PLATE 2 Andisolsa Typic Melanudand from western Tanzania. Scale in 10 cm
PLATE 10 Spodosolsa Humic Cryorthod from southern Quebec. Albic horizon at about 10 cm. Bar = 10 cm.
PLATE 11 Ultisolsa Typic Hapludult from central Virginia showing metamorphic rock structure in the saprolite below the 60-cm-long shovel.
PLATE 13 Typic Argiustolls in eastern Montana with a chalky white calcic horizon (Bk and Ck) overlain by a Mollic epipedon (Ap, A2, and Bt).
PLATE 15 A Typic Plinthudult in central Sri Lanka. Mottled zone is plinthite, in which ferric iron concentrations will harden irreversibly if allowed to dry.
PLATE 16 A soil catena or toposequence in central Zimbabwe. Redder colors indicate better internal drainage. Inset: B-horizon clods from each soil in the catena.
PLATE 17 Uneven water infiltration and movement in a sandy soil due to hydrophobic organic coatings.
PLATE 18 The darker surface soil was brushed aside to expose a hydrophobic layer caused by burning the chaparral vegetation. Water beads up rather than soaking into this layer. See page 300.
PLATE 19 The boundary between the Oe and the E horizons of a forested Ultisol.
PLATE 20 The effect of moisture on soil color. Right side of this Mollisol profile was sprayed with water.
PLATE 21 Effect of poor drainage on soil color. Gray colors and red redox concentrations in the B horizons of a Plinthaquic Paleudalf.
PLATE 22 The 10YR hue page of a Munsell color book. The standard notation is handwritten for the color with hue 10YR, value 5, and chroma 6.
PLATE 23 Road cut in southern Brazil exposing the profile of an Udalf with a sombric horizon. Humid, high-altitude tropical and subtropical mountains are the typical environments for the formation of this dark, humus-rich subsurface horizon.
PLATE 24 Thick clay skins or argillans in an argillic Bt horizon. Image made from a very thin, polished slice of soil, magnified with a petrographic microscope using plain polarized light (left) and cross-polarized light (right). Note the thin layers of illuvial clay.
PLATE 25 Connecticut River valley in western Massachusetts. Note variable alluvial soils and presence of riparian forest buffer along the river bank.
PLATE 26 Redox concentrations (red) and depletions (gray) in a Btg horizon from an Aquic Paleudalf.
PLATE 27 The waxlike ped surfaces in this Bt horizon from an Ultisol are clay skins (argillans). Bar = 1 cm.
PLATE 28 Erosion of convex sites by tillage and water has exposed red B-horizon material.
PLATE 29 Oxidized (red) root zones in the A and E horizons indicate a hydric soil. They result from oxygen diffusion out from roots of wetland plants having aerenchyma tissues (air passages).
PLATE 30 Dark (black) humic accumulation and gray humus depletion spots in the A horizon are indicators of a hydric soil. Water table is 30 cm below the soil surface.
PLATE 31 Urban soils (referred to by some as Urbents) often hold surprises in their profiles. Here a tree planting hole reveals a buried A horizon (top) and buried asphalt (lower).
PLATE 32 Soil saturated beyond its liquid limit by torrential rains caused a landslide and mudflow that pushed huge tropical cloud forest trees downslope like toothpicks and demolished a village at the foot of this mountain in Honduras.
PLATE 33 The red, kaolinitic soil in the foreground was hauled in to build up a stable roadbed across this low-lying landscape in South Central Tanzania. The black soils are rich in expansive clays, which would break up the pavement if used for the subbase.
PLATE 34 Mass wasting of clayey soils on steep slope may occur when saturated with water, as in this rotational block slide in East Africa. Note man in center for scale.
PLATE 35 Two large soil stockpiles on a construction site. The brown A horizon was set aside for landscaping topsoil; the redder B horizon (back) was stockpiled for use as fill and road base.
PLATE 36 An uneven layer of silt blankets a glacial deposit of coarse sand and gravel in this Rhode Island Inceptisol. The profile water-holding capacity varies with the thickness of the silt, causing an irregular pattern of drought-stricken turf grass (inset).
PLATE 37 Influence of soil fauna on microstructure in O (left) and A (right) horizons of a forested Ultisol in Tennessee. Particulate organic matter (POM) includes leaf fragments (lf), fecal pellets (fp) and root fragments (rf).
PLATE 38 Roots from sweet pepper plants follow organic-matter-lined earthworm burrows through the compacted B horizon of a Pennsylvania Inceptisol. Earthworm activity was encouraged by 15 years of no-till practices and cover crops.
PLATE 39 Plant roots grow along the gleyed coating of a fragipan prism whose reddish interior is too dense for roots to grow. The roots are squeezed flat between the prisms.
PLATE 40 This cicada nymph, nestled 60 cm deep in the B horizon of a forested Ultisol, will feed on oak tree roots for several years before emerging as an adult. Free water in the macropore bathes the cicada, whose burrowing promotes drainage and enhances root growth.
PLATE 41 Traditional humid-region farmers use slash-and-burn systems. They chop down patches of forest and burn the dead vegetation, returning many nutrients in the ash. Note fire in the background and burned logs in the foreground of this Sri Lankan womans new clearing. See Section 20.7.
PLATE 42 Drought-stressed grass shows importance of soil depth. The rectangular area of brown grass is underlain by a shallow (25-cm) layer of soil atop the roof of an underground library. The trees and green grass at right grow in deeper soil.
PLATE 43 The soil on the left of this hydrangea was limed, that on the right was acidified (with FeSO4). After a year, blue flowers formed on the low-pH side, pink on the high-pH side.
PLATE 44 Leaves from near the bottom of nitrogen-deficient (yellow tip and midrib), potassium-deficient (necrotic leaf edges), and normal corn plants. All the leaves came from the same field.
PLATE 45 This iron-deficient azalea was sprayed with FeSO4 on one side 3 days before being photographed. Soil pH higher than 5.5 can induce such iron deficiency.
PLATE 46 Magnesium deficiency causes interveinal chlorosis on the older leaves of this poinsettia.
PLATE 47 Phosphorus deficiency causes severe stunting and purpling of older leaves of this tomato.
PLATE 48 The color developed after wetting soil with a pH-sensitive dye can be compared to a color chart in order to estimate soil pH in the field. This soil has a pH of about 7. See page 377.
PLATE 49 Sulfur deficiency typically causes chlorosis (yellowing) on the youngest leaves first, or on all the foliage, as in the sorghum plant on the left. This contrasts with nitrogen deficiency, which causes chlorosis first on the oldest leaves. Plants growing on low-sulfur soil responded to sulfur addition.
PLATE 50 Nitrogen-deficient corn on Udolls in central Illinois. Ponded water after heavy rains resulted in nitrogen loss by denitrification and leaching.
PLATE 51 Slow-moving coastal plain stream choked with algal bloom caused by nitrogen and phosphorus from upstream farmland.
PLATE 52 Normal (left) and phosphorus-deficient (right) corn plants. Note stunting and purple color.
PLATE 53 Zinc deficiency on peach tree. Note whorl of small, misshaped leaves.
PLATE 54 Zinc deficiency on sweet corn. Note broad whitish bands.
PLATE 55 Eroded calcareous soil (Ustolls) with iron-deficient sorghum.
PLATE 56 Boron deficiency on alfalfa. Note reddish foliage.
PLATE 57 Pink blooms belong to pioneering redbud (Cercis canadensis L) trees, a nitrogen-fixing legume that enriches the soil for the other species (which eventually will take over as the forest matures).
PLATE 58 Nitrogen deficiency on a pine tree. The yellowing (chlorosis) occurs mainly on the older needles.
PLATE 59 The large soybean root nodule was cut open to show its red interior indicative of active nitrogen fixation. The red comes from an iron-coordinated compound very similar to the hemoglobin that makes human blood turn red when oxygenated.
PLATE 60 Looking like snow, the salt crust covering this soil formed when salt-laden groundwater in this salt marsh near the Great Salt Lake in Utah rose by capillarity and evaporated from the soil surface, leaving the dissolved salt behind.
PLATE 61 Sea spray has caused salt injury (brown leaves) despite the high salt tolerance of this Bermuda grass at Pebble Beach Golf Course in California.
PLATE 62 Its a good thing this homeowner readjusted his spreader before he finished fertilizing the lawn. Salt "burn" from too much nitrogen fertilizer.
PLATE 63 Iron deficiency causes yellowing with sharply contrasting green veins on the younger leaves. Rose growing in soil with pH 6.8.
PLATE 64 Stream polluted by acid drainage caused by sulfurization of soils forming in coal mine spoil. FeSO4 in the acid drainage oxidizes in the stream to cause the orange color. See page 585.
PLATE 65 Early stages of soil formation in material dredged from Baltimore Harbor. Sulfidic materials (black), acid drainage (orange liquid), salt accumulations (whitish crust), and initiation of prismatic structure (cracks) are all evident.