Agrochemicals: Types and their effects

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:

1. May kill beneficial bacteria

2. Increase nitrate level in soils

3. Alter the pH of the soil

4. Residual effect

5. Kill soil organisms

6. Toxicity and reduction in soil quality

2. Effects on water:

1. Water becomes unfit for consumption

2. Can promote the growth of algae

3. Leads to eutrophication due to excessive chemicals

4. Affect aquatic animals due to water pollution

3. Effects on air:

1. Residues and particles of these chemicals can lead to air pollution.

2. Pesticides drift happens when air carries agrochemicals particles from one place to other.

3. More amount of spray evaporation may happen due to low relative humidity and higher temperatures.

4. Effect surrounding organisms’ health due to inhalation of polluted air.

4. Effects on human health:

1. It causes variety of health effects, from simple skin and eyes irritation.

2. It also effects the nervous system, causes cancer and also reproductive problems.

3. Can cause nerve damage, infertility, hormones disorders and neurotoxicity.