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Even though nitrogen is a necessary element for life, too much of it in water can have negative effects on aquatic ecosystems and endanger human health. Agricultural runoff, where fertilizers containing nitrogen compounds can seep into rivers, lakes, and groundwater, is one of the main sources of nitrogen in water.
Anabaena, in association with the water fern Azolla, can contribute nitrogen up to 60 kg/ha/season and can also enrich soils with organic matter. [ 3 ] [ 4 ] Seaweeds are rich in various types of mineral elements (potassium, phosphorus, trace elements, etc.), hence they are extensively used as a form of manure replacement by people of coastal ...
Agricultural soil science is the application of soil chemistry, physics, and biology dealing with the production of crops. In terms of soil chemistry , it places particular emphasis on plant nutrients of importance to farming and horticulture , especially with regard to soil fertility and fertilizer components.
Nitrogen is plentiful in the Earth's atmosphere, and a number of commercially-important agricultural plants engage in nitrogen fixation (conversion of atmospheric nitrogen to a biologically useful form). However, plants mostly receive their nitrogen through the soil, where it is already converted in biological useful form.
Nitrogen is an essential element needed for the creation of biomass and is usually seen as a limiting nutrient in agricultural systems. Though abundant in the atmosphere, the atmospheric form of nitrogen cannot be utilized by plants and must be transformed into a form that can be taken up directly by the plants; this problem is solved by biological nitrogen fixers.
Nutrients in the soil are taken up by the plant through its roots, and in particular its root hairs.To be taken up by a plant, a nutrient element must be located near the root surface; however, the supply of nutrients in contact with the root is rapidly depleted within a distance of ca. 2 mm. [14] There are three basic mechanisms whereby nutrient ions dissolved in the soil solution are brought ...
Human impact on the nitrogen cycle is diverse. Agricultural and industrial nitrogen (N) inputs to the environment currently exceed inputs from natural N fixation. [1] As a consequence of anthropogenic inputs, the global nitrogen cycle (Fig. 1) has been significantly altered over the past century.
Whether nitrogen is mineralized or immobilized depends on the C/N ratio of the plant residues. [6] For example, incorporating materials high in carbon to nitrogen ratio such as saw dust and straw will stimulate soil microbial activity, increase demand for nitrogen, leading to immobilization. [7] This is known as priming effect. [8]