Tag: evs

For the development of any seedling or plants, both light and dark phases are required for proper growth. The seedlings that are growing requires light as the carbon sources in them and the other nutrients are present in its complete amount but when they are placed in the darkness they are unable to perform certain functions so there is less production of nutrients resulting in lower fresh weight. Thus, the light phase is the phase on which growth of the plant is dependent upon. 

The dry seeds of the pea have more dry weight as all the moisture in the seeds got absorbed and becomes hard due to the loss of water. In the germinated seed, more water is present so its fresh weight will be higher than the dry seed. Fresh weight is the weight of the living part of the plant while dry weight is the weight of the dry plant part.

Rate of decomposition of detritus depends upon chemical mature of detritus, temperature, soil moisture and soil pH. A soil temperature of 25oC and more hastens decomposition. A low temperature of less than 10oC reduces the rate of decomposition. Moisture is essential for decomposition. Excessive moisture also impedes decomposition probably due to anaerobiosis. Neutral and slightly alkaline soils are rich in detritivores, earthworms and decomposer microbes. Acidity decreases the number of detritivores and earthworms. Soil with a small amount of lignin/chitin/cellulose and rich in nitrogen and water-soluble substances(like sugars), decomposes rapidly.

As we know, the soil is made up of many layers. These layers are called horizons. The topmost among these layers is A horizon. It is the layer parallel to the soil surface. It is rich in organic matter. It also contains humus, which is necessary for the proper growth of plants. Thus, we can say that A horizon has many necessary ingredients to support the plant and animal life.

The horizon B is also known as the layer of subsoil. It is light brown in colour. it has lots of iron and clay minerals accumulated inside it. this layer contains more soluble minerals and clay inside it and so the plant roots reaching here can get maximum mineral content for their growth and development.

Soil is one of the most important abiotic resources of the environment. It provides habitat to a vast number of living organisms. It holds the roots of plants and trees. It provides the necessary nutrients to the plants when their roots absorb water from the soil, along with minerals and organic matter present in the form of humus in the soil. Soil also has spaces between its particles, providing space for air and water to percolate into it. So, the soil is a mixture of minerals, organic matter, air, and water.