Water management: ditchers
In the current climate change situation, shrewd irrigation water management is crucial for the best crop yield. Ditches and drains must be carefully planned and implemented: this is usually done with ditchers, solid machines that can work effectively in all soil types
Whether natural or made artificially ad hoc, ditches are intended to convey rainwater, irrigation and drainage water conveniently. More specifically, when built on the edges of plots of land, ditches are supplemented by a series of water intake points for watering, carried out using various techniques. Specific equipment, known as "ditchers," is usually adopted to make and maintain ditches and drains, particularly in relation to their original cross-section.
These machines are versatile operators that can be coupled with both tracked and wheeled tractors.
Regardless of the cross-sectional area of the linear trench made (or remodeled), all ditchers are equipped with a rigid frame to which the machine parts are attached. In general, they are carried connected to the tractor's three-point hitch and operated through the power take-off. Depending on the width of the digging section, the power required from the PTO varies between 25-30 up to more than 200 Hp for larger models. Despite the high powers involved, the forward speed must still be very low for good quality tillage, less than 1 km/h. Therefore, this entails using tractors with micro-reducer-equipped transmissions, capable of driving the tractor at very low speeds but at high engine speeds close to maximum power.
Ditchers are differentiated into two macro-categories, wheeled and vertical models, also known as "crackers".
Models in this category create and reshape ditches and canals with a typically trapezoidal cross-section. These machines are characterized by a mass ranging from 500 to 2,000 kg, logically depending on the size of the excavation to be made. They are based on a sturdy frame, which supports a large-diameter disc rotor, equipped with variously shaped knives on the peripheral circumference and on the outer part of the wheel, which cut and push away the loose soil through its impact on some baffle panels.
As the name suggests, single-wheel models are equipped with a single rotor and deflector. The rotor is parallel to the direction of advance, with an inclination of about 30° to the vertical; the soil thus displaced is thrown sideways by the centrifugal force imparted by the rotation and by the impact of the material on appropriately oriented baffles. This equipment is suitable for the creation of relatively small ditches. Positioning with respect to the tractor can be central, lateral, or even at the end of an extending arm or bilateral. In the first case, the machine is integral to the tractor through the three-point hitch and thus digs a furrow central to the path traveled by the tractor. Conversely, models with an articulated arm allow the creation of ditches that are also several meters away from the tractor and help work in situations where the travel of the machinery may not be optimal. Finally, bilateral ditchers are also available, which, thanks to the conformation of the supporting frame, allow the creation and maintenance of furrows to the rear of the tractor's tires, always, however, within its gauge.
The general structure is similar to that of the single-wheel models, but in this case, the digging and earth-breaking organs and deflectors are double: there are, in fact, two symmetrical rotors, usually working at an opposite inclination of about 30° to the vertical, complemented by two sets of baffles for moving away the displaced material. If the section of the ditch to be made is to be small, the inclination of the rotors is reduced to an angle of between 18° and 23°. However, at the other end of the spectrum, models with enlarged trapezoidal cross-sections are also available, which create wider sections at the top for the same depth, with side wall angles of up to 40-42°. Double-wheel ditchers also include models referred to as "super" or "big," which, as the name implies, can dig large ditches.
As, again, the name suggests, these have intermediate characteristics to those already illustrated. Basically, they are based on the architecture of single-wheelers, but in addition, a smaller rotor is installed in a mirror position, which acts as a cleaning disc to better profile the edge of the ditch on which it acts. This is an extremely useful solution for the construction of small ditches.
Bilateral or fixed vertical ditchers
They are mainly used for better regulation of excess surface water and for laying drainage pipes (or, conversely, for burying pipes intended for sub-irrigation) by creating deep slits in the soil a few centimeters wide. This machine is based on a rotor working parallel to the advance, equipped with knives and/or hoes capable of intercepting and ejecting soil from the furrow, integrated on the supporting frame with a series of complementary organs for the direct and contextual laying of pipes. These models are usually of a relatively small footprint and mass. This is a crucial peculiarity for fruitful use in some crops, such as orchards and vineyards, where excessive width may become a limiting factor due to the small planting sixth, while the possible high mass may cause such compaction as to hinder the proper development of crop root systems.
Complementary uses of ditchers
Besides digging ditches and canals and performing their maintenance (routine and extraordinary), ditchers prove useful when installing tunnels and cold greenhouses: When working at relatively shallow depths (30-40 cm), they are used to tamp down the plastic covering film on the long sides of these protected arrangements. In fact, the earth dislodged by the excavation covers the end edge of the cover, ensuring the tightness of the interior environment with respect to the exterior and creating a layer of earth above the film so that the latter is not damaged if heavy vehicles pass through.
The special section double-wheel ditchers
Double-wheel models have been built for large excavations, particularly for contractors who often have extremely high-power tractors suitable for operating with heavy and continuous loads. For this purpose, Cosmeco of Ostiglia (MN) offers the Big Storm model, of 2,000 kg mass, that can make canals up to 1.45 m deep, with a width of more than 2 m at ground level. Similarly, Dondi of Bastia Umbra (PG) offers the Super series, which opens canals more than one meter deep with a surface width exceeding two meters.
In order to adequately drive this equipment, tractors of 250-300 Hp and more are required, obviously with the 1,000 rpm PTO, in order to contain the torques involved, which are extremely high in any case.
Safety at work
Due to their typical operating characteristics, ditchers are dangerous equipment, especially when it comes to throwing stones and compacted clods of earth at considerable distances from the working point. Therefore, the baffles directing the flows of loose soil transverse to the direction of advance must be carefully managed to avoid causing the soil to fall back into the furrow created while preventing projection at excessive distances. This is why, both in the instruction booklet and directly on the equipment, clear and obvious danger warnings are placed, requiring any third parties to stand not less than 50 m from the machine's working area. It is also quite clear that for the tractor driver's complete safety, it is necessary to employ models equipped with a cab, which must logically be kept carefully closed while working.