ENERGY REQUIREMENTS FOR CONVENTIONAL TILLAGE FOLLOWING DIFFERENT CROP ROTATIONS
Energy savings can be made by improving tractor and implement performance during tillage. We studied the 
relationship between cropping history and energy requirements for moldboard plowing and seedbed preparation 
(two passes with a field cultivator) on a loam soil under nine previous management practices, ranging from 6-year 
bromegrass (Bromus inermis Leyss.) to 6-year conventional-till corn (Zea mays L.). Soil bulk density ( nb) and volumetric 
water content ( e) were measured before tillage. Draft, specific draft, ground speed, wheel slip, fuel consumption and plow 
depth were monitored during primary and secondary tillage using a 97 kW instrumented tractor. The nb, eand all of the 
primary tillage performance variables were significantly influenced by cropping history. Plow depth increased with 
decreasing nb (r = –0.41*). Draft (r = 0.44**), specific draft (r = 0.40*), wheel slip (r = 0.40*), and fuel consumption (r = 
0.35*) increased with increasing e, while ground speed decreased (r = –0.39*). The effects of previous management on 
tillage energy became less pronounced as number of secondary tillage operations increased. Soil fragmentation (Df) was 
measured after tillage, and was similar for all of the treatments despite different amounts of energy expended. 
Conventional tillage operations following long-term forages increase the energy required to produce a corn crop relative 
to continuous conventional-till corn.