What term describes the amount of nitrogen available to plants after organic materials are decomposed?

The amount of nitrogen available to plants after organic materials are decomposed is referred to as mineralized nitrogen. This process occurs during the decomposition of organic matter, where microorganisms break down complex organic compounds into simpler forms. Through mineralization, nitrogen that was previously part of organic matter is converted to inorganic forms, such as ammonium or nitrate, which are readily taken up by plant roots. This conversion is crucial for plant nutrition because plants can only absorb nitrogen in these mineralized forms.

Other terms like soil nitrogen balance, organic nitrogen reserve, and fixed nitrogen do not specifically convey the process of decomposition and the subsequent availability of nitrogen for plant use. Soil nitrogen balance typically refers to the overall assessment of nitrogen inputs and outputs in a given area rather than the process of making nitrogen available from organic materials. Organic nitrogen reserve indicates the nitrogen contained within organic matter but does not specify that it has been transformed into a usable form. Fixed nitrogen often refers to nitrogen that has been converted from atmospheric N2 into a form usable by plants, typically through biological or industrial processes, rather than the mineralization of decomposed organic matter.