Sept. 9,1918 Deep Tilling and Dynamiting in the Great Plains 
521 
elusion: that yields can not be increased nor the effects of drouth 
mitigated by tillage below the depth of ordinary plowing. 
The quite general popular belief in the efficiency of deep tillage as a 
means of overcoming drouth or of increasing yields has little foundation 
of fact, but is based on misconceptions and lack of knowledge of the form 
and extent of the root systems of plants and of the behavior and move¬ 
ment of water in the soil. 
LITERATURE CITED 
(1) Cardon, P. V. 
1915. TILLAGE AND ROTATION EXPERIMENTS AT NEPHI, UTAH. U. S. Dept. 
Agr. Bui. 157, 45 p., 21 fig. 
(2) Hastings, S. H., and Letteer, C. R. 
1913. EXPERIMENTS IN SUBSOILING AT SAN ANTONIO. In U. S. Dept. Agr. 
Bur. Plant Indus. Circ. 114. p. 9-14. 
(3) Mathews, O. R. 
1916. WATER PENETRATION IN THE GUMBO SOILS OP THE BELLE FOURCHE 
reclamation project. U. S. Dept. Agr. Bul. 447, 12 p., 4 fig. 
(4) Mosier, J. G., and Gustafson, A. F. 
1915. soil moisture and tillage for corn. Ill. Agr. Exp. Sta. Bul. 181, 
p. S 63 SM> 7 fig- 
(5) Noll, C. F. 
1914. deep versus ordinary plowing. In Penn. Agr. Exp. Sta. Ann. Rpt. 
1912/13, p. 39-47, 1 pi. 
(6) Ricks, J7 R. 
1915. corn, results from central station. In Miss. Agr. Exp. Sta, Bul. 
170 P- 3“ 12 * 
(7) - 
1915. forage crops. Miss. Agr. Exp. Sta. Bul. 172, 23 p., 5 fig. 
8) Rotmistrov, V. G. 
1913. THE NATURE OF DROUGHT ACCORDING TO THE EVIDENCE OF THE ODESSA 
Experiment field. Translation from Russian. 48 p.,21 fig. Odessa. 
