SOIL DEGRADATION & CONSERVATION – 06
First, Lichens, which grow on rock, appear in a destroyed region. The lichens help break down the rock. Then, as lichens die and decompose, and weathering breaks apart rock, soil begins to form. As soil becomes richer, small plants like Mosses And Ferns appear, and the lichens start to disappear. The soil continues to become richer as plants continue to die and decompose, and flowering plants and grasses appear, bringing insects to the region. In time, Shrubs And Small Trees Cover the region, creating a suitable habitat for reptiles, birds, and mammals. As the shrubs and trees grow, smaller plants die from lack of sunlight and add more organic material to the soil. Eventually, the shrubs and trees die because taller trees cover the region. This all happens gradually over a long period of time.
THE INFLUENCES OF HUMAN ACTIVITIES ON SOIL FERTILITY AND SOIL EROSION.
Soil is a non-renewable resource that once it is eroded it is not renewed. Soil erosion is the permanent change of the main characteristics of soil that could see it lose its fertility, pH, colour, humus content or structure. Soil erosion occurs naturally by wind or harsh climatic conditions but human activities include overgrazing, overcropping and deforestation. Overgrazing occurs when farmers stock too many animals such as sheep, cattle or goats on their land. The animals damage the soil surface by eating the vegetation and either digging into wet soil or compacting dry soil with their hooves. Overcropping is when the land is being continuously under cultivation and is not allowed to lie fallow between crops. This constant farming of the land reduces the soils ability to produce valuable humus for soil fertility as it is constantly being ploughed or stripped for crop growth. The soil becomes drier and less fertile.
is the cutting down of large areas of forests leaving an open, exposed landscape. Deforestation occurs for many reasons such as the Sale Of Wood, Charcoal Or As A Source Of Fuel, while cleared land is used as pasture for livestock, plantations of commodities, and settlements. The removal of trees without sufficient reforestation has resulted in damage To Habitat, Biodiversity Loss And Aridity (Drying Of Soil). THE NORTH AMERICAN PRAIRIES AND COMMERCIAL FARMING The problems occurred were Increasing Salinity, Soil Erosion And Loss Of Soil Fertility. Farmers managed to reduce salinity and erosion, to reduce salinity summer fallowing or leaving bare soil for long periods were stopped or reduced. Snow fences or barriers enabled snowdrifts to pile up which provide water then they melt in & to reduce erosion is used Contour Ploughing– along the contour lines instead of up and down slopes traps soil and water. Strip Cropping – growing as flax and tall wheatgrass at right angles to the wind.