Design Modification of Conventional Wheat Straw Chopper

Abstract

Agriculture has straight and indirect contribution to boost the economy of Pakistan. Wheat and paddy are among the major rotational crops of Pakistan. The straw management in combine harvested in wheat fields is a major problem. In the past the residual wheat straw in convectional harvesting was burnt in the field which resulted losses of 80% of Nitrogen, 25% P, 21% K and 4-60% S. To overcome this problem, locally available wheat straw chopper is used for cutting and collecting the wheat straw left behind the combine harvesters. These locally developed wheat straw choppers are heavy in weight having lower machine efficiency. A wheat straw chopper has been modified using locally available materials making it light weight and more efficient. The performance evaluation of wheat straw chopper has been carried out in the field and further improvements have been incorporated to increase its field efficiency. The modified wheat straw chopper has been tested for its performance at Chakra Farms of the University of Agriculture, Faisalabad during the wheat harvesting season. The experiment was consisted of factorial completely randomized design. Three wheat varieties V₁ (Sehar-2006), V₂ (Lasani) and V₃ (Faisalabad-2008) were selected in which modified wheat straw chopper was operated at two different tractor forward speeds S₁ (1.77 km h^-1) and S₂ (2.42 km h^-1) and at two different levels of moisture contents M₁ (moisture at the same day of combining), M₂ (moisture after one day of combining). Results showed that wheat straw yield (kg ha^-1) for V₁, V₂ and V₃ was found to be 1425, 1118 and 1179 kg ha^-1 respectively. Effect of moisture on wheat straw yield (kg ha^-1) was found to be significant, and higher wheat straw yield (kg ha^-1) was found to be at moisture content level M_1. The wheat straw yield and efficiency of the wheat straw chopper was found to be higher at S₁ (1.77 km h^-1) which is for wheat variety V₁ and 67.96% respectively. The average fuel consumption was found to be 9.3 lt ha^-1. Breakeven point of the wheat straw chopper was occurred at 225 hours of use.