Investigations at Burlington, Colorado. 



73 



loam at Burlington is underlaid at about 2.5 feet with hardpan, while powdery 

 loess occurs below this level. All of the soils are very fertile, their physical 

 effect upon the water-content affecting crop production to a far greater degree 

 than their chemical composition. 



June July August 



2 3 4 1 2 3 4 12' 















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Fia. 33. — Average daily soil-temperature at Lincoln (solid line), Phil- 

 lipsburg (long broken lines), and Burlington (short broken 

 lines), 1920. 



June July August 



3 4 1 2 3 4 1 2 2 



55 • 1 » 1 1 1 1 u 1 1 



Yiq. 34. — Average daily air-temperature at Lincoln (solid line), Phil- 

 lipsburg (long broken lines), and Burlington (short broken 

 lines), 1920. 



A study of the water-content to a depth of 4 feet shows that at both the 

 upland and lowland stations at Lincoln at least 7 per cent (and usually 10 

 to 20 per cent) available watei was present at all depths below 6 inches until 

 the middle of July. At no time during the growing-season was the supply 

 of available water, even in the surface 6 inches, entirely exhausted, a margin 

 of 4 to 9 per cent being maintained in the deeper soil even during the driest 

 part of the season. At Phillipsbuig the water relations were less favorable. 



