A380—120—75OO TEXAS AGRICULTURAL EXPERIMENT STATION ’ AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS W. B. BIZZELL, President BULLETIN NO. 259 _ JANUARY, 1920 DIVISION OF CHEMISTRY NITRIFICATION IN TEXAS SOILS !_. fwmlffifgl‘ 5Q 393710211; l. fi I1A,1;;=;‘¢;"!’\:iEI'I B. YOUNGBLOOD, DIRECTOR College Station, Brazos County, Texas STATION STAFFT ADMINISTRATION B. YOUNGBLOOD, M. S., Director A. B. CoNNER. B. S., Vice Director J. M. JoNEs, A. M., Assistant Director CHAS. A. FELRER, Chief Clerk A. S. WARE, Secretary _ _ . EICCUIIDC Assistant CHARLES Sosoux, Technical Assistant VETERINARY SCIENCE _ *M. FRANCIS. D. V. M., Chief _ H. SCHMIDT, D. V. M., Veterinarian D. H. BENNETT, V. M. D., Veterinarian CHEMISTRY _ _ G. S. FRAPS, Ph. D., Chief; State Chemist S E. AsBuRY, M. S., Assistant Chemist S Lounmn. B. S., Assistant Chemist _ I F. B. SCHILLING, B. S., Assistant Chemist J. B. SMITH, B. S., Assistant Chemist WALDO WALKER, Assistant Chemist HORTICULTURE _ H. NEss. M. S., Chief W. S. HOTCHKISS, Horticulturist ANIMAL INDUSTRY J. M. JoNEs, A. M., Chief; Sheep and Goat Investigations. . C. BURNs, B. S., Animal Husbandman in Charge of Beef Cattle Investigations (on leave) R. M. SHERWOOD. B. S., Poultryman J. B. IVICNULTY, B. S., Dairuman O. E. McCoNNELL, B. S., AnimatHusbandman in Charge of Swine Investigations . G. R. WARREN, B. S., Assistant Animal Hus- ENTOMOLOGY M. C. TANQUARY, Ph. D., Chief; State Ento- molooist H. J. REINHARD, B. S.. Entomologist H. B. PARKS, B. S., Apiculturist _ C. S. RUDE, B. S., Assistant Entomologist AGRONOMY A. B. CONNER, B. S., Chief _ A. H. LEIDIGH, B. S. Agronomist E. W. GEYER. B. ., Agronomist H. H. LAUDE, M. S., Agronomist PLANT PATHOLOGY AND PHYSIOLOGY J. J. TAUBENHAUS, Ph. D., Chief FEED CONTROL SERVICE F. D. FULLER, M. S., Chief JAMES SULLIVAN, Executive Secretary FORESTRY E. O. SIECKE, B. S., Chief; State Forester PLANT BREEDING E. P. HUMRERT, Ph. D., Chief FARM AND RANCH ECONOMICS H. M. ELIOT, M. S., Chief SOIL SURVEY "W. T. CARTER, JR., B. S.. Chief T. M. BUSHNELL. B. S., Soil Surveyor bandman _ _ W. B. FRANCIS, B. S., Soil Surveyor R. G. BREWER, B. S., Assistant Animal Hus- ————-———-———-, Soil Surveyor bandman SUBSTATIONS No. 1. Beeville, Bee County _ No. 8. Lubbock, Lubbock County I. E. COWART, M. S., Superintendent R. E. KARPER, B. S., Superintendent No. Troup, Smith County W. S. HOTCHKISS, Superintendent No. 3. Angleton, Brazoria County E. B. REYNOLDS, M. S., Superintendent Beaumont, Jelferson County A. H. PRmcE, B. S., Superintendent No. 5. Temple, Bell County _ D. T. KILLOUGH, B. S., Superintendent No. 6. Denton, Denton County _ C. H. McDowELL, B. S., Superintendent No. 7. Spur, Dickens County _ R. E. DICKSON, B. S., Superintendent tAs of December 30. 1919. D. L. JoNEs, Scientific Assistant No. 9. Pecos, Reeves County . W. JACKSON B. S., Superintendent No. 10. (Feeding and Breeding Substation) College Station, Brazos County -—-i——-——-—- , Superintendent E. CAMERON, Scientific Assistant No. 11. Nacogdoches, Nacogdoches County G.VT. McNEss, Superintendent **No. 12. Chillicothe, Hardeman County A. B. CRON, B. S., Superintendent V. E. HAFNER, B. S., Scientific Assistant No. 14. Sonora, Sutton-Edwards Counties E. M. PETERS, B. S., Superintendent IIn cooperation with School of Agriculture, A. 8c M. College of Texas. ‘In cooperation with the School of Veterinary Medicine, A. 8c M. College of Texas. **In cooperation with the United States Department of Agriculture. CONTENTS. PAGE Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5 Preliminary Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Method of Work Adopted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9 Rate of Nitrification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12 Yearly Nitrification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 13 Relation of Nitrates Produced to Nitrogen Content of Soil . . . . . .. 14 Relation of Nitrification to Composition of Soil . . . . . . . . . . . . . . . .. 18 Eifect of Additions in Soils With Low Nitrification . . . . . . . . . . . . . . 23 Nitrification of Organic Matter of the Soil . . . . . . . . . . . . . . . . . . . .. 26 Availability of Organic Matter of Soil . . . . . . . . . . . . . . . . . . . . . . . .. 2'7 Nitrifying Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 29 Nitrification of Manure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 31 N itrificationpf Sulphate of Ammonia . . . . . . . . . . . . . . . . . . . . . . . . .. 34 Nitrification of the Same Soil at Diiferent Times . . . . . . . . . . . . . .. 34 Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 35 Summary and Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 35 [Blank Page in Original Bulletin] BULLPYJFIN No. 259. l JANUARY, 1920- NITRIFICATION IN TEXAS SOILS BY G. S. FRAPS‘. While it is well known that" the quantity of nitrogen which can be taken up from the soil by crops depends, to a considerable extent, upon other things than the total amount of nitrogen in the soil; yet in Bul- letin 151 of this Experiment Station, it is shown that there is a rela- tion between the average nitrogen content of the soil, and the behavior’ of the soil toward crops in pot experiments. In the bulletin mentioned, it is shown that there is a relation between the number of crops de- ficient in nitrogen in pot experiments, and the total amount of nitrogen in the soil. The average quantity of the nitrogen withdrawn by the crops in the pot experiments increased regularly with the average quan- tity of nitrogen in the soil. The average nitrogen content of the crops also increased with the average nitrogen content of the soil. The effect of additions of nitrogen to the soil in the pots decreased as the per- centage of nitrogen in the soil increased. ' i The total nitrogen of the soil is, therefore, on an average, a measure »o,f the fertility of the soil with respect to nitrogen. This fact has not been so well brought out in field experiments, for the reasons that the soils used in the field experiments may have varied in composition in the different parts of the field, the conditions could not be controlled so well in field experiments as in pots, and experiments were not made with a sufficient number of soils in the field to estimate average results. The production of active nitrogen, or nitrogen which can be taken i up by crops, as pointed out in Bulletin 106 of this Experiment Station, depends to a certain extent upon the total nitrogen of the soil, the nature of the soil, the quantity of water contained therein, and the nature of the organic nitrogenous compounds in the soil. The tempera- ture, and other factors are also of significance. It was also shown in Bulletin 106, that the qu.antity of active nitrogen produced was related to the growth of the crops in pot experiments and to the quantity of nitrogen contained in the crops. The object of the present study is to ascertain, if possible, the rela- tion of the nitrate production in the soil to various factors which in- fluence soil fertility. ' PRELIMINARY W ORK. Previous work on nitrification, such as that described in Bulletin 106, was carried on with 500 grams of the soil in precipitation jars, which were maintained at a constant water content. This method is o-rdi- ' narily used, although with smaller quantities of soil in beakers. The method was not used in the present work, for the reason that a method ‘was desired which more nearly approached natural conditions, and also 6 TEXAS AGRICULTURAL EXPERIMENT STATION. that would permit several determinations of nitrates from the same sample. The soils in the jars are looser than those in the field, and therefore contain a larger quantity of air. They were kept at a uni- form condition of moisture, which is not the case in the field conditions. The nitrates Were permitted to accumulate until the end of the experi- ment, which is not the CdSQ in the field, asportions are Washed out by rain or taken up by the plant roots. For these reasons a method Was used in Which the soil was placed in ipercolators and, at intervale, extracted with water. The percolation with water would compact the soil, as is _done by rain; it would extract the nitrates, as is done by rain and plant roots; it would leave the soil in a saturated condition, from which it would gradually dry out, as is the case with the natural soil after a heavy rain. Successive extractions could also be made on the same soil. The soil could also- be manipu- lated, if desired. While the soil in the percolator is not claimed to be under the same conditions as the soil in the field, yet it is subject to a nearer approach to field conditions than the soil in precipitating jars or beakers. ‘ i The first one or two experiments were made on the soil placed in iron tubes. After that glass percolators were used. Recovery by Percolation. An experiment was made t0 ascertain the efficiency of the extraction of nitrate by percolation; iron percolation tubes, and 500 grams of soil were used. Two portions of the soil were used and to one portion, 0.5 mg. of nitrogen as nitrate was added. The percolation was continued either until 200 c.c. came through, or for the period of the day’s work. The nitrate was determined by phenol-sul-p phuric acid. Table 1.—Nitrate nitrogen removed by successive percolations in milligrams. Nitrate Nitrogen Lab. Addition of No. nitrate nitrogen First ] Second Third Fourth Total 970 0.5 mg . . . . . . . . . . . . . . . . .. 6.80 .75 .20 08 7.83 970 . . . . . . . . . . . . . . . . . . . .. 6.60 .50 .16 06 7.32 1119 0 5mg . . . . . . . . . . . . . . . . .. 1.70 05 .03 02 1.83 1119 . . . . . . . . . . . . . . . . . . . .. 1.40 .05 .03 01 1.49 1121 0.5 mg . . . . . . . . . . . . . . . . .. 2.22 15 .06 03 2.46 1121 . . . . . . . . . . . . . . . . . . . .. 1.60 2O .06 ' 04 1.90‘ 1201 0. 5 mg . . . . . . . 21.60 30 .22 12 22.24 1201' . . . . . . . . . . . . . . . . . . . . . 22.00 37 .12 06 22.55- 1406 0 5 mg . . . . . . . . . . . . . . . . .. 4.00 05 .06 02 4.13 1406 . . . . . . . . . . . . . . . . . . . .. 4.00 .05 .04 02 4.11 6268 0.5 mg . . . . . . . . . . . . . . . . .. 1.24 .05 .03 02 1.34 6268 . . . . . . . . . . . . . . . . . . . . . .60 05 02 01 0.68 Average . . . . . . . . . . . 6 2 21 .08 O7 The results of the experiments are given in Table 1. For practical purposes, the nitrate nitrogen is extracted by the first two percolations. It is true that some of the nitrates are extracted by the third and fourth percolations, and these amounts would affect the results to a slight ex- tent. This would be particularly the case with heavy soils through which the water does not pass readily. As the colorimetric method for determining nitrate nitrogen is not a very exact method, the writer believes that the amount of nitrate extracted in the third and fourth percolations is within the limit of error for the total amount of nitrates NITRII-‘ICATION IN TEXAS SorLs. 7 present in most cases. It was therefore decided to use only two extrac- tions ifor the work. ' Relation. of the Percolcttton- flI()/t}l70d to the Jar Method. In OPdGIi to study the relations between the amount of nitrate formed in jars and that produced in the percolators, an experiment was conducted in which one part of the same soils was placed in jars, mixed with water to one-third its capacity, inoculated with water from a fertile soil, and allowed to stand four weeks. Other portions of the same soils were weighed out, and placed in galvanized iron tubes. They were extracted immediately with water, by percolation, then allowed to stand four weeks, when another perco- lation was made; subsequently other percolations were made. The re- sults of the experiment are shown in Table 2. 'I‘ablc 2.—Nitrate produced ‘n percolators and in jars. (Parts per milllonf, _ l ' In percolators Lab. Jars. No. 0 weeks 4 weeks Total 327 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.0 30.7 34.7 4.0 869 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9.0 10.4 19.4 11.0 870 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 23.2 12.2 35.4 33.0 873 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 41.2 1.0 42.2 37.7 876 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.2 46.6 50.8 5.0 878 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3.3 0.8 4.1 2.2 882 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9.0 27.6 36.6 9.6 893 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5.6 0.8 6.4 3.2 938 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 34.8 41.0 75.8 66.7 964 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 26.5 7.7 34.2 23.3 969 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 34.2 27.1 61.3 40.0 1128 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 15.6 0.6 16.2 13.6 Average . . . . . . . . . . . . . . . . . . . . . .. 17.5 17 2 34.7 20.7 The amount of nitric nitrogen in the soil in the jars should be com- pared with the amount extracted from the percolator at the beginning of the experiment plus that found at the end of the four weeks. The amount of the nitric nitrogen in the jars was in all cases less than the amount extracted from the percolators in the corresponding period of time. In some cases, the difference was very large, while in other cases the difference was small. For example, with soil 327, 4.0 per million of nitric nitrogen were found in the jar, while 34.7 parts per million were extracted from the soil in the percolator. With soil 876, 5.0 parts per million were found in the jar, and 50.8 parts in the per- colator. These are very large differences. On the other hand, with soil 870, 33 parts per million were extracted from. the soil in the jar, and 35.4 parts from the soil in the percolator. With soil 908, 66.7 parts were extracted from the soil in the jar, and 75.8 from the soil in the percolator. The conditions for nitrification seem to be better in the percolator than in the jar. What these favorable conditions are, remains for fur-. ther study to determine. It is possible that nitrates are formed in the jars, and then partly destroyed, or that the presence of the nitrate de- creases the activity of the bacteria. _ ' Efiect of Water Content. In another experiment, six soils were se- lected and two percolators weighed out for each. Series A was per- 8 TEXAS AGRICULTURAL EXPERIMENT STATION. colated and then allowed to remain undisturbed for the period of four Weeks. Series B received sufficient Water at the end of each week to make the moisture content one-third of the saturation capacity of the soil. Table. 3.——Effect of water content. Nitrate nitrogen in parts per million. Lab. Kcptat1-3 _ No. water 0 weeks 4 weeks 8 weeks 12 weeks 16 weeks 20 weeks 11o B . . . . . . . . . . ...— 18.6 95.3 36.4 TT-iao - 8.2 T 114 B . . . . . . . . . . .. 43.8 27.6 68.8 2.5 1.6 1.1 142 B . . . . . . . . . . .. 0.4 0.5 29.3 60.6 39.6 37.6 324 B . . . . . . . . . . .. 12.8 95.6 26.9 13.2 6.1 4.0 I338 B . . . . . . . . . . .. 7.6 90.0 16.5 5.7 4.9 3.1 993 B . . . . . . . . . . .. _ 45.8 120.5 14.6 3.8 5.4 1.1 Average. 21 5 71.6 32.1 16.8 10.9 9 2 110 A . . . . . . . . . . .. 28.5 114.0 16.2 8.8 6.8 1.3 114 A . . . . . . . . . . .. 50.0 86.4 38.8 2.7 2.0 1.0 142 A . . . . . . . . . . .. 4.0 0.5 10.0 54.0 40.0 - 25.0 524 A . . . . . . . . . . .. 13.7 37.4 40.6 15.4 3.9 338 A . . . . . . . . . . .. 7.8 ' 82.9 33.9 16.0 4.9 3.2 933 A . . . . . . . . . . .. 40.9 109.6 27.6 3.0 5.1 4.2 Average... 24.1 71.8 27.8 16.6 10.7 as The results of this work are given in Table 3. There was some variation in the amount of nitrates found. The amount. of the evap- oration" from these soils was comparatively small, and only a small amount of water was needed to retain the moisture content at one-third the saturation capacity. In another set of soils, one series was kept undisturbed, water, when needed, being added to one-third of its saturation capacity, while the other set, at the end of eight weeks, on October 6, was emptied just before percolation, into porcelain dishes, mixed thoroughly, and then pereolated. A 1 Table 4.-—Efl'ects ‘of stirring. Nitrate nitrogen in parts per million. Ifilb. 0 weeks 4 weeks 8 weeks 12 weeks 16 weeks o. s18 B . . . . . . . . . . . . . . . . . . . . .. 38.5 15.4 as ' 2.1 2.0 850 B . . . . . . . . . . . . . . . . . . . . .. 1.0 42.3 13.2 2.0 1.7 882 B . . . . . . . . . . . . . . . . . . . . .. 16.5 67.3 11.8 1.8 1.6 894 B . . . . . . . . . . . . . . . . . . . . .. 66.6 48.4 10.5 1.6 2.6 895 B . . . . . . . . . . . . . . . . . . . . .. 0.9 61.9 14.3 1.2 2.4 932 B . . . . . . . . . . . . . . . . . . . . .. 15.7 55.2 4.4 6.9 2.3 Average . . . . . . . . . . . . . .. 23.2 58.4 10.5 2.6 2.1 818 A . . . . . . . . . . . . . . . . . . . . .. 35.3 66.9 19.0 1.0 0.0 850 A . . . . . . . . . . . . . . . . . . . . .. 0.9 43.2 30.7 6.0 1.7 882 A . . . . . . . . . . . . . . . . . . . . .. 17.7 75.4 11.0 2.6 1.9 894 A . . . . . . . . . . . . . . . . . . . . .. 70.6 42.6 16.7 0.2 1.8 895 A . . . . . . . . . . . . . . . . . . . . .. 0.5 44.7 40.7 2.1 1.3 932 A . . . . . . . . . . . . . . . . . . . . . .. 16.3 68.9 4.9, 6.0 3.7 Average . . . . . . . . . . . . . .. 23.4 56.9 20.5 2.9 1.7 The results are presented in Table 4. The amount of nitrates formed aftenthe eight weeks was small, and the stirring of the soil appeared to have little effect upon it. " Efiect of Lime. The effect of carbonate of lime was tried on some soils which did not nitrify very well, and the results are presented in NITRIFICATION IN TEXAS SorLs. 9- Tables 5 and 6. The results are somewhat peculiar. Without lime, soil 855 had not nitrified to any extent at the end of 16 weeks; While with 1 per cent. of carbonate of lime, it produced a decided amount of nitrates at the end of 20 weeks, and with 2 per cent. of carbonatebf lime it had produced a decided amount of nitrates at the end of 12 xveeks. Table 5.——Effects of Carbonate of Lime. Nitrate Nitrogen in parts per million of soil. 855 873 1128 A B A B C A C Carbonate of Date 0 5.0 10 0 0 5.0 10.0 0.0 10.0 Lime Added gm. gm. gm. gm. gm. Oweeks . . . . . . . Sept. 23, 1913 1.2 1.9 1.9 35.4 36.2 35.0 15.0 17.6 4weeks . . . . . . . .. Oct. 21, 1913 0.0 0.4 0.6 0.4 19.6 19.7 0.0 0.8 8weeks . . . . . . . .. Nov. 18, 1913 0.0 0.0 0.0 0.2 25.8 14.6 0.0 4.2 12 weeks . . . . . . . .. Dec. 16, 1913 0.0 0.2 25.0 7.4 0.3 2.9 0.0‘ 76.9 16 weeks . . . . . . . .. Jan. 13, 1914 0.0 0.8 24.0 22.7 1.4 1.2 0.0 25.5 2O weeks . . . . . . . .. Feb. 10, 1914 0.0 37.8 2.1 31.2 2.0 1.6 0.0 10.4 24 weeks . . . . . . . .. Mar. 10, 1914 0.0 20.7 0.4 6.9 0.8 1.4 0.0. 3.6 28 weeks . . . . . . . .. April 7, 1914 0.0 1.0 1.0 4.2 1.2 1.4 0.0 3.6 32 weeks . . . . . . . .. May 5, 1914 0.0 1.3 1.4 2.9 1.6 1.6 0.0 4.4 36 weeks . . . . . . . .. .Iune 2, 1914 0.0 1.7 1.8 5.5 2.5 2.4 0.0 5.4 40weeks . . . . . . . .. .Iune 30, 1914 0.0 2.0 3.1 2.7 3.4 3.4 0.0 8.8 44 weeks . . . . . . . .. Feb. 28, 1914 1.6 3.3 3.8 4.6 4.1 5.2 0.0 8.8 48 weeks . . . . . . . .. Aug. 25, 1914 0.0 2.7 2.4 1.8 2.7 2.3 17.8 4.4 52 weeks . . . . . . . .. Sept. 22, 1_914 0.0 2.4 2.7 1.6 3.2 2.3 39.6 5.6 56 weeks . . . . . . . .. Oct. 20, 1914 0 1.3 1.4 .6 1.2 1.0 46.4 2.9 60 weeks . . . . . . . .. Nov. 17, 1914 0 .8 .9 .8 1.0 .8 18.0 2.0 Table 6.——Effect of Lime. Nitrate Nitrogen in parts per million. 2826 3391 4233 Carbonate of Date A B C A B C A B C LimeAdded 0.0 5.0 10.0 0.0 5.0 10.0 0.0 5.0 10.0 gm. gm. gm. gm. I gm. gm. ____________ _____. I Oweeks . . . . . . . .. Sept.25 4.0 4.8 5.5 2.1i 3.2 3.2 0.8 0.8 0.9 4weeks . . . . . . . .. Oct. 23 2.3 28.4 24.2 0.0 12.8 11.8‘ 2.9 8.4 13.2‘ Sweeks . . . . . . . ..Nov. 20 29.6 15.8 15.6 . . . . .. 11.5 9.9 18.2 23.8 24.0 l2wecks . . . . . . . .. Dec. 18 4.0 7.6 8.6 . . . . .. 4.3 4.2‘ 9.7 16.9 7.2 16 weeks . . . . . . . .. Jan. 15 2.1 5.4 4.5 . . . . .. 2.2 2.3.- 1.4 5.4 3.0 20weeks . . . . . . . .. Feb. 12 3.2 5.2 6.2 . . . . .. 2.2 2.2: 1.7 4.1 3.1 24weeks . . . . . . . ..Mar. 12 3.0 4.3 4.5 . . . . .. 1.2‘ 1.0‘ 1.0 2.6 3.0 l . Soil 8'73 Without lime nitrified at the end of 16 weeks, With 1 per cent. carbonate of lime at the end of two weeks, and with 2 per cent. car- bonate of lime it nitrified during the first four weeks. Soil 1128 alone did not nitrify until 48 weeks, while with 2 per cent. carbonate of lime it nitrified decidedly at the end of 12 weeks. . - The effect of carbonate of lime on nitrification was studied in other experiments and will be discussed in more detail later on. It is a well known. fact that carbonate of lime will increase nitrification in the soil, but the fact has not been established that this nitrification has always been beneficial to the soil, or to the crops growing on it. METHOD OF WORK ADOPTED. After the preliminary work referred to in the preceding pages, the following general method was adopted for the nitrification in the per- colators :—— ' 10 TEXAS AGRICULTURAL EXPERIMENT STATION. rSoiZs for Nitrificatio-n. Weigh 500 grams of the soil into a perco- lator upon a porcelain crucible top. Secure 50 grams moist soil from three inches below the surface from a garden and shake up’ with 1000 c.c. water. Afte-r the soil has settled, add 50 c.c. of the supernatant liquid t0 each percolator. Empty each percolator in turn into a porce- lain dish, mix thoroughly and return to the percolators. Cover the percolators With a closely fitting wrapper of paper, to exclude the light and prevent the growth of algae. The next day make two percolations, and make other percolations at intervals of four weeks. COLORIMETRIO METHOD FOR DETERMINATION OF NITRATES IN SOILS. Standard Nitrate. (A) Dissolve 0.722 gm. C. P. potassium nitrate in 1000 c.c. water. (B) Dilute 100 c.c. of solution A to 1 liter; 1 c.c. equals .01- mg. nitrogen. Phenol Disulphuric Acid. Mix 1.5 gm. pure crystallized phenol with 100 c.c. cone. sulphuric acid (sp. gr. 1.8/4) and heat six hours in a boil- ing water bath, or inside a steam bath. Preserve in a glass stopped bottle. The phenol used above may be removed from the bottle by melting y it by warming. Standard Oolorivmetric Solution‘; Evapo-rate to dryness in a shallow porcelain» evaporating dish on a water bath in a room free from nitric acid the following quantities of the standard solution B: 5 c.c. or 10 c.c., 20 c.c. or 40 c.c. or the quantities experience has shown necessary. Add one cubic centimeter of phenol disulphuric acid while still on the bath, remove and stir well with a short glass rod. After not less than ten minutes dilute with water and make alkaline with ammonia, then dilute to exactly 100 c.c. When 10 c.c. of the potassium nitrate is used, 100 c.<':. equals 0.1 mg. N. and the other solutions are proportionately stronger. . Peroolating. Begin to percolate at 8 o’clock in the morning. Use (A) the first 200 c.c., the second 200 c.c., or (X) the quantity that percolates to 3 p. m. and (Y) the quantity that percolates during the night and sufiicient of the next day to make up 200 c.c. or the amount that percolates to 3 p. 1n. Make percolate (A) or (X) upto 500 c.c. and take c.c. (equivalent to 5 gm. soil). In other work the volume may be made up to 200 c.c. and 2 c.c. taken. Use 10 c.c. of B or Y (equivalent to 25 gm. soil). One o’clock is the most convenient time to evaporate the percolates. Percolates must be evaporated im- mediately and rapidly and must not be exposed to nitric acid fumes. Alitrate Determination. Evaporate the necessary volume of the per- colate (10 c.c. or 2 c.c. or 5 c.c. if the solution is very strong), as de- scribed above, and treat with phenol-sulphuric acid as directed for the standard colorimetric solution. Wash into a clean 150 c.c. beaker with about 25 c.c. water (the stream must be fine for this amount of water to be sufficient) and make alkaline with ammonia. Put in comparison cylinder and ascertain the approximate amount of standard solution to * match, and dilute the unknown to that volume. It sometimes happens that the solution is off color, due to iron, and must be filtered after the ammonia is added. Pour the standard solution into the standard NITRIFICATION IN TEXAS Sorts. 11 cylinder until the color is plainly deeper than that of the unknown. Place the "cylinders side by side on a block of Wood near a Window, put a piece of white paper under the cylinders, and lift them so that, the light will come up under the bottom while making the comparison. Run out the standard into its beaker until the colors match. Read the volume on the standard cylinder, pour about 20 c.c. of the standard back into its cylinder, and match the colors again. Do not read the volume during the process of color matching at any time, and do not make the second reading on the standard cylinder until you are sat- isfied that the colors are the same. If the readings agree within 5 c.c. or less for volumes over 50 c.c., and 3 c.c. or less for volumes less than 50 c.c., take the average of the two. If the results do not check within the above limits, repeat the matching until they do. The difference in volume of the unknown and the standard must not be greater than 50 per cent. of the solution of greater volume and the latter should always be the unknown solution. After some experience, it is possible to match the solutions at practically equal volumes, and whenever possible this should be done. If the unknown apparently is equal to 100 c.c. of the standard, make up the unknown to exactly 100 c.c., put 50 c.c. of this solution in the cylinder, match with the standard and multiply the standard reading by 2. Never match the unknown against the standard and never match the standard against the unknown without beginning with at least 20 c.c. of the standard solution, more than seems to be necessary to match. If the unknown is stronger than the strongest standard, make up to 100 c.c., take 20, 25, 33, or 50 c.c., according to strength, match, mul- tiply by 5 for 20 c.c., 3 for 33 c.c., or 2 for 50 c.c. Reporting Results. The results may be reported on tabulation blanks (form 139) for experiment work. In alkali soils, report on form 109. ~Use a column for the unknown and one for each standard. Put down the volumes which match. Report the nitrate nitrogen in parts per million; also put down the total volume of the percolate. lllcthod of Ualculafioat. As 10 c.c. of the percolate is diluted to 100, the number of mg. nitrogen in this 100 c.c. multiplied by 100 is equal to parts per million. If 2 c.c. of the percolate is taken, it is, of course, five times as many parts per million. If 10 c.c. of standard nitrate is diluted to 100 c.c., 1 c.c. of the resulting liquid contains 0.001 mg. N. Thus 1 c.c. .10 parts per million of the percolate, on 10 c.c. percolate. If 20 c.c. is taken, 1 c.c. l: parts per million. If 3O c.c. is taken, c.c. I .3 parts per million and so on. The percolate solution may be assumed to have a volume of 100 c.c. ; if the volume of the standard color made from 10 c.c. is A c.c., then in 10 c.c. percolate there are A times .001 mg. N., and in 1000 c.c. there are A times 0.1 mg. N, which is parts per million. The calculation is made in a similar way from other strengths of the solution. Factors for Calculating Nitrates in Percolates. Five c.c. of A or X when made up to 500 c.c.; if made up to 200 c.c., use 2 c.c.; and use 10 c.c. if B or Y are used. I40 I20 [00 8O 6o JGV/{rajilén 12 TExAs AGRICULTURAL EXPERIMENT STATION. Standard solution taken. Percolate 5 c.c l 10 c.c. 20 c.c. 30 c.c. t 40 c.c A 0r X . . . . . . . . . . . . . . . O. 1 .2 .4 .6 .8 Bor Y" . . . . . . . . . . . . . .. .02 .02 .08 .12 .16 Multiply volume ofstandard required to match the unknown by ap- propriate factor above. ~ RATE OF NITRIFICATION. In order to study the eifect of time upon the rate of nitrification, some of the experiments were conducted for long periods of time, in one or two experiments extending for more than three years. In most cases, the maximum nitrification takes place during the first period of four weeks. This may be considered as the normal nitrification. JUNE 3'13. 4:11.120, ‘n. gvmazsp/s QEC- 1431:. mo Fl GJ JXN . 13l‘!4-. 4-0 W e e k a Figure 1—-Production of Nitric Nitrogen in soils of Series 6. 41m. 123s. 7-0 60 6o 10o n20 With a number of other soils, the maximum nitrification takes place during the second period of four weeks. The proportion of soils 'n which this occurs is fairly large, being about ~10 per cent. of the gr , p in which the maximum nitrification occurs in the first four weeks. In another series of cases the maximum occurs 1n both the first and the second four weeks. NITRIFICATION IN Tnxxs SorLs. 13 With. a few soils, the nitrification is delayed to the third. period of four weeks or even longer, so that in so-me cases, as in soil 1128 already referred fto, the nitrification may not occur for even a year or more. Table 8” shows the distribution of the nitrification with a number of soils studied in our experiments. _ The extent of nitrification decreases with the length of time after the maximum to a degree depending upon the amount of nitrogen. orig- inally in the soil, and the maximum amount of nitrate produced. YEARLY NITRIFICATION. With some of the series of soils, as already pointed out, the experi- ment was_ carried on for several years, partly for the purpose of ascer- taining if there was any seasonal variation in the production of nitrate. The soils were not exposed to the regular season temperatures, as they were kept i.n a room which was heated by steam during the winter. The average results of three of these series is given in Table 7. Table 7.-—-Continued nitrification, parts nitrogen per million. Set 3 Set 6 Set 8 Period. . . Average Average Average Date I nitrate Date nitrate Date nitrate 0 weeks. . . .. May 1, 1913 12.4 May 6, 1913 12.7 May 8, 1913 6.9 4 weeks. . . .. May 29, 1913 36.3 Inine 3, 1913 47.1 June 5, 1913 27.0 8 weeks. . . .. June 26, 1913 16.3 July 1, 1913 27.5 Iuly 3, 1913 12.2 2weeks..... July 25, 1913 9.4 July 29, 1913 31.7 Iuly 31, 1913 5.3 6 weeks. . . .. Aug. 21, 1913 8.7 Aug 26, 1913 15.5 Aug. 28, 1913 5.1 i0 weeks. . . .. Sept. 18, 1913 4.8 Sept 23, 1913 9.1 Sept 25, 1913 3.7 i4 weeks. . . .. Oct. 15, 1913 4.0 Oct 21, 1913 40.9 Oct 3, 1913 1.5 ‘.8 weeks. . . .. Nov. 13, 1913 1.3 Nov 18, 1913 2.3 Nov 20, 1913 0.9 i2 weeks. . . .. Dec. 11, 1913 1.8 Dec 6, 1913 2.6 Dec 18, 1913 1.2 i6 weeks. . . .. Ian. 8, 1914 1.3 Jan 13, 1914 1.8 Ian 5, 1914 0.6 0 weeks. . . .. Feb. 8, 1914 2.0 Feb 10, 1914 3.1 Feb 12, 1914 0.9 4 weeks. . . .. Mar. 5, 1914 1.9 Mar 10, 1914 3.2 \/Iar 12, 1914 0.6 8 weeks. . . .. April 4, 1914 1.8 May 10, 1914 4.2 April 9, 1914 1.1 2 weeks. . . .. April 30, 1914 2.4 May 5, 1914 4.8 May 7, 1914 1.9 6 weeks. . . .. VIay 28, 1914 3.4 J ine 2, 1914 6.2 Tune 4, 1914 2.1 0 weeks. . . .. Iune 25, 1914 6.4 June 30, 1914 9.6 Iuly 2, 1914 3.1 4weeks..... Iuly 23, 1914 5.3 July 28, 1914 10.4 Iuly 30, 1914 4.0 8 weeks. . . .. Aug. 20, 1914 6.5 Aug. 25, 1914 8.2 Aug 27, 1914 3.3 2weeks. Sept. 7, 1914 5.4 Sept 22, 1914 7.2 Sent 24, 1914 2.5 6 weeks. '. . .. Oct. 15, 1914 3.5 Oct 20, 1914 3.6 Oct 22, 1914 2.1 0 weeks. . . .. Nov. 12, 1914 2.1 Nov 17, 1914 2.7 Nov 19, 1914 1.3 4 weeks. . . .. Dec. 11, 1914 2.0 Dec. 15, 1914 2.4 Dec 17, 1914 1.0 8 weeks. . . .. Jan. 9, 1915 .9 Jan. 12, 1915 1.7 Ian 14, 1915 0..7 2 weeks. . . .. Feb. 4, 1915 1.0 Feb. 1, 1915 1.9 Feb 13, 1915 8.0 Gweeks. . . .. Mar. 4, 1915 1.7 Mar. 9, 1915 3.0 Mar 13, 1915 1.1 00 weeks. . .. April 1, 1915 2.2 April 8, 1915 3.1 April 8, 1915 1.2 04 weeks. . .. May 1, 1915 2.8 May 6, 1915 3.8 May 6, 1915 2.0 08 weeks. . .. May 29, 1915 4.1 June 3, 1915 3.6 J ine 5, 1915 1.5 12 weeks. . .. Tune 24, 1915 3.8 June 29, 1915 4.7 l'ily '1 , 1915 2.0 16 weeks. Iuly 22", 1915 3.3 July 27, 1915 4.2 Iily 29, 1915 1.9 2O weeks. . .. Aug. 19, 1915 3.3 Aug. 27, 1915 3.5 Aug. 24, 1915 1.6 24 weeks. . .. Sept. 9, 1915 2.8 Sept. 22, 1915 2.4 Sept. 23, 1915 2.4 28 weeks. . .. Oct. 14, 1915 2.5 Oct. 19, 1915 2.1 Oct. 21, 1915 1.3 32 weeks. . .. Nov. 4, 1915 1.9 Nov. 19, 1915 1.8 Nov.18, 1915 1.0 36 weeks. . .. Dec. ,9, 1915 1.5 Dec. 14, 1915 1.8 Dec. 16, 1915 0.8 40 weeks. . .. Jan. 1, 1916 1.2 Jan. 11, 1916 3.2 Ian. 1 , 1916 1.0 44 weeks. . .. Feb. 3, 1916 1.2 Feb. 8, 1916 2.9 Feb. 10, 1916 0.7 48 weeks. . .. Mar. 2, 1916 1.6 Mar. 7, 1916 2.1 VIar. 7, 1916 0.4 52 weeks. . .. Mar. 30, 1916 1.0 Anril 4, 1916 1.9 April 6, 1916 0.7 56 weeks. . .. April 27, 1916 1.2 May 4, 1916 2.6 \/[ay 21, 1916 0.9 50 weeks. . .. May 27, 1916 1.8 June 1, 1916 3.6 line 2, 1916 1.4 54 weeks. . .. June 22, 1916 2.0 June 27, 1916 3.6 Tune 29, 1916 0.8 B8 weeks. . .. July 23. 1916 2.2 . . . . . . . . . . . . . . . . . . . . .. Izily 27. 1916' 1.7 The maximum nitrification occurred in the first period of four weeks. t decreased to a minimum with set 3 at the end of 28 weeks, November 14 TEXAS AGRICULTURAL EXPERIMENT STATION. 13, and at the end of 36 weeks, January 13-15, with sets 3 and 8. It then increased to a second maximum, much smaller than the first, at the end of 64 Weeks, July 28-30, with sets 6 and 8, and at the end of 68 weeks, August 20, with set The second minimum was reached o-n January 9-14, at the end of 88 wYeeIks. The third maximum was reached. at the end of 108 weeks, May 29, with set 3 ; 112 weeks, June 29, with set 6; 124 weeks, September 23, with set 8. The third maximum was reached in November with set 6, and March i with set 3 and 8. There is clearly a seasonal variation in nitrification. RELATION OF NITRATES PRODUCED TO NITROGEN CONTENT OF SOIL. Table 8 shows the average quantity of nitric nitrogen’ produced in the soils, arranged into groups, at the end of several periods of four ' weeks each. The quantity of nitric nitrogen in the original soil as. ascertained by the first percolation is also included, but this does not enter into the discussion. ‘The total nitric nitrogen produced during twelve weeks is given. The tables for 16 to 24 weeks and for 28 and 32 weeks are also given, Carbonate of lime had been added to most of , these sets at the end of 12 weeks. 15 "' NITRIFICATION IN TEXAS Sons. . / / w.wH no F2 oww N.wH w.wN ooN wNoH .w.No HZNh wflh m? ooN. w . . . . .w..=5< m? wow woo w.oH 5.2 w.wH wooH o.wN Nww moo? won o2. w oHoH b2wE< 22 w wow o.w o.N o.w Nww m.» w.NH wSH wit. N.NH H.HN How How Noo. . . . . . .. ....omm.wo>< .. .. NHo w.oH oHN how N.wH www NNw N.Nw oHH. NH oHoH Hmfiwwfio wo wow o.w o.N w.w w.mN o.w o.H. NHHH HSm mo owH oow oow ooo. NH oHoH wmwci No wow own». w.HH w.wH 1:. N.wH oNN 9S. oSw wwo. NH oHoH .wN:.~n< Ho wow - - u- ¢ - . . - . - - . - - - u...» %-w 7 m N.H. o.N no How o.w woH NEH wNw .N.NH 92 oNw o.Nw owo. . . . . . . .. ....omm.wo>< o.w o; o.w w.NN o.w w.w H.HH wwo o.w w.HH wwN w.wN wwo. NH oHoH Kmowoo oo wow ma. w.N N.w H.wN o.w w.» NZHH o.Hw o.w msw H.oN H.oN 2o. NH oHoH 23:22 ow wow ow o.w mo woo m.» HRH N.wH Nwo o.w N.oN w.wH w.wH wwo. 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On examination of the table, it is immediately seen that the average quantity of nitric nitrogen produced during each perio-d of four weeks increased with the total nitrogen of the soil. The same is also true if the total nitric nitrogen produced is considered. In other words, the nitrification, on an average, is in proportion to the total nitrogen of the soil. This is also shown in Figure 2. g. I80 /‘0 I I40 I I20. I a0 /0o I /2 wu‘: 60 12-24 wee/is 40 N/fm/‘e nifroy eh Q O v l l .0; l ,1‘) , Nlfroyen m so/l Figure 2——Relation of average nitrate production to nitrogen content of soil. l l ./.‘TO .20 .28’ i O 1'7 NITRIFICATION IN TEXAS Sous. h... w... w... ww. B... w... .... we N... 9w mw ww 3N. p . . . . . . . . . . . . . . . imfilww w... 1w... w... ww w... w... w... Nw w. NN w... w... o2. . . . . . . . . . . . . . . . . . . . ..000 00.0 050000 >000 00 000E050 0000 >. 000.0 0 > 0.00 00 .0 00 .0 00.. 0N. 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SSS SSS SS. SSS SN. SS. SS. . . . . . . . . . . . . .........ESSSSSSSSSSSSSSSSSSSSS NSS o ~ o - u u n ~ - u - o ~ Q ~ n 0 - n I 0 n g o I S - ~ S - . » S . - S v u SSS S S.S SSSS S.S SNS SS. SS. SN. SS. SS. . . . . . . . . . . . . . . . . ......SS_S SEES SSSSSSSSw SSS NSS S S.S RS. SS . NSS NS. NS. SS. SS. NS. ....... . . . . . ..ES2 SSE; 3S SSSSSSSZ SSSSQSSw SSSS , mvQEUQ @@Ufl GAY: wO SNNQOQ mXOQ fiOsflvmw |COO nmaaon OSMOSD QmJNO WMQQQ “ZQSZOM 053cm CUM UMMOJQ ITWZZ D>sb< ‘monk Nfliblilw |WNE IOHZZ umonnm SE2 SS8. NITRIFIOATION 1N "TEXAS SorLs. 23' At least six of these samples with high nitrification are acid. The acid character of the soil, therefore, does not prevent nitrification, for the soil may be acid and yet the nitrification may be higher than the average. However, the soils having a high nitrification. generally con- tain a larger amount of lime than those having a low nitrification. There are two different explanations of the fact that some sub-soils may possess a very low nitrification, and others a very high nitrification. The high nitrification may be due to the fact that the organic matter of these subsoils has been little afiected by nitrifying agencies in the past on account of unfavorable conditions for nitrification. The easily nitrified material has not been changed. When placed under conditions favorable to IlltTlfiCalllOH, this easily nitrified material becomes rapidly oxidized. This may account for the high nitrification on some of the subsoils. The low nitrification may be due to the presence of substances which interfere with the development of the nitrifying organism, or to a de- ficiency in substances needed in their growth, or to the presence of sub- stances which promote the growth of bacteria which denitrify the nitrate. Further Work presented in this bulletin throws some light upon this matter. EFFECT OF ADDITIONS ON SOILS .WITH LOW NITRIFICATION. Table 13 gives the efiect of additions on some soils having a low nitri- fication. The figures given are the totals produced at the end of the period of time stated. Thus soil 100 has produced 20 parts per million of nitrates at the end of 88 weeks. The additions made were di-calcium phosphate or potassium sulphate at the rat-e of 0.2 gram per 500 grams or a combination of the two. 24 TEXAS AGRICULTURAL EXPERIMENT STATION. Table 13.——Effect of additions on total nitrate produced per million. 12 24 36 48 6O 72 84 88 weeks weeks weeks weeks weeks weeks weeks weeks- 100A O None . . . . . . . . . . . . . .. 0 .5 5 .5 1.8 10.4 18.5 20.8 B D Dicalcium phosphate.. 0 .0 0 .0 2.6 31.1 52.5 64.5 C K Sulphate ofpotash.... 0 .0 0 .0 .0 .9 1.1 1.2 DDK Phosphate and potash. 0 .0 .0 .0 2. 9 27. 5 38.5 45. 3 312A O None . . . . . . . . . . . . . .. 93 12.2 13.4 16.0 18.2 21.2 24.3 25.2 B D Dicalcium phosphate. 8.8 10.8 11.4 13.9 15.8 18.9 21.2 22.3 C K Sulphate ofpotashJ... 7.3 9.9 10.3 -13.7 16.9 20.1 22.5 23.3 DDK Phsophate and Potash 7.4 9.6 11.0 13.3 16.5 20.1 22.4 22.7 1126A O None . . . . . . . . . . . . . .. .0 .0 .0 .6 10.0 29.8 32.9 32.9 B D Dicalcium phosphate. . .0 .0 17.2 39.0 42. 8 46.1 50.2 50. 6 C K Sulphate ofpotash.... .0 .0 .0 3.2 37.2 45.1 49.2 49.6 DDK Phosphate and potash. .0 .2 2. 0 32.8 45.4 52.9 55.4 56.4 1201A O one . . . . . . . . . . . . . .. 8.1 10.1 10.1 12.3 14.2 . . . . . . . . . . . . . . . . .. 12 D Dicalcium phosphate. 8.2 9.6 9.8 11.7 13.8 . . . . . . . . . . . . . . . . .. C K Sulphateofpotash.... 6.8 8.0 8.2 9.5 .1l.3 . . . . . . . . . . . . . . . . .. DDK Phosphate and potas . 7.7 9.3 9.5 10.3 12.3 . . . . . . . . . . . . . . . . .. 2347A O None . . . . . . . . . . .0 .5 3.9 20.4 33.1 . . . . . . . . . . . . . . . . .. B D Dicalcium phosphate.. .0 11.6 33.1 38.0 42. 6 . . . . . . . . . . . . . . . . .. C K Sulphate of potash... .0 ' ‘.0 5.6 17.3 22.3 . . . . . . . . . . . . . . . . .. DDK Phosphate and potash. .0 2.1 19. 9 29. 5 34. 3 . . . . . . . . . . . . . . . . . . 2351A O one . . . . . . . . . . . . . .. .0 .0 1.4 24.8 33.7 . . . . . . . . . . . . . . . . .. B D Dicalcium phosphate. .0 .0 17.3 26.5 33.1 . . . . . . . . . . . . . . . . . . C K Sulphate of potash.... 2.0 2.0 2.0 11.4 30.3 . . . . . . . . . . . . . . . . .. DDK Phosphate and potash .0 .0 2. 3 22. 5 29.2 . . . . . . . . . . . . . . . . . . 3251A O None . . . . . . . . . . . . . .. .0 .0 .0 .0 7.0 24.4 . . . . . . . . . . .. B D Dicalcium phosphate.. .0 .0 0 7.8 22.2 32. 5 . . . . . . . . . . .. C K Sulphate of potash.. .. .0 .0 0 5.0 26.0 35.5 . . . . . . . . . . .. DDK Phosphate and potash .0 .0 0 5.0 26. 9 33. 3 . . . . . . . . . . . . 3976A O None . . . . . . . . . . . . . .. .0, .0 0 .0 2.0 13.8 . . . . . . . . . . .. B D Dicalcium phosphate. .0 .0 0 .0 7.6 28.1 . . . . . . . . . . .. C K Sulphateofpotash.... .0 .0 .0 .0 .0 2.4 . . . . . . . . . . .. DDK Phosphate and potash. .0 .0 .0 2.1 15.8 25.9 . . . . . . . . . . .. 4596A O None . . . . . . . . . . . . . .. .6 5.5 15.7 21.7 29.3 34.3 . . . . . . . . . . .. B D Dicalcium phosphate.. .8 30.8 35.0 37.8 39.9 43.9 . . . . . . . . . . . . C K Sulphate of potash.. .. .0 .8 5.8 10.0 22.5 30.0 . . . . . . . . . . .. DDK Phosphate of potash. . 4.4 29.0 31.6 35. 6 38.6 43.8 . . . . . . . . . . .. 4645A O None . . . . . . . . . . . . . .. .0 .0 .0 .0 18.4 46.7 . . . . . . . . . . .. B D Dicalcium phosphate.. .0 .0 0 .2 25.9 35.5 . . . . . . . . . . .. C K Sulphate ofpotash.... .0 .4 4 .4 2.0 19.1 . . . . . . . . . . .. DDK Phosphate and potash. .0 .0 0 .0 19.1 33.2 . . . . . . . . . . . . 7090A O None . . . . . . . . . . . . . .. .0 .0 0 1.0 8.9 19.3 . . . . . . . . . . .. B D Dicalcium phosphate. .0 .0 0 7. 6 20.1 26.5 . . . . . . . . . . .. C K Sulphate of potash... .. .0 .0 0 3J6 12.0 19.3 . . . . . . . . . . .. DDK Phosphate and potash. .0 .0 0 1.0 18.0 28.7 . . . . . . . . . . .. The addition of di-calcium phosphate increases the nitrification with soil 100 at the end of 72 weeks, with soil 1126 at the end of 48 weeks, with soils 2347 and 2351 at the end of 36 weeks, with soil 3251 at the end of 60 iveeks, with soil 3976 at the end of 72 weeks, with soil 4596 at the end of 24 xveeks, and with soil 7090 at the end of 60 weeks. The addition of di-calcium phosphate, therefore, increases the produc- tion of nitrates, though a considerable period of time elapsed with most of the soils before this increase was apparent. The sulphate of potash decreased nitrification in soil 100. It in- creased the nitrification with soil 1126 at the end of 60 weeks although not to the extent of the phosphate. Tt increased the nitrification with soil 3251 at the end of 60 weeks. It decreased the nitrification with 3976, 2347, and 4685. The potash did not affect the nitrification with soils 312, 1201, 2351, 4596, and 7090. a The combination of phosphate and potash is not as good as the phos- phate alone in soil 100. It is somewhat better with soil 1126. It is not as good with soils 2347, 2351, 3976, and 4658, although the difference is‘ usually small. NITRIFICAIION IN TEXAS SoiLs. - 25 Table 14.—-Effect of carbonate of lime on soils which did not nitrify well. Parts of nitrate nitrogen per million. JP‘ "6 Total ' Total 5 8 t» a? Lab. No. Set 12 1s 2o 24 2s 2s <= 3 f; é’ s .No. weeks weeks weeks weeks weeks weeks 3.2‘ g5“ m <: "' 100 . . . . . . . . . . . . . . . . . . .. 22 .0 24.4 44.4 5.5 3.2 77.5 04 43 7 100 . . . . . . . . . . . . . . . . . . .. 23 0.7 18.6 46.4 6.2 \3.8 75.0 . . . . . . . . . . .. 100 . . . . . . . . . . . . . . . . . . .. 24 4.1 79.0 7.8 3.4 2.6 92.8 . . . . . . . . . . .. 100 . . . . . . . . . . . . . . . . . . .. 25 7.4 84.0 8.4 5.9 2.9 101.2 . . . . . . . . . . .. 100 . . . . . . . . . . . . . . . . . . .. 26 5.4 97.6 10.0 5.1 3.1 115.8 . . . . . . . . . . .. 100 . . . . . . . . . . . . . . . . . . .. 27 1.0 3.4 54.6 4.6 4.0 66.6 . . . . . . . . . . .. 100 . . . . . . . . . . . . . . . . . . .. 28 1.2 17.1 52.4 3.2 3.7 76.4 . . . . . . . . . . .. 100 . . . . . . . . . . . . . . . . . . .. 29 0.0 0.0 0.0 0.0 .1 .1 164 . . . . . . . . . . . . . . . . . . .. 30 .1 6.4 36.4 8.0 3.7 54.5 164 . . . . . . . . . . . . . . . . . . .. 31 1.3 38.6 37.1 5.9 3.4 83.2 164 . . . . . . . . . . . . . . . . . . .. 32 .7 29.6 33.4 6.5 3.6 73.1 164 . . . . . . . . . . . . . . . . . . .. 33 .5 3.1 33.2 7.4 3.4 47.1 164 . . . . . . . . . . . . . . . . . . .. 34 .0 3.4 49.0 8.1 3.4 63.9 164 . . . . . . . . . . . . . . . . . . .. 35 .1 2.7 52.4 6.6 3.6 65.3 64 . . . . . . . . . . . . . . . . . .. 36 .1 24.2 38.4 6.6 3.7 72.9 . . . . . . . . . . .. 1126 . . . . . . . . . . . . . . . . . . .. 23 1.4 40.4 11.8 5.2 3.4 60.8 029 27.1 2347 . . . . . . . . . . . . . . . . . . .. 24 8.4 26.6 9.9 3.6 4.4 44.5 027 27.1 3.251 . . . . . . . . . . . . . . . . . . .. 25 9.1 31.2 8.6 4.2 3.3 47.3 040 43.7 2351 . . . . . . . . . . . . . . . . . . .. 25 1.3 3.4 28.4 8.0 3.0 42.8 039 27.1 3976 . . . . . . . . . . . . . . . . . . .. 26 0.0 1.1 33.2 4.1 4.2 42.6 022 27.1 4596 . . . . . . . . . . . . . . . . . . .. 27 0.0 10.4 12.5 1.2 3.0 27.1 035 27.1 4645 . . . . . . . . . . . . . . . . . . .. 27 1.2 1.4 38.2 6.5 4.4 50.5 035 27.1 5711 . . . . . . . . . . . . . . . . . . .. 27 5.7 14.0 . . . . . . . . . . . . . . . . .. 14.0 038 27.1 7090 . . . . . . . . . . . . . . . . . . .. 27 ~0.0 10.1 11.3 2.6 2.8 26.8 039 27.1 7164 . . . . . . . . . . . . . . . . . . .. 29 5.1 2.2 3.4 1.6 2.5 9.7 038 27.1 1138 . . . . . . . . . . . . . . . . . . .. 31 .4 23.6 135.6 15.5 8.4 183.1 .06 62.6 2324 . . . . . . . . . . . . . . . . . . .. 32 1.3 8.6 50.4 3.5 2.8 65.3 047 43.3 3368 . . . . . . . . . . . . . . . . . . .. 33 .8 38.4 8.6 7.1 2.5 56.6 055 43.7 3398 . . . . . . . . . . . . . . . . . . .. 33 0 29.0 6.8 2.2 2.0 40.0 041 43.7 3402 . . . . . . . . . . . . . . . . . . .. 33 7 10.3 13.8 3.1 3.7 30.9 041 43.7 3417 . . . . . . . . . . . . . . . . . . .. 33 1 0 36.4 8.3 5.1 2.7 52.5 053 43.7 4586 . . . . . . . . . . . . . . . . . . .. 34 8 3 26.2 8.3 4.2 2.7 41.4 044 43.7 As previously stated, an addition of carbonate of lime at the rate of 5 grams to 500 grams of ‘soil was made in a number of the series at the end of twelve weeks. The results of this addition with respect to the s0il.s which do not nitrify well are given in Table 14. The amounts given are those formed during periods of 4 Weeks. It is evident that the addition of carbonate of lime in all cases increases the nitrification to a. considerable extent. The effect of the carbonate of lime is much quicker, and more effective than either the phosphate or the potash. It would appear from these results that the conditions in the soil unfavor- able to nitrification can be eliminated very rapidly by the use of 1 per cent. carbonate of lime. ' Rapid nitrification took place within four to eight weeks after the carbonate of lime was added, and there were only a. few soils in which the nitrification was not increased very highly by the carbonate of lime. These soils are 2348, 2711, 7164, and 4596. No. 2711 could be omitted, as it did not allow the Water to percolate after the first four weeks of adding the calcium carbonate. Even with these soils, it is not a refusal to nitrify at all, but only a low nitrification compared with other soils in the same group. Table 14 also contains a comparison from Table 8 of the nitrate produced for the group in which these soils belong. It is seen that the addition of calcium carbonate caused the nitrification t0 be greater than the average o-f the group, except with soils 4596, 5711, 7164, and 3398, and with two of these, it is practically equal to the average. 26 TEXAS AGRICULTURAL EXPERIMENT STATION. NITRIFIGATION OF THE ORGANIC‘- MATTER OF THE SOIL. ~ The following work was designed to test the nitrification of the or-V .1 ganie matter of the soil. - A quantity of soil 1956 was thoroughly mixed. To 400 gram portions of this soil in twelve percolators, 5 grams of cal-v i cium carbonate and 1 gram potassium phosphate finely pulverized were added.’ The first two portions of the soil received no further addition. To the others 100 grams of the soils to be treated were added in dupli- cate. The soils were then inoculated with nitrifying organisms from a fertile garden, as in all of these experiments, percolated at once, and again at the end of four periods of four weeks each. Table 15.—Nitrification of organic matter of soil in parts nitrate nitrogen . per million. v Total 4 8 12 16 4-8-12-16 Average Ga‘n weeks weeks weeks weeks weeks weeks ‘ 1956A . . . . . . .. 11.2 4.8 3.2 3.7 3.4 15.3 15.3 B . . . . . . .. 10.9 5.4 3.0 3.7 3.3 15.4 . . . . . . . . . . . . . . .. 4234A . . . . . . . .. 11.2 11.0 6.1 ‘ 4.4 4.8 56.3 26.8 113 B . . . . . . . .. 11.0 11.0 6.4 5.2 4.6 27.2 . . . . . . . . . . . . . . .. 4213A . . . . . . . .. 14.3 10.4 2.6 4.1 4.1 21.2 21.4 61 B . . . . . . . .. 14.5 10.0 3.9 3.8 3.7 21.5 . . . . . . . . . . . . . . .. 4580A. 13.6 13.0 6.2 6.1 5.8 31.1 31 3 16.0 B 15.9 13.3 6.2 6.1 5.9 31.5 . . . . . . . . . . . . . . .. 4586A. 12.6 12.5 3.7 2.7 3.9 22.8 23.2 7 9 . . . . . . .. 19.7 9.9 3.9 5.4 4.4 4291A 12.3 6.2 2.8 2.6 3.4 15.0 14.4 0 . . . . . . .. 13.0 5.8 2.5 2.8 2.7 Date percolated.. 3-22-15 4-19-15 5-17-15 6-14-15 7-12-15 Table 15 contains an illustration of one of these experiments. The gain of nitrate is the amount secured from 100 grams of soil. The part per million'is obtained by multiplying this by five. Table 16.-—-Nitrate nitrogen produced from organic matter of soils. 1 Nitri- i5 5 _ .. , . . . _'. p: a Lab. Set Gain Gain Per fi5; =0 4 nitrogen iapacity ‘Q-g-‘g v2 52-55 22.2 28.5 111.0 4.6 31 .04 4 27 7 . . . . . . .. 29.1 26.7 145.5 114.1 31 .05 79 29 1 3631 . . . . . . .. 10.3 10.7 51.5 22.9 34 .06 44 8 2 3634 . . . . . . .. 9.0 6.4 45.0 16.2 34 .05 36 8 6 4291 . . . . . . .. 2.3 4.9 14.0 23.9 34 .04 17o 5 4234 56 11.3 . . . . . . .. 56.5 92.6 34 .04 146 14 1 4213 . . . . . . .. 6.1 . . . . . . .. 30.5 25.5 34 .05 . 83 61 4580 . . . . . . .. 16.0 . . . . . . .. 80.0 33.7 34 .05 42 16 0 4536 . . . . . . .. 7.9 . . . . . . .. 39.5 3.3 34 .04 21 9 7132 57 6.2 . . . . . . .. 31.0 13.2 36 .04 42 7 7 7214 . . . . . . .. 12.5 . . . . . . .. 62.5 47.0 36 .06 76 10 4 7234 . . . . . . .. 2.9 . . . . . . .. 14.0 11.1 36 .04 76 6 7169 . . . . . . .. 9.3 . . . . . . .. 46.5 23.5 36 .05 61 9 3 7097 . . . . . . .. 10.6 . . . . . . .. 53.0 41.0 36 .05 i 75 10 6 1582 58 19.1 . . . . . . .. 95.5 22.1 41 .09 23 10 6 1593 . . . . . . .. 32.6 . . . . . . .. 163.0 103.6 41 .09 66 17 0 1923 . . . . . . .. 19.0 . . . . . . .. 95.0 43.4 .10 5o 5 1931 . . . . . . .. 27.7 . . . . . . .. 133.5 103.2 41 .03 74 17 3 3410 . . . . . . .. 28.0 . . . . . . .. 140.0 67.8 41 .09 48 15 5 112 59 24.4 . . . . . . .. 122.0 26.3 22 .04 .22 30 5 354 . . . . . . .. 7.6 . . . . . . .. 33.0 33.0 22 .03 232 12 7 312 . . . . . . .. 4.3 . . . . . . .. 24.0 16.6 22 .03 67 3 0 319 . . . . . . .. 3.7 . . . . . . .. 13.5 15.7 22 .02 33 92 306 . . . . . . .. 12.2 . . . . . . .. 61.0 52.6 22 .04 35 15 2 100 60 24.7 . . . . . . .. 133. 5 2.4 22 .04 33 4 4293 . . . . . . .. .0 . . . . . . .. .0 15.6 26 .03 . . . . . . .. 0 3976 . . . . . . .. 11.2 . . . . . . .. 56.0 .0 26 .03 18 8 3412 . . . . . . .. 14.6 . . . . . . .. 73.0 15.5 26 .02 21 36 5 4537 . . . . . . .. 15.6 . . . . . . .. 73.0 19.0 26 03 24 26 0 NITRIFICATION IN TEXAS SorLs. 27' Table 16 shows the results of several tests of soils. In each set, two samples of soil 1956 were included. In one experiment, sand was used in place of soil 1956. The results of this test are given in Table 16. The results ‘are somewhat different from that of soil 1956, although the difference is not great. AVAILABILITY OF ORGANIC MATTER OF SOILS. The nitrification of the organic matter of soil expressed in parts per million as given in Table 16, divided by the percentage of nitrogen in the soil, may be taken to give the availability of the nitrogen of the organic matter in the soil so far as the production of nitrates is con- cerned. This is the immediate availability. It has already been pointed out that the organic matter of the soil in many cases is nitrified very rapidly at first, but there is then a very rapid fallingofl’, and the nitrates produced after this are decidedly smaller. This is especially shown in the experiments already mentioned, in which the nitrification was car- ried on for two or three years. . After the easily nitrified nitrogen has been removed, the remaining nitrogen will be oxidized much more slowly. Thisis a wise provision of nature, because, if the nitrification continued at the same rate, the entire quantity of nitrogen in some soils would be removed in from 48 to 54 weeks in these experiments. The total nitrate nitrogen produced, in parts per million, and the percentages of the soil nitrogen nitrified during several periods of 24 weeks each, is given in Table 1'7. The quantity fluctuates, and finally becomes about 1 per cent. of the total soil nitrogen. Table 17.—Percentage of soil nitrogen nitrified. Set No. 3 .O81% N. Set No. 6 098% N. Set No. 8 .O48%[N.‘§ - .I §2 5E as E8 as T58‘ Date 513 Date gg U55‘ Date §f§ U’? --1 u-q L414 "-1 i2 s12 22 e2 22 i»; 24 weeks Sept. 18, 1913 79.5 9.8 Oct. 20, 1913171.8 8.9 Oct. 23, 1913 54.8 11.4 48 weeks April 4, 1914 10.1 1.2 May 10, 1914 17.2 1.7 April 9, 1914 5.3 1.1 72 weeks Sept. 7, 1914 29.4 3.6 Sept. 22, 1914 46.4 4.6 Sent. 24, 1914 16.9 3.5 96 weeks Mar. 4, 1915 11.2 1.2 Mar. 9, 1915 15.3 1.5 Mar. 3, 1915 14.2 2.9 120 weeks Aug. 19, 1915 19.5 2.3 Aug. 27, 1915 22.9 2.3 Aug. 24, 1915 10.2 2.1 144 weeks Feb. 3, 1916 11.1 1.2 Feb. 8, 1916 14.2 1.4 Feb. 9, 1916 7.2 1,5 168 weeks Tuly 23, 1916 9.8 1.2 June 27, 1916 13.8 _1.4 July 27, 1916 5.9 1.2 The availability of the soil nitrogen varies from 3.5 to 3'7 per cent. Apparently there are some cases where the nitrification is zero, but this is not correct, for the original soil nitrifies in each of these instances. The nitrification of six of these soils is over 25 per cent. See the last column of Table 16. 28. TEXAS AGRICULTURAL EXPERIMENT STATION. Aw _ . . . . . . . . . . . . . . . . . . . . . . . .....x%fi@nv>%vflflwvg@mmawx¢ ... 5N 8N m. N3 9.2 mm . S. 3. i. . 35. . . . . . . . . . . . . . . . . . . 59E: v22 on .E.~o:c: 9am @356 3Q. 9mm o 92: 90.3 Q3. nmé 2. 3 .2 wm. NS. S. . . . . . . . . . . ... . . . .59: 35mm 2E @529. @090 5Q. wz=aw=w>w 30A . . . . vmm mm Nhmmfl m8 52A: on. wo. ow. Ev. mo. ..............I..........©cwm@o.:com>~o>oo~ . . . . ... Aw Nlfl @@. xfi. @3- @@. .....................%ZHN@Q§HQQQZOWUUW.T~QZ . . . . . . .. o m4 wdh “fig v04 mo. I. S. mo. mo. .................I......icwmofinz/momnsmmfiwm . . . . . . .. o n .5 ~ .3 mhwm mm. 2. S... I. 3. S. ............Emo_ 2E mafifiwivmaw =3 02.22% w: . . . . . . .. . . . . . . mw@. MM. m#- $3. ..........................~%N_O>%@GNMZOMQ§@¢@M W. . woism Eva cob mo v15 W. cofiaua htbwé Inca amnion uiosa o3: Emu: 3E4 Smmifw 2%“ uiona wEMnam-“Zw awfi . $52 39¢ o>iu< ‘no.5 @5522 $32 -332 52E "am o>Su< . q .8956 a. §=A2i>~ as 9a Ami ...?» i: u. =asaon=sulmwfl 2%? Nlriiirioxrrox 1N TEXAS SorLs. .29 The chemical composition of these ‘soils is given in Table l8. The nitrification of three of these soils is below 6. The characteristics of these soils are also given in the table. No general relation can be traced, though two of the soils with high availability of nitrogen are poor or very poor in plant food. NITRIFYING CAPACITY. The results of the experiments above described gives the parts’ per _ million of nitrate produced from the nitrogen of the soil under favor- able conditions for nitrification. In other work presented in this bul- letin, the nitrification of the same soils untreated Was studied. The organic matter in both cases is the same, but in one ease the natural soil was used, while in the other ease the soil was added to a good soil, together with carbonate of lime and potassium phosphate, thereby ren- dering the conditions more favorable for the nitrification of organic matter of the added soil. A comparison between the amount of nitrate produced from the organic. matter oil.’ the soil and the amount of nitrates produced from the natural soil, throws some light upon the nitrifying power of the original soil. The comparison cannot be made a strict - one, "for the reason that these two pieces of work were carrieijl out at different times, and it has already been seen that the surrounding tem- per-attire may effect the nitrification. Nevertheless, the comparison gives some information of interest, and offers indications which will be fol- lowed up. The nitrification in the original soil may be considered as representing the product of the nitrifying capacity of the soil and the availability of the organic matter in the soil to nitrify. In Bulletin 106 (1908) of this Station, we used the term nitrifying capacity to signify the capacity of the soil to serve as a medium for the growth of nitrifying organisms, compared with some other soil of good nitrifying‘ power as a standard. Stevens and Withers used the term in practically the same sense (Centbl. Bakt, 1909). It is essential that the two soils should be provided with nitritiable matter and placed under conditions favorable for nitrification, the conditions being exactly the same for each soil, and that both soils at the beginning of the experiment should contain the same number of nitrifying‘ organisms of the same activity. We here use the term the “availability of the soil. nitrogen” to sigmify the capacity which the soil organic matter has to be changed into nitrates. Thus the availability of the soil nitrogen (A) multiplied by the nitrié tying‘ capacity of the soil (C), equals the nitrate produced (N). A C : N e _—_ Nya . In this case the term availabilitxj is restricted to cover the production of nitrates only. It must not be forgotten that other conditions, such as temperature and soil organisms, influence the total nitrates, but it is assumed that these are equalized as nearly as the experimental con- ditions allow. The nitrifying‘ capacity of the soil is thus equal to the nitrates pro-I dueed in the original soils, divided by the availability of the soil nitrogen. The nitrifying capacity as calculated in this way is given in Table 16. This method of estimating the 1iitril’_ving capacity of a soil is different 30 TEXAS AGRICULTURAL EXPERIMENT STATION. o Q .@ afi: if: and mm. mm. mmw. mo. ma. . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . 15m? =55 E585 8N m. . N3 w .2 mm. B. .3. mmo. $0. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . afibwaa v52 2.? E35 o ¢.@¢_ ¢.¢¢~ @.~¢ »m.@ mfi. -.mH wm. @_¢¢. mwo. . . . . . . . . . . . . . . . . . . . . . . . _ .._=@¢H>@¢wm@¢@ =¢m@@fl:=m zfiummmo nmmm o N; w .0»; fi fifi $4 8. NH. mo. ammo mmo. . . . . . . . . . . . . . . . . . . . . . . . . . . . . ficfim: 3cm =3 PéSm o m; ed.» Aifi we; mo. C. I. vmo. wmo. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135m uta3momnsm ooofi o.m @.@w m.~H _>.w wm. aw. mam. wmo. mmo. . . . . . . . . . . . . . . . . . . . . . . . . . . . ..>m=.=ca=»_=¢m»@w:Qw Em m; Th2 ms E. .2 2... w? 3. .3. mo. . . . . . . . . . . . . . . . s20 wémwwifio 8S >6... =3 85.5w 0 H.>~ H.¢~ m.wm mm. ofi. flm. -. wo. mo. . . . . . . . . . . . . . . . .....@=@w@=@H¢¢¢@@@=¢m=m zomwuflism G m. .@Aw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . .>%N@O >ZQ~WNMW flOamzQm ZOE UUN.QM§@ oow o.m @.~¢~ m N @¢.@ cfi. ho. mm. ewe. mmo. . . . . . . . . . . . . . . . . . . . . . . . . . ..>@N@O ~%@MHNM wvnwh T.QWQ5@ no.5; Bum no.2 “o Eva ~S€€< [coo smfion oiona 0E5. Ewan BEA swfiom 5w @393 wruwmmu 30A v64 0.2304 . $33 mEEsz vmm 2 -3: Z 53E @>$u< _ Em 2Q 3Q“ 436x93 coSmQmIQM: 33 was $2 Mo mcom uo QQSMmQQEoUIAwH Beau. NITRIFIOATION IN TEXAS SoILs. p 31 from that previously described, since the organic matter of the soil itself is used for the comparison. The tests should be made at the same time and under the same conditions. The nitrifying capacity of 29 soils given in Table 16 varies from 2 to 232. There are 8 soils with a nitrifying capacity of less than 25. There are 3 soils with a nitrifying capacity of. more than 100. This means that the original soil was a better medium for the growth of the nitrifying organisms than the mixture of the soil with sand and car- bonate of lime. The remainder of the soils are intermediate in char‘- acter. The low nitrification of some of the soils studied in this bulletin is thus due to the low nitrifying capacity of the soil. This can be rem- edied, as has been already shown, by the addition of carbonate of lime to the so-il. The addition of di-calcium phosphate was also of advan- tage, and the addition of sulphate of potash was occasionally of advan- tage, but the addition of carbonate of lime had the greatest and most effective action. i It does not follow from this that the carbonate of lime will necessarily increase the growth of crops on these soils. This matter will be studied in another bulletin. It does not follow that the use of carbonate of lime should be advised on these soils for the purpose of increasing their nitrifying capacity An increase in nitrifying capacity might have an unfavorable effect upon the fertility of the soil, and cause the organic matter to be nitriiied, the nitrogen lost, and the fertility of the soil to be rapidly decreased. This is particularly the case with the soils of the Southern States. NITBIFICATION OF MANURE. One series of experiments was made in which an addition of 50 milli- grams nitrogen in the form of sheep excrement was made to one soil, ‘ while another sample of the same soil received no addition. The per- colation was carried out as with the other experiments described in this bulletin. An illustration of one of these experiments is given in Table 20, and the results of the series are given in Table 21. 32 Table 20.——Production of nitrates from manure-warts per million. TEXAS AGRICULTURAL EXPERIMENT STATION. 1 ~mwhw~bo~~ww E [ omooNmwo~~>@ ~ wm~mwmmHwmNN O } v-l P i ‘ mwowwmwomowm § \ owmwmmm mmm~ IDQ v-iv-i Men ‘ a 1 I ~Hmoww>oomvm § 1 wmmmmmm ¢~mm "IQ; v-w-u ma.» 3 mowm~oom~oow § owmwoww mmmm 00¢) v-i v4 v-l N0 3 wvmmN~wooo~m § m Nwwww wmmm fig; v-l "9 3 wowmwfiwoovwm § ~ ¢o~@m wmmm Oq; v-iv-flw-i N0 3 ooommwwowooo § flwwmw ~¢o@ QDQ fiYlr‘<->'-a'»-J_~a' m~m-w-m_w' U'Q'QJ'0,Q‘ I-a'I--$-¢-I-a_I-u- IFJ-‘OJ .'b-3 .103 ~04. \/.\/‘\./~€:\/~