Understanding Substances that Increase Soil Fertility

When aiming to improve the growth of plants and increase food production, farmers often add substances to the soil. These substances help make the soil more productive, which is known as increasing its fertility. The question asks about a commercially produced chemical substance specifically used for this purpose.

What Improves Soil Fertility?

Soil fertility is key to successful plant growth. It's about the soil's ability to provide plants with everything they need, like nutrients, water, and support. To enhance soil fertility and get a better crop yield, materials rich in essential plant nutrients are added to the soil. These materials are broadly known as fertilisers.

Examining the Options

Let's look at the functions of the substances listed in the options:

• Herbicides: These chemicals are used to kill weeds, which are unwanted plants that compete with crops for resources. While removing weeds can indirectly benefit crops, herbicides do not directly increase soil fertility.
• Pesticides: This is a general term for chemicals used to kill pests that damage crops, such as insects, rodents, or fungi. Pesticides protect plants but do not add nutrients to the soil or improve soil fertility in themselves.
• Insecticides: These are a type of pesticide specifically designed to kill insects. They protect crops from insect damage but do not contribute to increasing soil fertility.
• Fertilisers: These are substances, either natural or synthetic (commercially produced chemical fertilisers), containing plant nutrients. When added to the soil, fertilisers supply these essential nutrients, directly improving soil fertility and supporting healthier plant growth, leading to increased crop yield.

The Role of Fertilisers in Soil Fertility

Commercially produced chemical fertilisers are manufactured specifically to provide plants with necessary nutrients like nitrogen, phosphorus, and potassium in easily absorbable forms. By replenishing these nutrients, fertilisers significantly improve soil fertility, which is crucial for modern agriculture to achieve high crop yield.

Therefore, the commercially produced chemical substance that increases soil fertility is fertilisers.