306 AGRICULTURE FOR BEGINNERS 



in the form of vegetable manures will keep the soil in the 

 porous condition needed. 



Second, after the water has entered the soil, it is equally 

 important to hold it there so that it may supply the grow- 

 ing crops. If the land is allowed to remain untilled after a 

 rain or during a hot spell, the water in it will evaporate too 

 rapidly and thus the well will go dry too soon. To prevent 



FIG. 266. THE DISK HARROW 



this the top soil should be stirred very frequently with a 

 disk or smoothing harrow. This stirring will form a mulch 

 of dry soil on the surface, and this will hold the water. 

 Other forms of mulch have been suggested, but the soil 

 mulch is the only practicable one. It must be borne in 

 mind that this surface cultivation must be regularly kept 

 up if the moisture is to be retained. 



Some experiments in wheat growing have shown how 

 readily water might be saved if plowing was done at the 



