660 FUNDAMENTALS OF FRUIT PRODUCTION 



and silt. Here, indeed, are marked differences in the average size of 

 soil particles, yet there are but slight differences in the way apple trees 

 grow in these soils. Soil E, a fairly typical loess of Nebraska, contains 

 no medium or coarse sand and comparatively large amounts of silt and 

 clay, yet it furnishes excellent drainage and is eminently suited to the 

 production of fruit, particularly apples. Though probably the Billings 

 clay loam (Soil M), with its 47 per cent, clay and 91 per cent, of clay and 

 silt combined is not an ideal soil for apples, it is a characteristic soil of the 

 Grand Junction section of Colorado and where the topography permits 

 reasonably good drainage, apple production is profitable. This par- 

 ticular soil serves to illustrate the point that the mechanical analysis of a 

 soil is not always an accurate index to its possibilities for fruit growing. 

 Though this analysis suggests very poor drainage and consequently a 

 lack of suitability for fruit crops, some of this land is fairly well drained 

 and does produce good fruit crops. However, it is but proper to state 

 that the majority of the Grand Junction orchards are on soils of a some- 

 what lighter character. The Maricopa gravelly sand of California is, 

 as the name suggests, comparatively light and open in character, con- 

 taining 57 per cent, fine, medium and coarse sand and 11 per cent, fine 

 gravel. It is considered very good for grapes; yet the Alamo clay adobe 

 with 95 per cent, of clay and fine silt is said to be fairly suitable for grapes 

 where the topography is such that drainage is not particularly poor.^^ 

 Probably the gray-brown clay of Sonoma, California, whose mechanical 

 analysis is shown in column in the table, represents more nearly average 

 soil conditions for the grape. Certainly it produces some of the best wine 

 grapes of the country. ^^ Citrus fruits likewise thrive on soils ranging 

 from heavy adobes to gravelly loams and gravelly sands. It is interesting 

 to note the texture of one of the pineapple soils of the Florida coast 

 (Soil H in the table) — over 98 per cent, fine, medium and coarse sand. 

 The mechanical analyses of many other fruit soils which might be 

 included would furnish little information, beyond that already given, 

 as to the actual soil requirements of the different fruits. It is evident 

 that the mechanical analysis of a soil carries some suggestion as to its 

 suitability for fruit crops of different kinds but it is an index only in so far 

 as it is an index of texture, drainage and aeration; these qualities depend 

 to a considerable extent on such factors as topography, hardpan, chemi- 

 cal composition, rainfall and the movement of underground water. 

 In other words, it is hardly practicable to attempt exact definition, in 

 terms of soil particle measurements, of the soil requirements for distinct 

 varieties of the same fruit or even of different fruits. 



CONSIDERED FROM THE STANDPOINT OF CHEMICAL COMPOSITION 



The statement has been made that, broadly speaking, the physical 

 condition of the soil is more important in fruit production than is its 



