Showing papers by "H. Henry Janzen published in 1989"

Microbially Mediated Increases in Plant-Available Phosphorus

Abstract: Publisher Summary This chapter elaborates the microbially mediated increases in plant-available phosphorus (P). The importance of microorganisms in soil nutrient cycling and their role in plant nutrition has been realized for a long time. Their active part in the decomposition and mineralization of organic matter and release of nutrients is crucial to sustaining the plant productivity. The concentration of total P in soils ranges from 0.02 to 0.5% and averages approximately 0.05%, the variation being largely because of differences in weathering intensity and parent material composition. The uptake of P from relatively insoluble sources can be affected by the type of plant growing in the soil. The effect of mycorrhizae on plant P uptake and the effect of soil P on mycorrhizae were among the first aspects of these symbioses studied. Under soil conditions, potential benefits of adding P-solubilizing (PS) organisms would depend on several factors, one of the most important being the activity of the PS microbial population already in the soil. In almost all cases, the major sources of PS isolates have been soils. The mechanism of action of PS microorganisms is also elaborated.