ISSN:
1573-5036
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary To simulate the condition of extensive surface area of roots per unit mass of soil in the rhizosphere in examination of the effect of plants on soil organic phosphorus, single corn seedlings were grown for short periods in 50-ml tubes containing (a) 0.5 g of soil and 30 ml of water. Controls included (b) water with a seedling present, (c) soil and water with no seedling, and (d) the original soil maintained in an air-dry condition. At the conclusion of the experiment, the seedlings were removed, and extractable organic phosphorus was determined on the water plus soil and on the original soil. Organic phosphorus in (a), minus organic phosphorus in (b), was essentially equal to organic phosphorus in (c) in two experiments in which the test period was 5 weeks (5 corn seedlings present successively, each for 1 week, in the cultures containing plants). In these experiments, the soil and roots were segregated by enclosure of the soil in an envelope made of Teflon-coated, glassfiber filter paper. These results verify previous work showing that soil organic phosphorus may be decreased by growing plants. The results indicate further that the effect does not require direct contact between soil solids and roots but takes place in consequence of transfer of substances in solution. In certain treatments in the 5-week experiments, the soil was present in suspension in direct contact with the roots. In these instances, organic phosphorus in (a), minus organic phosphorus in (b), significantly exceeded organic phosphorus in (c). An additional experiment indicated that this increase in organic phosphorus due to the presence of a plant was an artifact caused by abrasion of the roots by soil particles as they moved through the water in response to the continuous bubbling of air through the cultures to provide adequate aeration.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01372854
Permalink
