The Relation of Soil Texture and Color to the Organic Matter Content

The fertility of an agricultural soil is largely determined by its organic matter supply and many factors are known to influence the organic matter content. However, paramount of these factors are drainage, texture, and climate. Within a given climatic zone perhaps texture and drainage are the most important natural conditions that influence the organic matter content of the soil.. Since these factors control the organic matter content, well-drained soils of different textural relations will carry different amounts of organic matter. The porosity and clay content of a soil largely control the aeration and destruction of the organic matter. Therefore, well-drained soils of a given texture will have an optimum organic matter content, a point above which would be most difficult to maintain. Since the nitrogen and much of the mineral supply of the crop are largely supplied by decomposing organic matter, cultural practices that destroy the organic matter are largely followed. ' Thus, agricultural soils of a given texture are likely to have varying organic matter contents. These varying degrees of organic matter may bs used as a basis for classifying the fertility of a soil. However, supplementary applications of plant nutrients may somewhat offset this relation. During the months of October and November 1937 some 4000 Ap samples of the tomato producing soils around Camden, New Jersey were taken, classified according to soil texture and color of the dry soil, and analyzed for organic matter. These data are given in Figures 1., 2, and 3. To carefully analyze these data would require more space than is permitted and perhaps is not necessary. From an agricultural standpoint the soils shown in Figures 1 and 2 are the most important.