276 



Bulletin 232. 



The Soil. 



According to the Bureau of Soils, United States Department of 

 Agriculture, the Dunkirk series forms an important group of soils 

 and are "found in well-defined terraces along some of the great 

 lakes. These soils are composed of glacial material reworked and 

 redeposited when the lake waters reached a higher level than at 

 present." 



The Dunkirk clay, the most tenacious type of this series, is de- 

 scribed as follows: "Soil is a dark to black clay, six to twelve 

 inches in depth, underlain by a tenacious, mottled clay, beneath 

 which, at a depth of four to ten feet, occurs the typical bowlder clay. 

 Near ancient beach lines the soil is sometimes underlain by gravel. 

 Found upon lake foreland and in upland valleys. Derived from 

 deposition in quiet water. Some areas badly drained." As this 

 tj'pe occurs on the Station farm it is generally lighter in color than 

 the description above given, only appearing black in the ravines 

 and lower areas, and none of the black phase occurred in the tract 

 on which this experiment was conducted. The soil is quite ten- 

 acious and is difficult to work except when moisture conditions are 

 just right. It is usually difficult to get upon this land until late 

 in the spring, and early fall rains may prevent fall seeding. 



A mechanical analysis of the soil upon which the following experi- 

 ments were conducted was made by the Bureau of Soils with the 

 following results: 



Mechanical Analysis of Dunkirk Clay Loam, Cornell University Farm. 



CONVENTIONAL NAMES. 



Subsoil. 



Organic matter 



Fine gravel, coarse and medium sand. . . . 



Fine and very fine sand 



Silt 



Clay 



Total (not including organic matter) 



This analysis gives the percentage of silt much higher, and the 

 percentage of clay much lower than the analyses reported for Dun- 

 kirk clay. It is thought advisable, therefore, to classify this soil 

 as the silty phase of Dunkirk Clay Loam, no description of which 

 has been given. 



The tract on which this experiment was conducted had come 

 only recently into the possession of Cornell University. The former 



