Location, Exposure, Soils, and Windbreaks 19 



Gypsum rarely occurs, while marl is common, but the cas- 

 ual observer is not able to distinguish between the two. 

 They are usually light-colored, chalky materials, and may 

 occur in compact layers or mixed with earth. If the 

 layer is compact and near the surface, naturally the soil 

 is shallow, and so the plant-food is soon exhausted. While 

 it is true that tree roots may penetrate these layers, the 

 majority of them do not do so, but rather spread out 

 laterally, thus producing a shallow-rooted system. Here 

 the roots are exposed to sun and frost, and as the soil is 

 easily dried out, constant care is necessary to keep the 

 trees in good condition. It is on such soils that the so- 

 called tuft blight, or rosette, of apple trees occurs, and 

 where stunted trees with yellow foliage are often seen. 

 Much of the fruit grown under these conditions is under- 

 sized, and thus but comparatively small amounts can be 

 marketed as first-class. 



With proper attention to watering, cultivation, and 

 fertilizing, much can be done to ameliorate such subsoil. 

 In fact, a few growers are meeting with good success with 

 orchards on this kind of land. A system of green-manur- 

 ing, as set forth under the head of Shade-crops (Chapter 

 XII) , would be of special benefit under these conditions. 

 It has also been found by experience that certain varieties 

 of apples are much better adapted than others to such 

 soils. 



The base of both gypsum and marl is lime; and it is 

 thought by some investigators that the lime in the marl 

 is very harmful to fruit trees. Whether this is true 

 in the case of marly soils of this region remains to be 

 determined. 



