. Journal of agricultural research . throughout the wholegrowth of the plant, for 15 weeks. At each change of solution conduc-tivity measurements were made, and the average absorption of electrolytesfor the week was computed. The plants were grown two in each jar ofapproximately i,ooo-cc. capacity. After 10 weeks part of the jars werechanged to a concentration of atmospheres, while the other werecontinued with concentrations of atmospheres. In each case bothneutral (Pg to ) and acid (Pq to ) solutions were comparedunder otherwise similar conditions. The composition of t
. Journal of agricultural research . throughout the wholegrowth of the plant, for 15 weeks. At each change of solution conduc-tivity measurements were made, and the average absorption of electrolytesfor the week was computed. The plants were grown two in each jar ofapproximately i,ooo-cc. capacity. After 10 weeks part of the jars werechanged to a concentration of atmospheres, while the other werecontinued with concentrations of atmospheres. In each case bothneutral (Pg to ) and acid (Pq to ) solutions were comparedunder otherwise similar conditions. The composition of the solutionsis given in Table VIII. 94 Journal of Agricultural Research voi. xviii, No. Table VIII.—Composition of nutrient solutionsWATER CULTURES, SEMES 3 Osmoticpressure. Ph. NO3. POi. K. Ca. Mg. SO4. A tmos. P. p. m. P. p. on. P. p. m. P. p. m. P. p. m. P. p. m. 0. 10 5-5 88 23-7 27-5 . 10 80 10. 6 22. 9 .90 5-1 I, 100 180. 0 248. 0 296. 0 90. 0 344-0 .90 1,000 102. 0 395-0. /a7 //* //S> £^^. • Fig. 4.—Water cultures, series 3. Graph showing absorption of nutrients from solutions of two con-centrations and two reactions. Solutions changed weekly. In figure 4 the course of absorption is shown graphically, and compari-sons may be made with figure 3. The absorption is plotted for conve-nience as parts per million of total electrolytes absorbed, the calcula-tions being based on the conductivities of the solutions. These graphsdemonstrate clearly that in solutions of atmospheres concentration(Ph 5-5). of atmospheres (Ph ), and of atmospheres (Ph )absorption continues in a fairly uniform way for the entire time. The Oct. 15,1919 Relation of Nutrient Medium to Plant Absorption 95 solution of atmospheres concentration (Pg ), however, gives adifferent type of curve. During the fourteenth to sixteenth weeks, elec-trolytes instead of being absorbed were returned to the nutrient
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