Tillage is one of the most important operations in the preparation of land for growing crops. Among secondary tillage implements, power harrows, which have a series of PTO-driven rotors which rotate about their vertical axis, are widely adopted in soil-working operations. Typically, this kind of implement is highly energy consuming, due to the heavy mechanical loads required to pull the harrow and the PTO (Power Take-Off) torque needed to drive the rotors. This paper reports the results of extensive in-field experimentation in which the relationship between the operating conditions of a tractor - power harrow system and the mechanical loads (i.e. PTO torque and draught) were investigated in two different test site fields. The test parameters consisted of: nominal tractor speed (3, 6, 9 and 12 km h−1), nominal working depth (6, 9 and 15 cm) and rotor speed (285 and 411 rpm) at a PTO speed of 1000 rpm. The data was statistically analysed by means of a linear mixed effect model to assess the differences in the tractor - harrow system performances measured under different working conditions. The presented results show which operating conditions can be favourable regarding energy and fuel consumption as this information may be very useful to farmers to reduce costs. Moreover, the measured mechanical loads concerning PTO torque and draught may also be beneficial for manufacturers to improve the design of these kinds of implements.

中文翻译：

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不同工况下拖拉机-动力耙系统的性能分析

耕作是为种植作物准备土地的最重要的操作之一。在二次耕作工具中，具有一系列 PTO 驱动转子绕其垂直轴旋转的动力耙在土壤工作作业中被广泛采用。通常，由于拉耙所需的机械负载很重，以及驱动转子所需的 PTO（取力器）扭矩，这种类型的工具非常耗能。本文报告了大量现场试验的结果，其中在两个不同的试验现场研究了拖拉机 - 动力耙系统的操作条件与机械载荷（即 PTO 扭矩和吃水）之间的关系。测试参数包括：标称拖拉机速度（3、6、9 和 12 km h-1），标称工作深度（6, 9 和 15 厘米）和转子速度（285 和 411 rpm），取力器速度为 1000 rpm。通过线性混合效应模型对数据进行统计分析，以评估在不同工作条件下测量的拖拉机-耙系统性能的差异。呈现的结果显示了哪些操作条件对能源和燃料消耗有利，因为这些信息可能对农民降低成本非常有用。此外，测得的与 PTO 扭矩和吃水相关的机械负载也可能有利于制造商改进这些类型的工具的设计。呈现的结果显示了哪些操作条件对能源和燃料消耗有利，因为这些信息可能对农民降低成本非常有用。此外，测得的与 PTO 扭矩和吃水相关的机械负载也可能有利于制造商改进这些类型的工具的设计。呈现的结果显示了哪些操作条件对能源和燃料消耗有利，因为这些信息可能对农民降低成本非常有用。此外，测得的与 PTO 扭矩和吃水相关的机械负载也可能有利于制造商改进这些类型的工具的设计。