FERTILIZATION OF SPHAGNUM BOGS, ON THE BASIS OF CERTAIN FIELD EXPERIMENTS AT LETEENSUO Yrjö Pessi Society of Peat Cultivation, Experimental Station Leteensuo Received April 2, 1960 At the experimental station ofLeteensuo a number of tests have been established and continued through a prolonged period in order to study the fertlizing questions connected with the cultivation of Sphagnum bogs. So far these tests have been evaluated in thorough treatments of the phosphate fertilizing experiments (7,5). These experiments will therefore not be dwelt upon in the present work. Instead, we are now concerned with an experiment with increasing nitrogen quantities combined with stable manure fertilizing, and with a complete fertilizing experi- ment combined with liming. It should be pointed out that, with respect to peat cultivation in Finland, nitrogen fertilizing particularly is a many-sided question requiring careful delibera- tion, because the necessity of using nitrogen fertilizer and the required quantity is dependent not only on the type of peat but also on the geographical location of the bog in question. The nitrogen content ofpeat varies, for instance, with the peat type; on an average it is about 1.2 % for Sphagnum peat and 2.3 % for sedge peat (2). However, the nitro- gen is present in the peat in a not easily soluble form; consequently, there is little ammonia and nitrate nitrogen. Actually, the quantity of inherent nitrogen in peat that can be used by cultivated plants is essentially dependent on the amount of nitrogen mobilization that may take place. This, in its turn, is governed by numerous factors; among other things it is a fact that mobilization occurs in a different man- ner in different types of peat. In high-quality fens mobilization is comparatively lively, although the geographical location of the bog has to be taken into account; in Sphagnum bogs, again, mobilization is poor. Relatively great differences can be noted in this respect. In South Finland, where the soil temperature in the summer is higher than in bogs of more northerly location, nitrogen mobilization in high-quality fens is abundant enough to make nitrogen fertilizing virtually unnecessary for any one of our cultivated plants. However, Sphagnum bogs are always in need of nitrogen https://www.c-info.fi/en/info/?token=A4cgCwLVhUJMacTG.rBToz_xaEnKfXhQPfSlOWA.Mr43SetM2niJ7hi4-vTGsXXxk2V_sydBorNSGkvSCtSpU9AJY00F9r0WJMcORTsi3vqn4OgsSsJO77ba9s6UPw_thbDlLQkzGvnbgqe98ON-7qfp566cvWpgOFtaGEMQ14LhgoI_lt0Jjs55LRUIl2mGOlwOJ74Xpl8lLcc 145 fertilizing. The experiments described in the following throw light primarily on the significance of nitrogen fertilizing on a Sphagnum bog in South-Finland. The tests were established by A. Vesikivi; they were later continued by J. Törmä (1944), U. E. Hirvensalo (1945—1946), A. Isotalo (1947—1952) and S. Mikkola (1953—1956). The results of the experiment have previously been described by Vesikivi (7, p. 70) and by Takala (5). Test area and plans of experiment The peat of the test area is Sphagnum peat, mainly originating from Sph. fuscum moss. The peat layer has a thickness of more than 3 metres. The area was drained by open ditches, dividing it into strips 20 m in width. Complete fertilizing experiment The area was cleared for cultivation in 1932. In the winter of 1934, clay was added as a soil improving agent in a quantity of 300 m 3 per hectare. In the same year the test area was also fertilized with stable manure at 35 tons per hectare. The various treatments represented the fertilizer combinations P, PK, NP, NK and NPK. Liming was also combined with this experiment. The location of the treatments can be seen from Fig. 1. The fertilizers were given once a year. Liming was done in 1934, when 2000 kg slaked lime per hectare were given. The fertilizers employed in the test were superphosphate or Kotka phosphate, 40 or 50 % potas- sium salt, and calcium nitrate. The following nutrient quantities were applied per hectare: 40 kg P 20 5, 80 kg K 2O, and 30 kg N. Stable manure was applied to the entire test area in the spring of 1934 at a rate of 35 tons per hectare. The meadows were established as clover-timothy meadows. Fig. 1. The positicn of plots in the complets fertilizing and nitrogen fertilizing tests. I = treatments up to 1949, If= treatments since 1949 in the nitrogen fertilizing test. 146 At the Experimental Station of Northern Ostrobothnia a fertilizing and soil improvement test has been carried out in which the fertilizer combinations were the same as in the present test, except that there was a plot without fertilizing instead of our P treatment and that heavier phosphate fertilization was given. The liming, too, was done with greater lime quantities (1, p. 8). Nitrogen fertilizing experiment The area was cleared for cultivation in 1921. The first cultivated plant was sown in 1923, at which time the test proper began. In 1923 the area received clay as a soil improving agent in a quantity of 300 m 3 per hectare. In the same year, moreover, liming was performed, adding 4000 kg slaked lime per hectare. Originally, increasing nitrogen fertilizer quantities and stable manure were combined in this field experiment as follows: One of two strips 10 m in width and 100 m in length received per hectare altogether 20 tons stable manure in 1923— 1924, 30.6 tons in 1929, 30 tons in 1930, and 30 tons in 1933. Otherwise both strips carried the same treatments: 0, PK, NPK, 2NPK, and 3NPK (N = 15 kg N, P = 40 kg P 205, K = 100 kg K 2O; all per hectare). In 1949 the plan of the experiment was altered in that the nitrogen fertilizer quantities given to the test plots in the strip with stable manure were increased so that the new nitrogen fertilizer quantities were 6N and 9N (see location of treatments, Fig. 1). In 1948, the after-effect of nitrogen fertilization was studied. The fertilizers employed in this experiment were calcium nitrate, superphosphate and potassium salt. Crop yield results The weather conditions during the years of experiment have been described in a previous publication (4, p. 5). The hay meadows have been timothy-dominated. Usually a seed mixture containing 20 kg timothy seeds and s—B kg red clover seeds per hectare has been used. The seed quantity of oats was 200—220 kg well-germinating seed per hectare, except in 1958, when only 160 kg per hectare were used. The hay and straw crop yields have been given as in an air-dried state, the grain crop yields as dried. Complete fertilizing experiment The annual crop results in this experiment are shown in Table I in the Appen- dix, while Tables 1 and 2 give the average crop yields per year. Table 3 contains calculated values showing the degree of crop increase caused by each one of the three nutrients when given in addition to a basic administration of the other two. These values were computed from the crop yield of the completely fertilized plot, sub- tracting the figures obtained with the two-component combinations, each one in turn. The results reveal that nitrogen has the greatest significance among the three, with phosphorus next and potassium ranging last. This succession in importance of the fertilizers is consistent with the findings of Anttinen (1, p. 13). Most closely 147 Table 1. Complete fertilizing experiment. Average hay crop yields, kg per hectare and year (17 years). Withmit lime Limed Increase m Crop yield Increase in Crop yield Increase in yield due to yield yield liming P 1 770 - 2 920 - 1 150 PK 1 510 -260 2 840 -80 1 330 NP 3 310 1 540 4 060 1 140 750 NK 2 040 270 2 640 -280 600 NPK 3 080 1 310 4 410 1 490 1 330 Significant differences; Artificial fertilization 108* 144** 187*** Liming 172* 229* • 298* •• Table 2. Complete fertilizing experiment on Sphagnum bog. Average grain and straw yields of oats, kg per hectare and year (5 years). Without lime Limed Straw yield Increase in Fertilization Grain yield Increase Grain yield Increase Without Limed in grain in grain liming lime yield yield P 1 450 1 420 -30 3 140 3 970 PK 1 240 -210 1 550 130 310 2 470 4 070 NP 1 990 540 1 920 500 -70 4 810 4 930 NK 1 890 440 1 690 270 —2OO 3 600 3 900 NPK 2 090 640 2 010 590 -80 4 700 4 880 Significant differences: Artificial fertilization 76* 105** 144*** Table 3. Values showing the degree of crop increase (kg/ha) caused by each one of the three nutrients when given in addition to a basic administration of the other two. I = unlimed, II = limed. NPK Hay I 1 570 1 040 —230 II 1 570 1 770 350 Oats, grain yield I 850 200 100 II 460 320 90 Oats, straw yield I 2 230 1 100 —llO II 810 980 - 50 comparable with the present experiment are the basic treatments in his investiga- tion, i.e., stable manure plus clay, and stable manure plus clay plus lime. One ob- serves particularly the slight effect of potassium, in fact the yield-lowering effect of potassium. The effect of phosphate fertilizers on Sphagnum bog can be seen in detail 2 148 in the investigation of Takala (5). In table 4 are shown the results of one phosphate trial, which has been evaluated by Takala (P =2O kg P 20 5 per ha). Tables 1 and 2 reveal that liming considerably increases the hay crop yields but has a lowering effect upon the grain crops of oats. The same observation was made in all other Sphagnum bog liming experiments at Leteensuo (3, 4, p. 8—11). Table 4. Average annual yields of hay in one phosphate trial at Leteensuo, kg per ha (during 9 years) (according to Takala). P = 20 kg P 205 per ha, sf = superphosphate, tf = basic slag. Increase Increase Fertilization Yield ... Fertilization Yield . ... in yield in yield 0 1 904 0 + liming 2 256 352 Psf 4 149 2 245 Psf + » 4 588 2 684 Ptf 3 341 1 437 Ptf + » 3 375 1 471 2Psf 4 481 2 577 2Psf + » 5 254 3 350 2Ptf 3 470 1 566 2Ptf + » 3 422 1 518 Table 4 shows that in connection with liming the effect of phosphorus was parti- cularly enhanced in regard to the hay crops. Furthermore, the figures relating to the crop increase produced by potassium seem to indicate that the relation between potassium and calcium might also have significance with respect to the effect of potassium. The same trend can also be observed in Anttinen’s findings (1, p. 13). Nitrogen fertilizing experiment The preceding experiment has revealed the great importance of nitrogen in the fertilization of Sphagnum bogs. The nitrogen fertilizing experiment provides an opportunity to study the effect of varying nitrogen dosages. The annual crop yield results in this experiment can be seen from Table II in the Appendix. Table 5. Average hay crop yields up to 1949, kg per hectare and year (13 years). Crop yield Artificial No stable manure With stable manure increase fertilization . T r- ~, T caused bvCrop yield Increase Crop yield Increase J stable manure 0 1 590 2 160 570 PK 2 940 1 350 3 240 1 080 300 NPK 3 610 2 020 3 810 1 650 200 2NPK 4 340 2 750 4 480 2 320 140 3NPK 4 970 3 380 4 950 2 790 20 Significant differences: Artificial fertilization 276* 369** 485*** 149 Table 6. Average crop yields of hay and oats since 1949, kg per hectare and year (Plan of experiment altered in 1949). Hay (7 years) Oats (3 years) Fertilization Crop yield Increase Grain yield Increase Straw yield 0 2 010 - 960 - 2 110 PK 3 510 1 500 1 240 280 3 040 NPK 3 980 1 970 1 720 760 3 680 2NPK 4 840 2 830 1 820 860 4 300 3NPK 6 140 4 130 2 120 1 160 4 780 6NPK 7 330 5 320 2 680 1 720 6 920 9NPK 7 110 5 100 2 730 1 770 7 720 Significant differences 680* 920** 1 200*** Significant differences 450* 630** 890*** Meadows. Tables 5 and 6 and Figs. 2 and 3 show the average hay crop yields per year up to 1949 and since that year. The results were grouped in this way be- cause the plan of the experiment was altered in 1949. It can be seen that the highest Fig. 2. Average hay crop yields per year in the nitrogen fertilizing test up to 1949 (13 years). Fig. 3. Average crop yields of hay and oats per year in the nitrogen fertilizing test since 1949. 150 nitrogen dosage included in the original plan, 45 kg N per hectare, has been too small for hay meadows, since the crops increased fairly linearly up to the dosage of 6N. Table 5 and Fig. 2 reveal that stable manure increased the hay crop yield when little or no nitrogen was used; its hay crop-increasing effect becomes less with increased nitrogen fertilizing. However, the difference is not statistically significant. Cereals. In addition to hay, only oats and mixed peas and oats were used as experimental plants, except in 1959, when also barley was cultivated. The average crops, per year, of oats and of mixed peas and oats are shown in Tables 6 and 7 Table 7. Average grain and straw yields up to 1949, kg per hectare and year, for oats (grain crops of 6 years, straw crops of 5 years) and for mixed peas and oats (5 years). ....... N ° stable manure With stable manure Crop yield i ncrease causedArtificial r - fertilization Grain Straw Grain Straw b > - stable manure . Increase ... ... Increase .. ,yield yield yield yield Grain yield Straw yield Oats 0 650 1 680 1 000 2 900 350 1 220 PK 700 50 2 440 1 060 60 3 720 360 1 280 NPK 950 300 3 050 1 270 270 4 310 320 1 260 2NPK 1 120 470 3 670 1 460 460 4 940 340 1 270 3NPK 1 330 680 4 150 1 540 540 5 300 210 1 150 Significant differences: Artificial fertilization 41* 55** 75*** Stable manure 65* 88** 119*** Peas and oats 0 860 - 1 660 1 270 2 490 410 830 PK 1 680 820 3 250 1 780 60 3 740 100 490 NPK 1 880 1 020 3 930 2 060 790 3 990 180 60 2NPK 1 920 1 060 4 050 2 030 760 4 230 110 180 3NPK 2 150 1 290 4 500 2 110 840 4 540 -40 40 Significant differences: Artificial fertilization 159* 219** 301*** and Figs. 3 and 4; they, too, have been given separately for the period before and after 1949. It can be seen that the curves representing the crop yield figures have a course largely similar to that of the hay crop yields. However, Table 7 reveals that the effect of stable manure was different, both with respect to grain and to straw yield, from that in the case of hay. Its crop-increasing effect was equal in magnitude in connection with all artificial fertilizer combinations. Also, this effect was statisti- cally significant in every case at least with respect to the grain yield, as the F values indicate. The corresponding characteristic for the straw yield was not computed. Prolonged effect of stable manure. The effect of stable manure can still be observed in 1948, as late as 15 years after the most recent addition of stable manure to the proper test member. The crop yield increases possess statistical significance, the F value, 8.5, rating one asterisk. The prolonged effect of stable manure is also 151 evident from the fact that in the years 1934—1940, when no more stable manure Vas added, the increases in hay crops as well as in the grain crops of oats, caused by stable manure, were equal in magnitude to those during earlier years. If we compute the average effect of stable manure from the PK combination test and from all PKN tests, we find that it increased the average hay crops of the four hay meadows in the period 1934—1940 by 340 kg per hectare and year, while the corresponding figure for the period 1925—1928 (four hay meadows) was only 78 kg per hectare and year. Similar calculations show that the oats grain yield increased, owing to stable manure, by 570 kg in 1938, while in the three years when the stable manure addition was performed, i.e., 1923, 1930, and 1933, the average increase was 400 kg per hectare and year. The cause for the favourable effect of stable manure is likely to be found, partially at least, in the changes in microbial activity in the soil produced by it. Crop quality Studies relating to the quality of the crops exist only from the nitrogen fertilizing experiment. In 1958, the timothy content of the hay (from a seventh year ley) was investigated (5, p. 34). The timothy percentage of the different treatments, starting with the plot, withouth treatment, was found to be: 2.4; 13.1; 11.0; 26.8; 56.9; 72.5; 54.3. The timothy percentage was thus highest in the test member with 90 kg N per hectare. In the instance of the test member with the highest nitrogen fertilizer dosage the lodging of the hay, which would have given other plant species a better chance to gain the upper hand* is thought to be responsible for the fact that the timothy percentage went down once more (5, p. 35). Table 8. Strength of straw, 1000-grain weight and shooting capacity in 1958. Experimental plant: Orion 111 oats. Strength of straw 1000-grain Fertilization (0 _ 10) weight, g Shootmg, % 0 10 31.8 29 PK 10 31.1 8 NPK 10 30.2 6 2NPK 10 29.7 5 3NPK 10 31.4 8 6NPK 6.5 31.0 5 9NPK 2.5 31.2 4 Table 8 shows the results and observations from the crop quality determinations to which the oat crops of 1958 were subjected. Nitrogen fertilizing did not lower the 1000-grain weight to any noteworthy extent but it effected a slight reduction in the germinability. Impaired germinability was, namely, experienced that year, owing to night frosts. However, there are no significant differences in germinability be- 152 tween the crops reared with different nitrogen fertilizer dosages. The lodging of the crops in two test members, too, was caused by severe night frost (—13.0° C). This lodging serves to indicate that the highest nitrogen fertilizer dosages have produced a straw of different structure. On the other hand it does not necessarily indicate that the development of the cereal would have been markedly delayed in the test members with the highest nitrogen dosage, seeing that the germinability was re- duced in all test members. Conclusions The present investigation is an account of the results from two fertilizing experi- ments established on Sphagnum bog at the Experimental Station of Leteensuo. The experiments were carried out in 1923 and 1934. The following conclusions can be drawn from the results. Most important in significance among the different nutrients is nitrogen, phos- phorus ranging next, and potassium last. Potassium could even cause a reduction in the crop yields. The effect of liming was evident in the form of increased hay crops, whereas the grain yields of oats were reduced by it. Liming has improved the effect of phos- phorus particularly in the case of hay. The results also seem to indicate that the relation between potassium and calcium has significance in regard to the reduction of crop yield caused by potassium. Remarkable crop yield increases were obtained by nitrogen fertilizing. The hay crops and the grain and straw crops of oats increased almost linearly with the addi- tion of nitrogen, in the form of calcium nitrate, in quantities up to 90 kg N per hectare. Quantities in excess of this caused hardly any further increase in the crops. The said quantity is suitable for cover manuring of hay meadows, but the most advisable quantity for cereals is thought to be 45—60 kg N per hectare, so that lodging of the crops might be avoided. Nitrogen fertilization does not essentially affect the quality of the grain crops of cereals; on the other hand nitrogen promoted the retention of timothy in the meadow when nitrogen was used in quantities up to 90 kg per hectare. Stable manure increased the crops. This effect was most distinctly evident in the grain and straw crops of oats. The effect of stable manure was still present 15 years after the most recent addition of stable manure. REFERENCES (1) Anttinen, O. 1957. Rahkasuon lannoitus- ja maanparannuskokeen tuloksia. Referat: Ergebnisse eines Düngungs- und Bodenverbesserungsversuchs auf Sphagnum-Moor. Valt. Maatal. koetoim. julk. 155: 1—29. (2) Kivinen, E. 1948. Suotiede. Porvoo. 219 p. (3) Pessi, Y. 1958. Rahkasuoviljelyksenkalkituksesta. Summary: On the liming of cultivated Sphagnum bogs. Suovilj. yhd. v.k. 52—62: 29 32. 153 (4) Pessi, Y. 1959. Kivennäismaan vaikutuksesta rahkasuon maanparannusaineenaLeteensuon koease- man pitkäaikaisten kenttäkokeiden perusteella, Siimmary: On the effect of mineral soil as a soil improving agent on Sphagnum bogs on the basis of prolonged field tests at Leteen- suo Experimental Station. Acta agr. fenn. 94, 14: 241 268. (5) Takala, M. 1958. Salpietarilannoituksen vaikutuksesta niittonurmen satoon rahkasuolla. Summary: On the influence of nitrate fertilization upon the yield of hay meadows on Sphagnum peat bogs. Suovilj. yhd. v.k. 52—62: 33—36. (6) —1959. Suoviljelysten fosfaattilannoituksesta. Summary: On phosphate fertilization of peat soil. Ibid. 63: 30—38. (7) Vesikivi, A. 1935. Suomen suoviljelysyhdistyksenkoeasemien v:n 1934 koetuloksia. I. Leteensuon koeasema. Ibid. 39: 70. SELOSTUS: KAHKASUON LANNOITUS ERÄIDEN LETEENSUON KOKEIDEN PERUSTEELLA Yrjö Pessi Suoviljelysyhdislys, Leteensuo Tutkimuksessa on selostettu Leteensuon koeaseman rahkasuolle perustettujen lannoituskokeiden tuloksia. Koealueen turve on vähän maatunutta, Sphagnum fuscum rahkaturvetta. Koealueelle on li- sätty savea maanparannusaineeksi 300 m3 /ha. Seuraavat päätelmät voidaan esittää. Eri ravinteista on tärkein merkitys typellä, sitten fosforilla ja viimeksi kalilla. Kalilannoitus on jopa saattanut alentaa satoja. Kalkituksen vaikutus on ilmennyt siten, että heinäsadot ovat sen vaikutuksesta lisääntyneet, mutta kauran jyväsadot alentuneet. Kalkitus on parantanut fosfaattilannoituksen vaikutusta erityisesti heinällä. Tulokset viittaisivat myös siihen, että kalin jakalkin suhteella on merkitystä kalin vaikutuksen kannalta. Typpilannoituksella on saatu huomattavat sadonlisäykset. Heinäsadot sekä kauran jyvä- ja olki- sadot ovat nousseet lähes suoraviivaisesti lisättäessä typpeä kalkkisalpietarin muodossa aina 90 kg N/ha. Tätä suurempi määrä ei ole juuri lisännyt satoja. Heinänurmen pintalannoitukseksi mainittu määrä soveltuu, mutta viljalle lienee suositeltavin 45 60 kg N/ha lakoviljan välttämiseksi. Viljan jyväsadon laatuun ei typpilannoituksella liene sanottavaa merkitystä, mutta timotein säi- lymistä nurmessa on typpilannoitus edistänyt käytettäessä typpeä aina 90 kg/ha. Karjanlanta on lisännyt satoja. Selvimmin tämä vaikutus on esiintynyt kauran jyvä- ja olkisa- doissa. Karjanlannan vaikutus on ilmennyt vielä 15 vuoden kuluttua viimeisestä karjanlannan lisäyk- sestä. 154 Table I. Complete fertilizing experiment on Sphagnum bog. Crop yields, annually, kg per 0.1 hectare. I - unlimed, II = limed. Year Plant P PK NPK NP NK 1934 Oats grain I 188 190 249 239 242 II 178 184 237 237 205 straw I 349 324 475 480 478 II 353 394 471 456 380 1935 Ist year ley hay I 357 360 410 394 285 II 457 475 538 550 385 1936 2nd * » * I 419 432 532 507 294 II 469 469 592 572 297 1937 3rd * * * I 219 213 319 291 104 II 272 266 381 366 53 1938 Peas and oats grain I 180 124 201 220 72 II 218 150 210 238 87 straw I 240 170 277 311 97 II 363 270 362 360 139 1939 Oats grain I 227 223 271 263 253 II 175 212 235 223 219 straw I 433 423 527 521 289 II 520 559 565 550 499 1940 Ist year ley hay I 138 138 347 332 291 II 275 303 444 410 310 1941 2nd » » » I 263 227 381 334 228 II 263 278 413 391 294 1942 3rd » » » I 75 62 213 319 163 II 216 184 319 363 138 1943 Peas and oats grain I 77 99 152 131 118 II 146 144 170 163 138 straw I 153 123 300 287 234 II 335 353 440 395 293 1944 No results 1945 Oats grain I 107 78 167 180 161 II 147 143 164 179 141 straw I 264 198 452 492 408 II 435 418 494 553 401 1946 Ist year ley hay I 134 106 203 161 179 II 358 354 393 336 314 1947 2nd * » » I 203 133 381 352 296 II 323 296 511 444 519 1948 3rd » > »I 300 150 414 445 306 II 408 361 491 491 321 1949 4th » » » I 215 100 298 365 142 II 317 291 355 393 177 1950 Oats grain I 98 67 131 123 112 II 91 89 103 88 104 straw I 250 144 332 314 219 II 282 244 275 279 231 1951 Oats grain I 106 61 226 188 178 II 121 145 265 233 177 155 Year Plant P PK NPK NP NK straw I 252 148 565 599 406 II 397 419 635 625 437 1952 Ist year ley hay I 146 116 413 422 215 II 305 303 417 399 236 1953 2nd » » » I 56 40 257 259 164 II 291 293 464 419 304 1954 3rd » * » I 91 33 249 302 173 II 291 280 470 434 309 1955 4th » » * I 68 17 208 285 170 II 186 174 390 330 264 1956 sth » » »I 114 46 263 318 192 II 247 220 465 403 290 1957 6th » » » I 106 35 198 266 98 II 158 154 463 328 121 1958 7th » » »I 104 41 144 281 163 II 137 135 386 283 151 Table 11. Experiment with increasing nitrogen quantities. Crop yields, annually, kg per 0.1 hectare. I = without stable manure, II = with stable manure. Year Plant O PK NPK 2NPK 3NPK 1923 Oats grain I 71 68 128 165 200 II 107 109 157 186 216 straw I 209 217 352 495 559 II 246 270 392 484 544 1924 Peas and oats grain I 197 250 340 505 607 II 243 252 357 505 622 1925 Ist year ley hay I 123 535 555 610 637 II 160 522 595 595 600 1926 2nd » > » I 20 315 377 392 417 II 20 355 392 442 472 1927 3rd » » » I 84 152 220 315 383 II 63 189 262 325 362 1928 4th » * * I 26 155 225 302 410 II 44 174 196 279 365 1929 Peas and oats grain I 53 105 124 141 166 II 113 126 152 183 188 straw I 160 352 387 387 472 II 230 321 335 362 367 1930 Oats grain I 30 43 58 67 74 II 65 90 125 122 110 straw I 128 244 314 348 396 II 323 520 609 690 730 1931 Ist year ley hay I 62 160 217 313 442 II 157 212 302 407 517 156 Year Plant O PK NPK 2NPK 3NPK 1932 Oats grain I 87 106 130 159 182 II 105 115 134 167 192 straw I 167 205 239 309 348 II 181 230 261 350 399 1933 Oats grain I 34 34 43 54 56 II 74 74 85 89 106 straw I 110 290 292 310 362 II 297 382 437 417 455 1934 Ist year ley hay I 72 205 262 365 487 II 185 255 300 372 492 1935 2nd » » » I 140 327 419 482 513 II 289 336 416 508 594 1936 Peas and oats grain I 99 143 194 196 205 II 131 161 175 190 195 straw I 161 288 395 449 493 II 230 341 420 460 474 1937 Peas and oats grain I 92 142 196 207 214 II 106 138 172 182 207 straw I 161 276 378 401 469 II 223 393 405 455 474 1938 Oats grain I 114 94 129 147 163 II 176 177 178 206 201 straw I 226 264 328 372 412 II 404 458 455 528 520 1939 Ist year ley hay I 96 201 275 399 445 II 184 267 327 393 440 1940 2nd » » * I 19 238 294 366 402 II 97 286 363 419 452 1941 Peas and oats grain I 102 282 255 265 268 II 162 303 362 292 280 straw I 145 332 325 332 332 II 212 366 352 367 390 1942 Peas and oats grain I 87 168 170 182 220 II 125 160 170 170 180 straw I 202 379 480 456 482 II 351 451 483 470 567 1943 Oats grain I 52 77 81 83 125 II 71 70 84 108 99 1944 Ist year ley hay I 496 418 503 526 549 II 408 398 392 448 447 1945 2nd » » * I 362 435 535 643 702 II 498 508 582 681 695 1946 3rd » * * I 370 396 450 527 604 II 417 392 458 542 530 1947 4th » » » I 201 292 358 403 477 II 286 321 372 411 473 1948 sth » » » 1 212 271 252 170 222 II 246 337 296 214 206 Altered fertilizing plan O PK NPK 2NPK 3NPK 6NPK 9NPK 1949 Oats grain 157 184 261 287 304 317 340 straw 284 323 356 411 464 524 492 1950 Oats grain 73 100 120 124 187 280 270 straw 167 288 243 261 264 566 562 1951 Ist year ley hay 259 509 540 607 692 744 720 1952 2nd » » » 105 392 449 530 647 838 775 1953 3rd » * » 198 392 474.. 596 738 766 715 1954 ! 4th » » » 236 320 351 403 563 631 596 1955 sth » » » 237 254 292 378 519 744 714 1956 6th » » » 165 320 366 444 552 634 614 1957 7th » * » 205 269 317 431 584 771 841 1958 Oats grain 59 88 134 134 145 206 208 straw 181 300 506 619 706 987 1262 1959 Barley grain 38 52 66 81 124 214 180 straw 176 225 295 339 430 517 423 157