How reliable are existing chemical methods for determining soil deficiencies in ash constituents of plants?
1931
Fraps, G.S.
The capacity of a soil to supply plant food is only one of a group of factors which determines how much plant food can be taken up by the crop, or what use can be made of it. The other factors include depth of the soil, its physical character, the kind of crop grown, climatic conditions, and others. There are close relations between the plant food removed in pot experiments and the chemical analysis of the soil for total nitrogen, and for phosphoric acid and potash soluble in 1% citric acid or 0.2N nitric acid, as well as for other weak solvents. The chemical analysis offers a fairly accurate method of comparing the potential fertility of various types of soils, or the relative abundance or deficiency of nitrogen, phosphoric acid, or potash in a particular soil. In applying the chemical analyses to field work, the analyses can be grouped according to the quantities of plant food present, and the interpretation made according to the kind of crop to be grown, the characteristics of the soil type, and climatic or other factors which may affect the power of the plant to use the plant food. Chemical analyses in connection with field experiments are needed in order to set up standards of interpretation applicable to different soils, crops, and climatic conditions in various parts of the United States.
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