Soil Science and Fertilizers

The peel of fruits and vegetables contain cellulose and pectin. These are the biodegradable form of wastes. They can be decomposed with the action of the microbes. These wastes are used for the production of compost which can be used as manure for the agricultural crops. 

Compost acts as a soil conditioner that helps buffer soil pH and improves soil structure, effectively mitigating issues caused by chemical fertilizers.

Composting provides multiple benefits: it reduces landfill volume, produces useful soil amendments, and decreases reliance on synthetic chemicals.

The roots of the plants are held firmly in the soil. Different types of soil have different texture and particles. They have different levels of minerals and nutrients embedded in them. Roots absorb water from the soil by the process of osmosis. Along with water, mineral nutrients also enter the soil.

(a) Soil; because man and animals are biotic factors and temperature is climatic factor.

Top soil is the topmost and outermost layer of the soil, which is usually 2 inches to 8 inches layer. It is generally dark in colour due to humus, i.e., partially decayed organic matter, soil particles and living organisms as soil bacteria etc. 

Decomposers also break down the bodies of dead organisms resulting in nitrogen being returned to the soil as ammonia. In some conditions, denitrifying bacteria in the soil break down nitrates and return nitrogen to the air. This is usually in waterlogged soil. Hence, making it unavailable for plant roots. So, the correct option is 'Denitrifying bacteria'

Green manures are added to the soil to increase the productivity. Manures is of natural origin. The presence of nutrients in manure have a great role in increasing soil fertility. Biofertilizers are organisms which enrich the soil with nutrients e.g., Rhizobiumin symbiotic association with legume plants.

As rock becomes broken down through a variety of processes, such as weathering and erosion, the particles become ground smaller and smaller. The four main bases in a soil are Nitrogen, Phosphorus, Iron and Potassium.

Soil provides the physical medium, water, and mineral nutrients necessary for crop growth, making it the most fundamental component for agriculture.

Humus is the dark, organic material that forms in soil when plant and animal matter decays. It is a vital component of fertile soil.

Microorganisms are the primary decomposers in the soil. By breaking down organic matter, they accelerate the production of humus, which enriches the soil.

Humus improves soil structure, increases water retention, and provides essential nutrients, all of which directly enhance soil fertility.

Compost is organic matter that has been decomposed and recycled as a fertilizer and soil amendment. Compost is a key ingredient in organic farming. At the simplest level, the process of composting requires making a heap of wetted organic matter known as green waste (leaves, food waste) and waiting for the materials to break down into humus after a period of weeks or months. 

In shifting agriculture, after two or three years of producing vegetable and grain crops on cleared land, the migrants abandon it for another plot. Trees, bushes and forests are cleared by slashing, and the remaining vegetation is burnt. The ashes add potash to the soil. Then the seeds are sown after the rains.