NURSERY PRACTICE FOR PRAIRIE-PLAINS PLANTING 155 



tree, and to obtain a consistently good growth and high survival of 

 shelterbelts, even in periods of subnormal rainfall. Too much empha- 

 sis cannot be placed on attaining this goal, because nothing will 

 stimulate more interest in planting and care of farmstead plantings and 



shelterbelts in the plains region than the presence in each county of a 

 number of thrifty, well-planned belts of fast-growing trees planted with 

 the best technical guidance that Federal and State agencies can give. 



LITERATURE CITED 



(1) Bates, C. G. 



1930. THE PRODUCTION, EXTRACTION. AXD GERMINATION OF LODGEPOLE 



pine seed. U. S. Dept. Agr. Tech. Bui. 191. 92 pp.. illus. 



(2) Bouyoucos, George John. 



1937. evaporating the water with burning alcohol as a rapid 



MEANS OF DETERMINING MOISTURE CONTENT OF SOILS. Soil 



Sci. 44: 377-384, illus. 



(3) — 



1938. A RAPID METHOD FOR DETERMINING THE PERMANENT WILTING 



POINT AND FOR INDICATING UNDER FIELD CONDITIONS THE RELA- 

 TION of soil moisture thereto. Soil Sci. 45: 47-55, illus. 



(4) Brackett, E. E., and Lewis, E. B. 



1933. PUMP IRRIGATION INVESTIGATIONS IN NEBRASKA. Xebr. Agr. 



Expt. Sta. Bui. 282. 31 pp., illus. 



(5) Breazeale. J. F. 



1926. ALKALI TOLERANCE OF PLANTS CONSIDERED AS A PHENOMENON OF 



adaptation. Ariz. Agr. Expt. Sta. Tech. Bui. 11, 19 pp., illus. 



(6) and McGeorge, W. T. 



1932. NUTRITIONAL DISORDERS IN ALKALINE SOILS AS CAUSED BY DE- 

 FICIENCY of carbon dioxide. Univ. Ariz. Tech. Bui. 41. 

 153 pp., illus. 



(7) Briggs, Lyman J., and Shantz, H. L. 



1912. THE WILTING COEFFICIENT FOR DIFFERENT PLANTS AND ITS IN- 

 DIRECT determination. U. S. Dept. Agr., Bur. Plant Indus. 

 Bui. 230, 83 pp., illus. 



(8) Carter, J. C. 



1939. PROGRESS IN THE CONTROL OF ELM DISEASES IN NURSERIES. 



111. Xat. Hist. Survev, Biol. Xotes 10, 19 pp. 



(9) Chapman, A. G. 



1936. SCARIFICATION OF BLACK LOCUST SEED TO INCREASE AND HASTEN 



germination. Jour. Forestrv 34: 66-74, illus. 



(10) Ewing, Paul A. 



1934. pumping from wells for irrigation. U. S. Dept. Agr. Farmers' 



Bui. 1404, 28 pp., illus. (Revised.) 



(11) Flemion. Florence. 



1938. a rapid method for determining the viability of dormant 

 seeds. Boyce Thompson Inst. Contrib. 9: 339-351, illus. 



(12) George, Ernest J. 



1937. STORAGE AND DEWIXGIXG OF AMERICAN ELM SEED. Jour. ForeStTY 



35: 769-772. 



(13) Giersbach, Johanna, and Crocker. William. 



1932. germination and storage of wild plum seeds. Boyce Thomp- 

 son Inst. Contrib. 4: 39-51, illus. 



(14) Hartley, Carl. 



1921. damping-off in forest nurseries. U. S. Dept. Agr. Bui. 934, 

 99 pp., illus. 



(15) Hayes, F. A., and Stoeckeler, .1. H. 



1935. SOIL AND FOREST RELATIONSHIP- OF THE SHELTERBELT ZONE. 



U. S. Forest Serv. Possibilities of Shelterbelt Planting in the 

 Plains Region, sect. 12, pp. Ill 153. illus. 



(16) HlLGARD, E. W. 



1931. soils. . . . Rev. ed., 593 pp., illus. Xew York and London. 



(17) Hurst, W. M., Humphries, W. R., and McKee, Roland. 



1935. barrel and disk seed scarifiers. U. S. Dept. Agr. Cir. 345, 

 24 pp., illus. 



