
%0 Journal Article
%A Sparling, GP 
%A West, AW 
%A Reynolds, J 
%T Influence of soil moisture regime on the respiration response of soils subjected to osmotic stress
%J Soil Research
%D 1989/03/01
%V 27
%N 1
%P 161-168
%K 
%R https://doi.org/10.1071/SR9890161
%U https://www.publish.csiro.au/paper/SR9890161 
%X The influence of the soil moisture regime on the tolerance of the soil micro-organisms to increased osmotic stress was examined by laboratory tests with a range of New Zealand soils. Soils from various climatic regions (moist, intermediate and dry) were amended with glucose-NaCl solutions, incubated for 0.5 h, and the respiration rate over the following 2 h was used as a measure of the response of the microbial biomass to the changed osmotic potential. Osmotic potentials were varied between -4 and -80 bar by altering the concentration of NaCl. Air-drying the soils at 25°C decreased the respiration response of the microbial biomass by 3-60% but had little effect on the tolerance of the surviving populations to decreased osmotic potentials. In general, the soils showed the same patterns: an osmotic potential of -23 bar decreased the respiration response by 28-45% (18-44% after air-drying) and a -80 bar potential decreased it by 64-86% (52-84% after air-drying). For the majority of soils, a consistent relationship was obtained between the respiration rate of the moist soils and the osmotic potential applied. A reasonable prediction of the respiration response after air-drying could be obtained from the respiration response of moist soils at -25 bar osmotic potential. 
