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Humus has a characteristic black or dark brown color and is an accumulation of organic carbon. Besides the three major soil horizons of (A) surface/topsoil, (B) subsoil, and (C) substratum, some soils have an organic horizon (O) on the very surface. Hard bedrock (R) is not in a strict sense soil.
Humins are not considered to be a dangerous substance according to officially recognized hazardous material classification systems based on physical-chemical properties such as flammability, [8] explosiveness, susceptibility to oxidation, corrosiveness or eco-toxicity. [9]
Age and origin of the source material determine the chemical structure of humic substances. In general, humic substances derived from soil and peat (which takes hundreds to thousands of years to form) have higher molecular weight, higher amounts of O and N, more carbohydrate units, and fewer polyaromatic units than humic substances derived from ...
Plastic film is a thin continuous polymeric material. Thicker plastic material is often called a "sheet". Thicker plastic material is often called a "sheet". These thin plastic membranes are used to separate areas or volumes, to hold items, to act as barriers, or as printable surfaces.
Sheet moulding compound (SMC) or sheet moulding composite is a ready to mould glass-fibre reinforced polyester material primarily used in compression moulding. [1] The sheet is provided in rolls weighing up to 1000 kg. Alternatively the resin and related materials may be mixed on site when a producer wants greater control over the chemistry and ...
A common post-extrusion process for plastic sheet stock is thermoforming, where the sheet is heated until soft (plastic), and formed via a mold into a new shape. When vacuum is used, this is often described as vacuum forming. Orientation (i.e. ability/ available density of the sheet to be drawn to the mold which can vary in depths from 1 to 36 ...
Plastic mulch is often used in conjunction with drip irrigation. Some research has been done using different colors of mulch to affect crop growth. Use of plastic mulch is predominant in large-scale vegetable growing, with millions of acres cultivated under plastic mulch worldwide each year. [1] Disposal of plastic mulch is an environmental ...
Compost: fully composted materials are used to avoid possible phytotoxicity problems. Materials that are free of seeds are ideally used, to prevent weeds being introduced by the mulch. Rubber mulch: made from recycled tire rubber. Plastic mulch: crops grow through slits or holes in thin plastic sheeting. This method is predominant in large ...