Smithsonian Report, 1921. — Scofield. 



Plate 3. 



** ■*. 



". /^ •< i_ <« * •wft* '3BZJL ^? ^ • HJL - ' -V 



A "Hard Spot" in an Irrigated Field where the Soil Had Been Puddled 

 by the Irrigation Water and Had Baked on Drying Out. The Hard 

 Crust Is Often Two or Three Inches Thick. When Such a Crust Is 

 Formed on Newly Seeded Land the Seedlings Are Prevented from Com- 

 ing Up. 



214—3 



