Soil reactions of selected bullock drawn ploughs in two extreme soils

摘要

Establishing relations between the plough reactions and the soil constituency help in designing better soil working tools. It leads to minimized energy cost in tillage operations. A hydraulic six cell dynamometer was developed and used in a standardsoil bin to compare the mechanics of four bullock drawn tools, namely country plough, iron plough, Tenkasi plough and semi digger. The trials were conducted in two extreme soils namely black cotton and sand, at three levels of soil moisture content andthree operating depths. The measurements yielded the complete picture of plough mechanics. The country plough had substantially lesser horizontal reaction of 250 to 460 N in black soil and 165 to 270 N in sand. The iron plough had the maximum horizontalreaction of about 1000 N in black soil and 750 N in sand. But the unit drafts were 3.S to 4.8, 5.3 to 6.6, 4 to 6.1, and 2.65 to 4.25 N cm~(-2) for the iron, semi digger, Tenkasi and country ploughs respectively in black soil. This indicated that the semi digger demanded the maximum specific draft among the ploughs tested. The vertical soil reactions were all downward indicating a suctional force and they generally increased with depth of operation in both the soils. Clock-wise couples were present onlyfor the iron plough and the semi digger. In the semi digger, it increased non-linearly from 4000 Nm at 8 cm depth to 5000 Nm at 16 cm.