|Riassunto in Inglese:|
Traditional soil tillage for preparing the seed-bed is based on medium depth ploughing followed by refinement of the superficial layer. Such techniques can determine high energy costs, loss of nutrients, decrease of natural soil fertility and, in some cases, increase of erosion phenomena caused by wind and water. These negative effects can be reduced by introducing conservative soil tillage techniques, such as tilling without inversion of layers and minimum tillage, which aim at reducing the energy requirement of interventions. Traditional soil refinement tillage are normally performed by machines powered by the tractor PTO, like a rotary harrow, which prepare the seed-bed in a single pass and take full advantage of the power supplied by the tractor, especially those characterized by a wide working width. Conservative techniques are based on a wide range of possible interventions, such as soil unpacking, by means of combined cultivator, and minimum tillage (with disk harrow).
The Agricultural Machinery Testing Centre (CPMA) of CRA-ING, accredited as Testing Laboratory (ACCREDIA no. 1141) for tests on the performances of soil tillage machines, which applies a quality management system complying with the requirements of the EN ISO/IEC 17025:2005 standard, performed tests to compare the energy requirements and the work quality of a machine with working tools powered by tractor p.t.o. (rotary harrow) and two machines with passive working tools: a disk harrow and a combined cultivator. The tests were carried out on a flat, silty-clay untilled soil, using a 205 kW instrumented tractor. The objective of the study was to evaluate the energy parameters of each tractor-machine coupling and the quality of their work, in accordance with the protocol for the testing of functional characteristics of soil tillage machines, proposed by ENAMA, especially with reference to the capability of soil refinement as a function of working depth and speed. The tests results show a decrease of power and energy requirements proceeding from traditional to more conservative tillage methods, that can be synthesized in savings up to 42.6% for the fuel consumption for surface unit, and up to 45.9% for the energy per surface unit. Good seed-bed quality index were provided by the combined cultivator and the disk harrow.