ORCHARD SOILS 



659 



these larger components may have a relatively unimportant bearing; on 

 water holding capacity, aeration, root penetration and related features, 

 they do influence it materially in its relation to tillage practices and they 

 often prove a limiting factor in determining the kind of crop that can 

 be grown in it advantageously, or the kind of orchard culture that must 

 be practiced. Thus of two soils whose so-called "fine earth" might ana- 

 lyze the same, one might be suitable to the strawberry and the other 

 quite unsuited because of the presence or absence of large quantities 

 of rocks and coarse gravel. It is interesting to compare the mechanical 

 analyses of several soils used for fruit production. 



Table 15.- 



-ScHEME OF Soil Classification, Based on the Mechanical 

 Composition of Soils 



(1), (2) 

 2-0.5 

 milli- 

 meters, 

 per cent. 



(7) 

 Less than 

 0.005 

 milli- 

 meters, 

 per cent. 



(6), (7) 

 Less than 

 0.05 

 milli- 

 meters, 

 per cent. 



Coarse sand 



Medium sand . . . 



Fine sand 



Sandy loam 



Fine sandy loam 



Loam 



Silt loam 



Clay loam 



Sandy clay 



Silty clay 



Clay 



>25 

 <25 



>50 

 >20 

 <20 

 >20 

 <20 



0-15 



0-15 



0-15 



10-35 



10-35 



<55 



>55 



25-55 



<25 



>55 



0-10 

 0-10 

 0-10 

 5-15 

 5-15 



15-25 

 <25 



25-35 

 >20 



25-35 

 >35 



<20 



<20 



<20 



>20<50 



>20<50 



>50 



>60 

 <60 



>60 



(1) "Fine gravel," 2-1 millimeters. (2) "Coarse sand," 1-0.5 millimeters. (3) 

 "Medium sand," 0.5-0.25 millimeter. (6) "Silt," 0.05-0.005 millimeter. (7) 

 "Clay," less than 0.005 millimeter. The residue is composed of "fine sand," 0.25-0.1 

 millimeter and "very fine sand," 0.1-0.05 millimeter. 



Mechanical Analyses of Various Fruit Soils. — Soils A and C with their 

 subsoils B and D (Table 16) are fairly typical of the western New York 

 fruit district, one of the leading apple producing sections of the world. 

 Soil A, the Dunkirk sandy loam, contains 64 per cent, of medium and 

 coarse sand in the surface and slightly more in the subsoil and only 

 about 5 per cent, of clay in both surface and subsoil, while soil C, the 

 Dunkirk loam, contains only about 30 per cent, of medium and coarse 

 sand in the surface soil and a little more than half that amount in the 

 subsoil, but approximately twice as much of the finer materials — clay 



