639 185 spy 1 THE EFFECT OF LARGE APPLICATIONS OF COM MERCIAL FERTILIZERS ON CARNATIONS BY FRED WEAVER MUNCIE A. B. Wabash College, 1910 M. S. University of Illinois, 1913 THESIS Submitted in Partial Fulfilment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY IN CHEMISTRY IN THE GRADUATE SCHOOL OF THE UNIVERSITY OF ILLINOIS 1915 LIBRARY OF CONGRESS 002 755 986 4 • ACKNOWLEDGMENTS. The author desires to express his appreciation of the many helpful sug- gestions received from Dr. Geo. D. Beal, Dr. C. G. Derick and other members of the departments of Chemistry and Botany. THE EFFECT OF LARGE APPLICATIONS OF COM- MERCIAL FERTILIZERS ON CARNATIONS BY FRED WEAVER MUNCIE A. B. Wabash College, 1910 M. S. University of Illinois, 1913 THESIS Submitted in Partial Fulfilment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY IN CHEMISTRY IN THE GRADUATE SCHOOL OF THE UNIVERSITY OF ILLINOIS 1915 £ IX jQJ* I <\ (G Effects of Large Applications of Commercial Fer- tilizers on Carnations By Fred Weaver Muncie In the investigation of the use of commercial fertilizers in growing carnations by the Illinois Agricultural Experiment Station, it has been found that the lack of appreciation by florists of the relatively high plant food concentrations and often high solubilities of commercial fertilizers, as compared with manure, has often led to a complete loss of a crop of flowers in an effort to produce an extraordinarily large one. On this account, it was considered desirable to study the causes and effects of overfeeding with the more ordinarily used commercial fertilizers. The fertilizers chosen for the experiment were dried blood, sodium nitrate and ammonium sulfate, acid phosphate and disodium phosphate, and potassium sulfate. For comparison, sodium chloride and sodium sulfate also were used on some sections. Experimental work upon the subject was carried out during the years 19 12-15. Carnations are propagated by means of cuttings, and from these it was found impossible to secure a normal growth in either sand or water cultures. Hence, the experimental work was based upon the study of plants grown in soil carefully selected with the view to securing uniformity throughout the benches, watered to give as nearly as possible the same moisture " content,' and subjected very nearly to identical conditions of heat, ventila- tion, and illumination. For details regarding the type of soil, its prepara- tion, arrangement of sections, etc., the reader is referred to Bull. 176 of the Illinois Agricultural Experiment Station. The method consisted of weekly applications of the fertilizers at various rates upon isolated sections in the benches, beginning about October i and continuing until about May i or until injury became serious. Effects of Overfeeding on Condition of Plants. — The rapidity with which the sections of carnations became affected followed in a general way the solubility of the fertilizer used.* The solubilities** of the pure substances in water per hundred parts at o° are given in Table I. Table I. — Solubilities of Pure Salts in Water at o°. (Parts per ioo.) NaN0 3 (NH 4 ) 2 S0 4 NaCl KC1 K 2 S0 4 72.9 71.0 35-7 28.5 8.5 Na 2 HP0 4 .i2H 2 CaH 4 (P0 4 ) 2 .H 2 CaHP0 4 CaS0 4 .2H 2 6.3 4(15°) °-° 28 °- 2 4i Commercial acid phosphate consists of about equal parts of mono-calcium phosphate and calcium sulfate. Reversion to monohydrogen phosphate in presence of bases in the soil would further decrease the low solubility of the acid phosphate and by double decomposition with calcium, iron and other bases in the soil render the sodium phosphate first applied less soluble, as pointed out by Cameron and Bell. 7 Dried blood, giving soluble products at a rate depending upon the rapidity with which bacterial decomposition proceeds, could not be rated as having a known solubility without a study of the bacteriological activity of the soil mixture. Tests with litmus paper showed that the surface of the soil, neutral at the beginning of the experiment, became acid seven or eight days after the addition of the dried blood. Soil to which ammonium sulfate was applied became acid as quickly also. Single applications of ammonium sulfate and sodium chloride at the rate of 12.5 kg. per 100 sq. ft. made on December 3, 19 13, produced marked injury within a week's time. Equal amounts of potassium sulfate, at this time, followed by further applications at intervals of one or two weeks, at the rate of 1.25 kg. per 100 sq. ft., produced no signs of injury until about January 15, when a lack of turgidity became noticeable, fol- ■ lowed by a gradual stunting of growth, with the more pronounced signs appearing only after the middle of March. Signs of injury in sections treated in the same manner with sodium phosphate became evident even more slowly, while acid phosphate produced no apparent injury even in the largest applications. * The impurities in the ammonium sulfate, potassium sulfate (in this case 1.26% of chloride as sodium chloride) and disodium phosphate are not sufficient to interfere with the use of the solubilities of the pure substances as a rough measure of the solu- bilities of the fertilizers themselves. ** Van Nostrand — Chemical Annual, 19 10. The fertilizers may be grouped into the class, easily soluble and pro- ducing almost immediate injury; a second, moderately soluble and pro- ducing delayed injury; and a third, difficultly soluble and producing no apparent injury. On days of continuous sunlight a more or less pro- nounced softness of tissue could be detected by careful observation long before characteristic injuries became apparent. Effects of Overfeeding with Ammonium Sulfate. — A marked softness of tissue was the earliest sign of overfeeding with ammonium sulfate. A complete plasmolysis took place in that portion of the stem located two and three nodes below the bud and in the portion of the stem just above the node, so that the stem bent completely over. The shoots first affected were those with buds one-half to three-quarters developed. At the same time white spots 0.25 and 1.00 mm. in diameter appeared upon the upper leaves of these and the younger shoots. Microscopic examina- tion of these showed the chlorophyll bearing tissue entirely plasmolyzed. In contrast to the injury from other fertilizers, practically every flower split.* This splitting was not caused by the pressing outward of the petals as is usually the case, but by a weakening of the tissue at the line joining the sepals to form the calyx cup. Later stages resulted in the drying up of the leaf tips, and the appearance of the white depressions upon the older leaves. The sepal tips very early became brown. Later, pustule-like elevations about 1 mm. across appeared on them, caused by a crystal of ammonium sulfate beneath the epidermis. The injury from excess of ammonium sulfate was more rapid and pronounced in the presence of lime than without it. Effect of Overfeeding with Sodium Nitrate. — Injury followed heavy applications of sodium nitrate within a few days, the characteristic symptom being an even lightening of color of the foliage over the plant, followed by drying of leaf tips and petals and withering of the plant. Effects from Large Applications of Sodium Chloride. **— The first appear- ance of injury from large amounts of sodium chloride was two days after its application, a plasmolysis of the cells of the stem, causing it to lose its rigidity at the crown. When held within supports the plants appeared normal. Gradually, however, the plants lost their turgidity and the chlorophyll disappeared evenly throughout the entire plant. Tests made in the spring of 19 15 with heavy applications of sodium chloride and potassium chloride (12 kg. per 100 sq. ft.) showed the same effect from each of them, while sodium sulfate, like potassium sulfate, showed less injury and that only after a longer period. * Splits is a trade term denoting flowers with split calyces. ** Sodium chloride, while not strictly a fertilizer, was used in the experiments be- cause of its presence in considerable amounts in kainite and in some grades of com- mercial potassium sulfate. Effects of Overfeeding with Potassium Sulfate. — In earlier stages partial wilting occurred on days of sunshine. Drying up of the tips of the leaves and curling of the leaves upward upon their long axis followed, with often, also, a peculiar inhibition of growth on one edge of the leaf, with the same on the opposite edge of another portion, giving the leaf a wavy outline. A marked stunting of growth was observable. This affected most noticeably the lengthening of the stem, resulting in the later shoots assum- ing a rosette appearance, due to the leaves of normal length upon a stem with undeveloped internodes less than an inch in length. (The inter- node in full grown shoots is ordinarily three or four inches long.) The edges of the petals of the flowers after about the middle of January became quite generally withered or crinkled. Those in the center of the flower remained closed quite tightly, while the other two or three rows opened normally. Later, the buds remained closed, although the pistil often pushed its way out and might be seen extending an inch above the top of the bud. A marked increase in exudation of nectar in the flower was found to have caused the gluing together of the petals, and so prevented their opening. On cloudy days very frequently a calyx cup would be found completely filled with this exudation. The exudation was most plentiful in the flowers from plants receiving a moderately heavy application of potassium sulfate over a long period of time while the heavier applica- tions caused a noticeable but less plentiful increase. A small amount of nectar is found in normal flowers, and somewhat larger amounts in the flowers from plants receiving large applications of sodium phosphate, sodium chloride, ammonium sulfate, or potassium chloride, but not so generally nor in such large amounts as in the sections treated with potas- sium sulfate. Injury was less marked when ground limestone was added to the soil, in contrast to the effect of liming on the production of injury by ammonium sulfate. Effects of Overfeeding with Sodium Phosphate. — When moderately large amounts of sodium phosphate were added over a long period (as in 19 13-14) no injury was noticeable until about the middle of March, when a retardation of growth was evident from the decrease in height of the plants and abnormally small buds and flowers. These signs of inhibition became steadily more pronounced until the plants were removed from the benches, about May first. When larger amounts were used (as 12 kg. per 100 sq. ft. in 19 14-15) loss of turgidity in the plants, longitudinal rolling of the leaves, death of the leaf tips and softness of the petals of the blossom were evident. These signs of injury appeared, however, only after the middle of January and then only gradually. Injury was less when the soil was limed than when not. Effects of Overfeeding with Dried Blood. — In none of the experiments with dried blood did injury appear until about the middle of January. At that time a softness of the petals and irregularity of their arrangement, due to the partial opening of the inner and crinkling of the outer ones, became more or less common. The flowers became susceptible to brown- ing when a drop of water from syringing lodged on a petal in a position to be reached by the rays of the sun. The height of the plants was below normal in the spring but rather above in the fall; the color was good. If the applications of dried blood were not continued after signs of injury became apparent, the plants gradually recovered. The same held true for plants overfed with ammonium sulfate in contrast to those which had been injured by potassium sulfate, sodium phosphate, and sodium chloride. Effects of Overfeeding on the Mineral and Nitrogen Content of Plants. — Effects upon the dry weight and ash are shown in Table II, the samples being the foliage from the shoots gathered January 9, 1915. Table II. — Dry Weight and Ash in Foliage. Section No. 269. Treatment. Check. Moist weight. G. 27.6. Dry weight. %. 17.8. Ash (sulfated) per cent, of dry weight. 13.68. 271 125 P* 324 17.6 13-93 273 250 P 32.2 18.3 12 89 275 500 P 30-6 18.9 14 28 277 125 K 26.I 18.4 15 37 279 250 K 36.8 20.4 15 45 281 500 K 32.8 22 .6 15 59 283 Check 28.2 19.2 13 19 285 125 NaCl 42.9 22.8 14 45 The increase in both values as the applications of any one fertilizer in a series were increased is shown in the table. The higher values for plants treated with potassium sulfate and sodium chloride over those treated with sodium phosphate correspond to the higher osmotic pressure values obtained from the sap of these plants as well as to the more rapid injury from potassium sulfate. Determination of the total nitrogen and mineral content of the ash from various samples of plants treated with potassium sulfate gave the following values: * N, P and K in the tables are used to indicate ammonium sulfate, disodium phosphate and potassium sulfate, respectively, while NaCl indicates sodium chloride and A. P., commercial acid phosphate. The figures preceding the letters indicate the number of grams applied weekly per 20 sq. ft. of bench space. Table III. — Effect of Potassium Sulfate. Analyses. Per cent. Treatment. NasO. K2O. SO3. N(total). PiOt. Check 1 .09 5.38 1 .07 2.58 O.72 K 1-25 6.62 1. 91 2-53 O.70 0.16 1.24 0.84 — 0.05 — 0.02 The data show an increased sodium,* potassium and sulfur content, with practically a constant percentage of nitrogen and phosphorus. A similar study of plants to which ammonium sulfate had been ap- plied gave the results shown in Table IV. Plants to which sodium phosphate was applied showed a higher phos- phorus content, 0.60% P2O5 and 1.17% P2O5 in a sample of 19 15 in which the calcium content was decreased (2.31 and 1.63% CaO, respectively, in the last set of samples) ; the nitrogen content was increased by applica- tions of sodium phosphate, the values 1.99%, 2.84% and 3.30% being obtained from plants to which had been applied, respectively, none, 250 g. and 500 g. of sodium phosphate per 20 sq. ft. of bench space per week for several weeks. Table IV. — Effect of Ammonium Sulfate. Analyses. Per cent. Treatment. N (total). N(by MgO). SOa. P2O5. Check 2 . 05 0.168 0.75 . 93 N 2.93 0.364 2.10 1 . 14 0.88 0.196 i-35 0.21 The ratio 2N/SO3 in ammonium sulfate is 28/80 = 0.351, that of total nitrogen to sulfur increase is 0.652; and of nitrogen by MgO 0.145. The intake of sulfur when this fertilizer is used is less than is required for the nitrogen then, but in excess of that required to be combined with the nitrogen determined by MgO.** Limestone was found to depress the sulfur intake from ammonium sulfate. Since injury was greater in sec- tions so treated, the injury is not proportional to the intake of sulfur. The intake of phosphorus was increased by the addition of ammonium sulfate, probably due to acidity developed in the soil. Table V shows the total nitrogen content of some plants from Sections 264 (ammonium sulfate and lime) and 281 (ammonium sulfate). Samples * Mayer 22 states that the addition of soluble potassium salts to a soil causes a partial replacement of the sodium. ** The author would not care to report the presence of ammonium salts in plants not fed with it. It seems, rather, that MgO has caused some decomposition of the organic material; the error due to this is assumed to be the same in both samples. were collected on April 25, 1914. Section 281 had received but one application at the rate of 12.5 kilos per 100 sq. ft. on December 3, 1913, while applications at the rate of 1250 g. per 100 sq. ft. were made to Section 264 at 15 different intervals of about two weeks after December 20, 1913. Analyses were made of upper and lower portions of the plant separately in order to show any localization of nitrogen in the more vigorously grow- ing portion of the plant. Table V. — Total Nitrogen Determination on Foliage. Section. Portion. Condition. Nitrogen. 264-E upper half dead 4-58 lower half dead 4.07 264-P upper half dead 7.78 lower half dead 5 64 264-P upper dead 6. 14 lower dead 3-41 264-E upper alive 6.69 lower alive 5 70 264-E upper half dead 7.01 lower half dead 3-34 28I-E upper dead 4.60 lower dead 3.02 281-E upper partially affected 4-73 lower partially affected 3.78 28I-E upper half dead 4-73 lower half dead 2 94 281-E upper slightly affected 4-47 lower slightly affected 3-21 %. Sample No. Plant No. I I 2 3 4 4 5 1 6 7 11 8 9 4 10 11 11-15 13 16 14 15 20 16 17 7 18 The total nitrogen content of the plants varied from once and a half to more than twice the normal value found in the previous set. Average values for the plants from Section 264 are 6.44% and 4.43%, respectively; for those from Section 281; 4.63% and 3.24%. In each case the more vigorously growing portion contained the larger percentage of nitrogen and the increase over the lower portion is considerably greater in the section to which the smaller applications were made during the entire season. No clear relation is shown between the nitrogen content and the degree of injury. Considerable tolerance for ammonium sulfate is shown when it was applied to the soil in quantities not heavy enough to produce immediate, serious injury. The fact that the dead plants had no higher total nitrogen content than those only injured is evidence that part of the nitrogen when added in small quantities was changed to a nontoxic form, since the dead plants were in this condition as early as March 21, while the living ones though injured undoubtedly continued to take up the salt in solution until samples were taken. A series of ammonia determinations was made on the sap from "checks" and ammonium sulfate fed plants of the set of 1 2-9-14. Folin's micro- method for the determination of free 14 ammonia was used, the excess of IO sulfuric acid (0.01550) being titrated back with potassium hydroxide 0.02130 with sodium alizarin sulfonate as the indicator. Results are given in Table VI. Table VI. — Free Ammonia in Plant Saps.* Sample No. Treatment. Appearance. Nitrogen. Mg. N per cc. 5 check normal none 8 250 N normal 0.1834 7 500 N normal 1372 2 1000 N slightly injured 0.6390 1 1000 N badly injured 1 .0560 The white spots on the leaves of plants treated with ammonium sulfate, and of crystals imbedded beneath the epidermis of the sepals were studied by microchemical methods. 4 1. January 21, 19 14. Plant Number 4, Section 281, White Enchantress. Plant apparently normal. A drop of sap from the stem of a shoot was treated with a drop of ammonia-free hydrochloric acid and chloroplatinic acid, and evaporated at room temperature under a loosely covering watch- glass. A few crystal masses, tetrahedral and often aggregated in shape of a cross, appeared. They were yellow in color. Sap from Number 8, somewhat injured, and Number 12, badly affected, gave these characteristic crystals, also. 2. A section of the leaf showing white blotches was immersed in chloro- platinic acid after removal of the epidermis and allowed to remain over- night. Large and perfect crystals appeared, arranged usually around the injured spot, never in it. They were insoluble in 95% alcohol which removed the excess of chloroplatinic acid. 3. A drop of sap from plant Number 4, Section 281 was distilled with a pinch of sodium carbonate over a micro-burner and the distillate caught in a hanging drop of hydrochloric acid in a cover glass placed on a glass ring above it. Treatment as above gave small, yellow tetrahedra in- soluble in 95% alcohol. Ammonium salts were evidently present and apparently caused plas- molysis of certain of the chlorophyll bearing cells. Why injury of this type is caused by ammonium sulfate in contrast to the even lightening of the color of the whole leaf by the other soluble salts, sodium nitrate and sodium chloride, is not known. Nitrate determinations according to the phenolsulfonic method of Mason 21 were made upon the sap of a "check" and an ammonium sulfate fed plant from the set of March 9, 1915. The values of 0.01 and 0.40 mg. N as nitrate per cc. of sap, respectively, showed that nitrification was proceeding in the soil although it was quite strongly acid. 17 * In earlier stages of feeding with ammonium sulfate, samples have been taken in which no NH 3 was detected by this method. Total solids and ash were determined on the sap of the set of 1 2-9-14. The results, given in Table VII, are calculated to milligrams per cc. of sap. Table VII. — Total Solids and Ash of Sap. Sample No. Set date. Section. Treatment. Total solids. Mg. per cc. Ash.* Mg. per cc. 2 1 2-9-14 291 1000 N 91.9 3 293 1000 K IO4.9 19.2 5 289 check 63.8 II. 8 6 261 check 62 . I 12 . I 7 265 250 N 63.6 13-9 8 267 500 N 79-9 151 9 277 125 K 643 16. I 10 279 250 K 69.9 17 .2 11 281 500 K 75-7 17. I 12 283** check 72 . 1 I50 1 I -9-1 5 269 check 84.0 7-5 2 271 125 P 81.7 13.2 3 273 250 P 86.7 13-3 4 275 500 P 93 -o 15 1 5 277 125 K 92.3 13-4 6 279 250 K 106.3 20. 1 7 281 500 K 133-7 20.0 8 283** check 105. 1 14. 1 The average total solids content of the sap was 85 . 1 mg. per cc. and the ash content 14.9 mg. The influence of the fertilizer applications is seen in the increase in both values as the applications of any fertilizer were increased in a series of sections. Sample 3 of the first set and 6 and 7 of the second, all of which were from plants to which large applications of potassium sulfate had been made, showed particularly high values.*** The first set of data was obtained by drying the samples in a Sargent electric oven at 60-70 °, the second in a vacuum oven heated to 50 for 12 hours. The actual value for total solids depended on the length of heating but experiments with both sets of data given showed the same relative values after several successive heatings. * Ash determinations upon the sap were made by careful incineration of the solids in 1 cc. of sap in platinum dishes over a low flame to prevent mechanical loss of particles of the ash. The low chloride content obviates the danger of volatilization of potassium chloride by high temperatures. ** For some reason total solids and ash determinations always ran higher in sap from plants in Section 283 than from those in other "check" sections. The same dis- crepancy is seen in the osmotic pressure data for these two sets. *** The determination of total solids with accuracy is not possible on account of the uncrystallizable solutes in the sap, and on this account the mean molecular- weight calculations which often accompany osmotic pressure data were not made. Drying on the water bath was found to cause charring of the sap from plants which had been treated with ammonium or potassium sulfate. The first showed a higher acidity value, the second a higher sugar content. 12 Determinations of sodium and potassium in the ash from sap obtained on January 9, 19 15, from plants treated with potassium sulfate, were made in order to show the increased intake of potassium. Similarly, determina- tions of phosphorus were made upon the sap from plants fertilized with disodium phosphate. The results ; calculated to milligrams per cc. of sap, are given in Table VIII. Table VIII. — Mineral Content of Sap. Sample No. Section. Treatment. Na M 2O. K2O. Mg. Mg;P 2 07 Mg 9 277 125 K i-4 9-4 IO 279 250 K 1 3 10 1 II 281 500 K 1 3 10 1 12 283 check 1 2 8 4 I 269 check I 5 2 271 125 P 6 1 3 273 250 P 7 5 4 275 500 P 9 6 Effect of Overfeeding on Osmotic Pressure of Sap. — Sap was expressed from the stems of shoots after freezing them with an ice-salt* mixture, and the lowering of the freezing point determined by the method of Harris and Gortner** of allowing supercooling until the solution froze and cor- recting the value of A' obtained by the formula A = A' — 0.0125 wA' where A' is the maximum temperature attained in the system and u the difference between this value and the minimum temperature. The relation between A and the osmotic pressure given by Lewis 19 in the approximate equation ■k = 12.06 A was used in calculating the value for ir. Description of Experimental Method. — Choosing a time when for two or more hours previous no appreciable draft had been stirring the air in the greenhouse, from four to eight shoots at the same stage of growth were removed from each of the sections of plants and quickly taken to * Care was taken to select samples from the check and affected plants at the same time of day and shoots in the same stage of growth were taken, to insure freedom from variations in osmotic pressure due to differences in location and illumination, while the fact that the sections studied were usually adjacent obviated the difficulty that differences in temperature change the osmotic pressure of plants. See Dixon and Atkins, 11 Atkins, 3 Ewart, 13 Drabble and Drabble, 12 Cavara. 8 ** The method in genera! was an adaptation of that recommended by Gortner and Harris. 15 " 18 Andre 1 and also Dixon and Atkins 11 have shown that successive por- tions of sap expressed from unfrozen tissue become more concentrated, while the latter have shown that the sap from frozen tissue always has a lower freezing point than that from unfrozen, and that successive portions gave nearly identical lowerings, leading to the conclusion that sap so expressed is representative of that originally within the tissue. 13 the laboratory. After removal of the foliage from the stems, they were broken at the nodes and placed in hard glass test tubes (25 mm. X 150 mm.), stoppered with rubber stoppers and sealed with oil paper and rub- ber bands. Freezing was produced by the use of the ice and salt bath,* giving a temperature of — 15 ° or lower and allowing the tubes to remain in the refrigerator overnight. The tubes were then removed from the bath and after the walls had been cleaned with distilled water and wiped dry, the portions of shoots were removed, thawed gradually, and the sap ex- pressed by pressure from the screw of a tincture press set perpendicular to the wall upon two pieces of 3 / 8 inch plate glass. After a first expression, the shoots were rearranged and pressure again applied. The sap was filtered through an S. & S. 589 filter — with a watch glass over the funnel to minimize evaporation — into a small test tube; a drop of xylene was added as a preservative and the tubes placed at once in a refrigerator, at about io°. The sap after filtration was usually a clear, brown liquid without sediment. As soon as convenient the freezing-point determinations were made. A thermometer was used having a bulb about 5 mm. by 35 mm., the mer- cury tube enclosed in a hollow jacket, and graduated to — 6.5 in tenths of degrees, upon which, by the aid of a lens, hundredths of a degree could be read without danger from parallax. A stirrer of platinum wire and the thermometer were placed in the 5 cc. of sap contained in a test tube of Bohemian glass (15 X 120 mm.) and the whole cooled to about +2 in an ice and salt bath in a beaker. The tube was wiped free from water and placed within a hard glass test tube (25 mm. X 150 mm.) set two- thirds way into the ice and salt-freezing mixture. It was found saving of time to place this bath in a Dewar bulb, with inside diameter of 35 X 130 mm.; the top was closed with a piece of cork; the bath so arranged remaining effective for three hours or more of use. During the entire cooling, the sap was constantly stirred to prevent its freezing about the sides of the tube. The lowest temperature obtained was read to one- tenth, and the maximum, by the aid of a lens, to one-hundredth degree. The tube was removed to a beaker of water, and after the temperature had risen to about io°, the determination duplicated to within 0.01 , usually without difficulty on the first trial. A typical determination gave the following values: A' = 1.28 u = 4.12 A = 1. 214 A' = 1.27 u = 3.43 A = 1. 216 Average 1.2 15 from which w = 14.64 atmospheres. * It was found convenient in case less than a dozen tubes of material were frozen* to place the ice and salt bath in one or two one-liter Jena beakers. In this way the ice can be packed about the upper portions of the test tubes, and the beakers, with five or six test tubes in them, are narrow enough to keep the tops of the test tubes from touching the solution. H Osmotic Pressure Determinations. Treatment. IOOO N iooo K IOOO P check check iooo N iooo K iooo P check check check iooo N iooo N iooo K check check 250 N 500 N 125 K 250 K 500 K check check 125 P 250 P 500 P 125 K 250 K 500 K check 125 NaCl 500 A. P. Discussion of Results. — No comparison can be made between the values for the osmotic pressure determined in successive sets on account of variations due to temperature, physiological scarcity of water, etc., but the values obtained from plants in adjacent sections at the one time are regular enough to be comparable. From the values for osmotic pressure of Samples 7, 8, 2 and 1 of the set of 1 2-9-14 the conclusion was drawn that the osmotic pressure within the plants increased as the quantity of ammonium sulfate applied to the soil was increased. Samples 2, 3 and 4, and 5, 6 and 7 of the set of 1-9-15 gave similar results with increasing applications of sodium phosphate and potassium sulfate. The values obtained from the application of sodium phosphate were in every case lower than those obtained from appli- cation of equal quantities of potassium sulfate or ammonium sulfate. The Table IX — Sample Date. No. Section II-I2-I5 I 291 2 293 3 295 4 289 5 269 II-20-14 1 291 2 293 3 295 4 289 5 283 7 283 I 2-9-I 4 1 291 (iO A.M.) 2 291 3 293 5 289 6 261 7 265 8 267 12-9-14 9 277 (4 P.M.) 10 279 11 281 12 283 I-9-I5 1 269 2 271 3 273 4 275 5 277 6 279 7 281 8 283 9 285 10 287 A'. u. A. 7T. I.30 3-21 1 .2IO I4.6O 1-37 403 I .261 15-21 1.32 5i8 I.I9S 14.41 1. IS 3 90 I 054 12 .71 1 .00 1 . 10 O.946 II. 41 1-33 567 I . 196 I4.42 1.50 3 40 I.396 I6.84 1 . 10 4.80 O.994 11.99 1 .20 5-8o I.078 I3.00 1. 18 2.87 I .098 13-24 1.27 4-43 I . 160 13-99 1.66 5-34 I.SI3 18.24 i-43 4.78 I-305 15-73 1 .40 5 30 I .267 15-25 o.95 4-55 O.856 10.34 0.99 3-91 O.9OI IO.86 1 . 10 510 O.990 11.94 1.28 5-4° I. 174 14. 16 1.05 3-75 O.962 11 .60 1. 18 4.82 0.973 "•73 1. 18 4-32 I .076 13.01 1.06 4.14 O.967 11.68 1 .20 4.00 I . IOO 13-24 1.28 4.62 I . 169 14.08 1.32 4.98 I. 178 14.20 i-39 3-8i I.284 I5-50 i-35 2.65 I.265 15-29 1.58 4.92 I.448 17-49 1.87 4- 6 3 I .722 20.76 1.28 4.92 I . 161 14.04 1.88 2 .92 I. 771 21 .40 1.48 5-52 1.338 16. 13 15 samples taken on ,r.M, and IMM4 gave higher values for the sap from plants overfed with potassium sulfate than those treated with am- monium sulfate, but later in the year in the set of 12-9-14 (Samples ■ and 2) the relative values are reversed. In the set of 12-9-14 P^nts treated with potassium sulfate at the rate of .000 g. per section per application were still apparently normal ^al- though the osmotic pressure amounted to 15.25 atmospheres, while plants treated with one-half this weight of ammonium sulfate possessed an os- motic pressure of only 14.. 6 atmospheres and showed signs of injury. Injury on the other hand, had not appeared on plants treated with am- monium sulfate (250 g. per section per application) when the osmotic pressure amounted to 12.42 atmospheres as compared to ... 34 atmos- pheres in the adjacent "check" section (.2-9-14-10 a.m.). The higher value of Sample . over Sample 2 (of the set of 1 2-9-1 4- IO A.M.) was correlated with a greater degree of injury by the am— sulfate Injury appeared on the plants from sections to which potassium u ate was ippiied'only when an osmotic pressure of over twenty ^a mos- pheres was reached (1-9-15). and an osmotic pressure value up to .5.50 Atmospheres was found in plants on soil treated with sodium phosphate, St injury being apparent. The determination of the vakie on h sap from plants treated with acid phosphate gave .6. 11 atmospheres, "et iTe plants exceeded in size and vigor those to which no fert ize^ was applied (.-9-15). The conclusion to be drawn from these facts "thi wuh a single fertilizer, injury from overfeeding becomes apparent when a certain osmotic pressure is reached, but that this value ,s different "injury ' implications of sodium chloride at the rate of .25 g. per section per application, occurred at approximately the same tune, wis very similar to and was of about the same -e^e - ^t from ap- plications of potassium sulfate, in four times these quantities. The rela tWe osmotic pressure values are given in Samples 9 and .0 Uysh The solubilities of these salts, as pointed out on page 2785, at o are ™a « c rp^nectivelv giving a ratio roughly oi 4 to 1. ^Effects of 6 erf ed ng on the Total Acidity of the Cell Sap-Reaction Effec s overie g ^ ^.^ nQ fertlhzer luv rnuretaT nS or slightly alkaline in the fall, and th. a gradua chanre to slight acidity took place durmg the winter. Commercial acid phosphate dried blood and ammonium sulfate upon the sod each ncrlatd thftotal acidity,* the first one immediately after application, increased by addition of comrn "