UTILIZATION OF THE PHOSPHORUS OF ALGAL CELLS AS MEASURED BY THE NEUBAUER TECHNIQUE

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Abstract
The comparative availability of the P of algal material and liquid H3PO4 to barley plants was studied by the Neubauer technic. Variations in rate of appln., soils, time of incubation, micropopulation, and C-N and C-P ratios were considered. Although the usual Neubauer method of testing soils for available P indicated that the P of algae and liquid H3PO4 is taken up in approx. equal quantities by barley seedlings in 15 days, a detailed study employing a modification of the Neubauer technic to determine the rate of uptake of the P over a 35-day period showed that there are characteristic differences in rate of utilization between the 2 sources. The rate of utilization of P of liquid H3PO4 appears to be influenced to a greater extent by chemical than microbiological factors. This situation was reversed for the algal material. There also was some indication that over a long period the P of algae is slightly more available to plants growing in soils than is that of the wholly inorganic P of liquid H3PO4. The presence of available C and an active soil micropopulation appears to influence the rate of utilization of available P according to the C/P of the added material. Widening the ratio from 4.6 to 24.4 reduced, in the barley seedlings, the percentage P taken from the algal source.