2. Grey Forest and Podzolized soils.

Strictly speaking, grey forest soils are a zonal type for the Forest-Steppe zone. Chernozems are more typical for the steppes. Grey forest soils, as the name implies, were formed under “broad-leaved” forests. There are two subtypes: light-grey and grey forest soils.

Light-grey forest soils by an outward appearance are similar to soddy-podzolic soils, as their profile consists of the similar horizons. But podzolic process in them is expressed a bit weaker, as their parent material is mainly carbonatic and forest litter is richer in bases.

Total area of light-grey and grey forest soils is about 2.6mln ha, plowland being that of 2.1mln ha. Such soils are encountered not only in the Forest-Steppe zone but on the so-called “loess islands” of Polissya too.

The below described soil profile of the light-grey forest soil was investigated in the Lokhvytsya district of the Poltava region:

HE 0-22cm: humuso-eluvial horizon and a plow layer; light-grey, light loam, platy, loose, rich in SiO₂, with abundant roots of grasses. Transition very distinct.

Eh 22-34: eluvial horizon; whitish-grey, light loam, powdery-platy, loose, washed from clay particles, streaks of humus-containing material; transition distinct.

I₁(h) 34-67cm: illuvial horizon; dark brown, light to moderate loam, nutty-prismatic in structure, compacted, rich in clay particles, with “colloidal luster” on the facets of structure aggregates, rich in amorphous SiO₂; transition gradual.

I₂ 67-125cm: second illuvial horizon; red-brown, moderate loam, prismatic, compacted, rich in clay particles, with colloidal luster on the facets of soil aggregates (prisms); transition clear and easily detected with 10% HCl.

Pk 125-150cm and deeper: parent material; dull-yellow loess, light loam, rich in carbonates.

Such soil may be used for the cultivation of all zonal field crops, orchards, and berries. The practices of soil improvement should include the deepening of a plow layer, application of organic manures and mineral fertilizers, regular liming and the application of micronutrient fertilizers containing boron, manganese, and molybdenum.

The described soil is characterized by the following characteristics: pH_H2O 5.1; S=16.52meq/100g; d_v=1.35 g/cm³; TP (total porosity) = 48.40%V; Wilting coefficient=5.5%m; Field capacity=20.20%m; OM=3.19% m; Ch.a./Cf.a.=1.91; Total N=0.23%; Total P₂O₅=1080ppm; Total K₂O=17400ppm (1.74%), exchangeable K₂O being less than 1% of the total.

Grey forest soils are encountered mainly in the Western and Central provinces of the Forest-Steppe zone on well drained watershed plateaus and their slopes. In the left-bank province they are encountered as small islands among the dark grey podzolized soils on high right banks of the rivers. The soil described below was investigated on the territory of Vinnitsa agricultural experiment station:

HE 0-23cm: humus-containing eluvial horizon, brownish-grey, silty moderate loam, cloddy, slightly compacted, “dusted” with amorphous SiO₂; transition distinct.

I₁ (h) 23-43 cm: illuvial horizon; “humusified” in the upper part, grey-brown, heavy loam, nutty with cods, compact, rich in earthworm casts and channels, amorphous SiO₂ dusting on the facets of soil aggregates (nuts); transition gradual.

I₂ 43-89 cm: second illuvial horizon but without the streaks of humus –containing material; dark brown, heavy loam, prismatic, very compact, the facets of soil aggregates (prism) are covered with red-brown colloidal films and dusted with amorphous SiO₂; transition gradual.

I₃ 89-119 cm: third illuvial horizon, brown, heavy loam, cloddy-prismatic, compact with colloidal R₂O₃ and SiO₂ on the facets of prisms; transition clear.

Pi 119-140 cm: slightly illuvial loess, yellowish brown, cloddy, less rich in colloidal R₂O₃ and SiO₂. Transition distinct (line of carbonates).

Pk 140-260 cm: brownish yellow loess, light loam, carbonate accumulations in pseudomicellium form.

The practices of soil management are the same as for the previously described soil.

Some soil characteristics: OM=2.3%, pH_KCl=4.5; S=19.98 meq/100g; Hh=3.52meq/100g; V=85%; d_v=1.37g/cm³; D=2.66 g/cm³; TP=48.2%V; WC=6.1% m; FC=24% m; P_{aer.at FC}=15.6% V; Total N=0.13%; Total P₂O₅=872ppm; Total K₂O=14927ppm. Low total content of Mo (2ppm) and Cu (5ppm).

In the previous system of soil classification Dark grey forest soils belonged to the type of grey forest soil (or grey podzolized soils, as it is indicated on the soil map of Ukraine of 1973). In the present day system of soil classification proposed in due time by the “Kharkiv school of Ukrainian Pedologists”, these soils are considered as a subtype within the type of Podzolized soils, another subtype being podzolized chernozems.

Total area of the dark grey podzolized soils is about 1.9 mln ha of which nearly 1.6 mln ha are the plowland. The soils are generally more productive compared with grey forest soils. They are encountered primarily in Western and Central provinces on watershed plateaus with rolling Topography. On the left bank they “adhere to” the right banks of the rivers. Like small “islands” they may be encountered on the loess islands of Polissya. Below is the description of the soil from the pit dug near the city of Kharkiv on a level-surface watershed.

He 0-37 cm: humus –accumulative eluviated horizon; dark grey, heavy loam; cloddy with grains, loose, rich in grassroots; transition clear.

HI 37-68 cm: humus-containing illuvial horizon; brownish grey, light clay; with small-sized nuts dominating among the aggregates, compact; with SiO₂ dusting on the facets of soil aggregates; transition clear.

I 68-105 cm: illuvial horizon; cinnamon- brown, light clay, nutty-prismatic, very compact, red-brown colloidal films on the facets of nuts and prisms, scanty “crotovinas” (dissected mole tunnels); transition clear.

Pi 105-125 cm: slightly illuviated loess; transitive to parent material; brownish dull yellow (wheat straw colored), light clay, cloddy-prismatic, compacted, sparing, colloidal steaks on the facets of aggregates; transition very distinct (detected with 10% HCl).

Pk 125-200 cm: parent material: yellow with brownish tint loamy-clay loess, effervescent with 10% HCl, though without any visible forms of carbonate accumulation.

Care should be taken to maintain the proper nutrient regime of such soils by application of organic manures and mineral fertilizers. Liming should be regular, but not excessive. Full rate of liming calculated by hydrolytic acidity should be applied once every 8 to 10 years.

In this particular soil OM content was untypically high (7.29%). More typical figures are only about half of this value. But the type of humus was humatic-fulvatic (Cha/Cfa=0.72). pH_H2O=7.0; pH_KCl=6.3; S=31.52 meq/100g; Hh=3.87 meq/100g; V=89%; d_v=1.07; D=2.63; TP=59.3%V; WC=13.3m; FC=28.8%m; Total N=0.14%; Total P₂O₅=1238ppm; Total K₂O=18753ppm, exchangeable K₂O being only about 98ppm.

Another subtype of the type of podzolized soils is represented by Podzolized Chernozems. They are more deeply “humisified” compared with dark grey soils and less intensively podzolized. They are encountered in the same places as dark grey soils. The soils below was described near the village of Kibintsy; Mirgorod district, Poltava region:

He 0-41 cm: slightly eluviated horizon of humus accumulation: dark-grey, silty clay with coarse silt fraction domination; 0-27 cm: plow layer, loose, powdery with clods; below plow layer: compacted, granulated, facets of soil aggregates being dusted with amorphous SiO₂. transition clear.

Hpi 41-70 cm: upper transitive horizon; very slightly illuviated, brownish grey, silty clay, compacted, nutty with slight colloidal “varnish” on the facets of nuts, with numerous earthworm channels and casts and some residues of tree roots; transition clear.

PhI 70-96 cm: lower transitive horizon; nonuniformly “humusified”, moderately illuviated, grayish brown, silty clay, with large nuts of soil structure, compacted, with earthworm channels and casts, semidecomposed tree roots and mole channels (crotovinas). Transition gradual.

P(h) 196-120 cm: leached loess; brown with grayish “dirtyness”, clay loam, cloddy, compacted, enriched on crotovinass and earthworm channels. Transition distinct (detected with 10% HCl)

Pk 120-200 cm: parent material; dull yellow loess with pseudomicellium carbonate accumulations.

Total area of podzolized chernozems in Ukraine is about 2 mln ha of which 1.7mln ha belong to plowland. There are the soils of high productivity suitable for all zonal field crops and perennial plantings of fruits and berries. Occasionally they may need liming. Soil OM balance should be maintained. The above-described pedon posses or rather possessed following characteristics: OM=5.19%; soil humus of fulvate-humatic types (Cha/Cfa=1.13); pH_H2O=7; S=22.25 meq/100g; Hh=3.28 meq/100g; V=88%, d_v =1.19; TP=54.6%V; WC=11.5%m; FC=31.5%m; aeration porosity at FC=17.6%V; Total N=0.25%; Total P₂O₅=1268ppm; Total K₂O=18893 ppm of which exchangeable K₂O=164ppm.