Abstract
We investigated the efficiency of energy utilization for the various methods of grain harvesting which generally consumed a lot of labor and fuel.
1) From the viewpoint of the ratio of E1/E2 (energy output/direct energy input), a conventional combine (CC) was profitable to barley, wheat and soybean, but a head-feeding combine (HC) was profitable to rice.
2) When we plotted the data of load change from HC to CC on a surface F-T, it showed the typeII change. In this case, the reduction of T(h/ha) by introduction of CC was formed in compensation for increasing F(kg/h), but the conversion to a bigger machine was effective judging from the changes of L(kg/h) and T.
3) The harvesting loss of HC was smaller than that of CC in rice, but the loss of CC was smaller than that of HC in barley, wheat and soybean.
4) From the viewpoint of the ratio of E1/E2, both CC and HC were more profitable when these combines were operated at higher travelling speed than the ordinary.
5) From the analysis of fuel consumed in harvesting, the most predominant item was a [load by engine without working] which constituted 40-74% of the total fuel consumption. The item of [load by crop feeding] of CC was more effective than that of HC.
