Biofertilizers (Biology)

In the making of compost, the process of decomposition in pits is accelerated by earthworms and other microbes like bacteria and fungi. Hence, statement of option (c) is incorrect, while other three statements are correct.

Earthworms are key players in composting, particularly in a process called vermicomposting. They consume organic matter, break it down, and excrete it as castings, which are rich in nutrients and beneficial microbes. Additionally, their tunneling activity improves aeration and drainage in the compost pile.

Bacteria and fungi are essential for breaking down complex organic compounds into simpler ones, releasing nutrients and heat in the process. Different types of microbes work at different stages of composting, with bacteria often dominating the initial stages and fungi and actinomycetes playing a larger role later.

The combined action of earthworms and microbes significantly speeds up the decomposition process compared to relying solely on natural decomposition. This results in faster production of usable compost.

The capability of nitrogen use efficiency can be increased by all of the given options; frequent use of fertilizer in split application, use of nitrogen inhibitors and by using the slow release of nitrogen fertilizer. There are various bacteria in various crops which are liable for nitrogen stabilization.

Generally, the nitrogen-fixing bacteria are found in the roots of legumes (plants which give pulses) in special structure called root-nodules.

Rhizobium is the bacteria that live in symbiotic association with the root nodules of the leguminous plants. Fixation of nitrogen cannot be done independently.

That is why rhizobium requires a plant host. Rhizobium is a vital source of nitrogen to agricultural soils including those in arid regions. They convert dinitrogen into ammonia. Ammonia, being toxic in nature is rapid.

Plants that contribute to nitrogen fixation include the legume family – Fabaceae – with taxa such as clover, pigeon pea, chickpea, soyabean, alfalfa, lupinus, peanut, and rooibos, etc.

They contain symbiotic bacteria called Rhizobia within nodules in their root systems, producing nitrogen compounds that help the plant to grow and compete with other plants. Amaranth, purslane (kulfa) and spinach are not nitrogen-fixing plants.

Legume crops such as gram, peas, beans, peanuts, soy, are helpful in nitrogen fixation. Roots of legumes have nodules inside which Rhizobium bacteria are present. These bacteria take up nitrogen from the atmosphere and convert it into ammonia. Paddy fields generally lack nitrogen which is supplemented by the fertilizers.

The Rhizobium japonicum bacteria is responsible for the nitrogen fixation in soybean. Soyabeans inoculated with Rhizobium japonicum strains that synthesized the hydrogenase system fix significantly more nitrogen.

Leg-haemoglobin is found in root nodules of leguminous plants such as alfalfa and soybean. It is crucial for supplying sufficient oxygen to root nodule bacteria for nitrogen fixation to occur.

The earthworms are called the "Ploughers of the soil." The earthworms act like ploughs by naturally ploughing our soil and aerating it as well as letting in the necessary supply of air and water, helping plants to grow. They even help by breaking down organic matter, like leaves and grass by converting them into things that plants can use.