Effects of nitrogen fertilization on growth and yield of cassava in Hawaii: II dry matter production and efficiency of partitioning

“…Large N rates decrease root yields by favoring top over root growth (2). High hydrocyanic acid content in roots is also associated with high N fertilization (3,4). Moreover, cassava grows well at small N rates, but it extracts N in amounts that are two or three times the amount of N applied (5).…”