JOURNAL OF THE SCIENTIFIC AGRICULTURAL SOCIETY OF FINLAND 283 Maataloustieteellinen A ikakauskirja Vol. 49: 283-295, 1977 Effect of added magnesium, potassium, lime and nitrogen on oats I. Yields Raili Jokinen Agricultural Research Centre, Department of Agricultural Chemistry and Physics, 01300 Vantaa 30, Finland Abstract: With peat as the growth base the effect of the various combinations of three amounts of magnesium, of three of potassium, of two of lime and two of nitrogen on the grain and the straw crop yields, grown in pots, was investigated. During three seasons the magnesium fertilization did not affect the grain or the straw yield, the weight of the grain, or the rate of maturing in the first year. After the magnesium reserve had been exhausted the annual magnesium fertilization was needed to satisfy the requirements of an abundant crop. The highest level of potassium application together with a double magnesium fertilization rate caused a slight decrease in the yield, as the amount of water soluble salts in the growth base reached a high value. A deficiency in magnesium impeded more strongly the development of the grain crop than that of the straw crop; the maturing of the crop was delayed, and the grains were small. The ratio of potassium to magnesium in the annually renewed fertilization, when both nutrients were being used, did not affect the yield of oats. The amount of nutrients used had a more important significance than the ratio of the nutrients. Increase in the amounts of potassium, lime or nitrogen each had a diminishing effect on the yield if the plants were suffering from a deficiency of magnesium. Together with magnesium these treatments increased both the grain and the straw yields. Without the magnesium fertilization the highest rate of potassium increased clearly the value of the ratio K/Mg in the growth base, and caused a decrease in the yield. Introduction In investigations concerned with the uptake of nutrients by plants, solu- tionculture is often used. The concentration of the nutrient solution flowing into the growth base and the ratios between the nutrients can thus be main- tained at a constant level for the duration of the test. The uptake of nut- rients by the plants is in a test affected only by the properties of the nut- rients. When undecomposed peat (Sphagnum) is used as the growth base, the results are almost comparable with solution cultivation (Puustjähvi 1971). This kind of peat contains very little nutrients, however, it binds a lot of them and releases them again easily to be used up by the plants (Puustjärvi 1968). In the literature there is little information about the effect of various nut- rients on the development of grain and straw crops of cereals when cultivated https://www.c-info.fi/en/info/?token=ydvS-YhjlvksI3lT.TcZtpVI74IMRLJSxmXwdZg.ZtLycXCd0ZpA8StIkHTIWhQPre-0RedUVbvX2X3sbiHS7ujZ1i1sCBoa8tZGeFmEyX8iD7gl5E_B33Zldive5KZU_GDwgJiMakQ7rAlwlRtd9C_MUNJsouSUXAinEUeIaCipcmzoK2-2cajZQVmkBpgK5XRs3SSiwl4- in solution. In the experiments the crop of the test plant has often been harvested already at the vegetative stage. In pot experiments on various growth bases magnesium fertilization has either increased significantly the grain yield of cereals (Jerlström 1975), or it has had no effect (Sorteberg 1974). As far as the straw yields are concerned the results also vary. The yields of plants fertilized by magnesium and harvested at the vegetative stage depended among other factors on the amounts of potassium, calcium, and nitrogen (Falade 1973, Hansen 1972). The ratios between the nutrients, on the other hand, have seldom affected the yield (Omar and El Kobbia 1966, McLean and Carbonell 1972). In this investigation an attempt was made to clarify the effects of potas- sium and nitrogen fertilization, and of liming, on the grain and straw yields of oats, on the maturing, and on the grain weight when using magnesium fer- tilization. Material and methods The test was performed outdoors in the years 1970—1972 in Mitscherlich- pots (5 1). Undecomposed peat (Sphagnum, 250 g/pot, Table 1) served as the growth base, because it was desirable to keep the effects of the growth base on the nutrient uptake of oats to a minimum. In the factorial experiment there were three rates of magnesium application (Mg0 = 0, Mg4 = 200 and Mg2 = 400 mg/pot Mg), three of potassium (K 4 = 415, K 2 = 830 and K 4 = 1660 mg/pot K), two of lime (Cal = 2400 and Ca 3 = 7200 mg/pot Ca) and two of nitrogen (N 4 = 1000 and N 2 = 2000 mg/pot N). The fertilizations were carried out with all the combinations, and the test was repeated twise. All the nutrients were supplied as pure chemicals, MgS04 • 7H 20, K 2S0 4 , CaC03 , NH 4N0 3 . In addition, each pot was supplied with 436 mg Pas Ca (H 2P04 ) 2 • H2O, 1.8 mg Bas H3 B0 3 , 13 mg Cu as CuS04 • 5H20, 10 mg Mn as MnS0 4 • 7H 20, 11 mg Zn as ZnS04 • 7H 2 0 and 4mgMo as Na 2Mo04 • 2H2 0. The calcium carbonate was given only in the first year, and the fertilizations annually. Into each pot 25 oat (Pendek) seeds were planted. The crop was harvested when mature. Immediately after the cutting, the dry matter content (%) Table 1. The properties of peat (Sphagnum). PH H2 O 4.2 PH KCI 3.9 Density 60 g/dm3 Ignition loss 81 % Exchangeable cations Ca2+ 4.1 me/100 g of air-dry peat Mg2+ 4.1 » » » » K+ 1.4 » i) i) » H+ 139.0 • l .) » Cation exchange capacity 155.9 » » » » 284 285 of the whole crop (grains + straws) was determined by keeping it overnight in 60° C, and then 2 h in 105° C. The weight of the oat grain was deter- mined on the basis of four 100-grain samples. The proportion (%) of grains in the whole yield was calculated from the dry matter yields. The experiment continued over three seasons. The part of the experiment in which the higher rate of nitrogen was supplied was discontinued after the second year, because a further growth of the grain crop was beginning to dwindle in the pots lacking magnesium. The exchangeable cations of peat were extracted in 1 N neutral ammonium acetate (1: 60 w/v). The magnesium, potassium, and calcium contents of the extract were determined by means of atomic absorption spectrophotometry, and the exchangeable hydrogen by titrating the pH of the extract back to seven, using O.IN sodium hydroxide solution. The annual data results were tested by means of variance analysis, and the differences between averages by means of Duncan’s new multiple range test (Steel and Torrie 1960). The interdependencies between the nutrients and the yields were also studied by means of correlation analysis. Results Nutrient deficiency symptoms in plants In the oat shoots mild symptoms of magnesium deficiency were observed already in the first year in growths that had not received magnesium fertili- zation. In the following years the deficiency symptoms were very strong in the plants that had received the highest potassium rate. Tripling the liming lessened the deficiency symptoms with the low level of nitrogen application, but made them more pronounced with the high level of nitrogen application in the second year. In the plants that had received the lower rate of potas- sium there were potassium deficiency symptoms every year. Grain and straw yields The magnesium treatments did not have a positive effect on the grain and the straw yields in the first year (Table 2). In the pots that had received little lime the grain yield actually decreased with a magnesium sulphate fertilization, when the plants had received an abundant nitrogen and potassium fertilization. Tripling the rate of liming evened out the differences in the grain yields with various rates of magnesium. The increase in the potassium fertilization from K x to K 2 increased signi- ficantly both the grain and the straw yields, regardless of the rates of lime and nitrogen. The highest rate of potassium still increased the yields when using abundant nitrogen fertilization and liming. Tripling the rate of hming had a positive effect on the grain and on the straw yields at all the levels of magnesium application, when abundant nitrogen and potassium fertilization had been used. In the second year without magnesium fertilization the magnesium reserves of the growth base began to be exhausted, especially in the pots that 286 Table 2. Grain and straw yields of oats (g/pot dry matter) in different years. K, K 3 K« K, Kj K 4 Grains Ist year Nj Mg0 40.4»° 49.9cde 55.5eW 43.4<"= 55.7 et *hl 61.3«*'J Mgt 39.9»° 53.0 e'« 43.6° ctl 53.5« f«h 59.9 fen i Mg 2 40.3»» 50.2<=fe 51.7 cdet 42.6=° 52.8 defs 62.3 hl i N 2 Mg0 39.6»° 64.0Uk 68.2i« 32.0» 57.2"'*" 72,5k! Mgx 38.5»° 59.6'8 h 'J 64.3'J* 33.3» 57.8°re hi 75.5 1 Mg 2 40.1»° 56.2°re hl 59.0°'*°' 31.9 a 59.0e'*ni 76.21 2nd year N x Mg0 22.5° 29.0 d°f 27.1° d° 23.7° d 34.2rs>> 39.4 hi i Mgx 28.8 d°r 35.7« h 36.8ehi 31.7°'k 39.1 h| J 41.3'J Mg 2 32.4'k 35.1 W 34.4'e» 33.6r«h 39.4»>J 43.7J" N a Mg0 14.4° 5.8» 0.2» 5.1» 1.1» 0.5» Mgi 30.2ef ff 52.9 1 m 50.21 30.5°'* 48.7 kI 61.0° Mg 2 30.1°' 46.9" i 44.6Jk 30.6°'k 44.5J k 56.9 mn 3rd year Nx Mg0 3.4» 2.4» 0.5» 0.3» 0.1» Mg x 17.4° 20.1» 9.1" 18.9° 28.4 d 28.7 d Mg 2 19.3° 17.7° 6.4» 21.4° 28.4 d 31.0 d Straws Ist year Nx Mg„ 34.6» 41.2»°° d 45.1bcdefg 43.4»°cd 54.5 hI J 55.7'i k Mg x 36.3»° 44.2Dcdef 46_8 72d 69d 36» 24 b<= Mg, 194» 160» 1698 171» 139 t 106= Ca mg/100 g N, Mg, 908» 940» 910» 2100» 2172" 2253" Mg, 824» 819» 816» 2205" 2220" 2205" Mg 2 809» 809» 830» 2217 1' 2097" 2172" K mg/100 g N, Mg, 42» 68» 306° 47» 84» 222" Mg, 42» 66» 171" 33» 50» 66» Mg 2 43» 62» 200» 33» 53» 77» Conductivity 10 X mmho/cm N 2 Mg„ 1.7» 3.o»"<= 7.4*" 2.6»" 6.7'eh 7 . D ti Mg, 2.9» b0 3.2»»«* s.7**i* 2.9»"c 3.0ac 5.6 er« Mg 2 4.7"10 s.4<=* 7.6" 4.4bcbe s.iaet 7 () rg;h K/Mg N, Mg0 0.81 1.32 6.37 1.33 2.62 6.93 Mgl 0.13 0.30 0.74 0.15 0.43 0.86 Mg 2 0.07 0.12 0.37 0.06 0.09 0.23 Meaning of index letters same as in Table 2. 6). The peat, which served as the growth base, contained exchangeable mag- nesium 50 mg/100 g air-dry peat. At the end of the experiment the ex- changeable magnesium content of the peat had, without magnesium fertili- zation, dropped as low as to 8 mg/100 g. The annually supplied magnesium fertilization of 200 mg/pot was not sufficient, in conjunction with the strong liming, to maintain the magnesium content of the growth base at the original level if there had been a simultaneous strong nitrogen fertilization. The differences in the magnesium contents of the peat at the two nitrogen fertili- zation levels were in part caused by the annual magnesium fertilization. The liming clearly increased the exchangeable calcium content of the peat, but the other test variables did not affect it. The greatest potassium amount, supplied annually, has increased the ex- changeable potassium content of the growth base significantly in comparation with other potassium treatments, in low limed pots at all the magnesium levels, but in the strongly limed cases only without magnesium fertilization. The great excess of exchangeable potassium in ratio to exchangeable mag- nesium (K/Mg) in the pots that had received no magnesium fertilization, but the greatest potassium rate, probably is one reason for the reduction in the 292 Table 6. Exchangeable cations and conductivity value in the growth base at the end of the third year (Nj level). Kj K 2 K 4 Kt K 2 K 4 Mg mg/100 g Nx Mg0 17» 18» 17» 10" 10» 8» Mgx 119" 116" 119" 108" 87» 102b" Mg2 238 d« 249" 235 d" 224* 223d 255 e Ca mg/100 g Nj Mg0 948» 933" 814» 2340" 2050" d 2008" Mgi 858»b SSI» 1) 705» 2237 d" 2213 d" 2260" Mg2 797»»' 810»b 691» 1965" 2053" d 1968" K mg/100 g Nt Mg0 82 b 141" 423" 89 b 160" 446" Mgj 47» 57»b 288 d 33» 53» b 66»» Mg a 38» 93" 313 d 35a 54 ab 83b Conductivity 10 X mmho/cm Nx Mg0 2.8» 3.8»" 6.5 d"r 3.0» b 3.8» b 9.5 s Mgl 3.1»" 4.2»» 6.6 et 4.2»"° 5.0 b"d" 9.2» Mg 2 4.5»»" d 6.6 et 7.9 r« 4.7»bcde 6.2"det 9.7* K/Mg Nx Mg0 1.50 2.64 7.73 2.78 4.99 17.29 Mg t 0.12 0.15 0.75 0.09 0.19 0.20 Mg2 0.05 0.12 0.41 0.05 0.08 0.05 Meaning of index letters same as in Table 2. yield. The lowest potassium rate was quite deficient, since the plants had used up some of the potassium reserves of the peat itself. The magnesium and potassium fertilizations, given as sulphates, increased together, and separately, the concentration of water soluble salts (the con- ductivity value) in the growth base. The high conductivity values were, per- haps. partially responsible for the decrease in the yield in the pots that had received the abundant magnesium and potassium fertilizations. Discussion The magnesium reserves in the peat (exchangeable magnesium 50 mg/100 g) were sufficient in the first year for the production of an ample grain and straw yield. The positive effect of the magnesium fertilization on the yields of the following years in this experiment is probably principally caused by the depletion of the magnesium reserves of the growth base. Without a magnesium fertilization there remained in the peat after the experiment on an average exchangeable magnesium 13 mg/100 g. Augmenting the potas- sium and the nitrogen fertilizations or the liming, without magnesium, did 293 not affect the yield. In a pot experiment on peat, of 5 years' duration, carried out in Norway (Sorteberg 1974), magnesium fertilization (125, 250 and 500 mg Mg/5 1) did not affect the yield of oats. In the investigation it is mentioned that the peat contained little magnesium. In spite of that the plants grew well without magnesium fertilization. However, the magnesium content of the growth base was possibly greater than in the present investiga- tion. The slight reduction in the grain and the straw yields caused by the high magnesium rate, 400 mg/pot Mg, probably indicates that an excessive mag- nesium sulphate fertilization on an acid soil may impede the growth of plants (Schreiber 1950, Keränen and Jokinen 1964, Jerlström 1975). The yield decreased most clearly in pots that had received the high annual amounts of magnesium and potassium sulphate. At the end of the experiment the conductivity values of their growth bases were high, and this may have impeded the growth of oats at least to some extent. In a magnesium deficiency situation a magnesium fertilization appeared to increase the grain yield more clearly than the straw yield. Results that point in the same direction have also been obtained on mineral soils (Lehne and Koepke 1962, Jerlström 1975). The magnesium fertilization increased the weight of the grain (Wiehmann 1967) and promoted the development of the grain yield. A magnesium deficiency causes growth delay (Jerlström 1975), with the consequence that the grain fraction in the total yield dimini- shes, and the maturing of the crop is delayed (Scharrer and Mengel 1959, Keränen and Jokinen 1964). In pot experiments carried out on mineral soil (Jerlström 1975) and on peat (Sorteberg 1974), as well as in solution-culture experiments (Omar and El Kobbia 1966, Falade 1973), it has been observed, corroborating the results of the present pot experiment, that the yields of various plants increase upon increasing the amount of potassium, if a sufficient amount of the other nutrients is present. In the solution experiments only saturations of potassium exceeding 48 me/1 impeded growth. In the present investigation the annually supplied 1660 mg/pot K (8.5 me/1 of peat) did not depress significantly the grain and the straw yields of oats before the third year, when such a depression occured. In the first year, when there was a sufficient concentration of exchange- able magnesium and little potassium in the growth base, the effect of the magnesium fertilization on the yields did not depend on the potassium fer- tilization rate. In the second and the third years the magnesium fertilization increased the grain and straw yields the more the larger the potassium fertili- zation that had been supplied. An increase in the ratio of the annually supp- lied potassium and magnesium fertilizations increased the yields of oats. In a Polish pot experiment on a lowpotassium mineral soil, a magnesium fer- tilization increased the yield of spring wheat only when also potassium fer- tilizer was used abundantly (Mercik et al. 1976). In solution-culture experi- ments (Benko and Fecenko 1970) the yield of barley shoots did not de- crease unless there was a great excess of either potassium or magnesium (K/Mg 59:1 or 1:59) in the solution. 294 Liming promoted the growth of the roots of plants. However, the weights of the roots were not determined in this experiment. It was observed that the straw yield increased as a result of tripling the liming rate. At the same time the grain fraction in the total crop yield diminished. The yield of corn cut at the vegetative stage increased upon the adding of more calcium, both in solution-culture (Falade 1973) and in pot experiments (Hall and Heg- wood 1975). A high level of lime supply increased the yield of oats, and the uptake of magnesium by the yields, in every year (Jokinen 1977). For that reason, with insufficient magnesium in the third year adding more lime depressed the straw yield. REFERENCES Benko, V. & Fecenko, J. 1970. Effect of various K: Mg ratios upon the formation of dry matter and the uptake of nutrients by spring barley. Acta Fytotechnica 21: 91 104. Falade, J. A. 1973. Interrelationships between potassium, calcium and magnesium nutrition of Zea mays L. Ann. Bot. 37: 345 353. Hall, C. T. & Hegwood, D. A. 1975. Effect of soil calcium level in four soil pH-magnesium combinations on the calcium and magnecium level in sweet corn (Zea mays L.). Commun. Soil Sci. Plant Anal. 6: 555 570, (Ref. Fert. Abstr. 8: 310). Hansen, E. M. 1972. Studies on the chemical composition of isolated soil solution and the cation absorption by plants. I. Relationship between form and amount of added nitrogen and absorption on N, K, Na, Ca and Mg by barley. Plant Soil 37: 589 607. Jerlström, H.-G. 1975. Studier over möjligheterna att med växt- och jordanalyser beskriva magnesiumsituationen i svensk växtodling. Summary: Studies on the magnesium situa- tion in Swedish agriculture using soil and plant analysis. Inst, markvetenskap Avd. växtnäringslära Lantbrukshögskolan Uppsala. Diss. 197 p. Jokinen, R. 1977. Effect of added magnesium, potassium, lime and nitrogen on oats. 11. Nut- rient contents, cation ratios and magnesium uptake. J. Scient. Agric. Soc. Finl. 00: 49; 296-314. Keränen, T. & Jokinen, R. 1964. Magnesiumin puutteen torjuminen magnesiumpitoisuudel- taan erilaisilla kalkkikivijauheilla. Referat: Bekämpfung von Magnesiummangel mit Kalksteinmehlen veschiedenen Magnesiumgehalts. Ann. Agric. Fenn, 3: 244 255. Lehne, I. & Koepke, V. 1962. Die Wirkung einer Magnesiumdiingung magnesiumarmer Sand- böden in Abhängigkeit von Kalk- und Kaligaben. Albrecht-Thaer-Archiv 6: 194—207. McLean, E. O. & Carbonell, M. D. 1972. Calcium, magnesium and potassium saturation ratios in two soils and their effect upon yield and nutrient content of german millet and alfalfa. Soil Sei. Soc. Amer. Proc. 36: 927 930. Mercik, S., Goralski, J. & Gozlinski, H. 1976. Wplyw wspoldzialania potasu z magnezem oraz potasu z sodem na plonowanie i sklad chemiczny kiiku rosli n. Summary: Effect of potassium-magnesium and potassium-sodium interaction on yield and chemical composition of several crops. Polish Agric. Ann. 101, 3: 103—122. Serie A. Omar, M, A. & El Kobbia, T. 1966. Some observations on the interrelationships of potassium and magnesium. Soil Sci. 101:437 440. Puustjärvi, Y. 1968. Cation exchange capacity in Sphagnum mosses and its effect on nutrient and water absorption. Peat Plant News 1: 54 58. » 1971. The activities of calcium and potassium on water and peat cultures. Acta Agr. Fenn. 123: 70-73. Scharrer, K. & Mengel, K. 1958. Über den Kalium-Magnesium-Antagonismus bei Mais und Sonnenblumen. Z. Pflanzenern. Diing. Bodenk. 83: 149 162. Schreiber, R. 1950. tj'ber die Wirkung des Magnesiums auf den Ertrag und die Nährstoffauf- nahme von K 2O und MgO bei den Getreidearten. Z. Pflanzenern. Diing. 48: 37 64. 295 Sorteberg, A. 1974. Virkningen av magnesium pä avlingsstorrelse og magnesiuminnhold ved olike kalking og olike nitrogenforbindelser. Summary: The effect of magnesium applica- tion on yield and magnesium content as influenced by liming and different nitrogen sources. Forkn. Forsok Landbr. 25: 537 558. Steel, R. G. D. & Torrie, J. H. 1960. Principles and procedures of statistics. New York, To- ronto, London 481 p. Wiemann, H. 1967. Die Wirkung von Mangan, Bor und Magnesium auf Weizen besonderer Berucksichtigung der Kornproteine und der Stickstoffspätdiingung. Agrikulturchem. Inst. Rheinischen Friedrich-Wilhelms Univ. Bonn. Diss. 122 p. Ms received November 9, 1977. SELOSTUS Magnesium-, kalium- ja typpilannoituksen sekä kalkituksen vaikutus I. Kauran satoon Raili Jokinen Maatalouden tutkimuskeskus, Maanviljelyskemian ja -fysiikan laitos, 01300 Vantaa 30 Rahkaturve kasvualustana tutkittiin astioissa (5 1) kolmen magnesium- (Mg0 = 0, Mgt = 200 ja Mg, = 400 mg/ast Mg), kolmen kalium- (K, = 415, K 2 = 830 ja K 4 = 1660 mg/ast K), kahden kalkki- (Ca 4 = 2400 ja Ca3 = 7200 mg/ast Ca) ja kahden typpimäärän (Nt = 1000 ja Na = 2000 mg/ast N) eri yhdistelmien vaikutusta kauran jyvä- ja olkisatoon. Kolme vuotta jatkuneessa kokeessa magnesiumlannoitus ei ensimmäisenä vuonna vaikutta- nut jyvä- ja olkisatoon, jyvän kokoon ja sadon tuleentumiseen, koska kasvualustan sisältämä vaihtuvan magnesiumin määrä (50 mg/100 g ilmakuivaa turvetta) oli riittävä. Magnesium varo- jen loputtua 200 mg/ast Mg vuosittaisena lannoituksena riitti runsaan sadon muodostumiseen. Suurin kaliummäärä yhdessä kaksinkertaisen magnesiumlannoituksen kanssa aiheutti lievän sa- don alenemisen, sillä veteen liukenevien suolojen määrä nousi kasvualustassa korkeaksi. Magnesiu- min puute vaikeutti voimakkaammin jyvä- kuin olkisadon muodostumista, sadon tuleentuminen viivästyi ja jyvät olivat pieniä. Kaliumin ja magnesiumin suhde vuosittain uusitussa lannoituk- sessa, kun kumpaakin ravinnetta käytettiin, ei vaikuttanut kauran satoon. Ravinteiden määrällä oli tärkeämpi merkitys kuin ravinteiden suhteella. Kalium-, kalkki- tai typpimäärän lisäykset pienensivät kukin satoja, jos kasvit kärsivät magnesiumin puutetta. Yhdessä magnesiumin kanssa nämä käsittelyt lisäsivät sekä jyvä- että olkisatoa. Ilman magnesiumlannoitusta suurin kaliummäärä kohotti selvästi vaihtuvan kaliumin ja magnesiumin suhdetta (K/Mg) kasvu- alustassa ja aiheutti sadon alenemisen.