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Total Kjeldahl nitrogen or TKN is the sum of nitrogen bound in organic substances, nitrogen in ammonia (NH 3-N) and in ammonium (NH 4 +-N) in the chemical analysis of soil, water, or waste water (e.g. sewage treatment plant effluent).
However, the excessive or inefficient use of nitrogen fertilizers can lead to environmental problems such as nitrogen leaching, runoff, and emissions of nitrogen oxides (NOx). [4] Nitrogen leaching occurs when nitrogen compounds, primarily nitrates , move through the soil profile and enter groundwater, potentially contaminating drinking water ...
In agriculture, a soil test commonly refers to the analysis of a soil sample to determine nutrient content, composition, and other characteristics such as the acidity or pH level. A soil test can determine fertility , or the expected growth potential of the soil which indicates nutrient deficiencies, potential toxicities from excessive ...
Bacteria may on average add 25 pounds (11 kg) nitrogen per acre, and in an unfertilised field, this is the most important source of usable nitrogen. In a soil with 5% organic matter perhaps 2 to 5% of that is released to the soil by such decomposition. It occurs fastest in warm, moist, well aerated soil. [55] The mineralisation of 3% of the ...
The ISNT is a new (2007) method for measuring nitrogen available for plant uptake. ISNT estimates the amount of nitrogen present in the soil as amino sugar nitrogen. With respect to corn and soybeans, the optimal range for plant growth appears to be around 225 to 240 mg/Kg. Some form of nitrogen fertilizer is needed if levels are below this ...
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.
Soil acidification refers to the process by which the pH level of soil becomes more acidic over time. Soil pH is a measure of the soil's acidity or alkalinity and is determined on a scale from 0 to 14, with 7 being neutral. A pH value below 7 indicates acidic soil, while a pH value above 7 indicates alkaline or basic soil.
Nitrogen-15 (15 N) tracing is a technique to study the nitrogen cycle using the heavier, stable nitrogen isotope 15 N. Despite the different weights, 15 N is involved in the same chemical reactions as the more abundant 14 N and is therefore used to trace and quantify conversions of one nitrogen compound to another.