CEREAL CULTIVATION GREAT PLAINS 363 



391. The soil mulch. Some years ago there was 

 much discussion of the " dust mulch," considered by many 

 then to be essential in checking evaporation. A dust 

 mulch is now known to be very undesirable in the very 

 localities where evaporation is greatest, as it promotes 

 soil-blowing. It is probably not nearly the effective 

 means of conserving moisture that it was supposed to be, 



FIG. 114. Time-of -seeding test of winter wheat at the Newell, South 

 Dakota, substation. The plat on the right was sown much earlier 

 than the other. 



and, moreover, it soon forms a hard crust in heavy soils. 

 A better mulch is one of coarser particles, 3 inches or 

 more deep, and which leaves the surface rough (see Fig. 

 108). A cultivator used lightly is a good implement for 

 surface cultivation of light sandy soils. Mulch of hay or 

 straw is very effective for conserving moisture. This 

 may be raked off afterward, or if not in the way of the 

 crop, can be plowed under later. 



392. Time of fall seeding. Usually it is best to sow 

 winter grain early (Fig. 114). Sometimes after continued 

 dry weather, rather late seeding is necessary in order to 



