How does humus improve fertility of sandy soil?

Humus improves the fertility of sandy soil in several ways:

1. Water retention: Sandy soil has large particles that do not hold water well. Humus, which is rich in organic matter, acts like a sponge and helps retain moisture in the soil. This allows plants to access water for a longer period, reducing the risk of drought stress.

2. Nutrient retention: Sandy soil is often deficient in essential nutrients because they can easily leach out due to the coarse texture. Humus acts as a nutrient reservoir, binding and storing nutrients in its organic structure. This prevents them from being washed away and makes them available for plant uptake.

3. Soil structure improvement: Sandy soil lacks structure and tends to be loose and easily eroded. Humus helps to bind the soil particles together, creating aggregates that improve soil structure. This enhances the soil's ability to hold water, nutrients, and air, creating a more favorable environment for plant roots.

4. Microbial activity promotion: Humus provides a food source and habitat for beneficial soil microorganisms. These microorganisms break down organic matter, releasing nutrients in a form that plants can absorb. They also help to suppress harmful pathogens and improve overall soil health.

5. pH buffering: Sandy soil tends to be acidic, which can limit nutrient availability to plants. Humus has a natural buffering capacity, helping to maintain a more neutral pH range. This allows for better nutrient uptake by plants and promotes optimal growth.

Overall, the addition of humus to sandy soil improves its fertility by enhancing water retention, nutrient availability, soil structure, microbial activity, and pH balance.