Economic and technical feasibility of replacing conventional combines with a new straw crusher combine

Abstract

This study was conducted to investigate economic and technical feasibility of replacing conventional combines with a new combine harvester. In the new combine that called crusher combine, along with separating the wheat from the cluster and straw, the straw is also crushed and stored in a separate tank that is added to the combine behind the grain tank. Thirty conventional and new combine harvesters were randomly selected and examined.  Parameters such as; combine forward speed, reel index, field capacity, pre harvest loss, head loss, threshing and cleaning loss, total loss and quality loss were measured. Results show that total machine loss in conventional and new combines were 3.93 and 4.44% respectively. However, in the conventional combines, all the grain loss are thrown to the ground but in new combine 2.45% of grains fall down in the ground through of platform and 2.46% of grains through of threshing and cleaning units are mixed with straw and collected in straw tank and is used to feed livestock. The amount of straw harvested by the conventional and new combines was 1570 and 2970 kg/Ha and yield was, 2770 and 2920 kg/Ha, respectively. Farmers are keen on the new combine because of gathering more straw, crushing it and storing it in the tank. The rate of seed breakage in seed tank of conventional and new combines were 3.37 and 2.81% and seed germination percentage were 90.8 and 94.7%, respectively. In new harvesters, due to the severe blows to the crushing unit, about 12.5% of the seeds have fracture or invisible damage and are unable to germinate, therefore, the grain harvested with this combine is not suitable for use as a seed. The results show that using the new combine instead of the conventional combine increases the income of the farmer and the combiner by 7 288 790 and 1 636 049 IRR/Ha, respectively.