THE TRANSLOCATION OF CALCIUM IN A SOIL A THESIS PRESENTED TO THE FACULTY OF THE GRADUATE SCHOOL OF CORNELL UNIVERSITY FOR THE DEGREE OF DOCTOR OF PHILOSOPHY BY BENJAMIN DUNBAR WILSON FEBRUARY, 1918 Reprinted from Memoir 1 7. December, 1918 of Cornell University Afir'ultural Experiment Station THE TRANSLOCATION OF CALCIUM IN A SOIL A THESIS PRESENTED TO THE FACULTY OF THE GRADUATE SCHOOL OF CORNELL UNIVERSITY FOR THE DEGREE OF DOCTOR OF PHILOSOPHY BY BENJAMIN DUNBAR WILSON FEBRUARY, 1918 Reprinted from Memoir 17. December, 1918 of Cornell University Agricultural Experiment Station ^s CONTENTS PAGE Review of literature 299 Experimental work 301 Plan of the investigation 301 Soil used 302 Method of placing soil in pots 304 Treatment of pots 305 Experiments 1 and 2 306 Bicarbonate (HC0 3 ) content of the drainage water 308 Experiment 3 309 Method of sampling pots for analysis of calcium 310 Interpretation of analytical data 316 Results of experiment 1 319 Results of experiments 2 and 3 321 Summary 322 Conclusion 323 Acknowledgment 323 Literature cited 324 295 THE TRANSLOCATION OF CALCIUM IN A SOIL THE TRANSLOCATION OF CALCIUM IN A SOIL Benjamin Dunbar Wilson The presence of calcium in soil is of extreme importance. The action of this element, when applied in different chemical combinations to soil, has been investigated extensively. In spite of the fact that much has been written on the subject of calcium in soil, it is evident from a review of the literature that the movement of calcium in soil has received but little attention. Definite information in relation to the translocation of calcium in soil, under carefully controlled laboratory or field condi- tions, is unsupplied. The present investigation was undertaken in an attempt to answer the following questions: (1) Does the calcium applied to a soil move down- ward or does it remain in the upper few inches of soil? (2) If the calcium does move downward, to what extent does it move? REVIEW OF LITERATURE The only study that has been made on the downward movement of calcium in soils under controlled laboratory conditions, so far as the writer has been able to discover, is that of Brought on (1912). 1 In that experiment the movement of calcium thru sandy, loam, and clay soils was determined, the calcium being applied in different forms. It was found that the movement of calcium thru a soil was governed largely by the physical constitution of the latter, the calcium salts diffusing most rapidly thru a sandy soil, less rapidly thru a loam soil, and only slightly thru a clay soil. Some of the differences which the author reports in the movement of calcium, resulting from the different treatments that were used, might have disappeared had the treatments been repeated a greater number of times ; also, the method employed for sampling pots at different intervals necessitated a disturbance of the soils within the pots, which may have resulted in some mechanical movement of calcium. Several investigators have endeavored to determine the translocation of calcium in field soils by comparing the quantity of calcium found at Dates in parenthesis refer to Literature cited, page 324. 299 300 Benjamin Dunbar Wilson different depths in soils that had received an application of calcium in some form with that in other soils of the same type that had not been treated with any form of calcium. Mclntire (1913) analyzed a silty loam soil for calcium at different depths from plats that had received large appli- cations of either calcium oxid or calcium carbonate for a period of thirty years. From a comparison of the calcium found in the treated soil with that found in the soil from adjacent untreated plats, it was con- cluded that calcium applied in either form at the surface of such soil moves downward very slowly, most of it remaining for years in the surface soil. The analyses for calcium carbonate in the surface soils and subsoils of Broadbalk and Hoos fields at Rothamsted, which have been made at dif- ferent times since 1865 as reported by Hall and Miller (1905), show that the subsoils have decreased in calcium, as well as the surface soils, which latter had received large applications of calcium previous to 1865 and which since that time have received yearly, for more than fifty years, the same fertilizer treatments. The results indicate that there has been no accumulation of calcium in the subsoils, altho there seems to be a tendency for an increase in the subsoils where ammonium sulfate has been applied from year to year to the surface soils. Veitch (1904) studied the downward movement of calcium in soils by determining the soil acidity at varied depths. The results of his investi- gation showed that when calcium oxid was applied to soils its neutral- izing effect was exerted only to the depth to which it was incorporated with the soils during the various processes of preparation and culti- vation. Ames and Schollenberger (1916) present data to show the depth of soil affected by applications of calcium salts. Soils that had been so treated were sampled at different depths and their lime requirements determined by the Hopkins and vacuum methods. The indications were that light applications of lime have considerable effect on the subsoil, at least to a depth of twenty-four inches. White (1914) reports, from studies made on soils in the field, that calcium does not move horizontally to any considerable degree by diffusion, as soil rich in calcium carbonate was found within eighteen inches of soil distinctly acid. The Translocation of Calcium in a Soil 301 •King (1904) studied the capillary movement of calcium thru soils by filling galvanized cylinders, provided with reservoirs at their bases, with different types of soil. A calcium solution applied at the bottom of the soil columns was permitted to rise by capillarity thru the soils. The results of the experiment tended to show that there was a slight upward movement of calcium. A comparison of the calcium content of surface and subsurface soils as reported by Smith (1884), Snyder (1899), Ames and Gaither (1913), Shorey, Fry, and Hazen (1917), and others, does not permit of any general conclusion as to whether surface soils or subsurface soils contain the greater amount of calcium. Consequently such a consideration is of no value in a study of the translocation of calcium in soil. A review of the literature reveals the fact that the studies thus far made on the movement of calcium in soil have been confined almost entirely to field experimentation and have been carried on as side experi- ments. Results obtained under such conditions are not absolute. The calcium content of soils is not always constant, and in comparing one soil with another this fact alone may lead to erroneous conclusions. Some investigators have used a method for the determination of lime requirement as a measure of calcium in soils. Such a practice is open to criticism, as a lime requirement is an estimation of the absorptive power of a soil for basic material, not a measure of its calcium content. If calcium should liberate any of the soil bases, such a reaction might account for any decrease found in the lime requirement of the subsoil rather than the actual downward movement of calcium. As previously stated, very little experimental evidence is available concerning the movement of calcium in soil under carefully controlled conditions. In view of this fact the experiments detailed herein were undertaken. EXPERIMENTAL WORK Plan of the investigation The investigation consisted of three experiments. These are briefly outlined as follows: Experiment 1. — In the first experiment the translocation of calcium in soil was studied by leaching soil contained in pots with distilled water. The soil was placed in the pots in three layers. In some of the pots 302 Benjamin Dunbar Wilson calcium as oxid, and in others calcium as carbonate, was incorporated with the surface layer to test the possible downward movement of this element; in other pots the calcium was mixed with the bottom layer of soil to determine its tendency to move upward. The downward move- ments of calcium oxid and calcium carbonate, when applied to a soil in medium, large, and excessive amounts and in equivalent quantities of calcium, were collated. The oxid was added as burned limestone, and the carbonate as ground limestone and precipitated calcium carbonate. 2 The state of division of the ground limestone used in the experiment was such that it passed thru a 100-mesh sieve and was held on a 200-mesh sieve. One set of the pots was leached for six months and another set for one year, and at the end of each period the layers of soil in each pot were analyzed for total calcium in contemplation of determining its movement. The experiment was set up in quadruplicate. Experiment 2. — In the second experiment the downward movement of calcium was determined when lots of ground limestone, differing in fineness of division, were applied to the soil in equivalent quantities. Pots filled with soil in three layers were treated with the ground limestone in the top layer, and were leached with distilled water for one year. Limestone of four grades of fineness was used in treating the different pots, the treatment with each grade being repeated four times. Experiment 3. — In the third experiment a comparative study was made of the diffusibility of calcium in a cropped and an uncropped soil. Pots were filled with soil arranged in layers, treated in the surface layer with burned limestone, and leached with distilled water for five months. Soil used The soil used in the investigation was a Dunkirk clayey silt loam, a glacial till soil low in organic matter. It comprises the greater part of the soil on the farm of the Cornell University Agricultural Experiment Station, and for this reason it was selected for study. A chemical and a mechanical analysis of this soil, taken from the files of the Department of Soil Technology, Cornell University, follow: - Twice as much ground limestone as burned limestone was applied to the pots. Consequently the quantity of calcium added to the pots treated with ground limestone was slightly in excess of that added to the pots that received a treatment of burned limestone. As it is customary when applying calcium to field soils to follow such a procedure, this ratio was used in experiments 1 and 2. The Translocation of Calcium in a Soil 303 Chemical Analysis (Bulk) (An average of the analyses of nine samples) Surface per cent Organic carbon 1 . 670 Carbon dioxid : Trace Potassium oxid 1 . 740 Calcium oxid 0.430 Magnesium oxid . 450 Sodium oxid 1 .090 Nitrogen 0. 186 Phosphoric anhydrid . 123 Mechanical Analysis (An average of the analyses of three samples) Surface per cent Fine gravel 0.5 Coarse sand 0.8 Medium sand 0.6 Fine sand 2.7 Very fine sand 9.5 Silt 67.3 Clay 18.6 Total 100.0 A large quantity of soil was necessary to carry out the experiments, and this was collected at three different times. For convenience, the three soils thus obtained are designated as X, Y, and Z. Soil X was used for experiment 1, soil Y for experiment 2, and soil Z for experiment 3. All three soils were surface soils taken from a roadside adjoining Caldwell Field, a part of the experiment station farm. Each lot was taken to the greenhouse, where it was screened and thoroly mixed, the screenings being discarded. The three soils were in good physical condition. A representative sample was taken from each of the soils and prepared for analysis. The lime requirement and the calcium content of each are 304 Benjamin Dunbar Wilson shown in table 1. The lime requirements were determined by the Veitch (1904) method, and are expressed as parts per million of calcium oxid necessary to correct the acidity in the oven-dried soils. Calcium was determined as recommended by the Ohio Agricultural Experiment Sta- tion (Ames and Gaither, 1913). This method was used for all the deter- minations of calcium that were made thruout the investigation, and consists essentially in fusing the soil with a mixture of sodium and potas- sium carbonates, precipitating the calcium as calcium oxalate after the removal of silicon, iron, aluminum, and manganese, and titrating the filtered precipitate with a standard solution of potassium permanganate. TABLE 1. Lime Requirements and Percentages of Calcium in Soils X, Y, and Z Soil Lime require- ment of dry soil (parts per million CaO) Percentage of total calcium X 900 800 1,300 0.328 Y 0.300 z 0.220 Method of placing soil in pots Glazed earthen pots 10 inches in height and 9| inches in inside diameter were used for the experiments. In each pot was placed thirteen kilograms of soil to form three layers. Of the eighty pots used, seventy-two were filled in the following manner: Into the bottom of each pot was packed five kilograms of soil, which formed the bottom, or third, layer. Over the surface of this layer a piece of wire netting was placed, and on top of it another five-kilogram portion of soil was packed, which constituted the middle, or second, layer. The remaining three kilograms of soil made up the top, or first, layer, which was separated from the middle, or second, layer by a second piece of wire netting. The calcium oxid or calcium carbonate with which the pots were treated was incorporated with the soil making up the first layer before this was placed in the pots. The remaining eight pots were filled with soil so placed that the upward movement of calcium could be studied. In order to observe this move- The Translocation of Calcium in a Soil 305 ment, the three-kilogram portions of soil containing the calcium treat- ments were placed in the bottom of the pots, the top and middle layers consisting of five kilograms each. The layers were separated with wire netting, as described above. The soil was placed in the pots in layers in order that the calcium- treated soil might be separated from the untreated soil, as well as for a division of the latter, when the pots were opened. The object in dividing the untreated soil into layers was to make possible a comparison of the amounts of calcium in them with reference to their distance from the calcium -treated soil. Treatment of pots The treatment of the pots in the three experiments may be outlined as follows: Experiment 1. Translocation of Calcium Oxid and Calcium Carbonate in Soil Nos. of pots Treatment (pounds per acre) Treated layer 1, 2, 3, 4 5,6,7,8 9, 10, 11, 12. 13, 14, 15, 16 17, 18, 19, 20 21, 22, 23, 24 25, 26, 27, 28 29, 30, 31, 32 33, 34, 35, 36 37, 38, 39, 40 41, 42, 43, 44 45, 46, 47, 48 49, 50, 51, 52 53, 54, 55, 56 3,000 CaO. . . 3,000 CaO... 9,000 CaO... 9,000 CaO. . . 15,000 CaO.. 15,000 CaO.. 15,000 CaO.. 6,000 CaC0 3 . 6,000 CaC0 3 . 18,000 CaC0 3 18,000 CaCOj 30,000 CaCOs 30,000 CaCOs 30,000 CaC0 3 Top Top Top Top Top Top Bottom Top Top Top Top Top Top Bottom 306 Benjamin Dunbar Wilson Experiment 2. Downward Movement of Ground Limestone of Different Degrees of Fineness thru Soil Nos. of pots Treatment (pounds per acre) Fineness of limestone 57, 58, 59, 60 61, 62, 63, 64 65, 66, 67, 68 69, 70, 71, 72 9,000 CaCOs 9,000 CaCOa 9,000 CaCO* 9,000 precipitated CaCOa Thru 10-mesh sieve, held on 32-mesh sieve Thru 50-mesh sieve, held on 100-mesh sieve Thru 200-mesh sieve Experiment 3. Downward Movement of Burned Limestone thru Soil Cropped and uncropped Nos. of pots Treatment (pounds per acre) 73, 74, 75, 76. 77, 78, 79, 80. 3,000 CaO. 3,000 CaO. Planted (oats) Unplanted Experiments 1 and 2 The pots included in experiments 1 and 2 were leached with distilled water equivalent to a yearly rainfall of thirty-six inches. Of these seventy- two pots the following were leached for six months: 5, 6, 7, 8; 13, 14, 15, 16; 21, 22, 23, 24; 33, 34, 35, 36; 41, 42, 43, 44; 49, 50, 51, 52. All the others were leached for one year. The pots leached for six months and those leached for one year received a treatment of twenty-one and forty- two liters of distilled water, respectively. The first treatment of water was applied to the pots on December 22, 1915. The dates and the amounts of the subsequent treatments are shown in table 2. No water was applied after June 10 to the pots that were leached for six months. These pots were allowed to drain until June 28, which was just six months after the first drainage water had leached from them. The soil was then prepared for the analysis of total calcium as is described later. The pots leached for one year were sampled during the first week in January of 1917. The Translocation of Calcium in a Soil 307 TABLE 2. Date of Treatment and Amount of Distilled Wateb Applied to Pots of Experiments 1 and 2 Date Amount of water applied (in cubic centimeters) No. of treatment Pots leached for six months Pots leached for twelve months 1 1915 December 22 December 28 1916 January 5 January 8 January 18 February 14 February 21 March 6 March 20 April 10 April 24 May 6 May 8 May 22 May 29 June 10 June 27 Julv 11 July 27 August 17 August 31 October 3 October 10 October 24 November 6 November 20 November 22 December 1 December 10 600 1,100 1,100 1,100 800 2.400 800 1.600 1,600 2,400 1,600 1,600 800 1,600 800 1,100 600 2 1,100 3 1,100 4 5 1,100 800 6 2,400 7 800 8 1,600 9 1,600 10 2,400 11 1,600 12 1,600 13 800 14 1,600 15 800 16 1,100 17 1,600 18 1,600 19 1,600 20 2,400 21 1,600 22 2,400 23 800 24 2,400 25 1,600 26 1,600 27... . 800 28 1,000 29... 1,600 Total 21.000 42,000 The drainage from the pots was collected in granite-ware pans, the pots being supported on wooden blocks (fig. 72). The water passed from the bottom of the pots thru round openings about one-half inch in diameter. To prevent the soil from washing thru these apertures, a small paraffined flowerpot was inverted over them before the soil was placed in the pots. 308 Benjamin Dunbar Wilson This arrangement afforded excellent drainage. In all the experiments a quartz-sand mulch one-half inch thick, placed on the surface of the soil, prevented evaporation from the pots. Bicarbonate (HC0 3 ) content of the drainage water The amount of bicarbonate (HC0 3 ) contained in the drainage water from the pots leached for one year was determined frequently during the investigation. Samples for analysis were collected in small Erlenmeyer Fig. 72. arrangement of pots for leaching flasks placed in such a manner as to catch the teachings as they came from the pots. It was evident that the bicarbonate content of the solutions would depend somewhat on the amount of percolation that had occurred immediately before the samples were collected for analysis, but this fact was not objectionable as the determinations were made only that some idea of the abundance of the bicarbonate in the leachings might be known. It is seen from table 3 that the quantities of bicarbonate found in the drainage water from the pots, expressed in parts per million of solution, were sufficient to exert considerable influence on the solubility of the calcium oxid or calcium carbonate with which the pots were treated, and The Translocation of Calcium in a Soil 309 would lead one to believe that the water applied to the surface of the soil in the pots passed downward thru the soil, not between the soil and the sides of the pots. TABLE 3. Bicarbonate (HCO3) Content of Drainage Water from Pots Leached with Distilled Water for One Year (Average for similarly treated pots in parts per million of solution) Nos. of pots 1 to 4 . to 12. 17 to 20. 29 to 32 . 37 to 40 . 45 to 48 . 57 to 60 . 61 to 04 . 65 to 68 . 09 to 72 . Treatment (pounds per acre) 3,000 CaO 9,000 CaO 15,000 CaO 6,000 CaC0 3 18,000 CaC0 3 30,000 CaCOa 9,000 CaCO,, thru 10- mesh, held on 32-mesh. 9,000 CaC0 3 , thru 50- mesh, held on 100- mesh 9,000 CaCOs, thru 200- mesh 9,000 precipitated CaC0 3 Jan. 18 139 125 132 144 165 141 109 83 104 128 Date of collection of drainage water Feb. Mar. 21 20 112 113 135 112 125 130 92 71 100 115 110 92 139 82 88 113 87 55 82 01 Apr. 10 74 82 143 56 71 82 61 58 64 68 June 10 162 163 266 121 111 91 81 53 94 92 July Aug. 11 17 155 200 279 121 127 82 69 51 81 81 56 74 139 41 51 55 35 30 63 44 Oct. 3 42 60 122 39 37 34 28 21 32 30 Nov. 6 99 125 188 77 73 60 35 32 63 39 Experiment 3 As previously stated, the object of experiment 3 was to determine the effect of a crop on the downward movement of calcium in soil. Eight pots were used for this purpose. The soil was placed in them in three layers, as has been described, and each pot received a treatment of burned limestone equivalent to an application of 3000 pounds to the acre. The experiment was begun on February 18, 1916, when four of the pots were planted to oats. Thirty seeds, which had been previously sterilized with a solution of calcium hypochlorite as suggested by Wilson (1915) were planted in each of the four pots, and the plants were thinned to twelve in a pot on February 26. The crop was harvested on July 18, just five months after it was planted and about the time when the grain 310 Benjamin Dunbar Wilson was ripe. There was a good stand of oats on all the planted pots at the time when the crop was harvested. The four implanted pots were leached with distilled water at the same rate as were those in the foregoing experiments, which amounted to 17^ liters for five months. It was necessary to add more water to the pots on which the plants were grown, to make up for that lost by transpiration. During the period of growth 25| liters of distilled water was applied to these pots. In table 4 are shown the amount of water applied to the planted and the implanted pots from time to time during the experiment, and the dates of its application: TABLE 4. Dates of Treatment and Amounts of Distilled Water Applied to Pots of Experiment 3 No. of treatment Date Amount of water applied (in cubic centimeters) Planted pots Unplanted pots 1 1916 February 19 February 26 March 5 March 11 March 24 April 10 April 24 May 4 May 6 May 13 May 20 May 26 June 3 June 14 June 17 June 27 July 8 1,000 800 800 1,000 1,000 1,600 1,600 800 2,400 800 2,400 800 2,400 800 2,400 2,400 2,500 1,000 2 800 3 800 4 1,000 5 1,000 6 1,600 7 1,600 8 9 800 10 11.. 1,600 12 13 1,600 14 15 1,600 16 1,600 17 2,500 Total ... 25,500 17,500 Method of sampling pots for analysis of calcium When the last application of water had drained from the pots, the quartz-sand mulch was removed from the surface of the soil and the pots The Translocation of Calcium in a Soil 311 were allowed to stand for several days in this condition until the soil was dry enough to be in a good workable condition. A large spatula was used to loosen the soil from the sides of the pots, and by this means it was possible, when inverting the pots, to slide the soil from them as a solid cylindrical mass (fig. 73). In order to guard against the possibility that calcium salts might have been carried down mechanically, during the course of the experiments, between the soil and the sides of the pots, the outside soil of. the entire soil mass was removed with a knife, leaving what might be called an inner core of soil. This inner soil core was Fig. 73. cores of soil as they came from the pots, before and after division divided into three layers by inserting a spatula where the pieces of wire netting had been placed in the soil at the time when the pots were filled (fig. 74). The three layers thus obtained were placed in different receptacles, and a representative sample taken from each of them was air-dried. A portion of this air-dried sample was passed thru a 32-mesh sieve, oven-dried over night, and finally placed in an air-tight eight-ounce bottle, which was set aside until the soil could be analyzed for total calcium according to the method already described (page 304). None of the soil layers into which some form of calcium had been placed were analyzed for this constituent at the end of the experiments, 312 Benjamin Dunbar Wilson Fig. 74. left: the bottom of a core of soil. right: a core of soil divided into its three layers, showing wire netting used but the amount of calcium present in them at the beginning of the experi- ments is given in tables 5 to 9. The percentages of calcium found in the analyzed layers at the end of the experiments are taken as an indi- cation of the translocation of this element thru the soil, and are also given in the tables. TABLE 5. Experiment 1 — Percentages of Calcium in Second and Third Layers of Soil from Pots Leached with Distilled "Water for Six Months (Calcium treatments placed in first layer of soil) No. of pot Per cent of calcium in soil layers Treatment (pounds per acre) Begin- ning of experi- ment End of experiment Arithmetic mean Treat- ment desig- nation First layer Second layei- Third layer Second layer Third layer 3,000 CaO... 6,000 CaCOa. 1*1 U) IS) ill 0.69 0.73 r .37 .40 .33 1 .38 f .34 .34 1 .27 1 .31 .41] .38 i .39 .38] .281 .28 .33 f .29 j 370±.0098 .315±.0122 .390 ±.0049 .295±.0085 A A, The Translocation of Calcium in a Soil TABLE 5 (concluded) 313 No. of pot Per cent of calcium in soil laye rs Treatment (pounds per acre) Begin- ning of experi- ment End of experiment Arithmetic mean Treat- ment desig- nation First layer Second layer Third layer Second layer Third layer 9,000 CaO... 18,000 CaC0 3 r i3i 14 1 15 f I 16 J [41] 42 43 1 44 J 1.41 1.54 f .37 .31 .39 [ .35 f .33 I .29 ] .32 I .32 .32] .32 [ .33 .35 J .331 .31 1 .33 .33 J 355±.0122 315±.0061 330±.0049 325±.0036 B B, 15,000 CaO.. 30,000 CaCOa III 111 2.12 2.33 r .37 .38 1 .39 { .40 ( .30 J .33 1 .29 I .32 .371 .37 1 .37 f .35 J .31) .35 1 .32 f .38 J . 385 ±. 0049 310±0073 .365±.0036 340±0122 C c, 314 Benjamin Dunbar Wilson TABLE 6. Experiment 1 — Percentages of Calcium in Second and Third Layers of Soil from Pots Leached with Distilled Water for One Year (Calcium treatments placed in first layer of soil) No. of pot Per cent of calcium in soil layers Treatment (pounds per acre) Begin- ning of experi- ment End of experiment Arithmetic mean Treat- ment desig- nation First layer Second layer Third layer Second layer Third layer 3,000 CaO... 6,000 CaCO-3. { 1] 1 2 1 3 1 4J f 29 "I J 30 I 81 I 32 J 0.69 0.73 r .35 1 .34 .37 1 .30 f .32 .32 I .26 1 .31 .32) .36 .38 .32 J .25) .30 1 .29 .33 J 340±.0098 .303±.0103 .345±.0122 .293±0109 D D, 9,000 CaO... 18,000 CaC0 3 f 91 10 11 I 12 J (SI 1.41 1.54 f .30 .33 .30 1 .29 { .33 .33 .32 1 .30 .291 .31 .33 .28 J .35) .30 1 .32 .27 J .305±.0061 .320±.0049 .303 ±.0085 .310±0122 E E, 15,000 CaO.. 30,000 CaCOa (I) (I! 2.12 2.33 f .34 1 .32 | .30 i .34 f .31 .29 .30 1 .27 .39) .30 .34 .33 J .27) .27 .27 .28 J 325±.0073 293±.0061 .340±0122 273±.O019 F Pi The Translocation of Calcium in a Soil 315 TABLE 7. Experiment 1 — Percentages of Calcium in First and Second Layers of Soil from Pots Leached with Distilled Water for One Year (Calcium treatments placed in third layer of soil) No. of pot Per cent of calcium in soil layers Treatment (pounds per acre) Begin- ning of experi- ment End of experiment Arithmetic mean Treat- ment desig- nation Third layer First layer Second layer First layer Second layer 15,000 CaO.. 30,000 CaC0 3 (II (SI 2.12 2.33 r .32 1 .32 .34 { .29 f .29 I .29 .31 { .31 .301 .33 .35 f .28 J .351 .32 .28 f .30 J .318±.0066 .300±.0049 .315±.0122 .313±.0109 G G, TABLE 8. Experiment 2 — Percentages of Calcium in Second and Third Layers of Soil from Pots Leached with Distilled Water for One Year (Calcium treatments placed in first layer of soil) Fineness of limestone No. of pot Per cent of calcium in soil layers Treatment (pounds per acre) Begin- ning of experi- ment End of experiment Arithmetic mean Treat- ment desig- nation First layer Second layer Third layer Second layer Third layer 9,000 CaCOs Thru 10-mesh, held on 32- mesh f 57 ] 58 59 I 60 J 0.91 f .36 .30 .32 ( .33 .32 1 .33 ( .35 31 J .328 ±0085 .328 ±.0061 H 9,000 CaCOa Thru 50-mesh, held on 100- mesh f 61 ) 62 63 ( 64 J 0.91 f .28 .30 .29 ( .27 .27 1 .28 .25 .26 J .285 ±.0049 .265 ±.0049 I 9,000 CaCOs Thru 200-mesh ( 65 1 J 66 1 1 67 (68 J 0.91 f .29 .32 .27 ( -31 .28 1 .32 .29 .29 J .298 ±.0085 .295 ±.0061 J 9,000 CaCOs Precipitated CaCOs f 69 ] 70 71 I 72 J 0.91 1 . 33 .28 .35 ( .28 .29 1 .28 .33 1 .29 J .310 ±.0146 .298 ±.0081 K 316 Benjamin Dunbar Wilson TABLE 9. Experiment 3 — Percentages of Calcium in Second and Third Layers of Cropped and Uncropped Soil from Pots Leached with Distilled Water for Five Months (Calcium treatments placed in first layer of soil) Planted or unplanted No. of pot Per cent of calcium in soil layers Treatment (pounds per acre) Begin- ning of experi- ment End of experiment Arithmetic mean Treat- ment desig- nation First layer Second layer Third layer Second layer Third layer .218 ±.0090 3,000 CaO Planted (oats) 1 73 ) 74 75 ( 76 J 0.58 ( - 21 1 .20 .19 ( .24 .18) .24 .23 .22 J .210 ±.0073 L 3,000 CaO Unplanted f 77 ) 78 79 [80 J 0.58 f -18 • .22 .20 ( .18 .22 1 .19 .23 .18 J .195 ±.0073 .205 ±.0098 Li INTERPRETATION OF ANALYTICAL DATA The amounts of calcium present in the analyzed layers of soil at the end of the experiments, from the pots that had received the same calcium treatment, varied to some extent, as is seen from tables 5 to 9. The variation in the calcium content of the soil from pots similarly treated appears to be about as great as that shown by a comparison of differently treated pots. In view of this fact, it became necessary to determine the experimental error of the investigation, before any definite conclusions could be drawn regarding the movement of calcium thru the soil, in relation to the following points: (1) Did the analyzed soil layers contain more calcium at the end of the experiments than was contained in the original soils at the beginning of the investigation? (2) Did the layer of soil adjoining the one treated with calcium contain more of this element than the layer farther removed? (3) If calcium had moved thru the soil, did the degree of movement vary with smaller or larger applications of this constituent? In order to draw conclusions accurately from the data presented, the arithmetical mean value with its probable error, for the amount of calcium present in the soil layers resulting from different calcium treatments, was determined. These values are given in the tables and are used in interpreting the results of the investigation. For The Translocation of Calcium in a Soil 317 convenience the letters in the extreme right-hand column of each table are used to designate the different pot treatments. Peter's formula as given by Mellor (1909) was used in determining the probable errors. According to this formula ; the probable error, R, of the arithmetical mean of a series of observations is 2 (+ v) R = ± 0.8453 -—!==■ n\n-i in which - (+ v) denotes the sum of the deviations of every observation from the mean, their sign being disregarded, and n denotes the number of observations actually made. The increase of calcium in one layer of soil over that in another layer, in pots similarly or dissimilarly treated, or the amount of calcium present in the soil from a calcium-treated pot over that in the original soil at the beginning of the experiment, can be determined by subtracting the arithmetical mean value of calcium for any one particular soil from that for any other soil, the probable error of the difference being derived from the formula E = \ E ! 2 + E 2 - in which Ei is the probable error of one mean, and E 2 the probable error of the other. This procedure is followed in explaining the results of the experiments shown in tables 5 to 9. A comparison of the amounts of calcium found by analysis in the analyzed soil layers from pots that were similarly treated is given in table 10, which was compiled from the data given in tables 5 to 9 inclusive. This table shows that in eleven cases out of twenty there was a greater amount of calcium in the layer of soil adjoining the one that had been treated with calcium, that in eight of the cases the soil layer farther removed from the treated layer contained the greater percentage of calcium, and that in one case there was an equal amount of calcium in each of the untreated soil layers. The differences in the amounts of calcium in the two soil layers are not great enough to be of any conse- quence, however. Wood and Stratton (1910) have shown that in order to be significant, differences resulting from different treatments should be at least 3.8 times their probable error, corresponding to odds of 30 to 1 that such differences are real and not due to normal variation. As none of the differences appearing in table 10 are significant, it is safe to con- 318 Benjamin Dunbar Wilson elude that the soil layers which were analyzed did not differ in their calcium content for any one particular treatment. This being true, the remainder of the discussion of the results may be confined to a con- sideration of the soil layer adjacent to the layer receiving the calcium treatment. In every case, regardless of the position of the calcium-treated layers in the pots, this is the second layer of soil. TABLE 10. Comparison op the Amounts of Calcium in the Analyzed Layers of Soil from Pots Similarly Treated (For the differences to be significant, the mean must be 3.8 times the probable error) Layer Difference having Duration of No. of Treatment in amounts the greater experiment experi- of calcium amount of calcium ment In second and third layers A .020 ±.0109 Third Ai .020 ±.0147 .025 ±.0131 .010 ±.0071 .020 ±0061 Second Second Third Second Six months B B! C Ci .030 ±.0142 Third D .005 ±.0156 Third Di .010 ±.0149 Second 1 E .002 ±.0104 Second Ei .010 ±.0131 Second F .015 ±.0142 Third Fi .020 ±0064 Second Twelve months In first and second layers G 003 ±.0138 First G, .013 ±0119 Second In second and third layers H I .000 ±.0104 .020 ±0069 Second Twelve months 2 J .003 ±.0104 Second K ■ .012 ±.0167 Second L L. .008 ±0116 010 ±0122 Third Third Five months 3 The Translocation of Calcium in a Soil 319 Results of experiment 1 The differences in the percentage of calcium in the second layer of soil, resulting from different calcium treatments, are shown in table 11. It is evident from this table that in the one case when the mean is greater than 3.8 times the probable error, the soil from the pots receiving treat- TABLE 11. Comparison of the Amounts of Calcium in the Second Layer of Soil from Pots Differently Treated in Experiment 1 (For the differences to be significant, the mean must be 3.8 times the probable error) Treatments compared Difference in amounts of calcium in second layer of soil Treat- ment showing greater amount of calcium Duration of experi- ment Layer of soil in which calcium was placed Calcium treatments compared A and Ai .055 ±.0156 .040 ±.0137 .075 ±.0088 A B C Six months First B and Bi C and Ci Equivalent quantities of D and Di E and Ei F and F! .037 ±0142 .015 ±.0078 .032 ±.0095 D E, F Twelve months CaO and CaCOs A and B .015 ±.0156 .015 ±.0109 .030 ±.0131 A C C Six months First A and C B and C D i ff e r e n t quantities of CaO D and E .035 ±.0115 .015 ±.0122 .020 ±0095 D D F Twelve months D and F E and F G and Gi .002 ±.0163 G Twelve months Third Equi valent quantities of CaO and CaC0 3 ment C contained more calcium in the second layer than did the soil from the pots receiving treatment Ci. C being greater than Ci, and the difference between A and Ai being almost without the experimental error, it appears that the second layer of soil from the pots that were leached for six months contained more calcium when the first layer had been treated with burned limestone than when the first layer had received a treatment of ground limestone. When the soil with similar treatments 320 Benjamin Dunbar Wilson was leached for twelve months, this relationship between the burned and the ground limestone treatments is not shown, as can be seen from the table. It seems reasonable to believe that the results from the soil that was leached for the longer period are nearer the truth, as this soil had a longer time in which to become adjusted to the conditions of the experi- ment. If this assumption is true, it can be concluded from the results given in table 11 that the burned limestone did not move downward in the soil more rapidly than did the ground limestone. The table also reveals the fact that there was no more calcium present in the second layer of soil resulting from larger applications of burned limestone than there was from smaller applications of this substance, and that there was no appreciable difference between the amounts of calcium present in the second layer of soil from the pots that had been treated with either burned limestone or ground limestone in the third layer. The question now arising is whether or not the amounts of calcium present in the second layer of soil from the pots in experiment 1 which were treated with burned limestone (since the tendency was for the pots treated with burned limestone to contain more calcium in the second soil layer than those treated with ground limestone) are large enough, when compared with the amount of calcium in the soil at the beginning TABLE 12. Comparison of the Amounts of Calcium Found in the Second Later op Soil at the End of Experiment 1, with the Amount Present in the Soil at the Beginning of the Experiment (For the differences to be significant, the mean must be 3.8 times the probable error) Treatment Calcium present in second layer of soil at end of experiment Calcium present in soil at beginning of experiment Difference in calcium Duration of experiment .370 ±.0098] .355 ±.0122 .385 ±.0049 .328 ±.0156 .042 ±.0184 .027 ±.0198 .057 ±.0164 Six months .340 ±.0098 .305 ±.0061 .325 ±.0073 .318 ±.0066 .328 ±0156 .012 ±.0184 .023 ±.0168 .003 ±.0172 .010 ±0169 Twelve months The Translocation of Calcium in a Soil 321 of the experiment, to show that there was an upward or a downward movement of this constituent during the course of the experiment. Such a comparison is made in table 12. Treatment C shows a downward, movement of calcium into the second soil layer that is almost within certainty; but since treatments A, B, D, E, and F do not indicate such a movement, it can be concluded that there has been no downward move- ment of calcium within the soil. No upward movement of calcium resulted from treatment G, as can be seen from the table. Results of experiments 2 and 3 The results of experiments 2 and 3 are interpreted in the same way as are those of experiment 1, and are summarized in tables 13 and 14: TABLE 13. Comparison of the Amounts of Calcium Found in the Second Layer of Soil at the End of Experiment 2, with the Amount Present in the Soil at the Beginning of the Experiment (Limestone added in equal amounts. For the differences to be significant, the mean must be 3 . 8 times the probable error) Treat- ment Calcium present in second layer of soil at end of experiment Calcium present in soil at beginning of experiment Difference in calcium Duration of experi- ment Layer of soil in which calcium was placed Fineness of lime- stone applied H 1 J Iv .328 ±0085 .285 ±0049 .298 ±.0085 .310 ±.0146 .300 ±.0154 .028 ±.0176 .015 ±.0162 .002 ±.0176 .010 ±.0212 Twelve months First H— Thru 10-mesh sieve, held on 32- mesh I — Thru 50-mesh sieve, held on 100- mesh J— Thru 200-mesh sieve K — Precipitated CaCOs There was no movement of calcium from the first to the second layer of soil in the pots that were treated with ground limestone at the rate of 9000 pounds to the acre, regardless of the fineness to which the lime- stone had been ground, nor with an equivalent quantity of precipitated calcium carbonate. This fact is well brought out by the figures in table 13. The differences shown in the table between the amount of calcium in the soil at the beginning of the experiment and that found in the second soil layer at the end of the experiment are not great enough to indicate any movement of this element. 322 Benjamin Dunbar Wilson In table 14 it is shown clearly that growing oats on the potted soil treated with burned limestone at the rate of 3000 pounds to the acre had no influence on the downward movement of calcium thru the soil. There was no movement of calcium in the soil either with or without the growth TABLE 14. Comparison of the Amounts of Calcium in the Second Layer of Soil from Planted and Unplanted Pots in Experiment 3 (Calcium added in equal amounts as burned limestone. For the differences to be significant, the mean must be 3.8 times the probable error) Treatments compared Difference in amounts of calcium in second layer of soil Treatment showing greater amount of calcium Duration of experiment Layer of soil in which calcium was placed .015 ±.0103 L Five months First L and Z* .010 ±0088 Z *Z (original soil) = .220 ± .0049 of plants, as is shown by a comparison of the calcium present in the second soil layer at the end of the experiment with that present in the soil at the time when the experiment was begun. SUMMARY Calcium applied to a clayey silt loam soil in the form of burned lime- stone, ground limestone, or precipitated calcium carbonate, did not move downward in the soil to any appreciable extent when the soil was leached in pots for one year with distilled water. The soil from some of the pots that were leached for six months showed a slight movement of calcium when the soil had been treated with burned limestone, while the soil from the pots leached for twelve months with similar treatments did not show such a movement. This inconsistency cannot be explained unless there was a mechanical movement of calcium in the soil from certain of the pots that were leached for six months. As hereinbefore stated, the results obtained from the soil leached for the longer period are given preference over the others, and this permits The Translocation of Calcium in a Soil 323 the conclusion that neither small nor large applications of burned or ground limestone resulted in a downward movement of calcium. Calcium incorporated with the soil as burned or ground limestone and placed in the bottom of the pots did not move by diffusion into the upper soil layers. No . movement of ground limestone thru the soil was evident when applied at the rate of 9000 pounds to the acre, irrespective of the fineness to which the rock had been ground. There was no difference in the movement of limestone ground to pass a 200-mesh sieve and that held on a 32-mesh sieve. Precipitated calcium carbonate when applied to the soil in large amounts did not move downward to the untreated adjacent soil. Oats grown in pots on the soil that had been treated with burned lime- stone had no effect in bringing about a descent of calcium. It seems logical to believe that a soil deficient in calcium will absorb this constituent from the drainage water as it percolates thru the soil. No doubt this occurs, but the amount held by the soil is evidently so small that it cannot be detected by a chemical analysis. Conclusions drawn from small differences of calcium found in soil upon analysis are hardly trustworthy, as it is often difficult to obtain concordant results from the same sample of soil. When small differences are calculated to pounds of calcium in an acre foot of soil, as is often done, the real value of such results is questionable. CONCLUSION The results of this investigation are summarized briefly in the following statement: The translocation of calcium thru a clayey silt loam soil with a rather large lime requirement is extremely slow, since in these experiments no upward nor downward movement of this element was perceptible twelve months after small, large, or excessive amounts of calcium salts were applied to the soil. ACKNOWLEDGMENT The writer desires to acknowledge his indebtedness to Professor T. Lyttleton Lyon, under whose direction this work was done. 324 Benjamin Dunbar Wilson LITERATURE CITED Ames, J. W., and Gaither, E. W. Soil investigations. Ohio Agr. Exp. Sta. Bui. 261:449-512. 1913. Ames, J. W., and Schollenberger, C. J. Liming and lime requirement of soil. Ohio Agr. Exp. Sta. Bui. 306:279-396. 1916. Broughton, L. B. How lime is distributed through and lost from soils. Maryland Agr. Exp. Sta. Bui. 166:285-326. 1912. Hall, A. D., and Miller, N. H. J. The effect of plant growth and of manures upon the retention of bases by the soil. Roy. Soc. London. Proc. 77b: 1-32. 1905. King, F. H. Investigations in soil management, p. 1-168. (Reference on p. 62-86.) 1904. McIntire, W. H. Results of thirty years of liming. Pennsylvania State Coll. Rept. 19 11-12 2 : 64-75. 1913. Mellor, J. W. Higher mathematics for students of chemistry and physics, p. 1-641. (Reference on p. 524.) 1909. Shorey, Edmund C, Fry, William H., and Hazen, William. Calcium compounds in soils. Journ. agr. research 8:57-77. 1917. Smith, Eugene A. Table of analyses of Alabama soils and subsoils. In Report on the cotton production of the State of Alabama. Tenth U. S. Census (1880) 6 2 : 71-74. 1884. Snyder, Harry. The chemical composition of soils. In Soil investi- gations. Minnesota Univ. Agr. Exp. Sta. Bui. 65 : 1-39. 1899. Veitch, F. P. Comparison of methods for the estimation of soil acidity. Amer. Chem. Soc. Journ. 26:637-662. (Reference on p. 659.) 1904. Summary of experiments on the relation of soil acidity to fertility.* In Proceedings of the twenty-first annual convention of the Association of Official Agricultural Chemists. U. S. Bur. Chem. Bui. 90:183-187. 1905. White, J. W. The results of long continued use of ammonium sulphate upon a residual limestone soil of the Hagerstown series. Pennsylvania State Coll. Rept. 1912-13 2 : 55-104. 1914. Wilson, James K. Calcium hypochlorite as a seed sterilizer. Amer. journ. bot. 2:420-427. 1915. Wood, T. B., and Stratton, F. J. M. The interpretation of experi- mental results. Journ. agr. sci. 3:417-440. 1910. Memoir 15, Insects Injurious to the Hop in New York, the second preceding number in this series of publications, was mailed on November 19, 1918. LIBRARY OF CONGRESS 002 672 739 A WE