SUBSOIL A FACTOR IN GROWTH OF APPLE TREES 



blackjack oak. The post oaks on such soil grow taller and are more 

 slender. 



Baxter gravelly loam occurs principally on the slopes and supports 

 a mixed forest growth in which large red oaks predominate but which 

 includes chinquapin oaks, walnut, elm, dogwood, and a variety of 

 other trees. (PL 1, C.) The surface soil consists of light-brown or 

 slightly reddish-brown gravelly loam about 7 inches thick, beneath 

 which is lighter reddish-brown gravelly loam which, at a depth of 

 about 15 inches, grades into distinctly reddish-brown gravelly clay 

 loam, heavier in texture and containing more chert gravel. At a 

 depth of about 24 inches this grades into the red, gravelly clay of the 

 area. The gravel found in this soil is, as a rule, reddish brown, 

 rather soft, and somewhat porous. In no place is it cemented as in 

 the Lebanon soils. 



The principal variation in Baxter gravelly loam is in the depth to 

 the underlying limestone or to thin layers of unbroken chert. On 

 steep parts of the slopes, around the heads of small streams, and in 

 other places the loose, friable material is shallow and the surface is 

 very gravelly. In places, too, on the tops of ridges there is a tendency 

 toward slight cementation. Such areas are intermediate between the 

 Baxter and Lebanon soils. 



Newtonia silt loam 1 consists of dark-brown or reddish-brown silt 

 loam to a depth of 7 or 8 inches. Below this depth, the material is 

 heavier and redder in color. Below a depth of about 15 inches is 

 dull-red, friable silty clay loam which extends to a depth of about 30 

 inches. Below this depth the material has the same red color but is 

 more friable and is underlain by heavy beds of gravel or by solid 

 limestone. This red subsoil is in places 8 or 10 feet thick but in many 

 places is more shallow. It contains no impervious clay layers or 

 cemented hardpan like that found in the Gerald or Lebanon soils. 

 Parts of the Newtonia soils were originally prairie land, and in such 

 areas the soils are dark colored. In other parts they were forested. 

 In places the forest growth consists of tall, straight red oaks, (pi. 2, 

 A) , but in other places is a mixed growth of large trees. 



The most important difference in the character of the four soils 

 described is in the subsoil. The subsoils of the Gerald and Lebanon 

 soils are tight and nearly impervious and tend to restrict the free 

 movement of moisture, air, and plant roots. In wet weather they 

 become very wet, and in dry weather they dry out quickly, 



In direct contrast, the subsoils of the Baxter and Newtonia soils are 

 porous and friable, are not cemented, and allow the free movement 

 of moisture and deep root penetration. For this reason these soils are 

 much more able to withstand drought without injury to the crops. 



For purposes of this study these soils, and all soils in fact, may be 

 divided into two classes: (1) Those which have tight subsoils and (2) 

 those which have open or friable subsoils. In soils of the first group 

 the rooting of the trees is limited to a shallow surface layer in which 

 the moisture may and often does become exhausted and in which the 

 plant food, if not supplied by fertilization, soon becomes depleted. 



1 In Newton and Barry Counties, Mo., this soil was correlated as Hagerstown. In 

 Greene County, Mo., it was called Crawford, but it has recently been given the name 

 Newtonia. 



