158 



Nature-Study Agriculture 



Keeping a 

 dirt mulch 



The lesson 

 of a horse 

 track; the 

 subsurface 

 packer 



Deep 

 planting 



To have the soil retain as much as possible of the water 

 that it has absorbed, the surface must be kept loose- 

 This lessens the amount of moisture that can rise be- 

 tween soil particles through capillary attraction. (Exp. 

 2.) The surface should not be allowed to pack down 

 or to crust over ; so frequent harrowing or other shallow 

 cultivation is necessary, especially after each rain. 

 Instead of a roller, a subsurface packer is used to pack 

 the soil. This firms the lower soil but leaves the surface 

 loose (Fig. 125). 



It is said that H. W. Campbell, who has done much 

 to teach the methods of dry farming, observed that 

 wheat grew better in horse tracks than in other parts 

 of a field. He noted how the horse, in treading, packs 

 the soil, and that, as it withdraws its foot, loose dirt 

 falls into the hole, making a dirt mulch on the surface. 

 It was Mr. Campbell who invented the subsurface 

 packer, to do for all the ground what the horse's hoof 

 does for a small spot. 



The deeper the roots can be made to grow, the better 

 they are able to obtain moisture. The Indians in New 

 Mexico understood this before white men did. They 

 made holes in the ground with stakes and dropped the 

 seed corn into the holes. White men sent to teach them 



