Comparation on rape combine harvesting and two-stage harvesting

Abstract: In order to find out the differences between two methods of rape harvest, i.e. combine harvesting and two-stage harvesting and to provide a reasoning basis for choosing mechanized harvesting method, the simulation contrast experiments of the two harvesting methods were carried out in this paper, and the economic coefficient, grain water content, stalk moisture content, loss rate and seed quality were tested at different harvesting times. Artificial simulation of combine harvesting means artificial direct harvesting (ADH). First, the rape was cut down from a randomized plot of 5 square meters in the field, moved to a threshing ground, and then threshed and separated by manual labor immediately. The total loss was the sum of those occurred in oilseed rape due to natural shedding, crop disturbance by human being, and threshing and separation losses. The artificial two-stage harvesting (ATH) means cutting down the rapes and picking up them in different periods. The rape should be aired for 4~5 days after cutting down, then threshed and cleaned by manual labor. The artificial simulation experiments showed that the seed loss of ADH got to 3.2%, 50.8% lower than that of ATH, 6.51%, and the oilseed qualities of the two harvesting methods had no obvious difference, however the oil content of ADH was slightly higher than ATH, while its protein content was slightly lower. Besides, the two kinds of mechanized harvesting experiments were carried out. Fifteen types of combine harvesters produced by 12 enterprises were put in use in the two-stage harvesting. The loss rate, broken rate, impurity rate and operation efficiency were measured. Except the impurity rate, the measurements of mechanized two-stage harvesting (MTH) were better than mechanized combine harvesting (MCH). Further more, economic efficiencies of the two harvesting modes were analyzed. The fuel cost, labor cost, workload in life period, depreciation cost, income of yield increase and comprehensive benefit in the lifetime were compared. The results indicated that the economic benefit of MTH was 361 yuan/hm2 higher than that of MCH. In addition, the two harvesting methods were comparatively analyzed based on the machinery performance, adaptability and some other aspects. The time of vacating field for the next crop could be about 4.8 days earlier in MTH. And it had widespread adaptability to various rapes and different harvest conditions, also had superiority in seeds storage and straw chopping because of the lower moisture content. However, finishing the swathing and picking up in two operations was one of the imperfections, and another was its relatively poor ability of adapting to cloudy day or continuous rain. MCH was relatively more convenient and had higher efficiency for it could finish harvesting in shorter time, but it didn't well adapt to different crop morphologies, and had high loss rate if the rape of improper breed was not gathered in time. The analyses indicate that the two harvesting methods have their own advantages and disadvantages and adapt to different regions and conditions, so the two methods will have further development in China, and should be chosen and used in accordance with local conditions.