DEVELOPMENT AND EVALUATION OF CROP RESIDUE SHREDDER

Abstract

The study aimed at developing and evaluating a crop residue shredder. The components of the machine include a frame, hopper, shafts, electric motor, blades, sieve, spur gear, and outlet, to converts crop residues into a smaller form. The performance of the developed machine was evaluated using maize, millet and sorghum stalks as feeding materials, with varying speeds of 55 rpm, 110 rpm and 220 rpm. While operating at 200 rpm, the machine achieved a maximum shredding efficiencies of 82.5 %, 79.2 % and 77.5 % 82% for maize, millet and sorghum respectively. At the same speed of 200 rpm, the maximum throughput capacity of 14.6 kg/h with  maize stalk, while a  minimum  of 4.8 kg/h was recorded with the sorghum stalk at a speed of 55 rpm. Also, although the shredding of sorghum stalks required more energy than the others, there was a general trend of increasing power consumption and time of operation with decreasing speeds for feedstocks. More so, the  particle size distribution of crop residues was found to be dependent type of feedstock, as the sorghum was found to have had the highest retention (71 to 82%) in the sieves (2 – 4 mm) followed by millet (45.5 – 47.5 %) and maize (44.1 – 57.5 %), respectively. Additionally, operating the machine at higher speeds (220 rpm) generated much finer particles which could be aide rapid decomposition. The machine is user-friendly and adaptable to smaller scale farmers for carrying crop residue size reduction operations in Ghana and other sub-Saharan Africa countries.