The soil's acidity level plays a significant role in fertility. The number of nutrients contained in the soil can also determine whether it will remain fertile or become infertile. Bacteria are present in the greatest amounts. They contribute to major mineral recycling such as Nitrogen, Phosphorous, and Carbon, etc. Nitrogen fixers are present in soil which usually enhances the available nitrogen to plants and hence fertility. Bacteria help in fixing atmospheric nitrogen and increase the nitrogen available for the plants. Bacteria decompose the decaying matter and increase the nutrient content. They also help in improving the texture and quality of the soil. Microbes increase soil fertility through nutrient recycling such as carbon, nitrogen, sulphur, and phosphorus. Soil fertility decline occurs when the quantities of nutrients removed from the soil in harvested products exceed the quantities of nutrients being applied. In this situation, the nutrient requirements of the crop are met from soil reserves until these reserves cannot meet crop demands.

Bacteria change the soil environment so that certain plant species can exist and proliferate. Where new soil is forming, certain photosynthetic bacteria start to colonize the soil, recycling nitrogen, carbon, phosphorus, and other soil nutrients to produce the first organic matter. Bacteria increase soil fertility through nutrient recycling such as carbon, nitrogen, sulphur and phosphorus. Due to their close proximity to plant roots, soil microbes significantly affect soil and crop health. Some of the activities they perform include nitrogen-fixation, phosphorus solubilization, suppression of pests and pathogens, improvement of plant stress, and decomposition that leads to soil aggregation. Bacteria also help in the decomposition of dead organic matter and then give out simple compounds in the soil, which can be used up by plants. Due to their close proximity to plant roots, soil microbes significantly affect soil and crop health. Micro-organisms like bacteria and certain fungi decompose excretory products and remains of dead plants and animals into simpler substances. This increases the organic content of the soil, thereby increasing its fertility. Microorganisms help increase soil fertility. Some microorganisms such as bacteria are very good decomposers. They decompose dead organic matter. This substance when mixed with the soil will make it fertile. Unless the nutrients are replenished in the soil, it will become infertile. You can replenish nutrients stripped from the soil with fertilizer and by adding organic material, such as compost or well-rotted material. Crop residue also contributes to soil fertility. Soil fertility decline occurs when the quantities of nutrients removed from the soil in harvested products exceed the quantities of nutrients being applied. In this situation, the nutrient requirements of the crop are met from soil reserves until these reserves cannot meet crop demands. Fertile soils were also characterized by high water holding capacity and good soil workability. For infertile plots, the most important indicators included low yield, yellow leaves, slow growth, light coloured soils, soils with low water-holding capacity, and poor soil tilth. Large quantities of the salts dissolved in the water, such as sodium and chloride, are diffused into the soil and remain there after the water has evaporated. The salt stunts the crops and can even make soils infertile in the long run. Fertile soil will contain all the major nutrients for basic plant nutrition as well as other nutrients needed in smaller quantities

@ RK, soil microbes have a great role in maintaining soil fertility as they live close proximity to plant roots, and can significantly affect soil and crop health by performing nitrogen-fixation, phosphorus solubilization, suppression of pests and pathogens, improvement of plant stress, and decomposition that leads to soil aggregation. Moreover, they can release of plant nutrients from insoluble inorganic forms as well as after decomposition of organic residues . They can also form beneficial soil humus by decomposing organic residues and through synthesis of new compounds. The released nutrients into the soil due to microorganisms can very well be taken up by plants for their nutrition.

Dr J C Tarafdar thank you for your contribution to the discussion