SOILS AND FERTILIZERS 349 



make the most of the proper utilization of the conditions and re- 

 sources above mentioned. 



Drainage conditions, as such, have much to do with soil utili- 

 zation. Certain crops like rice will produce well only when the 

 soil is submerged with water for considerable periods of their growth, 

 and structure has much to do with ease of flooding and consequently 

 with cost of production. Others, like cranberries and peppermint, 

 will do well in bogs; celery, onions, cabbage, and potatoes do well 

 on muck if properly drained; pineapples grow on the loose beach 

 sand of Florida, which is excessively drained. 



It is not unusual to find the character and depth of the subsoil 

 influencing the drainage conditions of a field and affecting the 

 utilization of the soil. This is particularly marked in the case of 

 tobacco in southern Virginia and in North Carolina, where a few 

 inches difference in the depth of the clay subsoil below the surface 

 means the difference between the utilization of the soil .for bright 

 leaf cigarette tobacco or the heavy types of export or manufactur- 

 ing tobacco. Such variations also affect very materially the yield 

 of wheat and other crops, and thus influence the proper utilization 

 of the soil. 



Elevation and exposure are important factors in the utiliza- 

 tion of soil. Examples of this are seen in the fine quality of grapes 

 on the terraces and slopes in the lake region of New York, Penn- 

 sylvania, and Ohio ; in the protection from frost and the consequent 

 early maturity of truck crops on the peninsulas of the Atlantic 

 Coast States ; in the protection from frost on the foothills and moun- 

 tain sides. Citrus fruits can not safely be grown upon soils which 

 would otherwise be adapted to them in the San Joaquin Valley, 

 California, but are grown very successfully on the foothills border- 

 ing the valley. Peaches are successfully grown on the Maryland- 

 Delaware peninsula and in the mountains of western Maryland, 

 but not with safety on the intervening Piedmont Plateau (although 

 the soils are otherwise well adapted to the fruit), on account of 

 frosts which are liable to occur when the fruit buds are so far ad- 

 vanced as to be easily killed. (Bu. of Soils B. 55.) 



Adaptation of Soil to Crops. The principles governing the 

 adaptation of soils to crops may be briefly stated. The plant must 

 have in the soil and in the atmosphere a congenial and sanitary en- 

 vironment. The plant is fixed in position in a medium which has 

 previously been occupied by a crop, and which has thrown off waste 

 products. The sanitation of the soil must provide for the absorp- 

 tion and change to harmless forms of such waste products. 



Soils under different climatic conditions, with differences in 

 elevation, slope, drainage, and from certain obscure chemical powers, 

 apart from differences of texture, are able to provide more or less 

 perfectly efficient sanitary conditions for! certain crops. 



That these differences of adaptation of soils to crops do exist 

 is clearly indicated by the fact that natural plant associations differ 

 for all types of soils which have been encountered, both as to kind 

 of plants and relative numbers of the different species. The preva- 



