1. Humus is found in the topmost layer of soil (A-horizon).

2. Humus is a black or brown colored substance which makes the soil fertile.

3. It is an important source of nutrients for plants, and it helps the soil absorb water and air.

4. There are many ways to promote humus, including-

- Leaving crop residues in the field

- Using livestock manure

- making compost

The Madal is not an Indian musical instrument. The Madal is a traditional percussion instrument that is commonly used in Nepal. It is a double-headed drum played with both hands and is an integral part of Nepali folk and classical music. While there may be some cultural overlap and influences between India and Nepal, the Madal is not considered an Indian musical instrument.