收获机组技术生产率随地块条件的变化规律试验

Variation of technology productivity of harvesting outfit along with site conditions

针对土地经营规模多样化的现状,探索收获机组技术生产率随地块条件的变化规律,在综合分析收获机组作业时间构成的基础上,建立了收获机组作业各类时间项目与地块条件关系的数学模型,建立了不同卸粮条件下收获机组技术生产率与地块条件关系的数学模型。选择8种不同功率级的收获机组为研究对象,采用跟踪试验方法获取收获机组作业过程中各类时间消耗数据,验证了收获机组技术生产率随地块条件变化关系模型的正确性;采用MATLAB进行编程计算,研究得到不同功率级收获机组技术生产率随地块条件变化的定量规律:幅宽为2~3 m的小功率收获机组适宜的最小地块长度为400 m,最小地块面积为3 hm2;幅宽在4~5 m的中等功率收获机组适宜作业的地块长度为600 m,地块面积为5 hm2;工作幅宽为7 m以上大功率收获机组适宜作业的地块长度为800 m,地块面积为7 hm2。该研究可为完善农业机械化生产与管理理论、科学选择收获机械提供参考。

It is theoretical basis for harvest machinery selection to discuss technology productivity changing with plot conditions, which are plot area, length, width and so on under the condition of land managing scales over the wide range. Harvesting operation is one of the key processes of grain production, and choosing the appropriate harvesting machine is a vital step to reap the grain with larger technology productivity. A lot of researches on agricultural mechanization selection have been done by both domestic and foreign experts. It has been found that there are existing methods for agricultural machine selection such as fuzzy clustering comprehensive evaluation method, linear programming, and mixed integer linear programming. In these methods, the economic performance of the agricultural machinery unit is the objective considered in most cases. But the technical performances of agricultural machinery units, such as the practical productivity, are usually neglected. Plot conditions, including plot area, length, width, and distance between plots, are not considered in the methods, but they are important factors influencing the technology productivity of agricultural machineries. At the same time, it has also been found that the power of most agricultural machineries does not match the plot conditions in the practice of agricultural production. In this paper, the mathematic models calculating every kind of time consumption item during combined operation, including working time, turning time, preparation time before unloading, unloading time, preparation time after unloading and transferring time between plots, were established. On the basis of that, the mathematic models for calculating the combines' technology productivity under the condition of different unloading ways were also set up. These mathematic models contain the variables such as plot area, length, width and distance between plots, and reveal the regularities of technology productivities changing with plot conditions. Experiment was designed according to the method of tracing the practical operating process. Taking 8 kinds of typical combines for harvesting soybean as experiment objectives, the values of all kinds of time consumption items were tested under the condition of fixed distance during the process of normal harvesting operation after enough experiments were executed. All the data of time consumption items were checked using the normal distribution models and the error data were removed according to the 3-Sigma principle. The mathematic models of time consumption items and combine technology productivity established were proved to be correct by the experiments and the actual operating status. According to the models and tested data, the technology productivities of 8 kinds of combine harvesters changing with plot conditions were calculated after the MATLAB program was designed and executed. Curve groups of technology productivity of each kind of combine changing with plot conditions were drew out using the EXCEL. Thus, the quantitative regularity of technology productivity of combine changing with plot conditions was revealed. According to the regularity, the technology productivity became larger as the value of plot area and length became bigger, but the changing velocity of technology productivity became slow after a specific values of plot area and length. The technology productivity of combine with the header width of 2-3 m was higher when the plot area was more than 3 hm2 and the length was more than 400 m. For the combines with the header width of 4-5 m, the technology productivity was higher when the plot area was more than 5 hm2 and the length was more than 600 m. The technology productivity of combine with the header width more than 7 m was higher when the plot area was more than 7 hm2 and the length was more than 800 m. The results of the paper can provide the direct theoretical guidance for practical combine selection under the status of land managing scale with large range, and they are also the improvement and supplement for the theory of agricultural machinery selection.