Some Biological Aspects of Soil Fertility

Abstract

THE difficulties associated with their study have probably led to an under-estimation of the importance of the biological aspects of soil fertility compared with that of the purely physical and chemical factors. An outstanding difficulty is the impossibility of reproducing in pure cultures of soil organisms the conditions present naturally in the soil, and the danger of drawing deductions from such cultures as to what the behaviour of any organism will be in the soil, where it exists as a member of the mixed soil population in a continually shifting environment. Moreover, greatly as laboratory studies have advanced our knowledge of the processes of plant nutrition, they have usually failed to take full account of the complexities of the natural root environment engendered by the activities of various microorganisms in the soil.