DUST MULCH 



89 



Dust Mulch. Evaporation of soil moisture, particularly dur- 

 ing the hot, growing season of the year, is one of the greatest losses 

 of the farm. The modern methods in vogue in serni-arid regions 

 tend to prevent this loss. They are just as applicable to humid 

 regions during the growing season, because of the droughts which 

 usually occur. If the surface soil be kept loose so that the capillary 

 contact of the particles is broken, the loss through surface evapora- 

 tion is greatly reduced. Such a condition of the surface soil is 

 spoken of as a dust mulch. It can be readily produced by the use 

 of a harrow. The surface soil may be easily kept in this fine broken 

 condition before crops are sown, by the frequent use of a harrow 

 (Figs. 67, 68). In the so-called hoed crops, such as corn, cotton, 



FIG. 68. The weeder will produce a fine dust mulch and conserve moisture in the soil. 



(Bateman Mfg. Co.) 



potatoes, tobacco and others, a fine-tooth cultivator may be used 

 to stir the soil very frequently and thus prevent the formation of 

 a crust. 



The student should understand that a crust formed upon the 

 surface of soils, by drying rapidly after heavy rains have packed 

 the particles together, is very detrimental to the growth of all 

 crops. Such a crust causes very rapid evaporation of soil mois- 

 ture. The particles are so close together that the capillary climb 

 of water is direct and rapid. As soon as the ground begins to dry 

 enough to allow the use of a harrow or light cultivator these im- 

 plements should be used. The farmer who allows a crust to form 

 on any field loses water which the crop will need later. The same 



