No. 4.] SOIL VARIATION. 13 



at different localities within its area is determined by the 

 character of the soil." 



Having dwelt at some length npon the importance of soil 

 selection for the several different crops, I want to call your 

 attention at this point to the fact that the character of the 

 soil npon which a crop is grown is only one of several fac- 

 tors necessary for successful crop production. Climatic 

 conditions, embracing not only absolute temperatures but 

 also the rainfall, air drainage, soil drainage as affected by 

 topography, — the only kind considered until recently, — 

 elevation above sea level and with reference to local to- 

 pography, fertilization and care, are all important. Xo one 

 of these factors may be studied effectually unless the other 

 factors influencing production can be balanced. So soil com- 

 parisons can be of value only Avhen the other conditions are 

 equalized, and to do this a large number of field comparisons 

 is essential. 



Let us now go a step further, and consider not the adapta- 

 tion of soils to a given crop, but rather the adaptation of soils 

 to different varieties of the same crop. For some time I have 

 been especially interested in working out the conditions of 

 soil on which each variety of apple does best, and to some of 

 these soil adaptations I now ask your attention. Later any 

 discussion pertaining to them will be welcomed. 



BALnwaisr. 

 If soils are thought of as grading from heavy to light, cor- 

 responding to the range from clay to sand, then soils grad- 

 ing from medium to semi-light fulfill best the requirements 

 of the Baldwin. Following definitely the classification 

 standards of the Bureau of Soils (see table below) with ref- 

 erence to the proportions of clay, silt and sands, this group- 

 ing would include the medium to light loams, the heavy 

 sandy loams, and also the medium sandy loams, provided 

 they wevQ underlain by soil material not lighter than a 

 medium loam nor heavier than a light or medium clay loam 

 of friable structure. 



