BULLETIN No. 219 MARCH, 1923 Alabama Agricultural Experiment Station OF THE Alabama Polytechnic Institute AUBURN DAN T. GRAY, Director Fertilizer Experiment By J. T. WILLIAMSON AND M. J. FUNCHESS GLOWER (COASTAL'PLMN.© BLACI( BELT ®UPPEOASALA IK® ?IODT)T ®APPLACHANIPI.ATEA\J ®LIILSTONEYALLEYS @YIGIU\NDRIfl SUMMARY 1. Alabama farmers who are interested in the contents of this bulletin should first determine by the map on page 2 the soil division on which they are located. Results and recommendations for their particular division should then be carefully studied. 2. Nitrate of soda has returned better profits than cottonseed meal in all sections of Alabama. Nitrate of soda is recommended, therefore, in the formulas for each section. It should be used in accordance with the directions on pages 21 and 22. 3. The gray soils over yellow subsoils of southeast Alabama have a high potash requirement and a relatively low phosphoric acid requirement. Results of experiments and fertilizer recommendations for this section are recorded in Table 1, page 8. 4. On all red soils, gray soils with red subsoils, and, in the southwest part of the Lower Coastal Plain, gray soils over yellow subsoils, the potash requirement is less than on the gray soils of southeast Alabama. The return from phosphoric acid on these soils is relatively low. (See Table 1, page 8.) 5. A comparison of the fertilizer results before and after boll weevils appeared shows that the returns from all kinds of fertilizers, except nitrate of soda, were reduced by weevils. (See Table 2, page 10.) 6. Taken as a whole, the lowest returns from commercial fertilizers were obtained on Black Belt Soils. (See Table 3, page 12.) 7. The fertilizer requirements of the Upper Coastal Plain are very similar to those of southwest Alabama. In this division nitrate of soda produced especially good results. (See Table 4, page 13.) 8. Soils of the Piedmont Plateau need little or no potash. The response to nitrate of soda and acid phosphate on these soils was very good. (See Table 5, page 1..5.) 9. Appalachian Plateau soils respond more to phosphate than do the sandy soils of south Alabama. Nitrate of soda produced very good results; but the need for potash is only moderate. The profits from the use of fertilizers on the Appalachian Plateau were greater than the profits on any other soil. (See Table 6, page 16.) 10. The gray or yellow chert free soils, with heavy, yellow subsoils, of the Limestone Valley regions have a high potash requirement. They respond very well to acid phosphate and nitrate of soda. (See Table 7, page 18.) .11. Nitrate of soda produced greater returns on the red lands of the Limestone Valleys than on any other soils of Alabama. There is a strong need for phosphoric acid and a weak need for potash. (See Table 7, page 18.) 12. Acid phosphate produced greater returns on the Highland Rim-"Barrens"-than on any other Alabama soils. Potash, when used at a moderate rate, returned very good profits. (See Table 8, page 20.) 13. Experiments to determine the best time to apply nitrate of soda to cotton showed that early applications are more profitable than are late applications. (See Table 9, page 21.) 14. One ton of muriate of potash containing 50 per cent potash is equivalent to four tons of kainit containing 12.5 per cent potash. At present prices and freight rates muriate is cheaper than kainit. I FERTILIZER EXPERIMENTS WITH COTTON By J. T. WILLIAMSON AND M. J. FUNCHESS INTRODUCTION In 1911 the Alabama Legislature appropriated to the Alabama Experiment Station a sum of money to conduct local experiments with field crops, fruits, fertilizers, livestock, etc., in the several sections of the State. Reports of 226 fertilizer experiments with cotton which are recorded in this bulletin represent a part of the work that was made possible by this appropriation. During the progress of this work, one or more experiments were placed in each county of the State. For various reasons a number of experiments were discarded, leaving only 57 counties represented. One hundred forty-three farmers cooperated with the Experiment Station in conducting these experiments. The results have been divided into groups in accordance with the several distinct soil divisions of the State. These soil divisions are shown on page 2. Average results of experiments are recorded in the tables which follow. METHODS A representative from the Experiment Station selected the land and measured the plots for each experiment. Fertilizers for each plot and instructions concerning their application were sent by the Experiment Station to the cooperator. Each experiment was inspected one or more times during the growing season. All fertilizers, except nitrate of soda, were applied in the drill before planting. Previous to 1920, the nitrate of soda was applied when the plants were six to eight inches tall. During and since 1920 the nitrate of soda was applied at the first cultivation after cotton was thinned to a stand. VALUES ASSIGNED TO COTTON AND TO FERTILIZERS The following prices for fertilizers are used throughout this bulletin. Acid phosphate ------------- $15.00 per ton Nitrate of soda ------------ 55.00 " " Cottonseed meal ----------45.00 " " Kainit ------------------- 15.00 " " 6 The assumed value of seed cotton is placed at six -cents per pound, which equals approximately 13 cents per pound for lint cotton and $38.00 per ton for cotton :seed. In each table there is presented a column showing profits when seed cotton is valued at 10 cents per pound, which is equivalent to 23 cents per pound for lint cotton and $45.00 per ton for cotton seed. (The lower value assigned to cotton is probably lower than the average price received by farmers during the last ten years, due to the abnormally high prices of 1918-20.) The prices assumed for fertilizers are, roughly, equal to the average prices for fertilizers in normal times. The tables contain a complete record of the yields, so that other values may be assumed and profits calculated by any one who cares to do so. CALCULATIONS OF INCREASES FROM THE USE OF FERTILIZERS The increased yields attributed to fertilizers have been calculated in this bulletin as follows: the increase due to acid phosphate is obtained by subtracting the yield of plot six from that of plot nine; the increase due to 200 pounds of kainit is obtained by subtracting the yield of plot five from that of plot nine; the value of 100 pounds of kainit per acre is found by subtracting the yield of plot five from the yield of plot ten; and the value of cottonseed meal is obtained by subtracting the yield of plot eight from that of plot nine. To find the value of nitrate of soda, the yield of plot ten is subtracted from that of plot twelve. The figure thus obtained is added to, or subtracted from (as the case may be) the value of cottonseed meal which was obtained as explained above. EXPERIM'ENTS ON THE LOWER COASTAL PLAIN Results on the Norfolk Soil Group. The soils of southeast Alabama are different from those of southwest Alabama in many ways. In the southeastern section gray sandy soils with yellow sandy clay subsoils predominate. Fertilizer results obtained in a few counties in this section were different from those obtained on the red, heavier soils of this section, or on either gray or red lands of southwest Alabama. Consequently the results of the fertilizer experiments on gray soils with yellow subsoils in this section are presented separately from results obtained on all other 7 soils of the Lower Coastal Plain lands of south Alabama. The area referred to as "southeast Alabama" lies east and south of a line drawn between Russell and Barbour counties, between the upper and lower halves of Bullock and Montgomery counties, thence southward between Crenshaw and Butler, Conecuh and Covington, and Escambia and Conecuh to the Florida line. The average results obtained in twenty-four fertilizer experiments in these counties are presented in Table 1, under the heading "Norfolk Soil Group." A study of this table reveals that a complete fertilizer is necessary for the largest profits. In the complete fertilizer, potash produced the largest profit, nitrogen in nitrate of soda was next, and phosphoric acid took third place. One dollar's worth of potash produced cotton worth nearly $6.00; one dollar's worth of nitrogen in nitrate of soda produced cotton worth $4.10, as aganist $1.97 for cottonseed meal; and one dollar's worth of phosphoric acid produced cotton worth $2.97. Expressed in other terms, a ton of acid phosphate, costing $15.00, produced a half bale of cotton, worth about $45.00; a ton of cottonseed meal, costing $45.00, increased the yield a full bale, worth about $90.00; a ton of nitrate of soda, costing $55.00, increased the yield by two and one-half bales, worth about $225.00. These figures show very clearly that cottonseed meal should not be used as a fertilizer for cotton. Where as much as 200 pounds of phosphate and 100 pounds of nitrate of soda are used, at least 200 pounds of kainit is needed to balance the fertilizer. On gray soils, with yellow subsoil, in southeast Alabama, the need for potash is very great. Each ton of kainit in a good complete fertilizer produced an increase of one bale of cotton on soils of this kind. As a fertilizer for this territory, 200 pounds of acid phosphate, 100 pounds of nitrate of soda and 200 pounds of kainit (or 50 pounds of muriate) are recommended. Those wishing to vary from this recommendation should use more nitrate of soda. It is doubtful if more phosphoric acid or more potash will pay. TABLE 1.-Average Results of 88 Fertilizer Experiments with Cotton on the Lower Coastal Plain NORFOLK SOIL GROUP'GROUP GREENVILLE SOIL s, y V O o0 C a ONa KIN O z d .~ " FERTILIZER '~ ° c .n.(U s-' d 5 t ° (n 0 Via. ° 0 ed ° C ) Lbs. Lbs. Lbs. 6c* Oc* Lbs. Lbs. 200 Cotton seed meal 542 80$ 0.30$ 3.50 602 126$ 2, 240 Acid phosphate- __ 535 73 2.58 5.50 540 64 3 No fertilizer 45-------453 ___ __ 4 _ 4 200 Kainit______.._____ 606 144 7.14 12.90 541 65 205 otn edma 650 188 12.50 680 204 240 Acid phosphate 6 200 Cotton seed meal 252 9.5 200 Kainit74 2 1 9 65 9 1 200 Cotton seed meal 518 6c* 3.06$ 2.04 _ 2.40 5.94 lOc* 8.10 714 4.98 49 4.60 _ 5.00 14.10 7 9 8 - No fertilizer-- -240 Acid phosphate-- 475 655 ----193 8.28 44 492 10 11 12 * 200 Kainit_________ 200 Cotton seed meal 240 Acid phosphate-200 Kainit .________ 200 Cotton seed meal) 240 Acid phosphate_ _ 53 803 341 12.66 723 460 261 8.61 26.30 19.05 741 265 8.10 18.70 100 Kainit______No fertilizer---_____ 100 Nitrate of soda-240 Acid phosphate 100 Kainit_____ 745 269 9.09 19.85 -482--__ 757 281 11.56 763 301 12.76 24.80 22.80 Seed cotton at 6 cts. lb. or 10 cts. lb. Results on the Greenville Soil Group.-Results of 64 fertilizer experiments with cotton on soils of the Lower Coastal Plain, excluding the results on gray soils over yellow subsoils in southeast Alabama, are recorded under the heading, "Greenville Soil Group," in Table 1.. These results will apply to all red soils, to all gray soils over red subsoils in the Lower Coastal Plain, and to all gray soils over yellow subsoils in the southwestern part of the State. The calculated profits show that a complete fertilizer is best the soils of this division. The highest return per dollar invested was obtained from the use of kainit at the rate of 100 pounds per acre in a complete fertilizer. Cottonseed meal, in this same fertil- for izer, gave the lowest return per dollar izer. For one dollar invested nitrate of $2.49 worth of cotton; acid phosphate worth of cotton; and cottonseed meal worth of cotton. spent for fertilsoda produced produced $1.87 produced $1.36 On soils of this section, a ton of acid phosphate, valued at $15.00, produced 467 pounds of seed cotton, worth about $28.00; a ton of nitrate of soda, valued at $55.00, produced about 11/2 bales of cotton, worth about $1.35.00; and a ton of cottonseed meal, valued at $45.00, produced about two-thirds of a bale of cotton,, worth .about $60.00, showing that nitrate of soda is much more profitable than is cottonseed meal. A ton of kainit, valued at $15.00, produced $78.00 worth of cotton. Kainit used at the rate of two hundred pounds per acre produced no more cotton than did 100 pounds, showing that the average soil of southwest Alabama does not need more than 100 pounds of kainit to the acre in a complete fertilizer. A mixture of 200 pounds of acid phosphate, 100 pounds of nitrate of soda, and 100 pounds of kainit is a satisfactory fertilizer for this section. SEFFECT OF BOLL WEEVIL ON FERTILIZER RETURNS Thirty-five of.. the 88 cotton fertilizer experiments conducted on the Lower Coastal Plain were conducted before boll weevils arrived, and 53 were conducted under boll weevil conditions. The returns from fertilizers before and after boll weevils arrived are shown in Table 2. 10 TABLE 2.-Average Results from 35 Experiments Before the Boll Weevil Came and of 53 Experiments Under Boll Weevil Conditions on the Lower Coastal Plain WITHOUT WEEVILS Q) c PIC). KIND OF °N ON.m WITH WEEVILS z 1 2 3 bs. FERTILIZER b jC) 4 6 8 ILbs. Lbs. 6c* lOc* Lbs. Lbs. 6c* l0c* Cotton seed meal -_ 562 109 $ 2.04$ 6.40 602 114$ 2.34$ 6.90 2.34 5.10 550 62 1.92 4.40 522 69 240 Acid phosphate _ No fertilizer-----___426 -___-471---___-----5.10 9.50 556 68 2.58 5.30 2 0 0 Kainit------------ 563 110 200 Cotton seed meal 6 688 235 7.80 17.20 662 174 4.14 11.10 2 4 0 Acidphosphate 704 251 9.06 19.10 686 198 5.88 13.80 meal Cotton 20Kainit__seed-_; -_ 200 7 No fertilizer-___-472-___-______9------------661 208, .9.18 17.50 631 143 5.28 24 0 Acid phosphate-_, Kainit______-_200 Cotton seed meal 792 339 12.54 26.10 736 248 7.08 17.00 240 Acid phosphate 200 11.00 Ui200 Kainit-___-___-_ 10 11 200 Cotton seed meal 240 Acid phosphate100 ant___ _ 762 309 11.49 23.85 461 725 237 495 __-_ 7.17 16.65 100 Nitrate of ( * No fertilizer--_--__ - -- ------- soda__ 240 Acid phosphate -~. 100 Kainit_ ) 761 308 13.18 25.50 757 269 10.84 21.60 Seed cotton at 6 cts. lb. or 10 cts. lb. It is necessary to study returns from complete fertilizers only, because the largest profit was always obtained from plots receiving phosphoric acid, nitrogen, and potash. With no weevils present, a dollar's worth of acid phosphate returned $1.93 worth of cotton; after weevils arrived, $1.00 invested in acid phosphate duced an increase worth only $1.67. The increase from pro- a dollar's worth of cottonseed meal before weevils were present amounted to $1.75 and dropped to $1.40 with. weevils present. Results from potash were similar to, those of acid phosphate and cottonseed meal in that there was a smaller return from kainit with weevils. tban without weevils., In contrast with cottonseed meal, kainit, and acid phosphate, nitrate of soda gave considerably better returns with weevils present than it. 11 did before they came. Before the weevils arrived a ton of nitrate of soda applied to twenty acres of land increased the yield of seed cotton 2600 pounds. After weevils arrived a ton of nitrate of soda produced an increase of 2740 pounds of seed cotton, showing that, contrary to existing opinion, nitrate of soda is relatively more effective under present conditions than it was before boll weevils came into Alabama. Therefore, the presence of weevils increases rather than diminishes the efficiency of nitrate of soda. Cottonseed meal should not be used as a fertilizer for cotton under present conditions. EXPERIMENTS IN THE BLACK BELT Fourteen fertilizer experiments were conducted in the Black Belt. The possible profits to be derived from fertilizers applied to cotton on Black Belt soils are indictated in Table 3. The highest profit per acre was obtained from a complete fertilizer. Per dollar invested kainit produced an increase worth $4.48; acid phosphate, $2.53; nitrate of soda, $1.79; and cottonseed meal only, $1.13. The following table shows the average results obtained in the Black Belt: 12 TABLE 3.-Average Results of 14 Fertilizer Experiments with Cotton on the Black Belt z 40 6 4-J KIND OF N (U-S FERTILIZER 1 2 3 Lbs. 200 Cotton seed meal 240 Acid phosphate No fertilizer--- Lbs. Lbs. 651 108$ 6c" 658 545 US 1.98$ 5.10 l0c* 6.30 9.70 4 5. 6 7 200 Kainit_________ 668 125 7 200 Cotton seed mea 240 Acid phosphate_4 200 Cotton seed meal 723 180 200Kainit No fertilizer __,_546 6.00 11.00 4.80 12.00 6.96 7.56 9 10 11 12 * f200 Cotton seedl 200 200 240 100 240OAcid phosphate 714 171 13.80 17.80 meal 240 Acid phosphatei f100 Nitratephosphate-~- 539 of soda 770 240 Acid 1100 Kainit )____ Kainit Cotton seed meal Acid 'phosphate Kainit -- _ __ No fertilizer 799,2561 S_ 773 230 6.75 15.95 -_ 227 8.32 17.40 Seed cotton at .6 cts. lb. or 10 cts. lb. An application of 240 pounds of acid phosphate in a complete. fertilizer increased the yield by 76 pounds .of seed cotton, equivalent to 633 pounds of seed cotton from a ton of phosphate. One ton of cottonseed meal increased the yield by 850 in a complete fertilizerwhile a ton of nitrate of soda, pounds of seed cotton, which cost but little more than the meal, produced an increase of 1640 pounds of seed cotton. A ton of kainit, when used at the rate of 200 pounds per acre, increased the yield by 820 pounds of seed cotton, returning a profit on the kainit of $34.00 Cotton production in the Black Belt is now only a mere fraction of what it was before boll weevils arrived. Fertilizer returns for cotton in the Black Belt were lower than on any other soils. Profits from large applications of fertilizer to cotton in this section are -very uncertain. A mixture of 200 pounds of acid phosphate, 100 13 pounds of nitrate of soda, and 200 pounds of kainit will give fair results under cotton, in the Black Belt. EXPERIMENTS ON THE UPPER COASTAL PLAIN Results of fertilizer experiments with cotton on the Upper Coastal Plain are recorded in Table 4. The 46 experiments are divided into two groups, based on the kind of soils on which the tests were conducted. Results obtained on gray soils over yell owvsbsoiis are recorded in. the column headed, "Norfolk Soil Group." In the column headed "Greenville Soil Group" are recorded the. results obtained on red or gray soils over red or reddish subsoils. These results arc recorded in Table 4. soils, TABLE 4.--Average Results 46" Fertilizer Experiments Cotton on the Upper Coastal Plain NORFOLK SOIL of with GREENVILLE GROUP GROU P, acO K iN F D O a O aO ° Nab- W a .. ~~ c 4-1 Lbs.4, 1 200 Cotton'seedmeal 2 3 240 Acid: phosphate No .fertilizer-_. __ Lbs. L637 -_ Lbs. 177 $ _6c* l0c* Lbs. Lbs. 6.12 $13.20 768 '183 $ 6c* 582: 122 448 _ __564 5.52 10.40 672 87 _ _ 6.48$13.80 lWc* -_ 4 200 20S240 6 200 Kainit ___ __ otn5edma Acid 2006Cotton Kainit phosphate-- - 588 128 725 265 6.18 11.30 629 44 9.60 20.20 .825 2409.30 __ 19.50 ___52__ 805 220 --- 3.42' 6.90 1.14 '2^90 8.10 seed meal I___ 715 '255 17.70 9.40 7.20 16.00 ___--------------9.. 7 8 200 Kainit_____ 200 Cotton seed meal 9 240 Acid phosphate__ 200 Kainit.. 200 Cotton seed meal) 10 240 Acid phosphate 100 Kainit....._ 11 0240 No fertilizer------- 49_ Acid phosphate_ 647 187 782 S__ 322 7.92 15.40 11.52 24.40 712 127 878 4.32 293 _ __-- 9.78 21.50 12 240OAcid phosphate 100 Kainit_ ____ * 4100 800 340 13.35 26.95 883 298 10.83 22.75 600 _ _-- No fertilizer.--__ Nitrate of soda _._ - 464 ---.805 345 15.40 29.20 918 333 14.68 28.00 Seed cotton at 6 cts. lb. or 10 . ts. lb. 14. Fertilizer results in this division are very similar to those obtained on similar soils of the Lower Coastal Plain. On both divisions 100 pounds of kainit produced a greater increase than did 200 pounds. When used at the rate of 100 pounds, one dollar's worth of kainit made an increase worth $6.00 on the Norfolk soil group, and $4.64 on the Greenville soil group. On the Norfolk group, a dollar's worth of nitrate of soda produced an increase worth $3.05, and on the Greenville group the increase was worth $4.39. One dollar's worth of cottonseed meal produced only $1.80 worth of cotton on Norfolk soil group and $2.21 on Greenville soil group, showing that nitrate of soda is more effective than cottonseed meal. On the soils of this division of Alabama, it is recommended that a fertilizer composed of 200 pounds of acid phosphate, 100 pounds of nitrate of soda, and 100 pounds of kainit per acre be used. At present prices this fertilizer should return a profit of $20.00 to $25.00 per acre. EXPERIMENTS ON THE PIEDMONT PLATEAU Nine satisfactory experiments were conducted in the Piedmont Section, results of which are recorded in Table 5. The outstanding results of these experiments are the high returns from nitrate of soda and the low returns from potash. The Piedmont soils are richer in potash than those of any other section of Alabama. It appears that from the large amount of potash present in these soils cotton can secure nearly all of the potash needed for full growth. Table 5 follows. 15 TABLE 5.-Average Results of 9 Fertilizer Experiments with Cotton on the Piedmont Plateau VN Q O N N Z~ KIND OF FERTILIZER o J No 1 2 3 Lbs. 200 Cotton seed meaL 240 Acid phosphate__ No fertilizer200 Kainit 200 Cotton seed meal 5 240 Acid phosphate__ 200 Cotton seed . meal 200 Kainit----- , Lbs. Lbs 664 200$ 6c* 6.48 1.14 10c 12.00 7.50$15.50 602 466 508 13 44 2.90 6 91 10 240 Acid phosphate_. __ 200 Kainit_ 200 Cotton seed meal) 240 Acid phosphate__ 100 Kainit--_-) 7622 5612).299 7762 0 73 74 71.324.5.0 11 12 100 Nitrate of soda~ 240 Acid phosphate__ No fertilizer 459 816 352 ------ 15.8229.90 100 Kainit-----*Seed cotton at 6 cts. lb. or 10 cts. lb. An application of 200 pounds of kainit per acre on the Piedmont Plateau reduced the yield of.cotton. When applied at the rate of 100 pounds per acre there was a fair increase in yield. A ton of kainiit applied over twenty acres of land at 100 pounds per acre would increase the yield by pounds per acre. At present prices, a light application of kainit would return a small profit, but it is 420 pounds of seed cotton, or 21 doubtful if it pays to use any potash fertilizer on the average returns-on Piedmont land. On the other hand, a -ton of nitrate of soda, costing $55.00, produced 'an increase in seed cotton of 3280 pounds. At this rate a (lollar spent for nitrate of soda returned $3.57. One dollar's worth of cottonseed meal increased the yield by $1.60. Acid phosphate produced fair these soils. For one dollar's worth of phosphate there was an increase in yield worth $2.90. 16 of acid A fertilizer composed of 300 and 100 pounds of nitrate of soda will give good results on the red lands of the Piedmont. On the gray sandier soils acid phosphate may be reduced to 200 pounds per acre. Neither kainit nor cottonseed should be used at present prices. phate pounds phos- meal EXPERIMENTS ON THE APPALACHIAN PLATEAU Seventeen from on the Appalachian Plateau. The outstanding results of these experiments are the high returns from phosphoric acid and nitrogen. The highest profit per acre the use of fertilizers was obtained in the Appa- fertilizer tests with cotton were conducted lachian Plateau. Results of these experiments are recorded in Table 6. TABLE 6.-Average Results from 17 Fertilizer Experiments with Cotton on the Plateau PAppalachian ______n N " _: a': o z 0 - 42 24 FERTILIZER .4~. - 2' 3 4 1 Lbs. 200 Cotton seed meal 240 Acid phosphate .200 Lbs. Lbs.6c* lc* 655 183 $ 6.48 $13.80 - No fertilizer-Kainit-_----------- -- 647 474 534 170 __ _ ---2.22 8.40 15.20 ._ 62 4.70 5 20 0 Cotton seed meal 248cd0hsht. 0_oto .240 20 8 8 336 13.86 27.30. 6 7- ed - el -- 709 237 _ 8.22 17.70: -_ - No fertilizer 469_ _- 8 9 10 11 cid hosphate-- 681 209) 823 849 __ 4 9.24 17.60' 13.26 27.30 30.65 Cotton seed meal ) nt200 240OAcid phosphate 200 Kainit ---200 Cotton seed meal 240 Acid phospliate _ 351 377 _ __ 15.57 -_- 100 Kainit No fertilizer-- - 12 * 100 Nitrate of soda 100 Kainit---- 2 --32.90 240 Acid phosphate--. _ ~ 854 382 17.62 Seed cotton at 6 ets. lb. or 10 cts. lb. 17 For one dollar invested, acid phosphate returned$3.80; cottonseed meal returned $1.89; nitrate of soda returned $3.21; kainit, at the rate of 200 pounds per acre, returned only $0.60; and kainit, at the rate of 100 pounds per acre, returned $3.28. By using the right kind of fertilizers, farmers of this section may very profitably increase their cotton yields. In Table 6, for example, it is shown that the profit from the fertilizers applied to plot 12 was $17.62. On the heavier soils of this division, 300 pounds of acid phosphate, 100 pounds of nitrate of soda, and 100 pounds of kainit will return good results. On the lighter sandy soils, 200 pounds of acid phosphate will usually be sufficient to balance 100 pounds of nitrate of soda and 100 pounds of kainit. If it is desired to apply fertilizer at a heavier rate than indicated, nitrate of soda and acid phosphate should be increased in the proportions recommended above. More than 100 pounds of kainit will not pay. EXPERIMENTS ON LIMESTONE VALLEY SOILS The Limestone Valley soils of Alabama are found chiefly in those areas commonly known as the Tennessee River Valley and the Coosa River Valley. The soils in these two valleys are very similar in origin, composition, and fertilizer needs, as shown by a number of experiments. Consequently, all fertilizer experiments conducted in these two valleys are brought together in Table 7. 18 TABLE 7.-Average Results'of 22 Fertilizer Experiments with Cotton on LimestoneValley Soils DECATUR SOIL GROUP COLBERT SOIL GROUP ~CIC 0 d a O N cI 0)" z KINDOF + 0 -o % 0 a FERTILIZER p - 4J- 40, . Z .4C 1 2 3 4 Lbs. Lbs. Lbs. 6c* l0c* Lbs. Ls. 6c* l0c* 200 Cotton seed meaL__ 619 106 $ 1.86 510 120$-2.70$ 7.50 240OAcid phosphate__ _- 589 76 2.76 5.80 513 123 5.58 10.50 $6.10 No fertilizer------200 Kainit 6 7 eed al 240 phosphate-200 Cotton seed meal :cid 200 Kainit __-_ __--- --------A0Cidton 46039------ --523 10 -0.90-0.50 536 146 7.26 13.10 735 222 I S"221 7.02 15.90 4.14 10.90 - 612 222 650 260 384---- 7.02 15.90 9.60 20.00 682 169 542 ---105 .0 240 81 5200 Acid phosphate. 618 Kainit------9 10 111 200 240 200 200 240 No fertilizer..-----_ 3.00 7.20 671 281 13.56 24.80 12 Cotton seed meal Acid phosphate 791 278 8.88 20.00 Kainit Cotton seed meal Acid phosphate-287 10.17 21.65 100 Kainit )__ No fertilizer______ 538 100 Nitrate of soda-240 Acid phosphate866 353 15.88 30.00 772 382 15.12 30.40 734 344 13.59 27.35 8--7-----760 370 16.90 31.70 800 100 Kainit *Seed ---- cotton at 6 cts. lb. or 10 cts. lb. The soils of these valleys may be divided into two distinct groups, each having specific fertilizer needs. The typical red lands of these valleys together with the chocolate colored soils are grouped in the "Decatur Soil Group." The other group is composed of soils having gray or yellow chert free soils over yellow subsoils. It is called the The soils of these two groups the red lands and the gray or yellow lands respond to phosphate in a very striking manner. One dollar's worth of acid phosphate applied to cotton on the red land returned "Colbert Soil Group." $3.63 and on the gray or yellow lands it returned $4.07. On the red lands, a dollar spent for nitrate of soda returned $5.21, and the gray or yellow soils it returned $4.10. Returns from cottonseed meal. were "on 19 much better on the red than on the gray lands. On the red soils, a dollar spent for cottonseed meal returned $2.31 and on the gray soils it returned only $1.35. The soils of the two divisions differ widely in their response to potash. On the gray-yellow soil group, kainit at the rate of 200 pounds per acre was profitable; on the red lands, 200 pounds of kainit produced less cotton than did 100 pounds. When used at the rate of 200 pounds per acre on gray soils one dollar :invested in kainit returned $6.40 and on the red lands it returned only $2.24. One hundred pounds of kainit per acre on the red lands gave an increase worth $5.20 for each dollar invested, and on the gray lands the return per dollar invested in kainit was $9.76. The cherty gray soils over yellow subsoils, belonging to the "Clarksville Series," need only 100 pounds of kainit per acre. A fertilizer containing 200 to 300 pounds of acid phosphate, 100 pounds of nitrate of soda, and 100 pounds of kainit is recommended for the red lands of these valleys. The chert free gray lands will give good returns from a mixture containing 200 pounds of acid phosphate, 100 pounds of nitrate of soda, and 200 pounds of kainit. Special mention is made of the results obtained on red land near Russellville, Franklin County. The two experiments in question were conducted on land that had formerly been pastured, and had carried a good growth of lespedeza. As an average of two years' results, 240 pounds of acid phosphate increased the yield 400 pounds of seed cotton; 200 pounds of kainit increased the yield 118 pounds; and 200 pounds of cottonseed meal increased the yield only 28 pounds. Putting these results another way, $1.80 worth of acid phosphate produced an increase worth $24.00; the return from seventy-five cents worth of kainit was $7.08; while cottonseed meal was used at a loss. Lespedeza is well adapted to the soils of the Tennessee Valley. The full use of this crop as a means of increasing the humus and nitrogen content of these soils, together with a liberal use of acid phosphate and potash fertilizers, should produce splendid crops of cotton at a minimum cost on lands of this kind. 20 EXPERIMENTS ON THE "BARRENS" OF THE HIGHLAND RIM The average of six' cotton fertilizer experiments conducted on Clarksville silt loam soil of the Highland Rim, locally known as "Barrens," together, with thecalculated profits are recorded. in Table 8. TABLE 8.-Average Results 6 Fertilizer Experiments with Cotton on the Highland Rim of O .. N O W ° Z, c .U KIND OF FERTILIZERbn b91 4- 1 2 3 Lbs. 200 Cotton seed meal 240 Acid phosphate No fertilizer-__ Lbs. 657 713 200$ 7.50 $15.50 144 6.84 12.60 Lbs 6c* 10c* 513_-- 4 5 200 200 240 6 0 Kainit_______ Cotton seed meal Acid phosphate Cotton seed meal 10 3-1.68-1.80 845 3321362 2690 782575 _- 65 7 8 8 240 Kainitphosphate-_ 200 Acid 200 Cotton seed meal) 9~ 240 Acid No fertlizer-----554 ____762394180 726213 .48 15.24 --8.0 30.6G 200 Kainit_ ____ 200 Cotton seed meal) 10). 240OAcid phosphate 100 Kainit__ 11 No fertilizer--- phosphate- 897' 384 904 391 471 _ _ 16.41 32.05 _ _ _- 12 S100 Nitrate of soda.) 240 Acid phosphate100 Kainit *Seed - --)-- 836 323 14.08 27.00 cotton at 6 cts. lb. or 10 cts. lb. The outstanding result of these tests is the marked response to phosphoric acid. One dollar spent for acid phosphate produced an increase in yield worth $5.30? which is the highest return for acid phosphate in the State. One dollar spent for cottonseed meal returned $2.38, while a dollar spent for nitrate of soda returned $2.25. This is the only section of Alabama where nitrate of soda was not much more profitable than was cottonseed meal; and here the two have given identical returns. One dollar's worth of kainit, at the rate of 200 pounds per acre, produced an increase 21 $2.08, but when used at-the lighter rate of 100 pounds per acre, the return was $4.72 per dollar spent. A fertilizer composed of 200 or 300 pounds of acid phosphate, 100 pounds of nitrate of soda, or the equiva lent in cottonseed meal, and 100 pounds of kainit, will give good returns on the "Barrens." worth WHEN TO APPLY NITRATE OFSODA TO COTTON The average results of 24 experiments, conducted away from Auburn, comparing the value of nitrate of soda when applied to cotton at different stages.of growth, are recorded in Table 9. TABLE 9.-Average Results Obtained from Applying Nitrate of Soda to Cotton at Different Stages of Growth AV'AGE 10 EXPTS. AVERAGE 24* EXPTS. 1920-22 1914-22 cd-0 0O Z d TIME OF APPLICATION -u ao ono v e U bap Lbs. 0 100 At planting time 25 At planting ieoffrtcliain---- At time of first cultivation-100 When squares first appeared o ------------------100 When first bloomsc appeared 100 Three bloom 5100 time---------- - - Lbs. Lbs. 444-499 634 151 655 172 Lbs. Lbs. -_--_-_A 635 622 508 601 152 139 - weeks after -------- first 100 At planting time- -- - V 100 When first bloom appeared ------ appeared - 594782 47 118 111 649 647 517 627 623 134 132 ---- 112 108 I0--------- 299 750*** 59 235 --- *Includes 1920-22 expts. **Average 19 expts. ***Previous to 1920 first application was made at time of first cultivation,and second application made three weeks after first blooms appeared. The results of 24 soda should be applied early. The ten tests of 1920-22 indicate that when 100 pounds per acre is used it should all be applied either at planting time, the time experiments show that nitrate of 22 of the first cultivation after thinning, or, perhaps better, one-fourth at planting time and three-fourths at the time of first cultivation. However, application of all nitrate of soda at planting time causes grass and weeds to grow so rapidly that chopping and cultivation become difficult and expensive. If a small part of the nitrate of soda is applied at planting time it may be either mixed with the seed and applied through the planter, or it may be mixed with the acid phosphate and potash and the mixture applied in the drill just before planting. The average increase from 200 pounds of nitrate of soda per acre was much larger than from only 100 pounds per acre. For example, the greatest average increase from 100 pounds of nitrate of soda was 172 pounds of seed cotton per acre; and in the same experiments, the increase from the 200 pound application was 229 pounds . This increase represents a profit of $7.57 per acre from 100 pounds, and $12.44 per acre from 200 pounds. Stated in another way, 10 acres of land fertilized with nitrate of soda at the rate of 200 pounds per acre would return a profit of $48.70 more than the same ten acres fertilized with only 100 pounds of nitrate of soda per acre. Table 10.-GENERAL SUMMARY Average Increase Per Acre, Per Ton and Gross Return Per Dollar Invested in Fertilizers from 202 Experiments with Cotton, 191 1-1921, Inclusive Fertilizer 111 1 lrr ~ r~-\ l111 1 81~ r I Lower Coastal Plain Kind and amount of fertilizer per acre. Assumed value of seed cotton per pound. Upper Co astal Plain Limestone Valley C C -a C is Basis of Value O a -0 aa a I 14~ O~ 4c a r>1 - -+ a Tc 73 608 87* is, LQ c a a isai. a. O -. U 122 ACID PHOSPHATE Per acre--lbs. ____ (240 pounds per Per ton-lbs.742 per in a completeP dollari fertilizer) Per1invested----0c-COTTON SEED MEAL Per acre-lbs..___ fe6c- - 89 56 467 581 483' 50 417 2.97 1.87 1.93 1.67 4.94 3.11 3.221 2.78 725 950 1016 2.53 2.23 2.43 2.90 3.80 4.07 4.22 3.72 4.06 4 85 6.33 6.78 76 633 67 559 114 109 159 008 1324 3.63 5.34 6.06 8.83 2.28 (200 pounds fertilizer) per Per ton-lbs._. s acre-lbs.. p~rjPer ton-lbs. j)lc per in a complete Per dollar investedj NITRATE OF SODA 6c -------~ 148 .102 131 105 1480 1020 13 1050 1.97 1.36 1.75 1.40 85 135 850 1350 1.13 1.80 166 120 142 101 173 171 1660 1200 1420 1010 1730 1710 2.21 1.60 1.89 1.35 2.31 (100 pounds acr aomlee i Per 3.29 2.27 2.91 2.33 1.89 3(00 3.69 2.67 3.16 2.24 3.85 3.80 188 114 130 137 82 3760 2280 2600 2740 1640 4.10 fertiltzer KAINIT Per dollar invested 6c ------6c_______ lOc__._--- 140 201 164 147 127 239 103 2800 4020 3280 2940 2570 4780 2060 3 05 4.393.57 6 841 4 153 1530 6.12 10.20 2.49 15, 4.73 2.84 4.98 2.98 5.09 7.31 74 740 2.96 4.93 2 99 1 29 5.96 5.35 4.62 8.69 3.75 -35 3.21 2 77 5.21 2.25 Per (200.inpounds per Per acre-lbs.---Pernto-lbs.____: acre a complete dollar, invested fertilizer.) 61 104 610 1040 2.44 4.16 4 07 6.93 *82 57 53 820 570 530 -350 3.28 2.28 3 80 3 53-2.33 5.47% 56 1120 2,12-1.40 28 15 160 150 160' 0.60 6.40 1.00 10.67 560 2.24 3.73 '56 65 52 520 2.08 3.47 59 KAINIT Per acre-lbs. ____ (100 pounds per Per ton-lbs.---acre aomplete Per6dollarinvested__ fertilizer. Per dllar invested 731 65 74 1480 63 1260 .07.47 14601 1300 10 ------ 5.84 97 5.20 5.92 5.04 .798 4 481 4.64 6.00 10.00, 751 58 1500 11.60 7.731 211 41 420 820 28 1bbS 3 . 9 2440 1300 11.80 . 76 1221 5.20 4.72 8.671 7.87 5.4611627 'This value obtairied from a camparison of Plots 1 and 5 24 it F "