Evaluation of the diffusive gradients in thin-films (DGT) technique for measuring nitrate and ammonium in soil

Environmental context Nitrate (NO3−) and ammonium (NH4+) are the most important soil nitrogen forms for plant growth. However, conventional extraction techniques may introduce artefacts affecting measurement of plant-available N concentrations following sampling sample preparation processes. This is first study DGT technique being used to measure NO3-N NH4-N in a wide range soils, compared with KCl extraction, examined different factors that contribute plant-availability these ions soils. The knowledge would help optimise management practices, increase economic benefits reduce environmental impacts. Rationale availability uptake can be affected by numerous such as texture, moisture organic matter content, temperature microbial activity. Conventional affect processes, including drying, sieving, homogenising, freezing thawing. diffusive gradients thin-films (DGT) overcome some limitations has been successfully estimate fractions nutrients, P, K, Zn, Cu Mn Therefore, it evaluate use measuring NO3− NH4+ variety soils examine Methodology experiment evaluated ability using binding layers containing A520E anion exchange resin or Microlite® PrCH cation resin, respectively. results were those from extraction. Results A520E- PrCH-DGTs showed good detection limits (6.90 µg L−1) (6.23 able potentially available unfertilised mass accumulated on device increased linearly across ranging 5 300 mg kg−1 (depending type) 5–300 NH4-N; which equivalent fertiliser rates 75–450 kg ha−1 N. DGTs ten various physical chemical properties. determine mineral measured values significantly correlated each other (R2 = 0.53; P-value < 0.001), but relationship between two measurements was weaker 0.20, 0.045). Discussion suggest methods pools targeting pore water attached labile solid phases.