38 BULLETIN 142, U. 8. DEPARTMENT OF AGRICULTURE. 



becomes more compact and claylike. The lower part of the 3-foot 

 section is usually a brownish clay or clay loam containing consider- 

 able sand and gravel. At greater depths the material becomes dis- 

 tinctly gravelly and sandy, and numerous bowlders are encoun- 

 tered. The flat phase grades into the Clyde silty clay loam in 

 depressions where there has been a considerable accumulation of 

 organic matter, and into the normal or rolling phase of the Miami silt 

 loam where the topography becomes somewhat more rolling and 

 the covering of silt over the underlying sandy and stony clay is of 

 less depth. This phase of the type is practically stone free at the 

 surface. 



The surface of practically all of this phase is only very gently un- 

 dulating, while considerable tracts are nearly level. Some small 

 areas of low relief are found within the phase. The depressed and 

 nearly level areas are usually rather poorly drained, and only the 

 more elevated areas lying along the crests of low swells have fair 

 to good natural drainage. The greater part of the phase would be 

 materially benefited by the installation of tile underdrainage. 



The flat phase of the Miami silt loam originally supported a mixed 

 growth of hardwood timber in which beech predominated. It came 

 to be known as " beech land," in distinction from the more rolling 

 phase of this type, which was known as " sugar-tree land " because of 

 the greater abundance of sugar maple. With the exception of small 

 woodlots, the phase has been cleared, and probably 90 per cent of its 

 area is under cultivation. 



Corn is extensively grown, giving yields which average somewhat 

 below 40 bushels per acre. During exceptionally wet years the yield 

 is far below this, and extreme drought also exerts a very unfavor- 

 able influence upon the yield. This phase is not so well suited to 

 corn production as the more rolling part of the type, and the yields 

 are frequently below the average for the region. 



Wheat is commonly grown and constitutes the chief small-grain 

 crop on this phase of the type. The yields range from 12 to 20 

 bushels per acre, with an average of about 15 bushels. Oats are 

 also grown, and in years of abundant rainfall give excellent results. 

 The yields range from 30 to 50 bushels per acre, with an average 

 of approximately 35 bushels. 



Timothy and clover constitute the chief hay crops. Timothy is 

 well suited to this soil, while red clover is not so successfully grown 

 as on the more rolling phase. 



Tomatoes for canning are grown to some extent, and potatoes and 

 garden vegetables are produced for home consumption. 



Deep phase. — The deep phase of the Miami silt loam has been 

 mapped extensively in south-central Wisconsin, where it occurs in 

 Dane, Columbia, and Fond du Lac Counties. 



