较高浓度乙炔对秸秆还田土壤硝化作用的抑制

本研究探讨较高浓度乙炔对秸秆还田土壤硝化作用的抑制效果。在室内条件下，2％乙炔加入到施用尿素的土壤后好气培养108h，其间测定CO2和N2O释放量，培养结束后测定土壤无机N。在田间条件下，2％乙炔加入到不同含水量和矿化速率的原状土柱中，培养7d后测定土柱中无机N的变化量。结果表明，室内条件下，2％乙炔完全抑制土壤的硝化作用，对土壤有机N矿化作用的抑制作用为19．2％，并对土壤异养微生物的呼吸具有抑制作用。

Nitrification Inhibition by High Concentration Acetylene in Straw-amended Soil

The aim of the study is to evaluate the inhibitory effect of higher concentration acetylene on soil nitrification under straw amendment. In laboratory, the soil was added with 2% C 2H 2 and urea and incubated under aerobic condition for 108 h. CO 2 and N 2O were measured periodically and soil inorganic N was analyzed at the end of incubation. In field, two percent of C 2H 2 was added into intact soil cores different in moisture and N mineralization rate. Change in soil inorganic N content of each soil core was determined after 7d incubation. Under laboratory conditions, 2% C 2H 2 can completely inhibit soil nitrification. Also, 2% C 2H 2 can inhibit the mineralization of the soil organic nitrogen by 19 2% and the respiration of soil heterotrophic microorganisms to a great exfent. Under field conditions, however, the effect of 2% C 2H 2 to inhibit nitrification of straw amended soil could not be quantified in this study. The reasons for that un success might be the large variability of soil moisture and the poor consistence between compared the soil core and the treated soil core at the beginning of each incubation. The importance of heterotrophic nitrification in straw amended soil should be concerned.