Published online by Cambridge University Press: 27 March 2009
Soil fertility is often spoken of as though it were an absolute property of the soil; in reality it is a particular relationship subsisting between soil conditions on the one hand and crop growth on the other. The conditions conducive to soil fertility are the resultant of two main groups of factors, the intrinsic properties of the soil which are dependent on its chemical, physical and biological nature, and those extrinsic properties impressed on the soil by topographical and climatic factors*. These two groups cannot be sharply distinguished from each other, nor can any hard and fast line be drawn between the various factors comprised in them, because few are at present susceptible of exact measurement. In other words, that particular group of conditions that make up the fertility of a soil is an equilibrium brought about by the interaction of numerous factors some of which however can be varied by the agriculturist by manurial and cultivation operations.