Micronutrient concentration of Italian ryegrass (Lolium multiflorum L.) grown on different soils in a pot experiment Raimo Erviö and Jouko Sippola Erviö, R. & Sippola, J. 1993. Micronutrient concentration of Italian ryegrass (Lolium multiflorum L.) grown on different soils in a pot experiment. Agric. Sci. Finl. 2: 141-148. (Agric. Res. Centre, Inst, of Soils and Environment, FIN-31600 Jokioinen,Finland.) The uptake of micronutrients, B, Co, Cu, Mn, Mo and Zn, was studied in a pot experiment. The micronutrient concentrations of Italian ryegrass (Lolium multiflorum L.) ranged as follows: B 4.9-11.1, Co 0.01-2.30, Cu 2-15, Mn 29-225, Mo 0.01 -1.79 and Zn 23-75 mg kg' 1 DM. The micronutrient concentration of plant was compared with the AAAc+EDTA-extractable concentration in soil by soil type. The copper and zinc concentrations of ryegrass correlated stongly with the respective concentrations of all four soil type groups. The respective correlations of boron and manganese were good except in the silt soil group. Cobalt correlated best in coarse mineral and clay soils and molybdenum in clay and organic soils. Boron, cobalt, manganese and zinc concentra- tions ofryegrass were the higher the lower the soil pH was. In the whole material the following correlations were found between the micronutri- ent concentrations of ryegrass and soil: boron o.sB***, cobalt o.6B***, copper o.7o***, manganese 0.19 , molybdenum 0.69 and zinc 0.90 . The results indicate that interpretation of micronutrient soil test data may be more accurate when soil type is considered. Key words: Finnish soil types, AAAc+EDTA extraction, boron, cobalt, copper, man- ganese, molybdenum, zinc, micronutrient concentration Introduction Cultivated soils in Finland differ greatly of each other with regard to their genesis, texture and or- ganic matter content. One fifth of Finnish cultivated soils are organic, and the coarsest mineral soils like sands and glacial tills remarkably differ from clay soils in nutrient cocentration and nutrient fixation. In routine soil testing and fertilizer recommenda- tions concerning macronutrients, soils are classi- fied into four main types based on the above prop- erties. In micronutrient soil testing, at present, all soils are classified according to the same critical values. It is possible, however, that classification of soils might give a more accurate interpretation. Therefore more research on the micronutrient availability from Finnish soils is needed. Italian ryegrass is a suitable crop for pot experi- ments and therefore a frequently used test crop. Its micronutrient requirement is, however, low like that of all grasses compared to dicotyledons. This may make ryegrass a less suitable crop in testing soils for micronutrient deficiencies in pot experi- ments. The objective of this investigation was to study the growth ofryegrass on soils oflow micronutrient 141 Agric. Sei. Finl. 2 (1993) https://www.c-info.fi/en/info/?token=J-1EJGFyzYG64Z0b.cPV6SfX82OwX_KPwASrKeg.w79eR8BTdz_cnxQPx0MPLcfsGTUre0QpwEOQiTaNeYQ1pmch2jsMHbZHHxQLZaqg8nykyj1Kv96pmGi7vf66usrKtuOM5QcZ1FqzWiSDzt9klGWv7fwXPUUABjhSZIJYqjsnU_S4MOhTVSWRzkTlAU7LKvgXk0MJVquuqZ56EQ-o20RNvfDdGhY3zdpZ3XMNOEUcnxMjewCD1_TIOeyy_jIOU6HxnIG4MHikyslqAuhFgFppTfBh86Yj2oZbfsftFUkoOsiw9VWgJM-qjr9wSWeZsJRJaPpRaw Table 1. Mean soil characteristics (Ranges in parantheses). Soil type group No of pH(H zO) Org. C Particle size distribution CEC‘> AAAc-extractable elements mg H soil samples % clay silt coarse me 100g-' Ca K Mg P <0.002 0.002-0.02 >0,02 soil mm mm mm 77 15.0 900 75 80 7.6 (37-100) (8-29) Finesand and till 28 5.70 3.66 6 17 (5.0-6.5) (1.8-5.4) (0-28) (0-39) 31 15.7 1043 101 129 7.8 (10-45) (11-24) Silt 11 6.05 2.59 20 49 (5.6-6.5) (1.6-4.3) (10-29) (43-60) 21 24.0 1453 208 374 6.3 • (12-51) (16-36) Clay 16 5.73 3.15 47 32 (5.2-6.2) (1.6-4.3) (32-66) (16-47) Organic soils 19 5.10 30.4 74.0 2006 73 228 12.6 (39-112)(4.3-6.1) (13-49) 11 = potential cation exchange capacity Table 2. Mean extractable micronutrient concentrations of different soil types. (Ranges in parantheses.) Soil type group No of . AAAc+EDTA extractable elements mg H soil samples ~ ~ ~ ~ ~ Co Cu Mn Mo Zn Fine sand and till 28 0.480.52 1.6 71 0.046.7 (0.25-1.19) (0.12-1.35) (0.5-5.6) (8-220) (0.01-.17) (0.6-26.4) Silt 11 0.361.35 2.1 131 0.042.5 (0.16-.60) (0.60-1.95) (1.0-5.6) (28-322) (0.00-.12) (1.0-6.3) Clay 16 0.522.66 7.0 72 0.358.2 (0.20-.74) (0.40-7.0) (1.3-18.7) (9-180) (0.00-1.5) (1.1-27.0) Organic soils 19 0.760.77 3.8 45 0.106.9 (0.30-1.20) (0.15-1.35) (0.4-9.6) (2-124) (0.04-.57) (2.0-25.5) status, to quantify the uptake of micronutrients and to study the effect of soil types and some factors such as pH, organic carbon and extractable calcium concentration on the uptake. Material and methods Soil samples were collected from the plough layer of cultivated fields from 74 sites for a pot experi- ment. The samples represented typical arable Finn- ish soil types according to their micronutrient con- centration (Tables 1 and 2). The relatively low pH and macronutrient concentrations of the soils were corrected before homogenizetion of soils by addi- tional fertilization (Ca, Mg, K, P) to avoid defi- ciency in this respect. The soil concentrations in Table 1 were measured after addition of the nutri- ents. The experimental soils were homogenized and passed through a 2-mm sieve. Polyethylene Kick- Braukmann type pots and 7.5 I of soil were used. The test were made in triplicate. Soils were fertil- ized before sowing with 0.2 g nitrogen as NH4NO3, 0.5 g potassium as K2SO4 and 0.1 g phosphorus as Ca(H2PO4)2 H2O per 1 1 soil. Italian ryegrass (Lolium multiflorum, cvs. Avance) was sown on 17 May, 1982 and grown outdoors. After emergence, each pot was thinned to 60 seedlings. Watering to 70% offield capacity was done twice a week. Pots were harvested just before the emergence of the ear. The first harvest was cut at 42 days and the second harvest 17 days later. Macro- and microelement concentrations of rye- 142 Agric. Sd. Finl. 2(1993) Table 3. Mean micronutrient concentrations of ryegrass grown on different soil types at first harvest. (Ranges in paran- theses.) Soil type group No. of mg kg ' DM samples T ~ ~ ~~ ~~ B Co Cu Mn Mo Zn Fine sand and till 28 7.90.11 6.0 84 0.10 41 (5.8-11.1) (0.01-.53) (3-12) (49-157) (0.02-.52) (23-74) Silt 11 7.50.16 8.2 98 0.10 36 (5.4-9.3) (0.01-.51) (5-11) (29-225) (0.03-.27) (26-43) Clay 16 7.50.47 10.2 79 0.27 42 (4.9-8.7) (0.01-2.30) (6-15) (46-122) (0.02-.87) (27-75) Organic soils 19 8.50.16 6.7 80 0.27 39 (6.0-11.0) (0.03-.41) (2-10) (37-116) (0.01-1.79) (29-48) grass were determined after dry ashing by atomic absorption, except for boron which was analysed using azomethine-H reagent. For soil analysis, rep- resentative samples of each soil were air dried and passed through a 2-mm sieve. The pH was meas- ured from a soil water suspension (1:2.5). Organic carbon content was determinedby the dry-combus- tion method with a LECO CR-12 instrument. Co- balt, copper, manganese, molybdenum and zinc were extracted from soils using a 0.02 M EDTA + 0,5 N ammoniumacetate and 0.5 N acetic acid solu- tion (Lakanen and Erviö 1971), and calcium and other macroelements using AAAc solution (VUORI- NEN and Mäkitie 1955). The extraction ratio was 1:10 v/v and extractiontime I h. Micronutrient cen- trations were determined by atomic absorption spec- trophotometry using an air acetylene flame except for cobalt and molybdenum which were analysed in a graphite furnace. Boron was determined by the azomethine-H method after hot water extraction. Results and discussion The trace element concentrationofa plant growing poorly does not always indicate the concentration of micronutrient available in soil; total uptake would be a better index. However, in cases where micronutrient concentration does not affect the yield the concentration may be an equally good indicator. Italian ryegrass grew in all experimental soils well withoutany symptoms ofdeficiency. The yields ranged within narrow limits from 4.52 to 4.76 g/pot except the one soil (sandy till) which yielded only 2.77 g/pot. Therefore total uptake was not calculated; the evaluation of results was based on nutrient concentrations. The mean macronutrient concentrations and ranges in ryegrass dry matter were as follows: cal- cium 0.39% (0.27-0.51), potassium 6.0% (4.35- 7.44), magnesium 0.20% (0.10-0.29) and phospho- rus 0.45% (0.18-0.87). These values were within normal ranges, except for potassium which was rather high. So a deficiency in macronutrients was not expected to affect the micronutrientabsorption. The potassium concentrations of ryegrass dif- fered least between the soil type groups apparently due to the ample dose given as fertilizer. Ryegrass grown on coarse mineral soils contained less than average magnesium and phosphorus. On clay soils ryegrass contained more than average magnesium and on organic soils less calcium but more phos- phorus than the material on average. Ca, Mg and P concentrations of ryegrass very significantly correlated with their AAAc-extrac- table concentrations in soil (Ca: R= 0.25 , Mg: R=0.77 and P: R= 0.75 ). Exept the group of silt soils, significant correlations were observed also in the case of potassium. Micronutrient concentrations of ryegrass In general, the differences were relatively small in the micronutrientconcentrations of ryegrass grown on different soil types (Table 3). The group of clay 143 Agric. Sei. Fint. 2 (1993) Table 4. Correlation coefficients between micronutrient concentrations in the ryegrass of first (I) and second (II) harvest and water-extractable B and AAAc+EDTA -extractable Co, Cu, Mn, Mo, and Zn in soil. Soil type group Harvest No. of Micronutrient samples I ~ ~ B Co Cu Mn Mo Zn Fine sand and till I 28 o.6s**' 0.64*" 0.57*" 0.34** - 0.94*" II o.s6**' 0.61*" 0.57*" 0.33" - 0.84*" Silt I 11 - - 0.65*" - - 0.70*" II 0.51** - 0.70*" - 0.63'" 0.51** Clay I 16 0.56" 0.63*" 0.83*" o.sl*** o.9o*** 0.97*" II 0.48" 0.70*" 0.88*" o.s2*'* o.94*** 0.96*" Organic soils I 19 0.53*" - o.79*** 0.60*" 0.77*" 0.72*" II 0.46*" - 0.82*" 0.61*" o.Bs*** o.s9*** All soils I 74 0.58*" 0.68*" 0.70*" 0.19** 0.69*" 0.90*" II 0.57*" 0.71*" 0.80"* 0.17" 0.81*" 0.81*" t-test: *" P = < 0.001, " = P < 0.01 soils included four expe-rimental soils which had earlier been fertilized with micronutrients. Accord- ingly, fertilized soils raised the mean and maximum soil concentration, especially those of cobalt and molybdenum (Table 2). Even if the fertilized soils were excluded the mean cobalt value (0.26 mg I' 1) of ryegrass would be higher than those of other soils, while the mean molybdenum concentration (0.09 mg T 1) would be within the same range with other unfertilized mineral soils. Correlation of plant nutrient concentrations with that in soil and with some soil properties Boron The boron concentration of ryegrass correlated very well with the hot water-extractable soil boron in the groups of coarse mineral soils, clays and organic soils (Table 4). This correlation did not exist in the group of silt soils in the first harvest, which may be due to the limited number of experi- mental soils. The boron concentration of ryegrass was found to correlate positively with soil organic carbon in the whole material (Table 5) as has been observed previously in grasses (Tolgyesi and Kozma 1974). This is understandable because the concen- trationof water soluble-boron in soil increases with increasing organic matter (Gupta 1978). In the whole material the boron concentrationof ryegrass correlated slightly negatively with soil pH. TOL- GYESI and Kozma (1974) found the same with grasses. Sillanpää(1982) showed that soil pH had a relatively small effect on boron in plant at a slightly acid pH level, which was confirmed alsoby the present results. Cobalt The cobalt concentration ofryegrass grown on fine sand and clay soils very significantly correlated with soil-extractable cobalt, but no correlation was observed in the groups ofsilt and organic soils. The soil pH reflected in the ryegrass cobalt concentra- tion; with increasing pH the cobalt concentration of first harvest decreased only in the groups of silt and organic soils. In the second harvest this negative correlation was observed the whole material and all soil type groups. A similar negative correlation be- tween the cobalt concentration of ryegrass and soil pH has been observed earlier in some studies (Cop- PENET et al. 1972, Paterson et al. 1989). In- versely, Mokragnatz and Filipovic (1961) and McLaren et al. (1987), showed an increase in the cobalt concentration of leygrass with increasing soil pH. 144 Agric. Sd. Fint. 2(1993) Table 5. Correlation coefficients between soil pH(H 2G), extractable Ca, organic carbon content and micronutrient con- centration in ryegrass. No pH Extractable calcium Organic carbon content Ist harvest 2nd harvest Ist harvest 2nd harvest Ist harvest 2nd harvest Boron 1 Finesand, till 28 0.22* .19' 0.26** 2 Silt 11 - - - - -0.31* 3 Clay 16 -.39** 4 Organic soil 19 - 5 All soils 74 -0.14* -o.lB** 0.17** o.2s*'* 0.23*" Cobalt 1 Finesand, till -0.25* -0.26** -0.21* 2 Silt -o.s9*** -o.67*** -0.47** -o.ss**' -0.39* 3 Clay - -0.29* o.s4*** o.so*** o.62*** o.62*'* 4 Organic soil -0.32" -0.58*" - -0.48*" 5 All soils -0.16" 0.18" 0.13* Copper 1 Finesand, till ...... 2 Silt -0.37* -0.38* - - 0.36* 0.42** 3 Clay - -0.30* - 0.25* - 0.25* 4 Organic soil - 0.27* 0.40*" o.44*'* 5 All soils o.22*** 0.14* -0.19** -o.2s*** Manganese 1 Finesand, till -0.53*" -0.72*" -o.37*** -0.43*" -0.24* 2 Silt -0.69*" -0.76*" -o.64*** -0.66*" -0.34* 3 Clay -0.25* -o.42*** - - 0.29* -0.33** 4 Organic soil .... -0.32** -0.34** 5 All soils -0.14* -o.2B*** -0.19** -0.19** -0.12* Molybdenum 1 Finesand, till _..... 2 Silt 0.59*" - 0.48" 3 Clay - - 0.39" 0.46"* 0.27* o.42*'* 4 Organic soil 0.33** -0.29* o.63*** 0.71*" 5 All soils - o.so*** 0.53*" 0.12* 0.12* Zinc 1 Finesand, till -0.26** - - 0.21* 0.23* 2 Silt -0.41* -o.62*** - -0.44" 0.48*' 0.35* 3 Clay - -0.30* 0.32* - - 0.23* 4 Organic soil - - 0.44*" 5 All soils - -0.14* 0.14* - - -0.14* t-test: *** = P < 0.001, ** = P < 0.01, * = P < 0.05 Copper The copper concentration of ryegrass correlated very significantly with extractable copper in all soil type groups. The correlation was closest in the groups of clay (r=o.BB ) and organic (r=0.82 ) soils of the second harvest. KIEKENS and COTTENIE (1983) found also a relatively good correlation be- tween ryegrass and soil AAAc-EDTAextractable copper (r=0.40 ). The copper has generally been shown to be fixed into a nonsoluble form by soil organic matter (e.g. Broadbent and Ott 1957). In the whole material a significant negative correla- tion was found between copper concentration of 145 Agric. Sei. Finl. 2 (1993) ryegrass and soil organic carbon. A similar depend- ence of Cu concentrationbetween wheat straw and soil has been reported also by Sillanpää(1982) in a material including Finnish soils and by Luit and Henkens (1967) with ryegrass. With increasing extractable calcium also the copper concentration of ryegrass increased in the whole materialand especially in organic soils.With soil pH no dependence was found in the whole material. Brown and Jurinak (1964) could not increase the copper concentration of com by addi- tion of Ca. Beyme (1971) obtained a negative cor- relation between copper concentration of oats and soil pH, but Luit and Henkens (1967) did not report this kind of correlation in peat soil. Manganese The manganese concentration of ryegrass correl- ated with soil extractable concentrations in all soil groups exept for silt soils. The exceptional result for silt soils may be due to the higher pH range in this group which limits the availability of manganese. Using the same extraction solution Kiekens and COTTENIE (1983) obtained in a pot experiment with a material of 52 soils collected from several coun- * tries a negative correlation (r= -0.34 ). They re- ported that the most important parameter affecting the uptake of manganeseby perennial ryegrass was soil pH. In the present material a negative correla- tion was found with manganese concentration of ryegrass and the extractable Ca concentration of soil in the whole material as well as in finesand and sill soil groups. In the whole material a negative correlation was obtained between manganese concentration ofrye- grass and soil pH. This relation was most evident in the groups of finesand and silt soils, and no correla- tion existed in the group of organic soils. This relationship for grasses has long been known (Piper 1931, Steenbjerg 1933, Olsen 1934). Also Sillanpää(1982) obtained in a large interna- tional soil material a clear negative correlation be- tween manganese concentration of wheat and soil pH. He considered the effect on manganese so im- portant that he suggested a correction factor based on soil pH for the manganese soil test value. Molybdenum The molybdenum concentration of ryegrass correl- ated highly significantly with soil concentrations in the groups of clay and organic soils, but no correla- tion was observed in groups of finesand and silt soils in the first harvest. The molybdenum concentration of ryegrass was high when also the soil extractable calcium concen- tration was high (r=0.50 )in the whole material. The correlation was especially close in the group of organic soils (r=0.63 ). This dependence has been observed in many studies (Plant 1950, Gupta 1969, Jaakkola 1972). In the whole materialryegrass molybdenum con- centration did not correlate with soil pH although in many studies a positive dependence has been ob- served (Barshad 1951, Karlsson 1961). In the groups of silt and organic soils of the present study this positive dependence was observed in the first harvest. Zinc The zinc concentrationofryegrass correlated better than any other micronutrient with soil-extractable zinc in this study. The closest correlation occured in the group of clay soils (r=0.97 ) followed by finesand soils (r=0.94 ). A rather close correla- tion was observed also by Kiekens and COTTENIE (1983) between ryegrass zinc and AAAc-EDTA- extractable soil zinc. The increase of extractable calcium in soil also led to an increase of ryegrass zinc in the first har- vest. This correlation was closest in the group of . . ’N** , ,organic soils (r=0.44 ). The result disagrees with some earlier results where liming decreased the zinc concentration of cereal grains (Wear 1956). The zinc concentrationof ryegrass did not correlate with soil pH in the whole material, but a negative correlation was found in the group ofsilt soils. Also Sillanpää (1982) reported a negative correlation between Zn concentration of wheat straw and soil pH. The results show that there were differences be- tween soil types in the availability of micronutri- ents to ryegrass. The uptake of cobalt from organic 146 Agric. Sd. Fint. 2 (1993) soils, for example, was similar to silt soils despite a despite low soil concentration. Therefore it is obvi- twice as high extractable cocentration in silt soils. ous that the interpretation of micronutrient soil test Also the uptake of copper from finesand and silt results is more accurate when soil type is consid- was almost equal to the uptake from other soils ered. References Barshad, I. 1951.Factors affecting the molybdenum content of pasture plants: I. Nature of soils molybdenum, crowth of plants and soil pH. Soil Sci. 71: 297-313. Beyme, G, 1971. Beziehungen zwischen Zink- und Kupfer- gehalt in Haferpflanzen und Boden. Z. Pfl.emähr. Boden- kunde 130; 256-270. Broadbent, F. E. & Ott, J. B. 1957. Soil organic matter- metal complexes: 1. Factors affecting retention of various cations. Soil Sci. 83: 419-427. Brown, A. L. & Jurinak, J. J. 1964. Effect of liming on the availabilities on zinc and copper. Soil Sci. 98: 170-173. Coppenet, M, More, E., Le Corre, L. & Le Mao, M. 1972. Variations de la leneur en cobalt des ray-grass de tech- niques d’enrichissement. Ann. Agron. 23: 165-196. Gupta, C. 1969. Effect and interaction of molybdenum and limestone on growth and molybdenum content of cauli- flower, alfalta and bromegrass on acid soils. Soil Sci. Soc. Proc. 33: 929-932. 1978. Effect of soil properties on the extractable boron contents. Schweiz. Landw. Forsch. 17: 45-50. Jaakkola, A. 1972. Availability to plants of molybdenum in Finnish mineral soils. Acta Agr. Fenn. 120: 1-92. Karlsson, N. 1961. Om molybden i svensk vegetation och mark samt några därmed sammanhängande frågor. Sum- mary: On molybdenum in Swedish soil and vegetation and some related questions. Statens Lantbrukskem. kon- trollanst. Medd. 23: 1-243. Kiekens, L. & Cottenie, A. 1983. Estimation of trace ele- ment status by chemical soil and plant analyses. Rep. 1983 consult. Eur. Cooper. Network Trace Elements. Aarhus. Lakanen, E. & Erviö, R. 1971. A comparison of eight ex- tractants for the determination of plant available micro- nutrients in soils. Acta Agr. Fenn. 123: 223-232. Luit, B. van & Henkens, C. H. 1967.The effect of the copper status of the soil on the copper content of grass and clover. Vevsl. Landbouwk. Ouderz. 695. 33 p. McLaren, R. G., Lawson, D. M. & Swift, R. S. 1987. The availability to pasture plants native and applied soil co- balt and other soil properties. J. Sci. Food Agric. 39: 101-112. Mokraqnatz, M. & Filipovic, Z. 1961. Further evidence of the influence of soil pH on cobalt contents of grasses. Soil Sci. 92: 127-128. Olsen, C. 1934. Über die Manganaufnahme der Pflanzen. Biockem. Z. 269: 329-348. Park, C. S. & Park, N. J. 1966. The available boron content in soils of the upland crop area of Korea. Agric. For., Korea 9: 163-174. Paterson, J. E., Klessa, D. A. & MacPuERSON, A. 1989. Factors influencing the availability of soil cobalt and its uptake by herbage. 16. hit. Grassland Congr. Nice, France Proc. p. 19-20. Piper, C. S. 1931. The availability of manganese in the soil. J. Agr. Sci. 21: 762-779. Plant, W. 1950. The relation of molybdenum deficiency to the acid soil complex. Transact. 4th Int. Congr. Soil Sci. 2: 148-151. Sillanpää, M. 1982.Micronutrients and the nutrient status of soils: a global study. FAO Soils Bull. 48. 444 p. Steenbjerg, F. 1933. Undersogelser over manganinholdetin dansk jord. I. Det ombyttelige mangan. Tidskr. Planteavl. 39: 401-436. Tölgyesi, G. & Kozma, A. 1974. A päzsitfiivek börfelvételét befolyäsolö tényezok. Summary: Investigation on factors affecting boron uptake by grasses. Agrokem. Talajtan 23: 83-98. Vuorinen, J. & Mäkitie, O. 1955. The method of soil testing in use in Finland. Agrogeol. Pubi. 63; 1-44. Wear, J. J. 1956. Effect of soil pH and calcium on uptake of zinc by plants. Soil Sci. 81: 311-315. Manuscript received January 1993 Raimo Erviö Jouko Sippola Agricultural Research Centre of Finland Institute of Soils and Environment FIN-31600 Jokioinen, Finland 147 Agric. Sei. Fin!. 2 (1993) 1 SELOSTUS Italianraiheinän hivenravinteiden otto vaihtelevan määrän näitä ravinteita sisältävistä erilaisista maalajeista Raimo Erviö ja Jouko Sippola Maatalouden tutkimuskeskus Ulkona tehdyssä astiakokeessa Jokioisilla tutkittiin Italianrai- heinän (Lolium multiflorum L.) hivenravinteiden boorin, ko- boltin,kuparin, mangaanin, molybdeenin ja sinkin ottoa 74 maaerästä, jotka olivat kyntökerroksesta ja joiden hivenravin- netaso vaihteli. Maaerien pH-arvot, pääravinteiden pitoisuu- det ja humuspitoisuudet olivat maalajeille ominaista keski- määräistä tasoa. Maat ryhmiteltiin hietoihin ja moreeneihin, hiesuihin, saviin ja turve- sekä multamaihin. Raiheinän hivenravinteiden vaatimustaso on alhainen, ja heinäkasvoi normaalisti yhtä maata lukuun ottamattakaikilla koemailla, joillase myös antoi melko samantasoisen kuiva-ai- nesadon. Raiheinän hivenravinnepitoisuuksia verrattiin liukoisiin pi- toisuuksiin koemaissa kokeen alkaessa. Sekä ensimmäisen että toisen sadon raiheinän pitoisuuksien riippuvuudet tutkittiin. Koko aineistosta saatiin raiheinän boorin, koboltin, kuparin, molybdeenin ja sinkin pitoisuuksille erittäin merkitsevä ja man- gaanille hyvin merkitsevä riippuvuus maan helppoliukoisten vastaavien hivenravinteiden pitoisuuksista. Kummankaan sadon hivenravinteiden merkitsevää riippuvuutta ei todettu hie- sumaillakoboltin eikä mangaanin suhteen eikä myöskään hieta- mailla molybdeenin eikäeloperäisillä mailla koboltin suhteen. Raiheinä otti booria yhtä paljon hiesumaista kuin savimais- takin,vaikka hiesumaiden booritaso oli alhaisempi. Savimais- sa kasvaneen raiheinän kobolttipitoisuus nousi selvästikorke- ammaksi kuin hiesumaissa kasvaneen. Kuparia raiheinä sai yhtä paljon karkeista kivennäismaista kuin eloperäisistä mais- ta, vaikka eloperäisten maiden kuparipitoisuus oli kaksinker- tainen kivennäismaihin nähden. Eloperäisissä maissa kasva- neen raiheinän mangaanipitoisuus oli yhtä korkea kuin savi- maissa kasvaneen, vaikka eloperäisten maiden mangaanipi- toisuus oli vain puolet savimaiden mangaanipitoisuudesta. Sinkkiä raiheinä otti hiesumaista milteiyhtä paljon kuin muis- takin maista, siitä huolimatta että sen pitoisuus oli hiesumais- sa huomattavasti alhaisempi. Tulosten mukaan hapanammoniumasetaatti + EDTA -me- netelmällä uuttuvat hivenravinnemäärät kuvaavat hyvin rai- heinän hivenravinteiden saantia, ja tätenmenetelmä sopii käy- tännön hivenainemäärityksiin. Maan ja kasvin pitoisuuksien eri tasot maalajiryhmissä viittaavat siihen, että samantapainen maalajiryhmitys kuin pääravinteiden tulkinnassa,olisi tarpeen myös hivenravinteiden tulkintaa esitettäessä. 148 Agric. Sei. Finl. 2 (1993)