Journal Article

Nitrogen transformations in a flooded soil in the presence and absence of rice plants. 1. Nitrification

Freney, J.R, Luo, Q.X, Chalk, P.M, Chen, D.L. (Division of Plant Industry CSIRO, Canberra, A.C.T. (Australia).)

1998

Overview

Nitrification rates (n) in the floodwater of an alkaline clay were measured in the absence or presence of rice plants by inhibition of ammonium oxidation and 15N-dilution techniques. Floodwater nitrate concentrations in control treatments showed a marked diurnal variation, and were higher than in the inhibitor treatments after the first day. Ammonium concentrations in floodwater declined exponentially in all treatments, being markedly affected by diffusion and NH3 volatilization but little affected by nitrification and plant uptake. Nitrification rates in floodwater estimated by 15N-dilution were generally higher than the rates estimated by the inhibitor method. Estimates of n were generally higher during daylight hours than at night, and did not differ significantly between planted and unplanted pots. Microbial immobilisation of labelled ammonium and gross N immobilisation were not affected by addition of the nitrification inhibitor 2-ethynylpyridine.

• Publisher: Springer Nature B.V
• Subject: ALKALINE SOILS / Ammonia / Ammonium / ammonium compounds / chemical composition / CLAY SOILS / Dilution / Diurnal / diurnal variation / Diurnal variations / FLOODED LAND / Flooded soils / Floodwater / Immobilization / INHIBIDORES DE LA NITRIFICACION / INHIBITEUR DE NITRIFICATION / Inhibitors / isotope labeling / Microorganisms / Nitrates / NITRIFICACION / NITRIFICATION / NITRIFICATION INHIBITORS / nitrogen / Nitrogen isotopes / nutrient uptake / Oryza / ORYZA SATIVA / Oxidation / pyridines / soil bacteria / soil pH / SOL ALCALIN / SOL ARGILEUX / SUELO ALCALINO / SUELO ARCILLOSO / TERRE INONDEE / TIERRAS INUNDADAS / Volatilization / water stress