Resin Membrane for Assessment of Nitrogen Cycling and Mineralization

Resin Membrane Strips for Assessment of Nitrogen Mineralization/Nitrification

To evaluate soil health functions, we used resin membrane strip technology to compare the in situ rates of nitrogen mineralization/nitrification and nitrogen availability between two tillage practices: conservation tillage (No-till, NT) and conventional tillage (CT). We examined the daily supply rates of nitrate and phosphate. The ion exchange resins were employed to measure the relative supply rate of plant-available nutrients in soils and the rates at which they are released from soil organic matter. 

We used a strong base Anion Exchange Membrane of the quaternary ammonium functional group (i.e., positively-charged membrane) to simultaneously attract and adsorb all negatively-charged anions, such as nitrate (NO3-), phosphate (H2PO4-, HPO42-), and sulfate (SO42-), a measure for assessing soil nitrogen availability and its spatial distribution and phosphate (in the forms of orthophosphate) of hydrogen phosphate, HPO42−, and dihydrogen phosphate, H2PO4−.

Each set of resins (3- to 6 resin probes) is to be simultaneously buried in the rhizosphere at 2 -15 cm and retrieved successively, i.e., one after another weekly. 

Thus, the first resin remained in the soil for one week, the second for two weeks, the third for three weeks, and so on before being retrieved.

The significant trends of cumulative nitrate mineralization/ nitrification assessed by resin membrane strips will help to develop a functional relationship of nutrient cycling and release and to determine potential relationships between the water quality parameters and soil health functions.