Nitrogen fertilisers and nitrogen are the most important for plants, animals, and human beings. It plays a direct role in the growth and developmental related processes of the plants. The concept of producing good quality foods without using nitrogen is almost impossible. People can read a list of nitrogen fertilizers and can select any according to crop requirements.
Although Nitrogen is abundantly present in the atmosphere, plants are not able to use nitrogen directly. Usually, growing plants need about 3-4% of Nitrogen in their above growing tissues for normal functioning. Nitrogen requirements are significantly greater than the other nutrients and must be supplied by nitrogen-rich fertilizers to avoid nitrogen deficiency.
Structural Importance of Nitrogen and Nitrogen Fertilizers for Plants
Nitrogen is an important component of chlorophyll, proteins. It helps to promote the process of photosynthesis and plant growth. Moreover, nitrogen is also important for the enzymes that are biochemical molecules responsible for various biological and physiological plant processes. Nitrogen fertilizers can greatly improve all biochemical physiological plant processes.
Other than that nitrogen is also an important component of energy-related compounds such as ATP. Thus it helps plants to use and conserve energy for metabolic reactions. It is also an important constituent of nucleic acids and genetic materials that allow plants to grow and reproduce. Therefore the concept of life cannot be supported without the presence of nitrogen.
Soil Nitrogen Contents for Plant Growth
The nitrogen in the soil is found in the form of 3 different types. These are nitrate ions, ammonium ions, and organic nitrogen. Studies have reported that about 95-99% of the nitrogen in the soil is organic nitrogen. This organic nitrogen can be in the form of animal residues, plant residues, debris, dead bodies of organisms, soil organisms, soil biodiversity, and soil organic matter.
Solubility and availability of Nitrogen Fertilizers
An important factor is that organic nutrients or organic nitrogen are never directly available to the plants. Therefore, some additional factors or management measures should be considered to ensure their solubility, bioavailability, and uptake by the growing plants. Plants can only use nitrogen in inorganic forms such as nitrates and ammonium and each plant species has its own preference for intake. However high nitrogen organic fertilizers can greatly improve soil health.
Mobility of nitrates and ammonium in Soil
Usually, ammonium ions are bound to the negatively charged sites in the soil and have similar behavior in the soil like other cations. Whereas, nitrates can freely move in the soil but can be easily dissolved in the soil water. Or can be precipitated in the form of soluble salts. The precipitation takes place during dry conditions.
Naturally Occurring Nitrogen Sources
Nitrogen in the soil can be fixed from the atmosphere by the activities of rhizospheric bacteria. Besides, it can also result in the decomposition and disintegration of rocks and minerals. Or farmers and growers can apply it to the soil in the form of organic and inorganic fertilizers. The process of releasing nitrogen in the soil by decomposition of soil minerals is quite slow. Fertilizers with nitrogen are expensive but naturally occurring sources and natural nitrogen fertilizers can be used to cut the cost.
Atmospheric nitrogen is a major component of soil nitrogen. It can be further improved by enhancing the population nitrogen-fixing bacteria and best agronomic practices. Moreover, nitrogen fixation is also promoted by thunderstorms, lighting, and flashing. This is the reason why don’t legumes need nitrogen-containing fertilizers.
Growing Legume Plants to Reduce Nitrogen Fertilizer Needs
Growing legume plants for improved nitrogen fixation is also an essential approach to increase soil nitrogen. When the quantity of fixed nitrogen by rhizobia is increased than their own requirements, it will be added to the soil. This nitrogen can be then used by the legumes and other growing plants in the vicinity. Also, this is the reason behind no response of legumes towards added fertilizers. Natural fertilizers high in nitrogen can greatly improve soil health, soil fertility, and food production.