Mechanized Harvesting of Cereal Crops -An Overview of the Problems and Factors Affecting
2012
Ashoka, H. G. | Prashantha, G. M.
Harvesting is one of the most labor intensive operations in the production of crops. Development of mechanical harvesters/reapers operated by self mounted engines, power tillers, tractors and combined harvesters for harvesting crops like paddy, wheat and other cerealcrops are gaining the popularity. The efficiency of harvesting operation depends on the shear stress and the modulus of elasticity of the crop. The factors affecting the shearing principles are the moisture content, height and the diameters of cutting stem. The shearing stress of wheat stalk given the direct relation to wheat stems size and the moisture content, but has inverse relation with the cutting height of stalk because of a reduction in stalk diameter. The bending stress and modulus of elasticity has got inverse relation with moisture content (Esehaghbeygi et al., 2009). However the findings with the cotton crop contradicting with the shearing principle of wheat. The shearing stress and moisture content of cotton stalks leads to increasing the cutting efficiency, which means decreasing the shear stress (Metwalli et al. 1995). Also the reapers developed for harvesting crops like wheat and paddy could not become popular for harvesting finger millet and other rain fed crops because of varied crop materials. Several commercial reapers developed has got vide range of field capacities for wheat and paddy crops.
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