Q1.
You may have seen gardeners in your school or in a field near your house collecting dry leaves and plant waste and putting them into pits. Do you now understand why they do this?
Answer
Yes — they are making natural manure. The pit is Activity 2.7 done on a larger scale.
What happens in the pit:
- Dry leaves and plant waste are collected together, so that the microorganisms have a large, concentrated supply of food in one place.
- Covering the heap keeps it at a suitable temperature and holds the moisture in — manure formation occurs at optimal temperature and appropriate moisture level.
- Fungi and bacteria break down the complex substances of the leaves into simpler substances rich in nutrients — decomposition.
- The dark manure that forms is dug back into the soil, and those nutrients go to the next crop.
Why not simply burn the leaves: burning destroys the material and gives nothing back except ash and smoke. Letting microbes decompose it returns the nutrients to the soil and increases its fertility — the microbes recycle the waste instead of removing it. This is also why decaying plants and fallen leaves seem to disappear from a garden on their own after some time; microorganisms have decomposed them.