Fixation and release of potassium and ammonium ions in Danish soils

Abstract

Results of a laboratory investigation showed that anaong soils in Denmark it are chieIly those rich in clay minerals that will fix and release potassium and ammonium. The two cations were fixed in nearly equivalent proportions, but ammonium was fixed preferentially to potassium when added together to the soil.The maximum fixation reached 20 to 30 per cent of the addition in top soil layer but 50 to 80 in subsoil.Soils from a permanent Iertilizer experiment showed the strongest fixation and least release of potassium where no potassie fertilizer had been applied for more than 70 years. In soils irom another field experiment on residual e•iect of various nitrogenous fertilizers there was a small but signiIicant increase in content of inorganically fixed ammonium where urea had been applied.

Potassium Mobilization and Transformation in Red Paddy Soil as Affected by Rice

“…Zhou and Huang (2006, 2007) pointed out that the application of NH 4 H 2 PO 4 induced the release of interlayer K in K‐bearing minerals. Ammonium nitrate fertilizer could increase the content of soil Sol‐K owing to the exchange of NH 4 + to K + (Nielsen, 1972). At the panicle initiation stage, soil Sol‐K and Ex‐K were reduced, whereas soil Nonex‐K was improved.…”

Simultaneous extraction of tetracycline, macrolide and sulfonamide antibiotics from agricultural soils using pressurised liquid extraction, followed by solid-phase extraction and liquid chromatography–tandem mass spectrometry

“…Samples of soil were collected from the Ap horizon (0-20 cm) from two fields at a Danish research station, with well-described soil properties [17]. The two soils are a sandy soil (Lundgaard) and a loamy sand soil (Askov), respectively, representing typical Danish agricultural soils.…”

The difference of potassium dynamics between yellowish red soil and yellow cinnamon soil under rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation

“…This showed that fertilizer application probably induced the soil K equilibrium be transferred towards Sol-K. Zhou and Huang (2006) pointed out that the application of NH 4 H 2 PO 4 induced the release of interlayer K in K-bearing minerals. NH 4 + -N fertilizer could increase the content of soil Sol-K owing to the exchange of NH 4 + to K + (Nielsen 1972;Moritsuka et al 2004). At the late stage of rapeseed growth, soil Sol-K and Ex-K were reduced, and soil Nonex-K was improved.…”