Is二氧化碳 evolution in saline soils affected by an osmotic effect and calcium carbonate .pdf

Biol Fertil Soils (2010) 46:781–792 DOI 10.1007/s00374-010-0479-3 ORIGINAL PAPER Is CO2 evolution in saline soils affected by an osmotic effect and calcium carbonate? Raj Setia Petra Marschner Jeff Baldock David Chittleborough Received: 24 February 2010 /Revised: 24 June 2010 /Accepted: 24 June 2010 /Published online: 15 July 2010 # Springer-Verlag 2010 Abstract Salt-affected soils are widespread, particularly in respiration was reduced by more than 50% at EC 1:5≥ arid climates, but information on nutrient dynamics and 5.0 dSm− 1. In a further experiment, salinity up to an EC1:5 carbon dioxide (CO2) efflux from salt-affected soils is of 5.0 dSm− 1 was developed in the silt loam with NaCl or scarce. Four laboratory incubation experiments were con- CaCl2. No differences in respiration at a given EC were ducted with three soils. To determine the influence of obtained between the two salts, indicating that Na and Ca calcium carbonate (CaCO3) on respiration in saline and did not differ in toxicity to microbial activity. The effect of non-saline soils, a loamy sand (6.3% clay) was left different addition rates (0.25–2.0%) of mature wheat unamended or amended with NaCl to obtain an electrical residue on the response of respiration to salinity was conductivity (EC) of 1.0 dSm− 1 in a 1:5 soil/water extract. investigated by adding NaCl to the silt loam to obtain an Powdered CaCO3 at rates of 0%, 0.5%, 1.0%, 2.5%, 5.0% EC1:5 of 2.0 and 4.0 dSm− 1. The clearest difference between and 10.0% (w/w) and 0.25-2 mm mature wheat residue at salinity levels was with 2% residue rate. At a given salinity 0% and 2% (w/w) were then added. Cumulative CO2-C level, the