Maataloustieteellinen Aikakauskirja Vol. 57: 213—221, 1985 Effect of liming and N fertilization on growth, macronutrient content and uptake by mixed stands of three clovers and timothy RAILI JOKINEN Department of Agricultural Chemistry, University of Helsinki, SF-00710 HELSINKI, Finland Abstract. Mixed stands of clovers and timothy grew well in unlimed (Ca») acid soil (pH(CaCl 2) 4.8). The highest total yield of red clover-timothy was obtained at a low lime level (Ca! = 12 g/pot CaC03). The yield of red clover alone responded to liming similarly. The reducing effect of N fertilization (2000 mg/pot N as NH4N0 3 ) on the yield of clovers was greatest in the first growing season (cuts 1 to 4) without lime, and in the second growing season (cuts sto 7) with lime (Ca, = 12g/pot, Ca2 = 24 g/pot). Liming without N fertilization pro- moted the growth of timothy only in the two first cuts; N fertilization increased the yield at all lime levels. Liming increased the Ca content of clovers, but there were no differences between lime levels. Mg and K showed a decreasing trend. N fertilization did not affect the nutrient content of clovers. A good quality of clover yield reguired adequate amounts of other fertilizations than N. In timothy, the Ca content increased slightly at all lime levels; the N and K contents increased by N fertilization. The N uptake by red clover was highest at the Ca, level, by white clover and alsike clover at the Ca0 level. The proportion of clover was larger than that of timothy of the uptake of N, P, Ca and Mg. When N was applied, the uptake of K showed an opposite direction. Index words: pot experiment, mineral soil, liming, N fertilization, red clover, white clover, alsike clover, timothy, yield, macronutrient content, macronutrient uptake, pH(CaCI 2), exchange acidity, exchangeableCa, Mg, K, Ca/Mg. Introduction Farming of clovers has aroused great in- terest in Finland during recent years. Accord- ing to Pulu and Turtola (1983), the prob- lems related to practical farming include poor Present address: Department of Agricultural Chemistry and Physics, Agricultural Research Centre, SF-31600 JOKIOINEN, Finland. winter hardiness of these plants and soil acid- ity. Also the requirement of N fertilization of leys at the start of the growing season must be taken into consideration, since clovers are almost always seeded with timothy. In previous experiments on the effect of lime and N fertilization on the clover, atten- tion was focused to the yield, N content and N uptake (e.g. Munns 1965, MuNNsand Fox 213 JOURNAL OF AGRICULTURAL SCIENCE IN FINLAND https://www.c-info.fi/en/info/?token=KhZ_PVX-5ugn44Na.Z8tQcNTS3w1bEaPH7nRpYw.Ijeg7zQ0_3fszpIq5C5inQFDxrQ8_OdpfR-Gdo9osE05bvywRp7UtXsSTiVW7KtZXbvoXoNbg2lGpOLC19VfX50_ZfFdMAV4JdIiBlDOTSLlXNpxv82DAQ7TUAgpgLs9pxGFwXXOo4hZW_I-3qKS--wVg50kSAjFoDfx 1976, Munns et al. 1977, Rice et al. 1977, Craig et al. 1981, Ssali 1981, Aura and Kemppainen 1983). The contents and uptake of Ca, Mg and K have been studied less (e.g. Raininko 1968). The pots were seeded with a mixture of timothy (Phleum pratense, var. Nokka) and red clover (Trifolium pratense, var. Venla), white clover (Trifolium repens, var. Astra) or alsike clover (Trifolium hybridum, var. Högsta). The seeds of clovers were inoculated with Rhizobium strain suspension before sowing. The growth was cut four times, June 28, August 3, August 28 and October 7. The fresh yield was sorted out according to the two plant species, dried (60°C until dry + 2 h at 105°C) and weighed. After the 4th cut the covered pots were left in the net-hall over the winter. The aim of the present pot experiment was to give an account of the effects of three lime levels on the growth, macronutrient content and uptake of clovers (red clover Trifolium pratense, white clover Trifolium repens or alsike clover Trifolium hybridum) in mixed stands with timothy (Phleum pratense). The effect of N fertilization was studied at each lime level. In May 1983, fertilization was repeated like in 1982; no lime treatments were applied. Timothy and clovers were reseeded in their own pots and the growth was cut three times, July 11, August 8 and September 23. After the sth and 6th cuts the pots received N, P and K fertili- zation, half the amounts given before sowing. Soil samples were taken after the 7th cut, dried at room temperature until air-dry and crushed to pass a 2-mm sieve.Materials and methods The conditions of the pot experiment were probably unsuitable for alsike clover; it seemed to suffer especial- ly from the short cutting intervals. The pots of the whole experiment were harvested at the same time, and the growth of red clover and timothy pots determined the cutting time. For the inoculation of the seedes, the same strain ofRhizobium was used. It is possible that the no- dulation of alsike roots was weaker than that of the other clovers. The study was performed in conventional Mitscherlich pots and in a net-walled greenhouse. The soil, a Litorina fine sand (Table 1), was taken from the plough layer of an agricultural area. Moist soil was crushed to pass a 10-mm sieve. In October 1981, 5 kg of moist soil (4.3 kg air-dry soil) was weighed into each pot and limed with precipitated CaCO,, 0 (Ca,,), 12 (Ca,) and 24 (Ca 2) g/pot. The total number of pots was 72, i.e. 24 pots per lime level. De-ionized water was added to give a final moisture level of 25 %. The soils were incubated over the winter (October—April) out in the open air, exposed to the hard weather conditions of the Finnish winter. Seven cuts of all pots were analysed. One gram of plant material was wet combusted with the mixture of three acids, HCI04 , H2 S04 and HN03 (1:2.5:10). The con- tents of Ca and Mg were determined by AAS (Varian 1000) and the content of K by flame photometry (Corn- ing 400). The total content of N was determined by the Kjeldahl digestion and steam distillation method. The results are given on dry matter basis. In May 1982, the soils were fertilized with N (NH 4NO3 ). At each lime level, 500 mg/pot N was added to 12 pots, 12 pots being left untreated. All soils were fertilized with 200 mg P and 505 mg K (K 2HPG 4), 200 mg Mg (MgS0 4 • 7H 20), 5 mg B (H 3803),03 ), 15 mg Cu (CuSG4 • 5H20), 10 mg Mn (MnSO„ • 4H 2 G), 10 mg Zn (ZnSO 4 • 7H2 0) and smg Mo (Na2 MoQ4 • 2H2 0). Dur- ing the growing season fertilization was repeated after the second cut with the same amounts of N, P and K. The soil samples were suspended with 0.01 M CaCl2 for 4 h for determination of pH. Exchangeable cations, Ca, Mg and K, were extracted with 1 M neutral ammo- nium acetate (w/v = 1/20), adding four successive 50 ml aliquots of acetate to 10 g of soil in a centrifuge tube. The contents of Ca and Mg in the extract were determined by AAS and that of K by flame photometry. The exchange acidity (AI + H) was extracted with 1 M KCI and titrated with 0.01 M HCI (KAILA 1971). Table 1. Soil characteristics at oneset of the pot ex- periment. Particle size distribution Analysis ofvariance was carried out, considering lime level, N fertilization and interaction between Ca and N the sources of variation. Differences between individual treatments were compared with Duncan’s new multiple range test (STEEL and ToRRIE 1960). <2 % 2—20 pm, % 22.4 18.8 20—200 nm, Vo 57.2 >2OO ftm, % Org. C, % 1.6 3.0 pH(CaCl2 ) 4.8 Exchangeable (pH 7) Ca mg/kg Results 1128 Mg mg/kg K mg/kg 156 Soil analyses 222 Exchange acidity Al + H me/kg The pH(CaCl2) values of the soils treated in October 1981 with 0 (Cao), 12 (Ca,) and8.2 214 24 g/pot (Ca 2) of precipitated CaC03 were in April 1982 4.8, 6.5 and 6.9, respectively. Dur- ing the first growing season, considerable de- creases were observed in pH, the values being 4.4 and 5.6 at Ca„ and Ca, levels, respec- tively, but a slight decrease to 6.8 only was recorded at the Ca 2 level. By the end of the experiment pH(CaCl 2) still decreased by about 0.3 units at the Ca, and Ca2 levels (Table 2). Exchange acidity (A 1 + H) increased dur- ing the experiment in unlimed soils about three-fold when red or white clovers were grown with timothy (Table 2). The contents of 1 M KCI-extractable Al 3+ and H+ were in the original soil 2.8 and 5.4 me/kg and in the final unlimed soils 18.4and 6.4 me/kg, respec- tively. At the same time, the proportion of A1 of the exchange acidity increased from 34 % to 74 %. Alsike clover with timothy has a minor effect on exchange acidity, and still the increase found was concentrated in the Al- content. In limed soils the exchange acidity was mainly attributable to the H + -content. The amounts of applied K (total 2000 mg/ pot) were too small and therefore the content of exchangeable K was low in all pots at the end of the experiment (Table 2). The amounts of Mg added were adequate since the content of exchangeable Mg in red clover soils de- creased only slightly at the Cao level. At the Ca 2 level, some of the exchangeable Mg seemed to become non-exchangeable. The content of exchangeable Ca increased due to liming as expected, and so did the ratio Ca/Mg (me). Yields The total yield (7 cuts) of red clover- timothy was highest at the lime level Ca, with N fertilization (Table 3). Clover alone Table 2. Soil characteristics upon termination of the pot experiment. CSq Ca ] Ca, No Ni No N. No N, Red clover and timothy pH(CaCl2) 4.3“ 4.3“ 5.1» 5.2» 6.5“ 6.5“ Exchangeable Ca mg/kg 801“ 820“ 1635b 1683b 1695“ 1695“ Mg mg/kg 144b 142b 137b 127“ 130“ 121“ K mg/kg 69“ 65“ 75b 69“ 81“ 71 b Ca/Mg 3.4“ 3.5“ 7.3 b 8.1“ 12.6d 13.6“ Exchange acidity (AI +H) me/kg 26.5“ 25.4“ 5.8 b 5.7 b 2.3“ 2.5“ White clover and timothy pH(CaCl 2) 4.3“ 4.3“ 5.1 b 5.4b 6.6“ 6.7“ Exchangeable Ca mg/kg 799“ 823“ 1716» 1769» 2766“ 2836“ Mg mg/kg 154“» 161» 164» 166» 156“» 144“ K mg/kg 67“ 72“ 94“ 85» III d 89»“ Ca/Mg 3.2“ 3.1“ 6.4» 6.5» 10.8“ 12.1d Exchange acidity (Al +H) me/kg 28.3“ 26.1“ 4.0» 3.9» 2.0“ 1.8“ Alsike clover and timothy pH(CaCl 2) 4.5“ 4.5“ 5.6» 5.6» 6.7“ 6.6“ Exchangeable Ca mg/kg 938“ 923“ 1856» 1865» 2805“ 2805“ Mg mg/kg 175» 170» 172» 169» 148“ 141“ K mg/kg 79“ 78“ 106“ 88“ 98»“ 84“» Ca/Mg 3.3“ 3.3“ 6.6» 6.7» 11.5“ 12.1d Exchange acidity (Al +H) me/kg 18.5“ 18.9“ 3.0» 2.9» 1.6“ 2.0“ 215 Table 3. Dry-matter yields (g/pot) of clover and timothy in mixed stands. Cao Ca, Ca 2 N 0 N, N 0 N, N 0 N, Ist year (4 cuts) Clover 49.4" 33.9» Timothy 13.8» 31.6"" Total 63.2»" 65.5"" 2nd year (3 cuts) Clover 38.4» 35.0» Timothy 10.0» 17.7" Total 48.4» 52.7»" Ist +2nd year (7 cuts) Clover 87.8" 68.9» Timothy 23.8» 49.3' Total 111.6» 118.2» Ist year (4 cuts) Clover 52.0" 32.1" Timothy 17.3» 36.1" Total 69.3" 68.2" 2nd year (3 cuts) Clover 36.9" 31.8»" Timothy 7.0» 18.6»" Total 43.9"" 50.4" Ist + 2nd year (7 cuts) Clover 88.9" 63.9" Timothy 24.3» 54.7" Total 113.2"" 118.6" Ist year (4 cuts) Clover 32.7" 20.6»" Timothy 20.6» 40.9" Total 53.3» 61.5" 2nd year (3 cuts) Clover 31.4» 22.3» Timothy 4.6» 25.0" Total 36.0»" 47.3"" Ist+ 2nd year (7 cuts) Clover 64.1" 42.9»" Timothy 25.2» 65.9" Total 89.3» 108.8" Red clover and timothy 48.9» 43.8" 37.8» 34.4» 17.6" 29.6" 22.1" 35.0" 66.5"" 73.4" 59.9» 69.4"" 49.5" 38.9» 46.8" 39.7» 10.8» 30.7" 9.6» 29.1" 60.3" 69.6" 56.4"" 68.8" 98.4" 82.7" 84.6" 74.1» 28.4» 60.3" 31.7" 64.1" 126.8" 143.0" 116.3» 138.2" White clover and timothy 43.4"" 29.2»" 37.5"" 22.0» 20.3» 35.2" 21.3» 39.5" 63.7»" 64.4»" 58.8» 61.5»" 30.3»" 29.7»" 25.0»" 20.4» 8.9» 21.8»" 7.6» 29.7" 39.2»" 51.5" 32.6» 50.1" 73.7" 58.9" 62.5" 42.4» 29.2» 57.0" 28.9» 69.2" 102.9" 115.9" 91.4» 111.6"" Alsike clover and timothy 30.7" 14.9» 26.0"" 18.7» 22.5» 45.1" 26.7" 48.2" 53.2» 60.0" 52.7» 66.9" 26.4» 18.8» 27.7» 30.6» 6.6» 30.5" 10.5»" 21.9"" 33.0» 49.3" 38.2»" 52.5" 57.1"" 33.7» 53.7"" 49.3"" 29.1» 75.6" 37.2» 70.1" 86.2» 109.3" 90.9» 119.4" The results of one plant and one year provided with a common letter do not deviate significantly (P = 0.05). produced the highest yields at the Ca, level without N, and the beneficial effect of lime was most obvious in the 4th to 7th cuts (Ta- ble 4). In comparison to unlimed treatment, the lime level Ca2 decreased the growth of red clover at the beginning of the experiment (cuts 2 to 4) and increased it in the second year (cuts 5 to 7). Nitrogen fertilization depressed the growth of red clover in the first growing season most at the Ca„ level and seemed to cause a greater decrease than the Ca 2 treatment (Table 3). In the second year, the yield reduction due to N fertilization was significant in limed soils. Timothy benefited by N fertilization in the first year most without lime and in the second 216 year with lime. Liming without N increased the yield especially in the cuts 1 to 3. In later cuts there were no differences in yield. White clover-timothy produced the highest yield (7 cuts) without lime, and the yields were as high as those of red clover- timothy (Table 3). Liming decreased the yield of mixed stand mainly because of the re- stricted growth of white clover. Also N fer- tilization seemed to decrease the yield of clover. In the mixed stand of alsike clover- timothy, the total yield remained slightly lower than in the other mixed stands (Table 3). The effects of liming and N fertilization on alsike clover are similar to those on white clover. The yields of the first cuts consisted main- ly of timothy (results are not presented), and the proportion of clover variedbetween 3 and 19 %. The reseeded yield of the fifth cut con- tainedconsiderably more clover (11 to 60 %) than the first cut. In general, the proportion of clover in the mixed yield of other cuts in- creased to about 95 % with advancing growing season. Alsike clover was an excep- tion with decreasing proportions independent of lime level. M acr o n utri e nt contents of plants The N, P, Ca, Mg and K contents of the three clovers were similar, therefore the con- tents of red clover only are presented and dis- cussed. The Na content of white clover was exceptionally high (1 —6 mg/g) in comparison to red and alsike clovers (0.1—1 mg/g). Yet, independent of the Na content, the K content of all clovers were similar. In cuts 5 to 7, the N, P and K contents of red clover seemed to be somewhat higher with- out N fertilization and lime than with N and lime (Fig. 1). In the Ca and Mg contents the situation was opposite. When Ca was applied, the content of Ca increased, but there were no differences between the Ca, and Ca2 lev- els. The Mg content of red clover decreased with increasing liming. The contents of N and P were lowest in the first cut of both growing seasons increasing towards the end. The con- tents of Ca, Mg and K showed different trends. In the first year, the N, P and K fertiliza- tions were added before sowing and after the second cut, and this was reflected also in the respective contents of timothy (Fig. 2). In the second year, fertilizations were applied for each yield. The small yields obtained without N fertilization exhibitedhigher contents of N and P than with N. In that year the insuffi- cient supply of K caused only small changes in the K content of timothy. The Ca and Mg contents seemed to increase slightly from cut to cut. Fig. I. Macronutrient contents (mg/g dry matter) ofred clover (in mixed stad with timothy) at three lime levels without or with N fertilization. 217 M acr o n ut r i e nt uptake by plants The amounts of nutrients taken up by mixed stands of clovers and timothy decreased in the sequence red clover > white clover > alsike clover (Fig. 3). Chiefly, the differences in yields reflected the nutrient uptakes. The total uptake of Ca and Mg consisted mainly of the uptake by clovers independent of the N fertilization and lime levels. In the N-fertilized part of the experiment, the K uptake by timothy was nearly equal to that of red clover and exceeded the uptake by white clover and alsike clover. The N uptake by clovers was higher without than with N fertilization at all lime levels. The N uptake by white clover and alsike clover decreased with increasing liming. The uptake of N by red clover was lowest at the Ca„ and highest at the Ca, level. In the Ist cut all clovers took up N most at the Ca2 level, which may indicate uptake of soil N, mineralized due to liming (Table 4). In the later cuts, the N uptake followed almost always the size of yields. The N uptake by red clover in the 7th cut was highest at the Ca2 level, which may imply that the negative ef- fect of that lime level turned gradually posi- tive. Most of all, liming affected the Ca uptake by red clover and alsike clover. An increase was observed in the uptake by red clover between the Caj and Ca, levels, whereas a re- duction was observed between the Ca, and Ca2 levels. In alsike clover the Ca uptake in- creased with increasing liming. The Ca uptake Fig. 2. Macronutrient contents (mg/g dry matter) of timothy (in mixed stand with red clover) at three lime levels without or with N fertilization. Fig. 3. Macronutrient uptake (mg/pot) of three clovers and timothy in mixed stands at three lime levels without or with N fertilization. 218 Table 4. Dry-matter yields (g/pot) and N uptake (mg/pot) of red clover in seven cuts without N fertilization at three lime levels. Cut Ca0 Ca, Ca2 number Yield g/pot 1 2.1 b 2.0b I.l* 2 18.8» 17.8» 11.5a 3 14.9» 25.0» 12.8“ 4 13.5“ 14.2“ 12.4“ 5 7.5“ 10.1» 8.2“» 6 14.0“ 17.9» 16.6» 7 16.8“ 21.5» 22.0» N uptake mg/pot 1 58» 52» 29“ 2 660» 625» 435“ 3 580» 616» 496“ 4 500“ 506“ 464“ 5 226“ 332» 276“ 6 511“ 594» 555“» 7 634“ 800“» 850» The results of individual cut provided with a common letter do not deviate significantly (P =0.05). by white clover was nearly independent of the lime levels. The Mg uptake of all clovers decreased with increasing lime levels, and in this respect white clover was most sensitive. Liming did not af- fect uptake of P by red clover and alsike clover; P uptake by whiteclover seemed to de- crease. Discussion The effects of lime levels (Cao = 0 g, Ca, = 12 g, Ca2 = 24 g CaC03 ) and ammo- nium nitrate rates (N 0 = 0 mg, N, = 2000 mg N per 4.3 kg air-dry soil) on red clover, white clover and alsike clover in mixed stands with timothy were studied in a pot experiment during two growing seasons. All clovers produced high total yields (7 cuts) without lime in spite of the low pH(CaCl2) and high A 1 content of the soil. Before the experiment, the content of ex- change acidity in the soil was 8.2 me/kg; A1 accounting for about 34 %. At the end of the experiment, the exchange acidity increased to 24.8 me/kg, A 1 accounting for 74 % the ex- change acidity and about 24 % of the effec- tive CEC. According to Kamprath(l97o) the Al concentration for optimum growth of soy- bean should not exceed 20 % of the CEC. Liming of the acid soil decreased the growth of red clover in the first four cuts, and there- after the yields increased. Munns and Fox (1976) reached similar results with some leg- umes in a pot experiment when oxisol was limed to pH 6. A decrease in clover yields with high lime levels was observed also by Ssali (1981) in a soil with organic matter content exceeding 3 %. The possible reason for the decreased growth may be e.g. the high Ca con- centration in the soil (Munns and Fox 1976), the inbalance in Ca/Mg (Jokinen 1981 a), the incapacity to take up non-exchangeable ca- tions (unlike ryegrass) and decrease in nodule number, nodule weight and N fixation (Edwards et al. 1981, Ssali 1981). Edwards et al. (1981) obtained the highest yield increases of cowpea with 2.5 t/ha lime at pH 4.3; higher lime amounts decreased the yield. According to RiCEet al. (1977), red clover was not sensi- tive to soil acidity in the pH(H 20) range 4.9—7.2. As concluded on the basis of the yield and N uptake without N fertilization, white clover and alsike clover were not sensitive to soil acidity and high A 1 content, since the yields were the highest without lime. For red clover, a suitable pH(CaCl2) range seemed to be 5—6, as determined on the basis of yield and N uptake. In the second growing season with N addi- tion and K shortage, timothy seemed to be stronger than clover in the competition on K, and therefore the K content of clover re- mained lower than without N. The earlier re- sults of field studies also imply the existence of competition on K between clover and timothy (Raininko 1968, Jokinen 1969). The pH(Ca€l2 ) values near 6.5 at the lime level Ca2 seemed to be too high for the clo- ver, as concluded on the basis of the decreased yield and N uptake in the first growing sea- son. The negative effects of direct liming on 219 clovers may be avoided by liming the field be- even the N content. When P, K and Mg are fore the establishmentof the clover mixed ley. The target pH and amount of lime may vary depending whether high yields or great N up- takes are wanted. The macronutrientcontent of clover seemed to be almost unaffected by N fertilization, References Aura, E. & Kemppainen, R. 1983. Kalkituksen jakarjan- lannan vaikutus puna-apilan typensidontaan:Summary: Effects of liming and manuring on the nitrogen fixa- tion of red clover. SITRA/Biologisen typensidonnan ja ravinnetypen hyväksikäytön projekti. Julkaisu 5; 33—44. Craig, L.A., Wiebold.W.J. & Mclntosh, M.S. 1981. Nitrogen fixation rates ofalfalfa and red clover grown in mixture with grasses. Agron. J. 73: 996—998. Edwards.D.G., Kang, B.T. & Danso, S.K.A. 1981 Dif- ferential response of six cowpea (Vignaunquiculata (L.) Walp.) cultivars to liming in an ultisol. Plant and Soil 59: 61—73. Jokinen, R. 1969. The influence of clover content of mixed ley on magnesium and potassium in red clover and timothy. J. Scient. Agric. Soc. Finl. 41: 3—ll. 1981. Effect of liming on magnesium status of some mineral soils and on the fate of fertilizer magnesium. J. Scient. Agric. Soc. Finl. 53: 126—137. Kaila, A. 1971. Aluminium and acidity in Finnish soils. J. Scient. Agric. Soc. Finl. 43: 11—19. Kamprath, E.J. 1970. Exchangeable aluminum as a cri- terion for liming leached mineral soils. Soil Sci. Soc. Amer. Proc. 34: 252—254. Munns, D.N. 1965. Soil acidity and growth of a legume I. Interaction of lime with nitrogen and phosphate on growth of Medicago sotiva L. and Trifolium subter- given in adequate amounts the quality (the macronutrient content) of clover will not be dependent on N fertilization. In the case of timothy, nitrogen fertilization increased the nutrient contents. raneum L. Aust. J. Agric. Res. 16: 733—741. & Fox, R.L. 1976. Depression of legume growth by liming. Plant and Soil 45: 701—705. —, Fox, R.L. & Koch, B.L. 1977. Influence of lime on nitrogen fixation by tropical and temperate legumes. Plant and Soil 46; 591 —601. Pulu, S. & Turtola, A. 1983. Puna-apilan menestymi- nen ja viljelytekniikka suomalaisilla maatiloilla. Sum- mary: Management and persistence of red clover on Finnish farms. SITRA Nitrogen Project. Biologisen ty- pensidonnan jaravinnetypen hyväksikäytön projekti. Julkaisu 3; I—l6o,1 —160, 7 app. Raininko, K. 1968. The effects of nitrogen fertilization, irrigation and number of harvestings upon leys estab- lished with various seed mixtures. Acta Agr. Fenn. 112: 1 137. Rice, W.A., Penney, D.C. & Nyborg, M. 1977. Effects of soil acidity on rhizobia number, nodulation and ni- trogen fixation by alfalfa and red clover. Can. J. Soil Sci. 57; 197—203. Ssali, H. 1981. The effect of level of CaC03 , inocula- tion and lime pelleting on the nodulation and growth of beans in five acid soils. Plant and Soil 62: 53—63. Steel, R.G.D. & Torrie, J.H. 1960. Principles and pro- cedures of statistics. 481 p. New York. Ms received September 9, 1985 SELOSTUS Kalkituksen ja typpilannoituksen vaikutus apiloiden ja timotein sekakasvustojen satoon ja ravinnepitoisuuksiin Raili Jokinen Helsingin yliopisto Astiakokeessa (maata 4.3 kg/ast, pH(CaCl2 ) 4.8) tut- kittiin kolmen kalkkimäärän (Ca = 0 g, Ca, = 12 g, Nykyinen osoite: Maatalouden tutkimuskeskus, maanvil- jelyskemian ja -fysiikan osasto, 31600 JOKIOINEN Ca 2 = 24 g/ast CaC03) ja typpilannoituksen (N 0 = 0 mg, N, = 2000 mg/ast N, NH4NG3:na) vaikutuksia ti- motein kanssa sekakasvustona viljeltyjen puna-, Valko- ja alsikeapilan satoon (yhteensä 7 niittoa) sekä pääravin- teiden pitoisuuksiin ja ottoon. 220 Maat kalkittiin syksyllä 1981 ja pH(CaCl2)-arvot mi- tattiin huhtikuussa 1982 ennen lannoitusta jakylvöä se- ka syyskuussa 1983 sadonkorjuun jälkeen.Tulokset oli- vat seuraavat; pH(CaCl2) Kalkitus 1982 1983 Ca„ 4.84.3 Ca,(n. 5 t/ha) 6.55.1 Ca 2(n. 10 t/ha) 6.96.5 Ilman typpilannoitusta puna-apilan ja timotein seka- kasvusto tuotti parhaan sadon pienellä kalkkimäärällä ja valkoapilan sekakasvusto ilman kalkitusta, mutta alsike- apilan sekakasvuston satoonkalkkimäärillä ei ollut mer- kitsevää vaikutusta. Kalkitus lisäsi timotein satoa vain kahtena ensimmäisenä korjuukertana. Typpilannoitus vähensi apiloiden satoa ensimmäisenä vuonna kalkkimäärästä riippumatta. Toisena vuonna puna-apilan sato väheni vain kalkituissa astioissa. Typ- pilannoituksella ei ollut vaikutusta muiden apiloiden sa- toon. Timotein sato lisääntyi typpilannoituksella jokai- sena korjuukertana jakaikilla kalkkimäärillä. Apiloiden ja timotein sekakasvuston satoon typpilannoituksella oli selvin japositiivinen vaikutus suuren kalkkimäärän saa- neissa astioissa. Runsaimmat sadot saatiin typellä lannoi- tetuista kasvustoista silloin, kun puna-apilan sekakasvusto sai pienen kalkkimäärän, valkoapilan kasvusto jäi ilman kalkkia ja alsikeapilan kasvusto sai suuren kalkkimää- rän. Sekakasvustojen ottaman typen määrä ei lisääntynyt typpilannoituksella, mutta timotein osuus typen otosta lisääntyi. Eniten typpeä otti puna-apilan sekakasvusto pie- nen kalkkimäärän tasolla ja muut apilat ilman kalkitus- ta. Suurella kalkkimäärällä saatiin pienempi puna-apilan kuiva-ainesato mutta suurempi typpisatokuin ilman kal- kitusta. Apiloiden kalsiumpitoisuus kohosi hieman, mutta magnesium- ja kaliumpitoisuus pieneni kalkin määrää li- sättäessä. Typpilannoitus ei muuttanutapiloiden typpi-, fosfori-, kalsium- ja magnesiumpitoisuutta. Kaliumlan- noituksen niukkuus toisena vuonna vaikeutti apilan ka- liumin saantia. Jos apiloille annetaanriittävästi muita ra- vinteita kuin typpeä, sadon ravinnepitoisuudet pysyvät korkeina. Timotein typpi-, fosfori- ja kaliumpitoisuus muuttui lannoituksen mukaan. Kalkituksen positiivinen vaikutus timotein kalsiumpitoisuuteen oli vähäinen. Puna-apilaa sisältäville kasvustoille tulisi ehkä käyttää kalkitusaineeksi dolomiittikalkkia jo maan ravinnesuh- teen Ca/Mg (me) optimialueen s—B alarajalla, sillä api- lan magnesiumin otto näytti vähenevän kalkitsematto- maan verrattuna pienelläkin kalkkimäärällä ja Ca/Mg arvoilla 7 —B. Apilat eivät ottaneet vaihtumatonta mag- nesiumia. 221