Effects of Harvesting Frequency on Leaf and Root Yields of Cassava

Abstract

S U M M A R Y Total fresh leaf yield of cassava (Manihot esculenta Crantz) variety Isunikankiyan was not significantly affected by harvesting frequency, unlike variety TMS 30211. Compared with plants whose leaves were not harvested, there was a decrease in total fresh tuberous root yields of 56-76%, 34-62% and 15-32% when leaves were harvested at 1-, 2-and 3-month intervals respectively. The two cassava varieties reacted differently to leaf harvests in terms of tuber yields. Harvesting the top leaves of cassava at 2-or 3-month intervals is recommended to ensure reasonable yields of both leaves and tuberous roots.The tuberous roots (tubers) of cassava (Manihot esculenta Crantz) provide the basic food for many people in the tropics but the leaves are also a popular food for many African peoples, whilst there is an increasing interest in their use as a livestock feed (Cresswell, 1978). Cassava leaves are a good source of protein, vitamins and minerals. Oyenuga (1968) reported that local Nigerian varieties averaged 14.7% protein, 8.4% ether extract and 16.1% total ash and Eggum (1970) found that the amino acid content of leaves of three Nigerian varieties averaged 6% lysine, 2% methionine, 11% aspartic acid, 6% valine, 5.5% arginine and 2.2% tryptophan. Cassava leaf meal is nearly equivalent to alfalfa meal in feed value (Khajarern et al., 1977).However, Ahmad (1973) and Singh and Chaudhury (1975) have reported adverse effects of leaf harvesting on yields of tubers and it seems that methods must be developed to allow for harvesting cassava leaves while at the same time maintaining reasonable tuber yields. An experiment was therefore conducted to investigate the effects of frequency of leaf harvests on yields of fresh leaf and tubers, yield components and dry matter in two cassava varieties and the results are reported herein. MATERIALS AND METHODSLeaves from the top 30 cm of each branch of two cassava varieties, Isunikankiyan and TMS 30211, were harvested by plucking them from the stems at various intervals of time. A 2 x 4 factorial design was used with treatments arranged in four randomized complete blocks, one factor being the two varieties and the other the timing of leaf harvests, namely no harvest or harvests at % Present address: Njala University College, PMB, Freetown, Sierra Leone.

Effect of Genotype and Periodic Pruning on Storage Root Yield and Yield Components of Some Cassava Genotypes Under Rain-Fed Conditions In Ghana

“…Even though periodic pruning at 2-3 month intervals have been reported to result in marginal reduction in storage root yield (Dahniya et al, 1981;Lockard et al, 1985) the results from this study suggested otherwise. Periodic pruning generally had a significant negative effect on storage root yield but there were genotypic differences in the extent of reduction.…”

“…Erect non-branching genotypes are more likely to be severely affected as compared with profuse branching genotypes owing to their rapid initial vegetative growth at the expense of storage root bulking. In a study involving two cassava varieties with different growth habits, Dahniya et al (1981) reported a greater storage root yield reduction in an erect local cassava variety Isunikakiyan than TMS 30211, a branching type when they were both pruned. From the results of this study, it can be inferred that 96/1642, Afisiafi, Esambankye, Agbelifia and Bankyehemaa are relatively tolerant to periodic pruning as their storage root yield reduction was just around 50%.…”

Cassava leaves as animal feed: Potential and limitations

“…month growing season and obtained within 86% of the normal yields of roots (Table 1). Dahniya et al (1981) recommended a harvesting frequency of 2-3 months, starting from 4 months, for best all-round yields of roots and leaves in 12-month cultivars. However, the variation that appears to exist among cultivars in their tolerance to defoliation needs to be taken into consideration before making any recommendation of harvesting frequency.…”

Apical Shoot Harvest Affects Growth and Apical Shoot and Fruit Yields of Pumpkin

“…Increasing the length of harvested apical shoots to 60 cm, and interval of removal to 2 weeks decreased the quality of apical shoots as a result of an increase in the fiber content (Dahniya, Oputa, and Hahn, 1981;Dahniya, Hahn, and Oputa, 1985;Olasantan, 1988Olasantan, , 2001Olasantan and Bello, 2004). The 30-cm long apical shoot harvests at 1-or 1½week intervals were found to be the most valued apical shoots to consumers in term of size, softness, palatability, and possibly the nutritional values, as reported for sweet potato by Dahniya, Hahn, and Oputa (1985).…”

“…In previous studies, growth and yield responses of crops such as cassava (Dahniya, Oputa, and Hahn, 1981), sweet potato (Dahniya, Hahn, and Oputa, 1985), and okra (Olasantan, 1988), whose leaves are used as a vegetable, depend on the variety, and frequency and severity, of young leaf and shoot removal. This project was undertaken to investigate the effect of harvesting apical shoots on yields of fresh apical shoots and fruit, and other growth parameters of pumpkin at varied population densities and sowing dates.…”