Experimental research into the effect of harrowing unit’s operating speed on uniformity of cultivation depth during tillage in fallow field
¹National University of Life and Environmental Sciences of Ukraine, 15 Heroyiv Oborony street, UA03041 Kyiv, Ukraine
²Dmytro Motornyi Tavria State Agrotechnological University, 18B Khmelnytsky Avenue, UA72310 Melitopol, Zaporozhye Region, Ukraine
³National Scientific Centre, Institute of Agriculture of NAAS of Ukraine, 2b, Mashinobudivnikiv street, Chabany vil., Kyiv-Svyatoshin Dist., UA08162 Kyiv Region, Ukraine
⁴National Scientific Centre, Institute of Mechanization and Electrification of Agriculture, 11 Vokzalna street, Glevakha stl, Vasylkivsky Dist., UA08631 Kyiv Region, Ukraine
⁵Estonian University of Life Sciences, Institute of Technology, 56 Kreutzwaldi street, EE 51006 Tartu, Estonia
Retention of soil moisture is an urgent topic of the day in the cultivation of agricultural crops. Using fallow fields is one of the ways to solve the named problem, but the tilling of such fields requires observing some special conditions, in particular, the capillary effects in their upper soil layers must be cut down. For that purpose, the authors have proposed a special harrow equipped with the tools capable of fulfilling the above-mentioned task. The authors have carried out extensive field experiment research into the tillage of fallow soils with the use of the said implement. In order to apply the implement, a new harrow unit has been developed. The results obtained during the experiment research have been processed with the use of statistical methods and it has been established that the depth of harrowing in the tilled field decreases, when the operating speed of the combined unit under consideration increases to 3.3 m s–1. At the same time, the variances of oscillations of the parameter under research in accordance with the Cochran’s C test remain uniform. Also, the frequency of the harrowing depth oscillations changes insignificantly. That is supported by the correlation lengths of the normalized correlation functions of the process under consideration, which, at the above-mentioned operating speed, stay within the sufficiently narrow range of values: 0.16–0.20 m. According to the results of the experimental investigations, the maximum value of the normalized cross-correlation function for the relation between the oscillations of the field harrowing depth and the oscillations of the field’s longitudinal profile does not exceed 0.12. This testifies to the absence of any substantial interrelation between the said two stochastic processes, which is quite reasonable in view of the small values of the variance and period of the oscillations of the field’s longitudinal profile. The probability of the new combined tractor and harrow unit maintaining the tolerance of the fallow field cultivation depth oscillations within the range of ± 1 cm is equal to 82%. Within each 1.85 m of the distance travelled by the combined soil cultivation unit under consideration, only one instance of the field cultivation depth deviating from the ± 1 cm tolerance can be expected.