16 The Bulletin. 



have so decreased in yield as to make their continued cultivation unprof- 

 itable and have been discarded after the first season. 



The present practice of our farmers is to purchase a new variety of 

 plant, as cotton, corn, or wheat, wholly on catalogue descriptions or the 

 advice of some friend, and without regard or information as to the type 

 or character of the soil on which the plants have been developed. The 

 originators of these new varieties never think to say anything about the 

 soils on which they were grown, never, perhaps, suspecting that the soil 

 type could influence the future tendencies of the plant. These different 

 varieties are thus taken out of their original soil environments, subjected 

 to a continual round of readjustments to new conditions, and as a result, 

 our crop yields are kept permanently below a reasonable average by 

 reason of the adverse circumstances in which the plants are forced to 

 grow. 



SUMMARY AND CONCLUSION. 



In this paper we have found (1st) that with given climatic conditions 

 the plant, sooner or later, becomes adapted to the soil type on which it 

 is placed. (2d) When the variety is removed to a radically different 

 soil type the new soil type and the plant variety react on each other in 

 such a way as to break up the original characteristics of the variety and 

 gradually develop a variety better suited to the conditions. This we 

 called readjustment to the new environments and tried to show that 

 during this period the productivity of the variety is likely to fall far 

 below the point of profitable production. (3d) We have tried to show 

 also that the remedy recommended by some that each farmer should 

 become a plant breeder and breed varieties for each of his soil types will 

 almost surely prove impracticable since the great majority of them 

 would require to be taught both the characteristics of a distinct variety 

 and what constitutes a distinct type of soil. This, we, feel, is a State and 

 National problem. When a State has a large number of soil maps it is 

 ready for the soil expert and the plant breeder to go to work. Other- 

 wise the national government should not be slow to launch out into this 

 new field of agricultural research. (4th) We have found also that the 

 most important result of systematic seed selection is in accelerating the 

 complete adaptation of the given variety to the given soil type. (5th) 

 That a radical change produces a change in the characteristics of the 

 variety and generally greatly reduces the yield of the plant. (6th) 

 When seed selection and adaptation are carefully combined we find the 

 results to be cumulative in the desired direction. 



We conclude, therefore, that, from an economic point of view, it pays 

 best to grow our staple crops only on soils to which they are adapted or 

 on soils similar to, or identical with, those on which they have been 

 developed. 



