Storage of soil samples leads to over-representation of the contribution of nitrate to plant-available nitrogen

Delays between soil sampling and processing for analysis are common in both research agronomy, but the effects of storage conditions on measurements plant-available nitrogen (N) rarely considered. With increasing recognition organic N pools soils, such as amino acids peptides, it is necessary to determine how sample handling impacts outcomes quantification. In this study, we used situ microdialysis approximate plant availability acids, ammonium nitrate, then compared potassium chloride (KCl) extract samples taken from excavated when field, after 24 h refrigerated storage, 1 month, either or air-dried. Nitrate levels measured with KCl extracts increased immediately continued accumulate next day month stored samples. Amino acid remained more constant; however, showed a decline acid-N The proportional representation in-field was most similar microdialysis. Soil should be processed close possible, duration reported. influence must considered interpreting test results.