AbstractsBiology & Animal Science

Phosphorus deficiency is one of the major agricultural problems. Although most of our Canadian soils are well supplied with total phosphorus, only a very small proportion of this is available to plants. [...] We may state the question thus: Does the large quantity of organic phosphorus in our soils represent simply an accumulation of the end products of the decomposition of organic material added to the soil, thus being inactive and of little use for the phosphorus nutrition of plants; or does it still constitute an active part of the phosphorus cycle in our soils, being a store, as it were, of organic phosphorus continuously being synthesized by micro-organisms or repleted from plant residues, and simultaneously being decomposed and mineralized by other micro-organisms, thus providing a source of phosphate readily available for plant assimilation? Before this question can be answered, a great deal has to be learned about the nature and properties of the organic phosphorus in soils. Undoubtedly, phosphorus in the soil takes part to some extent in a dynamic biological cycle, as do nitrogen, carbon and sulphur. Just as the availability of nitrogen in the soil is greatly influenced by soil conditions (pH, moisture etc.) so also it is probable that the transformations of phosphorus are likewise affected and thus it may be possible to change the conditions in our soils so that organic phosphorus may be more readily mineralized. [...]