Agricultural and Food Science in Finland, Vol. 10 (2001): 33–43. Vol. 10 (2001): 33–43 33 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 10 (2001): 33–43. © Agricultural and Food Science in Finland Manuscript received October 2000 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 10 (2001): 33–43. Soils in an agricultural landscape of Jokioinen, south-western Finland Markku Yli-Halla Agricultural Research Centre of Finland, Resource Management Research, FIN-31600 Jokioinen, Finland, e-mail: markku.yli-halla@mtt.fi Delbert L. Mokma Michigan State University, Department of Crop and Soil Sciences, East Lansing, MI 48824, USA Eleven pedons in an agricultural landscape at elevations 80–130 m above sea level in Jokioinen, south-western Finland were investigated and classified according to Soil Taxonomy, the FAO-Unesco system (FAO), and the World Reference Base for Soil Resources system (WRB). The soils were related to geomorphology of the landscape which is characterized by clayey fields and forested bed- rock high areas covered with glacial till. A Spodosol/Podzol was found in a coarse-sandy soil in an esker while the sandy loam in a bedrock high area soils did not have an E horizon. A man-made mollic epipedon was found in a cultivated soil which had a sandy plow layer while clayey plow layers were ochric epipedons. Cambic horizons, identified by structure and redox concentrations, were common in cultivated soils. In a heavy clay soil, small slickensides and wedge-shaped aggre- gates, i.e., vertic characteristics, were found. Histosols occurred in local topographic depressions irrespective of the absolute elevation. According to the three classification systems, the following catenas are recognized: Haplocryods – Dystro/Eutrocryepts –Haplocryolls – Cryaquepts – Cryo- saprists (Soil Taxonomy), Podzols – Regosols – Cambisols – Histosols (FAO–Unesco), and Podzols – Cambisols – Phaeozems – Gleysols – Histosols (WRB). Key words: soil formation, artificial drainage, structure, redoximorphic features, vertic characteris- tics, catenas, Soil Taxonomy, FAO-Unesco System, World Reference Base for Soil Resources Introduction The landscape in Jokioinen in south-western Fin- land is characterized by clayey fields which are surrounded by forested bedrock high areas, cov- ered mostly by glacial till, and by eskers con- sisting of coarse sandy glacial outwash. In addi- tion to these mineral materials, there are peat formations in the depressions of the landscape. mailto:markku.yli-halla@mtt.fi 34 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Yli-Halla, M. & Mokma, D. L. Soils of Jokioinen Glacial till covers 29% of the area, clayey soils 53%, organic soils 5%, silt and sand 5%, rocky areas 7% and rivers and lakes about 1% of the area (Urvas 1997). The most important river of the region is River Loimijoki. It has carved itself through the clayey lacustrine deposits which are sometimes as deep as 30 m (Rainio 1997). Intensive crop production takes place in southern and western Finland in similar land- scapes. The present landscape was formed by the Weichselian glaciation and the evolutionary stages of the Baltic Sea. At Jokioinen, the sea level during the ice melt period about 9 500 years ago was at 135–140 m above the present sea level (Rainio 1997). The fine-grained sediments in the region were deposited in the Yoldia sea (10 200– 9 500 BP) which covered practically the whole landscape. Owing to isostatic rebound, even the lowest areas of Jokioinen have been above sea level at least 8000 years. The soils have thus been subject to pedogenic processes much longer than in a landscape in Helsinki where most agricul- tural land has emerged from the sea less than 2000 years ago (Mokma et al. 2000). A vast number of agricultural experiments have been carried out in the study area, due to fact that Agricultural Research Centre of Finland is situated in Jokioinen. Maps of quaternary de- posits of the region have been published, but the soils have not been investigated for pedogenic features. The purpose of this study was to inves- tigate the pedogenic properties of typical soils of Jokioinen and relate their occurrence to the geomorphic setting and development of the land- scape. Material and methods Out of the 11 pedons studied, eight (03...09, 11) are in agricultural use. They have mostly been cultivated since the 17th century. First they were drained with open ditches and starting about 70 years ago they were pipe-drained. Two pedons (01, 02) are forested and one (10), within the floodplain of River Loimijoki, has been cropped but has been abandoned for some decades. The elevation varies from 80 to 130 m above sea lev- el. The studied pedons are within 60°48’ – 60°54’N and 23°27’- 23°32’E and their accurate coordinates are given according to the Finnish KKJ system (basic coordinates) in Table 1. Pro- files 02, 05...10 are within 1 km2 (Fig. 1) while the rest are 3–10 km North or North-east of them. The cultivated soils represent the important ex- perimental fields of Agricultural Research Cen- tre of Finland and the other three soils are repre- sentative for the forested and floodplain areas. Out of the cultivated soils, five (04...08) are clay- ey throughout the profile. Three (04, 07, 08) of the clayey pedons are similar to pedons 05 and 06, and therefore their data are not presented. Pedon 07 is slightly different from the other four by having less than 60 percent clay in the pro- file (45–65% vs. 65–95%). The pedons were described (Table 1) and sampled in June 1997 and August 1999 accord- ing to the methods of Soil Survey Staff (1993). Pedon 05 was not sampled. Particle size distri- bution was determined by the pipette method after digestion with hydrogen peroxide. Organ- ic C was determined using the Leco dry com- bustion apparatus (Laboratory Equipment Cor- poration, St. Joseph, MI). Soil pH was measured in water (soil:water 1:2.5 by volume). Base sat- uration, on the basis of the sum of exchangeable Ca, Mg, Na, K and H, was determined by am- monium acetate extraction (pH 7.0). In two pe- dons (01 and 02), Fe and Al were extracted with 0.5 M ammonium oxalate (pH 3.0) to check for the presence of spodic horizons. Phosphorus (P) was extracted with 1% citric acid to identify an- thropogenic accumulation of P in the soil (Soil Survey Staff 1975, FAO 1988). The pedons were classified according to Soil Taxonomy (Soil Sur- vey Staff 1998), the FAO-Unesco system (FAO 1988) and the World Reference Base for Soil Resources system (FAO 1998) assuming that the pedons have a cryic temperature regime (Yli- Halla and Mokma 1998). 35 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 10 (2001): 33–43. Results and discussion Coarse and medium textured soils Pedon 01 represents the highest part (elevation 130 m) of the esker Kukonharju, which is the largest esker of the area. The mineral material (<2 mm) is dominated by coarse sand while the clay and silt, 10% or less (Table 2), had been sorted out. Therefore, these materials are pre- ferred for construction materials, and mining of sand and gravel is common in this esker. In the horizons below 35 cm more than 60% of the mass consist of material larger than 1 cm. As a result of the vegetation (Scotch pine, lichens, some mosses and grasses) the profile has an O hori- zon. The soil has a continuous thin albic hori- zon (7.5YR 4/1) (Table 1). The low pH, >0.6% organic C, the color (7.5YR 4/4) of the Bs1 ho- rizon and the presence of an albic horizon are evidence of the presence of spodic materials, which is further confirmed by the accumulation of oxalate-extractable Al and Fe (0.55%) in the Bs1 horizon and depletion of these elements (0.07%) in the E horizon. The soil is a Haplo- cryod (Soil Survey Staff 1998) and a Podzol (FAO 1988, 1998) (Table 3). Pedon 02, at the elevation of 110 m, con- tained many stones, often larger than 15 cm in diameter, preventing digging a pit deeper than 70 cm by shovel. Differing from profile 01, this profile contained as much as 33–40% of silt in the fine earth fraction even though sand was the dominant particle size. The particle size distri- bution shows that the soil has not been subject to intensive sorting. This forested area is more moist than the Kukonharju esker (pedon 01) and it is vegetated by spruce, mosses and grasses. Despite the brown color (7.5YR 4/3 and 10YR 4/4), low pH and sufficient contents of Fe, Al and C, the Bw horizon doesn’t meet the criteria Fig. 1. Location of eight of the investigated pedons. The pedons 01, 03 and 11 are north of the area in the map. ®Maanmittauslaitos /National Land Survey of Finland, permission number 526/MYY/00. 36 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Yli-Halla, M. & Mokma, D. L. Soils of Jokioinen Table 1. Description of soil profiles from the Jokioinen area. Horizon Depth, cm Color matrix Color mottles Texture Structure Jokioinen 01, x=2474380, y=6747420 Oa 0–7 7.5YR 3/2 sapric E 7–10 7.5YR 4/1 lfs 1f sbk Bs1 10–35 7.5YR 4/4 lfs 1m sbk 2Bs2 35–64 7.5YR 4/6 vgrs 0sg 2BC 64–75 10YR 4/4 ex cob s 0sg 2C 75–90 10YR 4/4 ex gr s 0sg Jokioinen 02, x=2470930, y=6744340 Ah 0–15 7.5YR 3/2 l Bw1 15–25 7.5YR 4/3 sl Bw2 25–45 10YR 4/4 sl Bw3 45–55 10YR 4/6 sl C 55–70 2.5Y 5/4 sl Jokioinen 03, x=2471520, y=6748730 Ap 0–27 10YR 4/3, 10YR 5/3 dry sil 1c pl Bw1 27–36 10YR 4/6 f2f 10YR 6/8 sil 1vc pl Bw2 36–62 2.5Y 5/3 m3f 2.5Y 5/4 1vc pl/1m sbk c3p 10YR 4/4–5/8 c2p 2.5YR 6/2 C1 62–72 10YR 5/3 c2p 7.5YR 3 /4 sic 1f pl/2f abk 2C2 72–80 2.5Y 5/4 c2p 10YR 5/6 sil 1) 1m pl 3C3 80–89 2.5Y 4/1 m2p 5YR 3/3 c 1f pl/2f abk f1p 2.5YR 4/6 4C4 89–123 10YR 4/2, 10YR 5/3 c2f 10YR 5/2 and 2.5Y 6/4 c2d 10YR 4/6 sl 1) 1m pl 5C5 123–132 2.5Y 4/1 m2p 7.5YR 3 /4 c 1m pl/2m abk 6C6 132–215 10YR 6/4 c1d 10YR 6/1 ls 2) 1m pl c1d 10YR 5/6 Jokioinen 05, x=2470960, y=6743980 Ap 0–22 10YR 4/2, 10YR 7/3 dry c 2m sbk Bw1 22–40 10YR 4/2 c 3c pr/3m abk 4) Bw2 40–72 10YR 3/2 c1f 10YR 3/3 c 3) 2m abk 4) Bw3 72–112 10YR 3/2 c2f 10YR 3/3 c 1m abk 4) Cg 112–150 10YR 4/1 m2p 10YR 5/4 c Jokioinen 06, x=2471090, y=6743850 Ap 0–23 10YR 4/2, 10YR 6/3 dry f1f 10YR 4/3 c 2f gr 5) 1m abk 5) AB 23–45 10YR 4/1 m3f 10YR 4/1 c 1f abk c2f 10YR 4/4 Bg1 45–60 10YR 4/2 c2p 7.5YR 4/4 c 2m abk m3f 10YR 5/1 7) c1f 10YR 2/2 8) Bg2 60–91 10YR 4/2 m2p 7.5YR 4/4 c 6) 1c pr/2m abk m3f 10YR 5/1 1) c1f 10YR 2/2 8) BC 91–142 10YR 4/2 m2p 7.5YR 4/4 c 6) 2c pr/2m abk m3f 10YR 5/1 7) c1f 10YR 2/2 8) continued on the next page 37 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 10 (2001): 33–43. continued from the preceding page Horizon Depth, cm Color matrix Color mottles Texture Structure Cg 142–169 10YR 4/2 m3f 10YR 5/1 7) c 6) 2m pl/2m abk c3p 7.5YR 4/6 c1f 10YR 2/2 8) Jokioinen 09, x=2470840, y=6743530 Ap 0–30 10YR 3/2, 10YR 5/2 dry sl 1c sbk Bw1 30–40 10YR 5/3 c3p 7.5YR 4/6 sl 1m sbk Bw2 40–45 10YR 5/3 f2p 7.5YR 4/6 sl 1m sbk 2Bw3 45–70 10YR 4/2 m2p 7.5YR 5/6 sic 2c sbk/2f-m abk c2f 10YR 5/2 2BC 70–100 10YR 4/2 m2p 7.5YR 5/6 c 2c sbk/2f abk m3p 5Y 5/1 7) 2Cg 100–150 10YR 4/2 c2f 10YR 3/4 2vc pr/2m abk m3p 2.5Y 5/1 7) Jokioinen 10, x=2469790, y=6743740 Ap 0–15 10YR 3/2, 10YR 6/1 dry c 3f gr Bg 15–39 10YR 4/2 c1p 7.5YR 3/3 c 2f sbk/2f abk Oab1 39–55 10YR 3/1 m3p 5YR 3 /47) sapric 2m pr/2m abk Oab2 55–80 10YR 3/2 → 2/1 9) c3p 7.5YR 3 /4 7) sapric 2c pr/2c pl Oab3 80–110 10YR 3/3 → 3/2 9) sapric 1c pr/2c pl Cg1 110–120 10YR 3/2 c 2c pl Cg2 120–128 5Y 4/1 c 10) 0m Jokioinen 11, x=2473730, y=6754660 Oap 0–35 5YR 2.5/2, 7.5YR 4/2 dry sapric 1c sbk/2f sbk Oa1 35–59 5YR 2.5/1 sapric 3c sbk/2f sbk Oa2 59–80 2.5Y 2.5/1 sapric 2m pl Oa3 80–104 10YR 3/2 sapric 1vc pl/1vc abk 2Cg 104–135 5Y 5/1 c 0m 1) thin (<2 mm) strata of vfsl and sil 2) thin (<2 mm) strata of vfsl 3) at 44 cm, thin (<2 mm) strata of si 4) slickensides/ pressure faces at 22–40, 60 and 100–110 cm 5) granular at 0–7 cm, blocky at 7–23 cm 6) thin (<2 mm) strata of si 7) continuous coatings on ped faces 8) Mn oxide nodules 9) The lighter color changes into the darker one within 1 min of exposure to air. 10) Many dead fine roots and remnants of grassy plants Abbreviations: Texture: c=clay, sic=silty clay, l=loam, sil=silt loam, sl=sandy loam, vfsl=very fine sandy loam, vfsil very fine silt loam, ls=loamy sand, sl=sandy loam, lfs=loamy fine sand, vgrs=very gravelly sand, ex cob s=extremely cobbely sand, ex gr s=extremely gravelly sand Mottles: f=few (<2% of surface), c=common (2–20%), m=many (>20%), 1=fine (<5 mm), 2=medium (5–15 mm), 3=coarse (>15 mm), f=faint, d=distinct, p=prominent Structure: 0=structureless, 1=weak, 2=medium, 3=strong, vf=very fine, f=fine, m=medium, c=coarse, gr=granular, sbk=subangular blocky, abk=angular blocky, pl=platy, pr=prismatic, m=massive, sg=single grain. Slash between the struc- tural attributes means that the coarser aggregates part to the finer ones. 38 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Yli-Halla, M. & Mokma, D. L. Soils of Jokioinen Table 2. Selected physical and chemical properties of pedons in Jokioinen. P was extracted with 1% citric acid. Clay stands for particles <0.002 mm, silt for 0.002–0.06 mm and sand for 0.06–2 mm. Index stands for 0.5 x Fe + Al, extracted with acid oxalate. Depth pH (H 2 O) Org. C Clay Silt Sand CEC pH 7.0 Base >2 mm Index cm % % % % cmol kg-1 saturation, % % % Jokioinen 01 0–7 4.02 29.4 7–10 4.00 2.0 2 9 89 2 0.07 10–35 4.96 0.82 2 8 90 14 0.55 35–64 5.34 0.30 0 6 94 89 0.28 64–75 5.38 0.29 1 8 91 82 0.33 75–90 5.66 0.14 1 3 96 81 0.21 Jokioinen 02 0–15 4.67 5.37 8 40 52 15.8 14 0 0.55 15–25 4.85 3.14 8 38 54 11.8 10 41 0.69 25–45 5.14 1.87 6 33 61 8.1 8 54 1.10 45–55 5.31 0.83 4 32 64 5.4 10 46 0.80 55–70 5.33 0.40 4 33 63 3.2 11 57 0.44 P Jokioinen 03 mg kg-1 0–27 5.91 1.56 13 54 33 11.3 59 131 27–36 6.38 0.39 4 54 42 4.08 49 36–62 6.50 0.18 2 56 42 2.86 44 62–72 6.76 0.35 50 43 7 20.1 82 72–80 6.71 0.20 3 62 35 7.05 55 80–89 6.73 0.39 63 30 7 89–123 6.61 0.13 2 48 50 123–132 6.29 0.47 87 7 6 132–215 6.58 0.05 1 22 77 Jokioinen 06 0–23 6.09 2.67 57 32 11 24.6 74 255 23–45 6.47 1.00 81 16 3 33.1 87 55 45–60 6.94 0.43 73 25 2 26.9 91 60–91 7.14 0.35 76 24 0 28.3 92 91–142 7.13 0.30 89 11 0 31.1 93 Jokioinen 09 0–30 6.54 2.44 13 14 73 14.9 86 347 30–40 6.79 0.47 8 19 73 5.11 90 75 40–45 6.86 0.14 9 15 76 4.54 89 41 45–70 6.95 0.23 45 42 13 24.8 92 85 70–100 7.20 0.23 57 37 6 27.1 92 200 100–150 7.33 0.32 69 27 4 29.2 92 213 Jokioinen 10 0–15 5.18 10.1 68 32 0 15–39 5.20 10.1 68 31 1 39–55 5.38 19.7 65 33 2 55–80 5.65 22.6 64 32 4 80–110 5.73 20.1 69 29 2 110–120 5.85 11.1 76 23 1 120–128 6.09 3.4 70 30 0 Jokioinen 11 0–35 5.70 25.9 138 20 277 35–59 5.11 22.3 125 20 88 59–80 5.11 33.2 141 21 59 80–104 4.60 18.3 86.7 23 107 104–135 5.20 1.7 82 14 4 29.7 45 288 39 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 10 (2001): 33–43. Table 3. Classification of the investigated pedons according to Soil Taxonomy (Soil Survey Staff 1998), FAO-Unesco system (FAO 1988) and Word Reference Base for Soil Resources (WRB) system (FAO 1998). Profile Land use1) Elevation m Soil Taxonomy FAO-Unesco WRB 1 Kukonharju f 120 Entic Haplocryod Haplic Podzol Haplic Podzol 2 Ojainen f 110 Typic Dystrocryept Dystric Regosol Dystric Cambisol 3 Rehtijärvi c 106 Aquic Eutrocryept Dystric Regosol Dystric Cambisol 4 Kotkanoja c 100 Typic Cryaquept Vertic Cambisol Vertic Cambisol 5 Ojainen c 92 Vertic Cryaquept Vertic Cambisol Vertic Cambisol 6 Ojainen c 90 Typic Cryaquept Vertic Cambisol Vertic Cambisol 7 Ojainen c 90 Typic Cryaquept Vertic Cambisol Vertic Cambisol 8 Ojainen c 82 Typic Cryaquept Vertic Cambisol Vertic Cambisol 9 Ojainen c 85 Aquic Haplocryoll Eutric Cambisol Haplic Phaeozem 10 Luhta p 80 Terric Cryosaprist Terric Histosol Thaptohistic Gleysol 11 Kuuma c 108 Terric Cryosaprist Terric Histosol Sapric Histosol 1) c=cultivated, p=previously cultivated, f=forested of spodic materials. This is due to the fact that no albic horizon was present and insufficient accumulation of Fe and Al (0.69%) relative to the horizon above (0.55%) was measured. Low base saturation throughout the profile suggests that many base cations have leached. It is likely that upon further leaching of base cations an E horizon will develop and the soil will approach the Spodosol order. Currently this soil is a Dys- trocryept (Soil Survey Staff 1998). In the FAO- Unesco system, criteria of a cambic horizon in- clude, among other requirements, a minimum clay content of 8% and a minimum thickness of 15 cm. The Bw1 horizon is thus too thin to be a cambic horizon in that system, and the soil is a Regosol (FAO 1988). In the World Reference Base for Soil Resources (WRB) system, there is no textural requirement for a cambic horizon, and therefore Bw1 and Bw2 together qualify for a cambic horizon and the soil is a Cambisol (FAO 1998). Pedon 03 (elevation 106 m) is in a small es- ker which for the most part consists of fine sandy loam, coarse silt and fine sand being the princi- pal particle sizes. In addition, at 60, 80 and 120 cm, there are thin (10 cm) horizons of silty clay loam or silty clay with abrupt boundaries. The lithological discontinuities in this pedon reflect differences in velocity of water which was a function of the rate of melting of the gla- cial ice. The fine sandy loam has a base satura- tion of 44–49%, which is considerably higher than in the coarser soils 01 and 02 but much low- er than in the clay-textured horizons of this soil and in the clayey soils of this study. In spite of the location in an esker above the surrounding fields, there are redox depletions (2.5Y 5/4) in the fine sandy loam above the clayey horizon, reflecting slow water movement through the clay. This soil is an Eutrocryept (Soil Survey Staff 1998), and a Cambisol (FAO 1998) but, owing to a clay content <8% in the B horizon, it is a Regosol in the FAO-Unesco system (FAO 1988). The Soil Map of Denmark, Finland, Norway and Sweden (Rasmussen et al. 1989) and the Soil Geographic Database of Europe (European Soil Bureau 1998), following the classification of FAO (1974), both indicate that Cambisols and Podzols are the two dominant soils in this area. However, in our study Podzols were only found in sandy materials while Regosols, not recog- nized in the map and database mentioned above, seemed to occupy areas of non-podzolised loamy soils. Clayey soils The clayey lacustrine sediments dominate the cultivated land. These soils are represented by 40 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Yli-Halla, M. & Mokma, D. L. Soils of Jokioinen pedons 04...09. In addition to clay, many pedons have thin strata of silt. These soils are artificial- ly drained and they have a structure at least down to the depth of drainage tiles (about 1 m). In the upper part of the B horizon, the structure is (sub)angular blocky but in lower horizons it be- comes prismatic. The matrix color is commonly 10YR 4/2. None of the clayey soils had the gleyic matrix colors (2.5Y or yellower) even in the deepest horizons sampled, differing from the clayey soils of the Helsinki area (Mokma et al. 2000). Instead, the prism faces in the Bg and BC horizons are grey (2.5–5Y 5/1). These faces rep- resent the cracks through which most of the wa- ter drains away. All of these soils had many re- dox concentrations in the subsoil and were con- sidered to have an aquic moisture regime. The ped faces do not have continuous coating of iron hydroxide and thus do not have the gleyic color pattern (FAO 1998). Cambic horizon was iden- tified in all clayey soils on the basis of redox concentrations and structure. These soils are also characterized by black Mn nodules. Pedon 05 is heavy clay with a very well de- veloped prismatic structure. Large prismatic ag- gregates or peds occur immediately below the p l o w l a y e r a n d c o u l d b e p i c k e d b y h a n d (Fig. 2). These prisms had a length of about 18 cm and a diameter of 5–7 cm, and at the end of a dry summer of 1999 there were cracks 1 cm wide between the prisms. Small slickensides, or pres- sure faces, were commonly observed at 35–40 cm, but they occurred also at 60 cm and 100–110 cm. Wedge-shaped peds with 60° angles were ob- served at 100–110 cm. This is the first pedon in Finland where vertic characteristics have been morphologically described. According to Soil Taxonomy, this pedon is tentatively classified as a Vertic Cryaquept, because the coefficient of linear extensibility was not determined. In pedons 04, 06...08 pressure faces or wedge-shaped aggregates were not observed even though they do crack. The reason may be that the other pedons are closer to the bedrock high areas from which water is running as later- al flow. Pedon 05, being also close to a major ditch, may be drier and can be more conducive to cracking. Pedons 04, 06, 07 and 08 classify as Typic Cryaquepts according to Soil Taxono- my and Vertic Cambisols according to FAO- Unesco and WRB system. The Vertic Cambisol classification is in agreement with the Soil Map of Denmark, Finland, Norway and Sweden (Rasmussen et al. 1989) and the Soil Geographic Database of Europe (European Soil Bureau 1998). Pedon 09 represents an area within the clay- ey fields which has a 45-cm topsoil of sandy loam while the subsoil is clayey. The sandy loam plow layer is sufficiently dark to meet the color Fig. 2. Prisms taken right below the plow layer of pedon 05. Pho- to: Markku Yli-Halla. 41 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 10 (2001): 33–43. requirements of a mollic epipedon. Also, other criteria of Mollisols (Soil Survey Staff 1998) and Phaeozems (FAO 1998) are met here but in the FAO-Unesco system (FAO 1988) and the earlier versions of Soil Taxonomy P content excluded this soil from those taxa. This soil is similar to the pedons Helsinki 02 and 03 (Mokma et al. 2000). Also in the Jokioinen area the mollic epi- pedons are met only in plow layers which are predominantly sandy while the clayey plow lay- ers seem to have, owing to a lighter dry color, ochric epipedons. Soils containing organic materials Pedon 10 is in the lowest position of this land- scape (80 m), behind the levee of the river Loimi- joki. This area floods frequently and pedon 10 has 39 cm of mineral soil material over sapric materials. These sapric materials became darker in color within a few minutes after exposure to air, suggesting that these horizons are continu- ously saturated. This pedon has a uniform tex- ture throughout the investigated depth, suggest- ing that the source of the sediment has not changed over time. The sapric materials indicate more abundant water / biological activity dur- ing the deposition of those horizons and stabili- ty of land surfaces as compared to the earlier or more recent times when mineral materials were deposited. The histic horizon between 39 and 110 cm is diagnostic for Histosols of Soil Taxonomy and FAO-Unesco system and the pedon classi- fies as a Terric Cryosaprist (Soil Survey Staff 1998) and a Terric Histosol (FAO 1988). According to the WRB system, pedon 10 is not a Histosol because the histic horizon doesn’t start within 30 cm of soil surface. Strictly fol- lowing the Key (FAO 1998), this soil is a Cam- bisol, a name which poorly reflects the proper- ties of this soil, neglecting the organic materials which present stability problems for use and management. This soil is saturated with water for considerable periods and has continuous coat- ings of Fe hydroxide on ped faces at 39–80 cm. Even though the matrix color of those horizons is 10YR, not 2.5Y or yellower, we conclude that this soil has gleyic properties below 39 cm. A name Thaptohistic Gleysol (FAO 1998) is in ac- cordance with soil properties and topographic position of this soil. Sapric materials also occur in local depres- sions higher in the landscape which have no or limited outlets for water like pedon 11 at an ele- vation of 108 m. In this pedon 1-m thick sapric materials have accumulated on heavy clay (82% clay) which has deposited between ridges of gla- cial till. This pedon classifies as a Terric Cryo- saprist (Soil Survey Staff 1998), Terric Histosol (FAO 1988), and Sapric Histosol (FAO 1998). Conclusions The catena of this landscape (Table 4) represents a toposequence from high to low elevations and a hydrosequence from dry to wet sites, except the organic soils which can occur at any eleva- tion in local depressions. Owing to the absence of the gleyic color pattern in clayey soils, it can be concluded that these cultivated soils would have cambic horizons even if there were no hu- man influence, as opposed to the clayey soils in Helsinki (Mokma et al. 2000) which are young- er and have a lower topographic position. Even though the predominant clay mineral in these soils is illite (Sippola 1974), very high clay con- tent is conducive to cracking but the climate may be too cool and humid for the soil to crack suffi- ciently for the development of Vertisols. Weakly developed Spodosols/Podzols are present in forested sandy soils with minimum clay and silt contents but it is likely that much of the forested sandy loam soils of the area are not Spodosols/Podzols. Owing to the differ- ences in the criteria of the cambic horizon in the FAO-Unesco and WRB systems, many of the sandy loam soils are Regosols in the FAO- Unesco system and Cambisols in the WRB sys- tem. Some cultivated soils which have a sandy loam plow layer are Cambisols in the FAO- 42 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Yli-Halla, M. & Mokma, D. L. Soils of Jokioinen Unesco system and Phaeozems in the WRB sys- tem. The Cambisols of these two systems seem to have different morphologies. In this landscape, Soil Taxonomy and the WRB system classify mineral soils quite analogously, particularly In- ceptisols and Mollisols (Soil Survey Staff 1998) being equivalent to Cambisols and Phaeozems (FAO 1998), respectively. Table 4. Relationships between the landforms and soils in the Jokioinen landscape according to Soil Taxonomy (Soil Survey Staff 1998), FAO-Unesco system (FAO 1988) and Word Reference Base for Soil Resources (WRB) system (FAO 1998). Classification L a n d f o r m system Dry esker Depression Bedrock high Cultivated land, Cultivated land, Floodplain sandy clayey Soil Entic Terric Typic Aquic Typic and Terric Taxonomy Haplocryods Cryosaprists Dystrocryepts Haplocryolls, Vertic Cryosaprists Aquic Cryaquepts Eutrocryepts FAO- Unesco Haplic Terric Dystric Eutric Vertic Terric Podzols Histosols Regosols Cambisols, Cambisols Histosols Dystric Regosols WRB Haplic Sapric Dystric Haplic Vertic Thaptohistic Podzols Histosols Cambisols Phaeozems, Cambisols Gleysols Dystric Cambisols References European Soil Bureau 1998. The soil geographical data- base of Europe at scale 1:1000 000. INRA, Orleans, France. FAO 1974. Soil map of the world at 1:5000 000. Unesco. Paris. – 1988. FAO-Unesco soil map of the world. Revised Legend. World Soil Resources Report 60, FAO, Rome. Reprinted as Technical Paper 20, Internation- al Soil Reference and Information Centre, Wagenin- gen. 144 p. – 1998. World Reference Base for Soil Resources. World Soil Resources Report 84. FAO, Rome. 88 p. Mokma, D.L., Yli-Halla, M. & Hartikainen, H. 2000. Soils in a young landscape on the coast of southern Fin- land. Agricultural and Food Science in Finland 9: 291–302. Rainio, H. 1997. Kivennäismaalajit. Maaperäkartan 211304 selitys. (Mineral soils. Legend to the map of quaternary deposits). Maanmittauslaitos – National Land Survey. Rasmussen, K., Sippola, J., Urvas, L., Låg, J. & Troeds- son, T. 1989. Soil map of Denmark, Finland, Nor- way and Sweden. Scale 1:2000 000. Landbrugsfor- laget. Oslo, Norway. Sippola, J. 1974. Mineral composition and its relation to texture and some chemical properties in Finnish sub- soils. Annales Agriculturae Fenniae 13: 169–234. Soil Survey Staff 1975. Soil Taxonomy: A basic system of soil classification for making and interpreting soil surveys. USDA-SCS Agricultural Handbook 436. U.S. Government Printing Office, Washington, D.C., USA. – 1993. Soil Survey Manual. 2nd ed. USDA-SCS Ag- ricultural Handbook 18. U.S. Government Printing Office, Washington, D.C., USA. – 1998. Keys to Soil Taxonomy, 8th ed. U.S. Govern- ment Printing Office, Washington, D.C., USA. Urvas, L. 1997. Maaperäkarttaselitys Forssa. Summa- ry: Soil map of Forssa. Maatalouden tutkimuskeskuk- sen julkaisuja. Sarja A 16. 18 p + appendices. Yli-Halla, M. & Mokma, D.L. 1998. Soil temperature re- gimes in Finland. Agricultural and Food Science in Finland 7: 507–512. 43 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 10 (2001): 33–43. SELOSTUS Jokioisten seudun maannokset Markku Yli-Halla ja Delbert L. Mokma Maatalouden tutkimuskeskus ja Michiganin osavaltion yliopisto Jokioisissa tutkittiin 11 maaprofiilia noin 1,5 metrin syvyyteen ja määritettiin niissä esiintyvät maannok- set. Maista kahdeksan oli viljeltyjä, kaksi oli metsä- maita ja yksi Loimijoen tulva-alueella oleva entinen viljelymaa. Maannokset nimettiin amerikkalaisen Soil Taxonomy -järjestelmän, FAOn-Unescon järjestelmän (FAO) ja World Reference Base for Soil Resources -järjestelmän (WRB) mukaan. Tutkitut maat ovat 80– 130 m meren pinnan yläpuolella ja ne ovat olleet alt- tiina maannostumisprosesseille yli 8000 vuotta. Kui- van ja hiekkaisen Kukonharjun maa oli podsoloitu- nutta, mutta hienojakoisemmassa metsämaassa ei vie- lä voitu havaita podsolille tyypillistä valkomaaker- rosta, vaikka maa oli hapan ja siinä oli matala emäs- kyllästysaste. Kaikkiin viljeltyihin kivennäismaihin oli kehittynyt rakenne salaojitussyvyyteen saakka, ja niissä oli ruostelaikkuja. Tällä perusteella niissä kat- sottiin olevan cambic-horisontti, ja maat olivat Cam- bisol-maita (FAO, WRB) ja Inceptisol-maita (Soil Taxonomy). Yhdessä aitosavimaassa oli runsaan hal- keilun lisäksi maakokkareiden kutistumisesta ja tur- poamisesta johtuvia liukupintoja, jollaisia ei ole Suo- messa ennen todettu. Maassa, jonka muokkauskerros oli karkeaa hietaa ja syvemmät kerrokset savea, oli viljelytoimien seurauksena syntynyt mollic-pintaker- ros, ja tämä maa oli Mollisol (Soil Taxonomy) tai Phaeozem (WRB). Tutkittu viljelty turvemaa on syn- tynyt aitosavipohjalle. Loimijoen luhta-alueella on kivennäismaakerrosten alla 30–40 % orgaanista ai- nesta sitältäviä maakerroksia. Soil Taxonomy -järjes- telmän pääryhmistä alueelta löytyi Spodosol-, Incep- tisol-, Mollisol- ja Histosol-luokkiin kuuluvia maita, FAOn-Unescon järjestelmän Podzol-, Regosol-, Cambisol- ja Histosol-luokkiin kuuluvia maita ja WRB-järjestelmän Podzol-, Cambisol-, Phaeozem-, Gleysol- ja Histosol-maita. Title Introduction Material and methods Results and discussion Conclusions References SELOSTUS