The influence of the soil type on the plant variety

In this paper we have found: That with given climatic conditions the plant, sooner or later, becomes adapted to the soil type on which it is placed. 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. 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. Otherwise, the national government should not be slow to launch out into this new field of agricultural research. 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. A radical change produces a change in the characteristics of the variety and generally greatly reduces the yield of the plant. When seed selection and adaptaton 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.