a consistent soil composition the parameters of the harvesting operation performed define the operation profile 36 and the composition of the test plot soil defines the soil profile 32 the seventh step 44 in this embodiment 20 is to predict operation effects 46 that are resultant upon performance of the operation given the predicted operation characteristics 40 operation effects 46 are also indicative of operation suitability 6 and include but are not limited to crop yield impact and fuel cost in the illustrated embodiment 20 these effects 46 are determined by referring to empirical tables 48 giving values for known operation characteristics 40 soil profile 32 and operation profile 36 for example a table 48 giving values for crop yield impact may be developed by measuring crop yields under a number of soil compaction levels on a test plot having a consistent soil composition examples outlining the development of such tables 48 may be found in soybean growth and yield as affected by subsurface and subsoil compaction j f johnson et al agronomy journal vol 82 no 5 september october 1990 fig3 illustrates a second embodiment 21 of the present invention whereby the method predicts operation variables 8 indicative of operation performance suitability 6 at a node 12 within the field 10 the first step 22 u2032 in this embodiment 21 is to access values predicted for weather conditions.