Protect soil against erosion

Depending on product functions, reclaimed fibres can be looked upon as conventional in technical textiles, particularly in nonwovens (mobility textiles which mainly serve to cover up surfaces or to insulate materials, agrotextiles, and geotextiles which are used to protect soil against erosion). In all these cases, reclaimed fibres are used because of low prices, or because they merely cover something up. However, reclaimed fibres are also applied in nonwovens to utihze highly valuable functional components. This concerns fibres which would not be available at a competitive price if made from primary materials, such as... 

Erosion is particularly damaging to recently-cultivated soils that have no vegetative cover and where contour farming is not practiced. Much attention is now being given to farming systems that protect soil against raindrop impact, and decrease the velocity of the runoff water. 

As already mentioned, hydrophilic polymers can be used to form thatch that protects seeds and soil against erosion. In particular, poly(vinyl alcohol)... 

Mother earth never attempts to farm without live stock, she always raises mixed crops great pains are taken to preserve the soil and to prevent erosion the mixed vegetable and animal wastes are converted into humus there is no waste the processes of growth and the processes of decay balance one another ample provision is made to maintain large reserves of fertility the greatest care is taken to store the rainfall both plants and animals are left to protect themselves against disease. 

Animal manures are sometimes used as trash mulches and merely left on the surface. In such cases decomposition is retarded because of lack of moisture, and some of the ammonia formed may be volatilized. Most of the nutrients are, however, leached into the soil and any losses sustained are balanced against the benefits derived from soil protection against erosion. The more bedding material in the manure, the more effective this type of use is likely to be. 

Densely growing crops on slopes are less erosion prone and have a more prolific root system, which protects the soil against water and wind loss. The residual effects of greater organic production improves soil aggregation. 

For protection against erosive forces from weather, flora and fauna, etc. the permeable cover layer should have a thickness of at least 1.5 m. The protective layer can be prepared from sand or from cohesive soil. If cohesive soil is used as a protective layer, a foil or gravel layer must be used to separate the cover layer from the underlying clay in order to prevent water accumulation. 

Protection of soil against rain, erosion, splashing, washing, compaction, etc. 

A wooden or metal containment box surrounding the treated area is commonly used when a small quantity of test material is to be applied. The box, typically rectangular in shape and partially buried beneath the soil surface, serves to isolate the treated area from surrounding soil and protect against wind and water erosion. A one- to two-nozzle application boom that moves along guy wires or tracks is often used to ensure even application. Radiolabeled materials having two or more label positions often serve as replicates in these studies. 

Researchers working for the Nebraska Agricultural Experiment Station developed the stubble-mulch or crop residue mulch practice, a highly effective method of soil erosion control (Douley and Russel, 1939). Stubble mulching used subsurface tillage implements that left crop residues on the soil surface and provided some protection against wind and water erosion (Zingg and Whitfield, 1957). 

The focal areas of this book have relatively minor relationships to the primary formation of the Earth s crust which has caused a certain distribution of the chemical elements. They mainly deal with products of the alteration of the crust in geologic processes. We can presently still observe the weathering of solid rocks, the erosion of mountain ridges, and the transport of eroded materials as suspended and dissolved constituents in river and rain water, in ice and wind. In-situ weathering forms soils, and soils are the basis of food production for human nutrition. Therefore, soUs need special protection against the impact of toxic substances (see Part I, Chapters 4 and 5). 

Severely-eroded soils may have nearly all of the topsoil removed in certain places where the full impact of the wind is exerted, and where there is no protection against such erosion. Since topsoil consists of both small and large particles, the soil as a whole is... 

Chepil (1957) states that the amount of vegetative material required to protect against wind erosion depends primarily on surface roughness, degree of cloddiness, size of field, and strength of the wind. Five hundred pounds per acre of air-dry wheat stubble may be adequate on slightly erodible soil, one ton on moderately susceptible soil, and at least 4 tons on very erodible dune material. The effectiveness per unit of added material decreases as the amount added increases. 

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