WHEAT 51 



soil to settle or become moderately compacted by rain, 

 plowing for wheat should be done, if practicable, at least 

 several weeks before the anticipated date of sowing the 

 seed. In Oklahoma it has been found advantageous 

 to plow for wheat as early as midsummer. Plowing 

 three to six weeks before seeding is often advisable; 

 but when wheat follows catch-crops of cowpeas, it is 

 often necessary to sow it soon after plowing under the 

 cowpea stubble 'and to rely upon harrowing and rolling 

 to compact the soil. Immediately after plowing and 

 before the upturned soil has dried into clods, the field 

 should be harrowed. Harrowing should be repeated 

 at such intervals between the dates of plowing and 

 sowing as to prevent the formation of a crust or the 

 growth of vegetation. 



If no rain falls near the time of plowing, it will be advisable 

 to employ the roller or plank drag in addition to the harrow, in 

 compacting and pulverizing the seed-bed for wheat. In case the 

 soil is excessively dry, it may be necessary to use *iie roller after 

 sowing the seed, to enable moisture from the subsoil to be con- 

 veyed more easily by capillary attraction through the rolled soil 

 to the seeds, which, by means of the roller, are pressed into close 

 contact with the particles of soil. 



However, the same compactness that makes it easier for the 

 moisture in the rolled soil to rise from the subsoil to the seed also 

 makes it easier for this moisture to continue to rise to the sur- 

 face, where it would be lost by evaporation. Hence, evaporation 

 must be decreased by forming a mulch, or layer of loose soil on 

 the surface, which is most easily done by using a harrow or 

 weeder after the roller. 



The sowing of wheat on land which has not been plowed, but 

 merely disked, is sometimes practiced on clean mellow soil in 

 higher latitudes. This procedure has been found insufficient in 

 the South. 



