1, which pollutes air and water environment and causes soil hardening.
Pesticides lost to the environment float into the atmosphere through evaporation and transpiration, and the floating pesticides are adsorbed by dust in the air. Spread with the wind. Causing atmospheric environmental pollution. Pesticides in the atmosphere flow into the water again through rainfall, thus polluting the water environment and causing harm to people, especially aquatic organisms. At the same time, pesticides lost to the soil will also cause soil hardening.
2、? Enhance the resistance of bacteria and pests to pesticides.
Long-term use of the same pesticide will eventually enhance the drug resistance of bacteria and pests. In the future, in order to control the same kind of germs and pests, the dosage of pesticides must be continuously increased, otherwise the purpose of eliminating germs and pests cannot be achieved. Form a vicious circle.
Step 3 kill beneficial creatures
Most pesticides kill all kinds of organisms indiscriminately, including those beneficial to people, such as frogs, bees, birds and earthworms. The reduction or extinction of these beneficial insects and birds actually reduces the natural enemies of pests and will lead to an increase in the number of pests and affect agricultural production.
4, wild animals and livestock poisoning
Wild animals and livestock eat food contaminated by pesticides, which can cause acute or chronic poisoning. The most important thing is that pesticides affect the reproductive ability of organisms. For example, many birds and poultry are affected by pesticides, and the weight of eggs is reduced, and the eggshells are thin and easily broken. The extinction of many wild animals is directly related to pesticide pollution.
5. The harm of pesticides to human health
There are over 500 kinds of synthetic chemical pesticides. The widespread use of these pesticides not only causes environmental pollution, but also harms human health.
⑴? organophosphorus pesticide
(2) Organochlorine pesticides
6. Harm of pesticides to animals and plants
(1) hinders the deep holes of crop roots and the absorption of soil moisture, resulting in weak seedlings, dead seedlings, lodging and yield reduction.
⑵ Residual fragments will also enter the food of cattle, sheep and other poultry with the orange stalks and feed of crops. After livestock take the residual film fragments by mistake, it can lead to gastrointestinal dysfunction, obesity decline and even death.
(3) Burning sundries will cause secondary air pollution.
(4) Some residual films are blown to the corners of fields, ditches, ponds and rivers, or hung on trees, causing environmental hazards.
Benefits:
Agricultural function
China is a populous country, and grain production plays an important role in the development of agricultural production. Usually, the way to increase grain output is to expand the cultivated land area or increase the output per unit area.
According to the national conditions of China, there is little potential to continue to expand the cultivated land area. Although there are still many uncultivated land in China, most of them have problems of high investment and great difficulty. This determines that the way to increase grain production in China must be to increase the output per unit area.
Fertilization can not only improve soil fertility, but also improve crop yield per unit area. Chemical fertilizer is the most basic and important material input in agricultural production.
According to FAO statistics, chemical fertilizer accounts for about 40% ~ 60% of the total crop yield increase. China can feed 22% of the world's population with 7% of the world's arable land. It can be said that chemical fertilizer played a decisive role.
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