FEN FERTILIZATION WITH POTASH IN THE LIGHT OF TESTS AT LETEENSUO EXPERIMENTAL STATION Yrjö Pessi Society of Peat Cultivation, Experimental Station Leteensuo Received July 28, 1960 Numerous experiments intended to clarify the fertilizing questions of peat land have been established at the Experimental Station of Leteensuo and carried on through fairly long periods without interruption. Short-time reports of these experiments have been given in several connections. The results obtained over longer periods have recently been analysed with reference to the Sphagnum bog fertilizing tests, which have thrown light on the effects of nitrogen and phosphorus as well as potassium fertilization (5, 6). Moreover, Takala (6) has reported on the experiments arranged with a view to clarifying the effects of phosphate fertili- zation. In the following, the significance of potassium fertilization on the fen area of the Experimental Station of Leteensuo will be described on the basis of the results derived from three field tests. The persons supervising the experiments in different years have been mentioned in a previous publication (4, p. 2). With reference to shorter periods, these tests have been analysed by Malm (3) and Hir- vensalo (2). The author has previously examined the results of one of these tests over a longer period (5). Test ground The peat of the areas is forest sedge peat and their bog type prior to clearing was that of a wooded swamp with herbs and grasses. The depth of the peat layer is more than 2 m. The test areas are drained by open ditches dividing the land into strips 20 m in width. The quality of the peat is illustrated by the chemical analyses made from the plot adjacent to the site of claying test No. 1 (7, p. 32; 8). The chemical composi- tion of the clay and sand used as soil improving agents and the results of the soil analysis can also be found in the said publication by Vesikivi (7, p. 34). https://www.c-info.fi/en/info/?token=RYwyJymCfq07J8Rv.eO7Egn3-nX7Rf-gVAckftQ.TNtgD6J_HIzm0zF6NlIeglLQC28mHLD-Ecn2Eo6b0lb73YXnPeZ9fT5bmaLjAX9uSHATUcZ4iH_uDDLPRT6bjBfY487-IG7sQer-nPN1X6Wnwd9BOs_KR3jXCB7V5aHSPwyB-YZtOFzz3jdje6qYBeSBElTg3UZhU0k2sFM 230 Arrangement of tests Test No. 1. The test area was cleared for cultivation in 1904. In 1905 clay was added as soil improving agent in a quantity of 400 m 3 per hectare. The test was started in 1905. The treatments were: 0, P (40 kg P 20 5 per hectare), K (100 kg K 2O per hectare), PK, and PK plus liming. The location of the test plots can be seen from Fig. 1. Liming was done as follows: in 1905, 2 tons slaked lime per hectare; in 1923, 1927 and 1933, 1 ton per hectare each. Fertilization was carried out according to plan during the period of 1905—1918. In the years 1919— 1922 all test plots were given phosphate and potassium fertilizer. From 1923 on- wards, fertilization again proceeded according to the original test plan, but the fertilizer quantities given to root crops were doubled. Test No. 2. The test area is located adjacent to that of Test No. 1. No clay was added. The test was started in 1933, but its test plan was altered in 1937. Initially, it consisted of the following treatments: P (P= 40 kg P 2 05 per hectare), PK4 (K, = 60 kg K 4O per hectare), PK 2 (K 2 = 60 kg K2O per hectare), P2K1# and P2K2 . In 1937, K 4O was replaced with the equivalent quantity of potassium sulphate and K2O with the equivalent quan- tity of K 4O . The location of the test plots can be seen from Fig. 1. Test No. 3. Cultivation of the test area was commenced in 1921. One half of the test strip was clayed (adding 200 m 3 clay per hectare) in 1923 and in 1941. The potassium fertilizer quanti- ties applied at first were: 0, 20, 40, 60, and 80 kg K 2O per hec- tare; in 1930 they were replaced by the following series: 0, 30, 60, 90, and 120 kg per hectare (see 5, p. 4). The notations employed in this paper with respect to the treatments in this test refer to the latter series. The entire area has been fertilized annually with phosphate fertilizer equivalent to about 300 kg superphosphate per hectare. Crop yield results The weather conditions during the test years have been described in a previous publication (4). The annual crop yields in tests No. 1 and 2 can be seen from Tables I and II in the Appendix. The corresponding figures relating to test No. 3 have been published before (5). Meadows. The average annual hay crops obtained in the tests during the test period are shown in Tables I—31 —3 and in Fig. 2. Table 1 reveals that potassium fertilization has increased the hay crop yield, this increase being significant at a level of 95 %. However, the increase in crop yield obtained in the case of the PK treatment shows that potassium fertilization in combination with phosphorus Fig. 1. The position of plots in the tests No. 1 and 2. 231 Table 1. Test No. 1. Average annual hay crop yields (during 19 years), kg per hectare. Treatment Crop yield Increase in yield O 2010 - P 4840 2830 K 2770 760 PK 6510 4500 PK + lime 6640 4630 666 • 866 »• 1152 »•» had a remarkable compound effect; the crop yield increases produced by P and K individually add up to 3590 kg per hectare, whereas their use in combination increas- ed the crop yield by 4500 kg per hectare. The test plan of test No. 2 did not include a plot without treatment. The fertilizing effect of potassium alone is therefore unknown. However, Table 2 reveals that the use of potassium in addition to phosphorus has a remarkable effect. Potas- Table 2. Test. No. 2. Average annual hay crop yields (during 8 years), kg per hectare. Treatment Crop yield Increase in yield P 3900 - PKso, 6100 2200 PK„ 6390 2490 P2Kso 4 6540 2640 P2Kjj 6850 2950 566 » 762 •• 1010 ••• sium sulphate was somewhat less efficient than potassium salt, but there are no statistically significant differences between the effects of the different fertilizer types. Doubled potassium quantity, on the other hand, increased the crop yield with reference to that obtained with the single quantities in a degree approaching statistical significance. No plot without treatment was included in test No. 3 either. It can be seen from the results shown in Table 3 and Fig. 2 that potassium fertilization increased the hay crops considerably from those obtained in the P treatment. On the unclayed test strip, the increase was higher than on the clayed strip in the instance of the first four potassium fertilizer quantities in the series, but the highest potassium fertilizer addition produced about equal crop yield increases on both strips. This serves to show that clay has a considerable potassium fertilizing effect (cf. 1) but also other effects which cannot be reproduced with potassium fertilization. 232 Table 3. Test. No. 3. Average annual hay crop yields (during 23 years),,kg per hectare. K,O Unclayed Clayed 1 Crop yield Increase in Crop yield Increase in yield yield O 1153 - 4402 30 3410 2257 5705 1303 60 6135 3982 6476 2074 90 6011 4858 6789 2387 120 6274 5121 7219 2817 fertilizing 189 * 251 ** 323 *** claying 119 * 158** 204 ••* 1 Clay addition: twice 200 m 3 per hectare Cereals. In likeness with the hay crop yields, the cereal crop yields have been presented in Tables 4—6 and in Fig. 2. It can be seen that potassium fertili- zation has resulted in an increased grain yield of oats in tests No. 1 and 3, while in test No. 2 potassium fertilization tended to cause a slight decrease in the crop yield, although there are no statistically significant differences. Nor can any effect of potassium fertilization on the grain yield of spring wheat be seen in the same test. On the other hand, the straw yield was increased also in this test. Possibly this is due to inundations, which occurred repeatedly in the spring several years running and which may have transported such quantities of mud to the test area that adequate potassium fertilizer action has been produced. Root crops. Root crops were cultivated during several years on the test area of test No. 1 only. The results reveal that potassium alone does not produce much of an increase in the crop yield. Potassium in addition to phosphorus has a remarkable effect. Fig. 2. Average annual hay crop yields and grain yield of oats in the test No. 3 233 Table 4. Test No. 1. Average annual grain and straw crop yields of oats (12 years) and barley (7 years), kg per hectare. Treatment Grain yield Incr. in grain yield Straw yield Oats O 1230 - 2180 P 2630 1400 4300 K 1490 260 2510 PK 3000 1770 5330 PK + lime 2860 1630 505(P 285 • 381 •• 501 ••• Barley O 560 2130 P 1320 760 3900 K 820 260 2700 PK 1740 1180 4810 PK + lime 1940 1380 5010 506 • 685 •• 918 ••• Table 5. Test No. 2. Average annual grain and straw crop yields of oats (5 years) and spring wheat (2 years), kg per hectare. Treatment Grain yield Incr. in grain yield Straw yield Oats P 2680 4310 PKso, 2530 - 150 4950 PK,, 2670 - 10 5 260 P2Kso, 2600 80 4950 P2K,„ 2590 - 90 5090 Spring wheat P 1960 - 4380 PKso, 1960 0 4700 PK,„ 2080 120 4820 P2Kso, 1870 - 90 4940 P2K,„ 2040 80 4800 Conclusions On the fen area of the Experimental Station of Leteensuo, with a peat layer consisting of forest sedge peat, potassium fertilization produced a considerable increase of the hay crop yield on the clayed as well as the unclayed bog, when phosphate fertilization had been added. However, clay displayed a considerable 234 Table 6. Test No. 3. Average annual grain and straw yields of oats (during 7 years), kg per hectare. K 2 O Unclayed Clayed Grain Increase Straw Increase Grain Increase Straw Increase yield in yield yield in yield yield in yield yield in yield 0 1335 3317 - 2087 4509 30 1883 548 4392 1075 2468 381 5205 696 60 2229 894 5099 1782 2612 525 5701 1192 90 2327 992 5424 2107 2710 623 5739 1230 120 2271 936 5557 2240 2771 684 6044 1535 Grain yield, fertilizing 160* 217** 291 *** claying 103* 140 ** 187 *** Table 7. Test No. 1. Average annual root and top yields of swede (during 4 years), kg per hectare. Treatment Root yield Incr. in root yield Top yield O 5230 - 2530 P 21540 16310 10560 K 6300 1070 2650 PK 29850 24620 11840 PK + lime 32480 27250 13190 12790 » 20838 •• potassium fertilizing effect and also other effects, which probably cannot be repro- duced by fertilization. The effect of potassium fertilization on the summer cereal crop yield was different in different tests. In two of them, potassium fertilization increased the grain yield but not in the third. The results obtained in this latter instance are thought to have been influenced by the addition of mud through the action of floods. Potassium fertilization had remarkably increased the root crop yields. When phosphate fertilization had not been added, the effect of potassium fertilization was small asa rule. There was no marked difference between the effects of potassium salt and potassium sulphate, although it should be noted that the tests did not contain any treatments with potatoes as the experimental crops, which might show up this difference most clearly. 235 Appendix I. Annual crop yields in test No. 1, kg per hectare X 10“1 . Year Test plant Treatment 0 P K PK PK+lime 1905 Oats grain • 89 240 101 275 222 straw 102 297 110 328 243 1906 Turnip roots 826 1069 709 949 1061 tops 448 520 454 534 526 1907 Swede roots 1616 3373 1892 4390 4530 tops 687 1138 758 1299 1261 1908 Pea seed 75 177 97 137 133 haulm 105 244 109 227 216 1909 Oats grain 122 239 151 295 235 straw 196 361 204 444 353 1910 Sugar Beet roots 219 1048 453 2719 1816 tops 225 655 540 2750 1813 1911 Oats grain 172 242 163 289 240 straw 283 420 266 452 393 1912 Sugar Beet roots 136 617 258 832 864 tops 158 856 379 1742 1635 1913 Oats with Vetches, green fodder 233 477 189 459 430 1914 Swede roots 255 1759 151 1389 1366 tops 124 799 58 579 625 1915 Pea seed 30 78 22 67 51 haulm 113 301 65 276 228 1916 Oats grain 97 225 113 263 295 straw 217 491 264 558 512 1917 Spring Wheat grain 55 171 64 254 246 straw 260 553 232 721 702 1918 Swede roots 47 995 97 1450 1820 tops 37 645 65 795 980 1919 Barley grain 47 82 72 138 166 straw 299 367 282 494 470 1920 No results 1921 Ist year ley hay 449 644 395 618 706 1922 2nd » » » 647 731 655 705 772 1923 3rd » » » 289 589 232 674 586 1924 4th » » » 289 491 240 649 613 1925 sth » * » 70 380 550 695 700 1926 6th » » » 30 265 425 500 530 1927 7th » » * 10 245 200 415 395 1928 Bth » » » 20 245 320 475 487 1929 . 9th » » » 15 278 40 560 610 1930 Oats grain 93 147 122 244 231 straw 227 359 303 596 599 1931 Turnip roots 166 1237 116 4139 4800 tops 75 765 60 1420 1560 1932 Barley grain 14 32 18 82 87 straw 165 295 235 480 430 236 Appendix I. Annual crop yields in test No. I, kg per hectare X -1 . Year Tes plant Treatment ft P K PK PK-j-lime 1933 Ist year ley hay 155 420 255 780 745 1934 2nd » » » 90 453 108 735 720 1935 3rd » » * 91 372 119 720 619 1936 4th »» » 55 348 58 665 685 1937 Spring Wheat grain 56 112 68 163 172 straw 101 241 120 354 393 1938 Potato 931 1163 1235 1405 1414 1939 Barley grain 59 82 112 109 136 straw 231 325 292 401 486- 1940 Swede roots 172 2488 379 4710 5275 tops 164 1640 180 2063 2408 1941 Barley grain 55 109 59 180 200 straw 364 455 396 416 421 1942 Ist year ley hay 348 630 460 636 608 1943 2nd » * • 340 713 368 778 895 1944 3rd » * • 432 667 365 740 768 1945 4th . » . 346 747 301 809 886 1946 sth > * » 113 530 112 590 639 1947 6th »» * 38 451 53 633 642 1948 Oats grain 114 332 147 373 385 straw 174 395 173 412 494 1949 Oats grain 238 352 340 417 401 straw 331 620 488 646 674 1950 Barley grain 91 232 116 274 311 straw 214 426 261 504 548 1951 Oats grain 104 300 118 316 315 straw 156 382 178 438 440 1952 Oats grain 123 366 182 382 345 straw 262 481 342 780 666 1953 Barley grain 40 96 72 70 92 straw 148 396 254 426 450 1954 Oats grain 112 206 123 202 236 straw 240 354 266 408 442 1955 Barley grain 84 288 121 365 362 straw 70 462 169 643 699 1956 No results 1957 Oats grain 75 209 101 199 138 straw 130 352 151 386 361 1958 Oats grain 133 296 125 343 345 straw' 299 642 270 942 888 237 Appendix 11. Annual crop yields in test. No. 2, kg per hectare x 10-1 . Year Test plant Treatment P PKt 0 PK20 P2K, O P 2K28 1933 Potato 759 932 937 1118 1068 1934 Potato 2414 2676 2554 2591 2780 1935 Barley grain 129 149 142 147 148 straw 441 492 479 491 487 1936 Ist year ley hay 575 666 753 731 763 Treatments changed P PK PK 48 P2K P2K48 k2so 4 Ka S0 4 1937 2nd year ley hay 597 731 804 810 816 1938 3rd » » ' * 285 575 578 632 622 1939 4th * » * 216 435 463 525 567 1940 sth * * * 160 419 414 400 428 1941 Oats grain 290 225 277 213 231 straw 370 415 409 383 1384 1942 Potato 968 1203 1290 1188 165 1943 No results 1944 » » 1945 Barley grain 187 168 197 165 191 straw 532 525 560 517 558 1946 Spring Wheat grain 228 232 239 234 226 straw 433 462 466 471 470 1947 Spring Wheat grain 163 160 177 140 182 straw 442 478 497 517 489 1948 Ist year ley hay 441 562 592 577 584 1949 2nd » * * 361 533 561 575 652 1950 3rd » » » 396 742 786 817 856 1951 4th » » » 482 828 805 827 885 1952 Oats grain 327 343 365 366 343 straw 586 680 785 744 732 1953 No results 1954 Oats grain 128 114 110 148 158 straw 284 340 392 352 366 1955 No results 1956 » » 1957 Oats grain 284 258 241 223 223 straw 395 426 436 431 417 1958 Oats grain 309 326 343 351 342 straw 519 613 608 554 645 238 REFERENCES (1) Anttinen, O. 1957. Saraturvesuon saveus- ja lannoituskokeen tuloksia. Referat: Ergebnisse eines Lehmzufuhr- und Düngungsversuchs auf Seggentorfmoor. Valt. maatal. koetoim. julk. 163: 1-20. (2) Hirvensalo, U. E. 1947. Nousevien kalimäärien vaikutuksista savetulla ja saveamattomalla muta- suolla. S. suovilj. yhd. vuosik. 50; 43 57. (3) Malm, E. A. 1932. Nousevien kalimäärien vaikutuksesta sekä saveamattomalla että savetulla muta- suomaalla Leteensuon koeasemalla. Ibid. 35; 87 99. (4) Pessi, Y. 1959. Kivennäismaan vaikutuksesta rahkasuon maanparannusaineena Leteensuon koe- aseman pitkäaikaisten kenttäkokeiden perusteella. Summary: On the effect of mineral soil as a soil improving agent on Sphagnum bogs on the basis of prolonged field tests at Leteensuo Experimental Station. Acta agr. fenn. 94, 14: 241 268. (5) —»— 1960. Kivennäismaan merkityksestä mutasuon maanparannusaineena Leteensuon koe- aseman pitkäaikaisten kenttäkokeiden perusteella. Summary: On the significance of mineral soils as a soil improving agent on fens on the basis of prolonged field tests at Leteensuo Experimental Station. Ibid. 95, 3: 1—27. (6) Takala, M. 1959. Suoviljelysten fosfaattilannoituksesta. Summary: On phosphate fertilization of peat soils. S. Suovilj. yhd. vuosik. 63: 30 38. (7) Vesikivi, A. 1929. Suonsavetuksen ja -hiekoituksen taloudellisesta kannattavaisuudesta. Referat: Über die Rentabilität der Lehm- und Sandmischkultur auf Moorboden. S. suovilj. yhd. tiet. julk. 12: 1 131. (8) —»— Suonsaveuksen ja -hiekoituksen lannoitusvaikutuksesta. Referat: Über die Düngewirkung der Lehm- und Sandmischungen auf Moorboden. Ibid. 14: 1 29. SELOSTUS: MUTASUON KALILANNOITUKSESTA LETEENSUON KOKEIDEN PERUSTEELLA Yrjö Pessi Suoviljelysyhdistys, Leteensuon koeasema Kalilannoitus on Leteensuon pitkäaikaisissa kokeissa lisännyt huomattavasti heinäsatoja sekä savetulla että saveamattomalla mutasuolla, jotka ovat saaneet fosfaattilannoituksen. Savella on ollut huomattava kalilannoitusvaikutus, joskin myös muita vaikutuksia, joita lannoituksella ei voitane korvata. Kevätviljasatoihin kalilannoitus on vaikuttanut eri tavoin eri kokeissa. Kahdessa kokeessa se on lisännyt jyväsatoja, mutta ei yhdessä. Viimeksimainitun kokeen tulokseen lienee vaikuttanut tulvan koealueelle kuljettama liete. Juurikasvien juurisatoa kalilannoitus on lisännyt huomattavasti. Mikäli fosfaattilannoitusta ei ole annettu, on kalilannoituksen vaikutus jäänytyleensä vähäiseksi tai lähes olemattomaksi kaikilla kasveilla. Kalisuolan ja kaliumsulfaatin välinen eroavuus on ollut lähes olematon, joskin on todettava, ettei koekasvina ole ollut perunaa, jolla näiden lannoitteiden välinen ero tulisi ehkä parhaiten esiin.