Agrochemicals or agrichemicals, is a common name given to chemicals which are used in agriculture, to aid plants and crops growth and safety. Agrochemicals were manufactured to protect agricultural crops from pests and for augmenting crop yields. It is a costly input for agriculture.
Classifications of Agrochemicals:
In most of the cases, agrochemicals refer to pesticides which include insecticides, herbicides, fungicides, rodenticides, molluscicides, and nematicides. Agrochemical also includes fertilizers and soil conditioners.
Pesticides: Pesticide is a chemical or a substance used to destroy or control some types of plants or organisms also known as pests, which are harmful to cultivated plants or to animals. Pesticides mostly work through poisoning pests.
Insecticides: It is used to destroy insects. Insecticides can be ovicides that kill eggs, larvicides to kill larvae. Pesticides examples: Organochlorines, organophosphates, carbamates, and pyrethroids.
Herbicides: It is used to control or kill weeds and herbs. Herbicides examples: Gramoxone and glyphosate.
Fungicides: It is used for controlling fungi and oomycetes. Fungicides examples: Mankocide.
Algaecides: used for controlling algae. Also known as algicides.
Rodenticides: It is used to prevent spread of rodents like rat, mice. Examples: Klerat.
Molluscicides: used to control molluscs like snails and slugs. Examples: Slugit.
Nematicides: It is used to control or killing nematodes. Examples: Furadan.
Fertilisers: This are chemical compounds used for promoting plant growth. They are used to mitigate nutrient deficiency in the soil. Typically, it is applied to soils or to plant tissues. Fertilisers can be categorized into two categories: organic and inorganic fertilisers. Organic fertilisers are naturally existing substances prepared through natural processes. Inorganic fertilisers, also referred to as synthetic fertilizers are manufactured artificially using chemical processes by utilizing natural deposits, which are altered chemically.
Soil conditioners: To keep all soils in good condition, the best thing to do is to add things that keep it in good condition. These good things are called soil conditioners that includes manure, compost, peat, livestock manures and leaves. All these things are laid on top of the soil and then mixed. Soil conditioners enhance aeration and water holding capacity of the soil.
Liming and acidifying agents: Soils sometimes can be too acidic or too alkaline for proper growth of crops. In these cases, liming and acidifying products are added to soil to adjust its pH. When the soil is too acidic, calcite on the form of powdered limestone is added primarily, whereas for more alkaline soil sulfur compounds are added to neutralize.
Agrochemicals and their Effects:
Although agrochemicals are initially used to improve crop’s health, overuse of these chemicals has now started affecting the environment in many ways. Excessive utilization of these chemicals generate residues that cause nutrients imbalance and reduction of the yielding capacity of crops.
1. Effects on Soil:
May kill beneficial bacteria
Increase nitrate level in soils
Alter the pH of the soil
Kill soil organisms
Toxicity and reduction in soil quality
2. Effects on water:
Water becomes unfit for consumption
Can promote the growth of algae
Leads to eutrophication due to excessive chemicals
Affect aquatic animals due to water pollution
3. Effects on air:
Residues and particles of these chemicals can lead to air pollution.
Pesticides drift happens when air carries agrochemicals particles from one place to other.
More amount of spray evaporation may happen due to low relative humidity and higher temperatures.
Effect surrounding organisms’ health due to inhalation of polluted air.
4. Effects on human health:
It causes variety of health effects, from simple skin and eyes irritation. It also effects the nervous system, causes cancer and also reproductive problems. In addition, this kind of chemicasCan cause nerve damage, infertility, hormones disorders and neurotoxicity.
Moreover, agricultural chemical inputs and their environmental impact derived from the production of wheat, maize and rice seem to be main focal point. For environmental objects impacted by agricultural chemicals, particular attention in the literature has been paid to soil, air and water, studying the potential risks of environmental pollution to fishes, bees and human health. Major concern is given to the process of environmental pollution caused by agricultural chemicals. For example, the impact process of excessively using agricultural chemicals on nitrogen and phosphorus cycles, as well as water eutrophication and other problems caused by this process, has raised widespread concern. Close attention has been paid to methods to control these negative effects. For example, these is research about methods to biodegrade nitrogen, phosphorus and other chemical pollutants in environmental media, to achieve the sustainable development of agriculture.
With the increase of chemical fertilizer, the pollution of agricultural soil by chemical fertilizer is more and more serious. A large number of chemical fertilizer loss, so that the harmful substances in chemical fertilizer and excess ammonia, phosphorus and other nutrient elements cause pollution to the soil, thus deteriorating the physical and chemical properties of the soil. Long term excessive application of chemical fertilizer will change the pH value of soil, acidify or alkalize the soil, and directly affect the normal growth and development of crops; at the same time, excessive or improper application of chemical fertilizer will cause adverse effects on soil microorganisms, resulting in the reduction of soil organic matter and the decline of soil fertility.
Pesticides play an active role in agricultural production and play an important role in the integrated control of plant diseases and insect pests. However, in the process of using pesticides, most of the applicators can not use them reasonably, which leads to the decrease of pesticide utilization rate, the widespread abuse of pesticides, the frequent occurrence of drug accidents, the serious environmental pollution, the high residue of agricultural products, and seriously affects the quality and efficiency of agricultural products in agrochemistry.