Determination of tractive resistance of a wide-level chain harrow for soil mulching

BACKGROUND: One of the prerequisites for implementation of the mini-till and the no-till technologies is accumulation of mulch layer. Chain harrows show high efficiency in soil mulching, but the working bodies used on them are not fully capable of providing sufficient depth of cultivation, as well as crushing and mixing of crop residues with soil. Taking into account the high prospectivity of the mini-till and the no-till technologies, the research aimed at improving machines for soil mulching and chain harrows in particular is relevant. AIM: Development of the wide-level chain harrow and the working body ensuring intensification of soil mulching processes, theoretical and experimental evaluation of traction resistance of the machine. METHODS: Based on methods of agricultural mechanics, the research of traction resistance value of the harrow with the improved chain working body has been carried out. The laboratory-field experiment on estimation of traction resistance value of the wide-level chain harrow was carried out. RESULTS: Based on the analysis of drawbacks of the default working body of the V.I. Dvurechensky’s chain harrow, it was proposed to move the ripper tooth to the fixing plate located in the center of the link. This technical solution is designed to provide better burial of the teeth in the soil, as well as the intensity of shredding of plant residues. It is theoretically and experimentally found that the value of traction resistance of the improved chain working body depends on the weight and the main design parameters of ripper teeth: length, tooth sharpening angle and cross-sectional diameter. The conducted laboratory-field experiments helped to find that at changing the working velocity of the machine from 15 to 21 km/h, the value of traction resistance increases from 26.2 to 32.3 kN, respectively, with the value of tractor slip not more than 3.0%. Based on the analysis of the obtained values of traction resistance and agrotechnical indicators of operation, the reasonable velocity of the machine is determined and should be 18 km / h. CONCLUSION: The value of traction resistance of the chain harrow with the improved working organ has been experimentally determined, which allows recommending a tractor of a reasonable traction class. The efficient technological mode has been revealed.