INFLUENCE OF TILLAGE PRACTICES ON CROP PARAMETERS AND THE PERFORMANCE OF AN AUTOMATED CASSAVA PEELING MACHINE

Abstract

Cassava peeling has been identified as the only un-mechanized unit operation in the processing of cassava tuber to useful products. This research work is aimed at etermining the effect of tillage practices on the crop parameters and the performance of an automated cassava peeling machine. Two field experiments were conducted between May 2014 to April 2015 and May 2015 to April 2016. Eight tillage methods used for the experiment were; Ploughing + Harrowing, Ploughing + Harrowing + Ridging, Manual Ridging, Zero or No-till, Ploughing + Harrowing + Manual Digging + Saw-dust placed at the base, Ploughing + Harrowing + Ridging + Saw-dust placed at the base, Manual Ridging + Saw-dust and Manual Digging + Saw-dust placed. Two improved cassava varieties, TME 419 and TMS 0581; four fertilizer rates (933.75, 622.50, 311.25 and 0) kg/ha of NPK 15:15:15 were used. The tillage treatments and fertilizer rates were imposed on rain-fed and irrigated cassava fields. The experiment was 8x4x2 factorial combinations of tillage methods, fertilizer rates and rain-fed or irrigated scheme arranged in split-split plot design with three replications. The tillage methods constituted the main plot while fertilizer rate and soil moisture levels were the sub and sub-sub plots. The treatment plots were 3x3 m while the total field plot was 1,156 m2. A line spacing of 1 meter between the cassava plants was observed. Cassava stems of 20 cm long were planted at depth of 5-10 cm. The cassava plants were harvested 10th -11th months after planting. The effect of treatments on some physical and mechanical properties of cassava tubers and on the performance of an automated cassava peeler was evaluated using automated cassava peeler developed at the department of Agricultural and Environmental Engineering, Federal University of Technology Akure (FUTA). Empirical models were developed using linear regression for predicting the interaction between soil, crop parameters and performance of cassava peeler. The results show that Ploughing + Harrowing tillage practice gave the best engineering properties and performance of an automated cassava peeler of fresh root cassava tubers with length of 26.32±2.18ab cm, width of 5.16±0.36a cm, thickness of 5.04±0.30a cm, size of 8.71±0.66a cm, aspect ratio of 20.42±0.63a %, surface area of 265.23±30.47a cm2, sphericity of 33.84±0.71a cm, roundness of 56.01±3.291ab, unit mass of 0.83±0.10ab kg, unit volume of 0.840.44±0.10ab m3, true density of 1.07±.023a kg/m3, bulk mass of 12.92h kg, bulk volume of 12.40h m3, bulk density of 1.06 d kg/m3, porosity of -1.98±4.92 a %, coefficient of static friction of 3.16±0.19b, compressive extension at break of 43.16±0.66b mm, compressive strain at break of 2.16±0.03e mm/mm, compressive load at break of 11698.9±178.71f N, compressive stress at break of 2.72±0.04d , energy at break of 191.62±2.93e J, extension at break of -43.163±0.66b mm, compressive load at maximum compressive extension of 11698.90±178.71f N, compressive strain at maximum compressive extension of 2.16±0.03e mm/mm, maximum compressive extension of 43.16±0.66b mm, compressive stress at maximum compressive extension of 2.72±0.04d MPa, modulus automatic of 1.89±0.03c MPa, compressive load at yield of 4966.40±75.86d N, compressive extension at yield of 19.65±0.30 a mm, compressive strain at yield of 0.98±0.015b mm/mm and compressive stress at yield of 1.16±0.02d MPa peeling efficiency of 92.90 %, percentage of broken tubers of 16.20 %, percentage of flesh loss from tuber of 9.70 %, machine throughput capacity of 1.35 tonnes/hr, mass of unpeeled patches of 0.88 %, material recovery of 88.90 % and optimum speed of 600 rpm, respectively compared to the other seven tillage practices used. Cassava variety TMS 0581 compared to TME 419; 622.50 kg/ha of NPK 15:15:15 fertilizer rate compared to other rates of 933.75, 311.25 and 0 kg/ha and irrigated compared to rain-fed soil gave the best engineering properties and performance of cassava peeling machine. The evaluation parameters could be determined from the model equations developed. Ploughing + Harrowing tillage practice, TMS 0581 cassava variety, 622.50 kg/ha fertilizer and irrigated soil gave the best engineering properties and cassava peeler performance. The study had provided relevant data required by farmers, food processors and engineers for the design and fabrication of systems for planting, handling and processing of cassava tubers into useful products