8.6 Render the text into Russian using no dictionary:

Humus. The humus which consists of the colloidal residue of organic matter has great effects on soil texture and fertility. Whenever it is present in considerable quantity it imports its black or dark - brown colour to the soil and since dark – coloured materials absorbs more of the sun’s heat than light – coloured ones, its presence tends to rise the soil temperature. Moreover, in well aerated soils humus is constantly undergoing oxidation, with liberation of simple compounds of nitrogen which can be taken up by plant roots. Most important is the fact that humus has many of the properties of mineral colloids – it increases the soil’s power of retaining moisture and it absorbs and holds plant nutrient substances. When organic matter is added to light soils the resulting humus tends to bind the mineral particles into crumbs which absorb and hold water like miniature sponges.

It has already been noted that “row”. What is extremely deep rooted and drought resisting, and on all except very light soils gives the best yields in dry and sunny seasons; it is also more resistant to winter frost than either barley or oats.

Perfect crops of wheat can be grown on heavy loams and clays. Satisfactory crops can be grown on light land in good condition. When wheat is grown on peaty soils quality is usually poor, while the vegetation is luxuriant and the yield of straw very large.

Text 9 Soil Zones

9.1 Read the following international words and translate them: color, finally, climate, zone, factors, horizon, topography, dominate, practice, chance, texture, region, erosion, problem, productive, result, profile, bulldozer.

9.2 Say it in Russian: surface, short grass prairie, tall grass prairie, mixed aspen parkland, boreal forest, moisture effectiveness, A horizon, local topography, soil conservation, conservation tillage, lack of moisture, limiting factor, medium texture, yield, crop failure, wind speed, moister conditions, humid continental climate zone.

9.3 Read and translate the text with the help of a dictionary.

E

After planting, fertilizer is applied

arly settlers noticed that in moving from the south to the north eastern edge of the agricultural zone, the colour of the surface soil changed from brown to dark brown, then to black, dark gray and finally light gray. In the same direction the vegetation changed from short grass prairie, to tall grass prairie through mixed aspen parkland and finally to boreal forest. These changes represent a cooler, wetter climate in northern compared to southern parts – a response to greater “moisture effectiveness”. A soil’s colour can tell us something about its characteristics, particularly how much organic matter it contains. The darker the soil, the more organic matter is present in the A horizon. Areas of predominately one soil colour are called soil zones. The zones are formed as a result of the interaction of the soil forming factors of climate and vegetation. Local topography or parent material variations may dominate. By understanding different types of soils agricultural managers may choose the best techniques for soil conservation and crop production such as summer fallowing, fertilization, rotations, conservation tillage and straw management.

The Brown soil zone is found where the climate is warm and dry. Lack of moisture usually is the main limiting factor to crop production. The vegetation in this zone comprises short prairie grasses and the surface A horizon (topsoil) usually has less organic matter (about 2%) and is thinner (about 12 cm) than similar horizons in other zones. Over three quarters of the soils in this zone are of medium texture (loam) formed on flat to hilly topography.

Dark Brown soils were formed in the central agricultural region with a more productive prairie grass cover yielding A horizons of about 17 cm thick and an organic matter content of 4 to 6%. As in the Brown zone, most soils are of loam texture, but are formed on a generally flat topography. Wind erosion is less a problem, because of lower wind speeds and moister conditions than in the Brown zone. Farmers have a more varied choice of crop rotation, but soil salinity must be watched carefully.

The Black and Dark Gray soil zones roughly correspond to the humid continental climate zone and the aspen parkland vegetation zone. The tall grass and parkland prairie (aspen trees) are much more favourable to good crop production due to slightly cooler temperatures and more effective moisture levels. The abundance of vegetation, decomposing after it dies, adds more organic matter to the soil. The cycle continues, the rich black soil is formed. This extra organic matter in black soils gives them their dark colour. A horizons in this soil zone are usually 20 to 25 cm deep and contain 7% organic matter. Wind erosion and salinity are much less of a problem than in Brown and Dark Brown soils.

The Gray zone occurs further north, where the climate is cooler and wetter. The cooler temperatures result in an increase in soil moisture. These higher more moisture penetrates the soil profile and leaches minerals and nutrients out of the upper layers. As a result, gray top soils tend to be shallow and less fertile than black soils. The A horizon of native soils usually have a layer of organic matter 5-6 cm deep. Surface horizons in this zone are low in organic matter (often less than 2%) and are deficient in major plant nutrients such as nitrogen, phosphorus and sulphur. Soil acidity is a problem in some areas. Parent materials in this zone are varied and extensive areas of organic soils can be found. A major problem for farmers is wet land in the spring time and early frosts.

Forest soils lie north of agriculture boundary. The transition zone comprises parkland and tall grass prairie and rapidly changes to boreal forest as one moves north. Further north, much of the land is covered by the rock with only a thin layer of soils to support vegetation such as mosses, lichens and shrubs as well as trees such as jack pine and black spruce.

9.4 Give English equivalents: сельскохозяйственная зона, цвет почвы, органическое вещество, почвообразующие факторы, материнская порода, внесение удобрений, севооборот, соленость почвы, щелочность почвы, кислотность почвы, уровень влажности, обилие растительности, ветровая эрозия.