Effects Of Some Field Practices On The Yield And Quality Of Cassava (Manihot esculenta Crantz) Planting Material

ABSTRACT

The use of cassava stems as planting materials is limited by scarcity, poor quality, high cost and inappropriate field techniques (land preparation, planting spacing, and field maintenance). To enhance the supply of stem for planting cassava varieties, the existing production practices were evaluated and techniques for increasing the number and quality of cassava planting materials were investigated. Seventy-four cassava farms, purposively selected in 11 major cassava growing States in Nigeria were surveyed for percentage missing stands. Twenty-five centimeter long Standard Stakes (SS) of 43 Cassava Mosaic Disease Resistant (CMDR) varieties were cut using secateur, machete, Okoli-cutter, hand-held saw and motorized-rotary saw. The cuttings were planted at 100 x 50 cm spacing in a Randomized Completed Block Design (RCBD). The experiment was carried out at Onne and was replicated thrice. Five nationally released varieties out of the 43 CMDR varieties were evaluated in treatment combinations: three node-stake categories, three fertilizer types (400kg/ha each) NPK16:27:10 + Agrolyzer (DAP:21% N + 53% P, 3.2kg/10kg) (F1); NPK15:15:15(F2); NPKSMg 13:9:27:5 (F3) and three planting spacings [80 x 37.5 cm (S1), 80 x 50 cm (S2) and 100 x 50 cm (S3)], in a split-split plot design, three replications at Onne and Ogurugu. Patterns of stake distribution were evaluated in 43 CMDR varieties in a RCBD, four replications at Ibadan, Akure, Onne and Zaria. In all the experiments, the number of nodes, stem weight and diameter per SS were assessed for stem quality. Data on SS yield, quality and percentage missing stands were collected and analyzed using descriptive statistics as well as ANOVA (P=0.05). The percentage missing stands in fields (1-3 months after planting) varied from 18.6 to 32.6%. Mean SS of 5.2 ± 0.3 was obtained from fields planted with SS cut with Okoli-cutter, hand-held saw, and motorized-rotary saw while that of secateur was 4.8 ± 0.3. These differences were not significant, but motorized-rotary saw cut faster with less stem damage than others. Spacing (S1 - 10.8±2.2 SS; S2 - 11.85±1.8 and S3 - 7.56±0.5) and number of nodes (2 nodes - 9.9±2; 3 nodes - 8.7±2 and 4 nodes - 11.6±2) did not significantly affect SS yield. Application of fertilizers increased the SS yield by 71.6% (F1), 69.9% (F2) and 80.8% (F3) at Onne and 72.6% (F1), 76.3% (F2) and 83.9% (F3) at Ogurugu. However, there was no significant difference in SS yield under different fertilizer applications at Ogurugu and Onne. There was no significance difference in SS yield at Ibadan, Akure, Onne and Zaria. However, 38.7% of the SS were from the main stem, while 25.8%, 19.3%, 12.8% and 8.5% were from primary, secondary, tertiary and quaternary stems respectively. The mean number of nodes, stem weight and diameter per SS was 12±2.1, 70.1±13.2 (g) and 2.1±0.2 (cm) respectively.

Planting spacing of 80 x 50 cm gave optimum standard stake yields, and could be recommended for stem production. Applying Nitrogen-Phosphorus-Potassium- Sulphur-Magnesium 13:9:27:5:4 fertilizers gave the best standard stake yield. Motorized-chain saw should be used to cut cassava stems.