In recent years, various types of agricultural plastic films have been widely used as greenhouses and plastic film coverings, and have played a positive role in the production of vegetables, peanuts, rice, and other crops. However, if there is poor management and recycling, a large number of residual film fragments will be scattered in the fields. Unexpected negative effect. According to the survey, the annual agricultural film residues in farmland in China is 3.06kg/ha, the residual rate is 1.3%, the plastic film is 10.5kg/ha, the residual rate is 12.3%, and even some vegetables and peanuts have a residual rate of up to 40%. -60%. In addition, the components of urban waste have also undergone great changes, and various types of waste that are not easily or degradable in the environment such as plastic products, glass sheets, and scrap metal account for a considerable proportion. Some of the wastes in some developed country cities account for about 10%-25% of the above-mentioned wastes, of which plastic waste accounts for 6%-15%, and this kind of waste is also increasing in China. If the sorting and recycling are not complete, it will be transported into the farmland together with other ingredients as fertilizer, which will have an adverse effect on the growth of soil and crops. 1. Damage to soil-plant system by cover film and residual film Since the rainfall leaching is blocked and the temperature in the shed is significantly increased, the soil evaporation intensity is high. When there are more soluble salts in the subsoil and groundwater, salt will accumulate on the surface and cause excessive salt damage to the crop. This problem needs attention in areas where there is a threat of salinization in northern China, and in areas where coastal beaches are rich in salt. 2. Under low temperature conditions, the microbial activity is weakened, which is not conducive to the transformation of nitrogen into effective nitrogen. If ammonia nitrogen is used excessively, the crop absorbs excessive ammonia nitrogen and causes deeper leaf color and poor stem and leaf development; if too much organic fertilizer is applied, ammonia and nitrous acid escape from the soil after conversion to ammonia and nitrous acid. When ammonia nitrogen reaches a certain concentration in the shed atmosphere, it will cause harm to the aerial parts of vegetables. 3. Insufficient illumination in the shed, reduced photosynthesis, and decreased disease resistance of crops. In addition, soils in sheds are continuously used as the same crops for many years. Changes in soil microbial population will also lead to increased soil and crop diseases. Second, after the agricultural film pieces enter the farmland, the impact on soil physical properties and crop growth. Due to the obstruction of plastic residues, soil moisture movement is hindered, and porosity and permeability are reduced, which is not conducive to circulation and exchange of soil air, resulting in high carbon dioxide content in the soil, which is not conducive to the normal growth and development of crops. 2. The poor physical properties of the soil led to difficulties in the rooting of the crops, resulting in a decrease in fertilizer absorption and water absorption and a reduction in production. In the soil with plough layer and residual film, it is difficult for the root system of the crop to penetrate the plastic film to form a curved transverse development, resulting in shorter root system, smaller root nutrient range, and more obvious reduction in yield. According to the survey, land that has been continuously covered with agricultural film without completely removing the remaining film is generally reduced by about 10%, and some even reach 26%. 3. Some plastic products (such as polyvinyl chloride plastics) or additives contain harmful components and are toxic. Contact with seeds or young sprouts will inhibit seed germination or cause burns to shoots and seedlings. In addition, plasticizers (phthalate ester compounds) in plastic products have toxic effects on plants, especially vegetables, and phthalate ester compounds can also enter the environment from various sources, pollution Foods, grains, vegetables, etc., and there is a clear enrichment, they enter the food chain affect the health of people and livestock. Diisobutyl phthalate is mainly volatilized from the film to the air, and then enters the mesophyll cells through the pores and pores. The growing points and young leaves of plants are more active and susceptible to damage. Its toxic effect is mainly to destroy chlorophyll and hinder the formation of chlorophyll, affect photosynthesis, growth retardation, plant type dwarf slender, severe and even death. The typical symptoms of vegetable damage by diisobutyl phthalate in the film are chlorosis, leaf yellowing or curling. Such as sensitive canola, cauliflower, cucumber and tomato, etc., the performance of new leaves and young shoots into yellow-white, old leaves and cotyledon edges yellow, small and thin leaves, growth is weak, and gradually dry and die. The symptoms of the victim usually appear 6-10 days after the film is covered. The long-time coverage, high temperature, high humidity, low seedling age, and poor ventilation are serious consequences. Diisobutyl phthalate also has hydrophilicity, which can contain 10,000 to 20,000 in the water droplets on the inner wall of the film. Water droplets contact the blades, which can cause harm and yellow spots on the leaves. The final cell necrosis and dry. Third, prevention and control measures 1. Strengthen publicity efforts and call on people to minimize the use of plastic products for daily use (such as food bags, garbage bags, etc.). 2. It is necessary to timely and thoroughly remove the abandoned agricultural plastic film and reduce its residual amount in the soil. 3. Optimize and improve the recovery and management of waste plastic products from the price and management system, so that waste plastics can be recycled. 4. Develop new environmentally friendly agricultural films such as controlled photolysis and thermal decomposition (50°C--60°C) to reduce the amount of agricultural residues. Use plasticizers that are small in molecular weight, low in biological toxicity, and easily degraded to minimize their damage to food, vegetables, and humans.
Yingmed offers you a series of cotton or non woven gauze for your choice. 100% cotton materials include Gauze swabs, Gauze roll, Prewashed laparotomy sponge, Wow gauze Bandage, Absorbed cotton wool and Gauze ball. Paraffin impregnated gauze pad is special for fire scalding. Non woven swabs are various from size, ply, edge, color, sterile or non sterile, and package.
Other cotton materials like Cotton elastic bandage, Paris bandage and Trangle bandage, cotton ball and cotton swab will be found in our other category.
Natural Cotton Roll,Absorbent Cotton Roll,Medical Cotton Wool,Medical Non-Woven Swab
NINGBO YINGMED MEDICAL INSTRUMENTS CO.,LTD , https://www.chinayingmed.com