35 



that "the general distribution of the Lobolly Pine is deter- 

 mined by historical and climatic factors, yet its relative 

 abundance at different localities within its area is deter- 

 nained by the character of the soil." 



I want to call your attention at this point to the fact 

 that, the character of the soil upon which a crop is grown 

 is only one of several factors necessary for successful crop 

 production. Climatic conditions embracing not only abso- 

 lute temperatures but also the rainfall, air drainage, soil 

 drainage as effected by topography — the only kind consid- 

 ered until recently — elevation above sea level and with ref- 

 erence to topography, fertilization, and care are all impor- 

 tant. No one of these factors may be studied effectively un- 

 less the other factors influencing production can be bal- 

 anced. So soil comparisons can only be of value when the 

 other conditions are equalized, and to do this a large num- 

 ber of field comparisons is essential. 



Let us now go a step farther and consider not the adap- 

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

 soils to different varieties of the same crop. For some time, 

 the Department of Agriculture has been especially interest- 

 ed in working out th.e conditions of soil on which each varie- 

 ty of apple does best, and to some of these soil adaptations 

 I now ask your attention. Later I shall welcome any dis- 

 cussion pertaining to them. 



BALDWIN SOILS 



If soils are thought of as grading from heavy to light 

 corresponding to the range from clay to sand, then soils 

 grading from medium to semi-light fulfill best the require- 

 ments of the Baldwin. Following definitely the classifica- 

 tion standards of the Bureau of Soils with reference to the 

 proportions of clay, silt, and sands, this grouping would in- 

 clude the medium to light loams, the heavy sandy loams, 

 and also the medium sandy loams provided they were un- 

 derlain by soil material not lighter than a medium loam nor 

 heavier than a light or medium clay loam of friable struc- 

 ture. 



From this broad generalization it will be seen that the 

 surface soil should contain an appreciable amount of sand. 

 The sands moreover should not be all of one grade ; that is, 

 a high percentage of coarse sand would give a poor soil, 

 whereas a moderate admixture of it with the finer grades of 



