Effects of Elevated Atmospheric CO2 Level on Soil Nutrient and Enzyme Activities in Cotton Fields with Different Levels of Nitrogen

LIU Yu; GAO Zhi-jian; YIN Fei-hu; LNing

doi:10.3969/j.issn.1004-3268.2014.11.014

Abstract：Through a plot experiment,the soil nutrient and enzyme activities in cotton fields with nitrogen levels(N0:0 kg/ha,N150:150 kg/ha,N300:300 kg/ha,N450:450 kg/ha)under different CO2 concentrations(CK:360μmol/mol,C540:540μmol/mol,C720:720μmol/mol)were studied. The results showed that soil organic carbon content declined and the available phosphorus content increased with the increase of atmospheric CO2 concentration;when the CO2 concentration increased,soil pH values were significant different between N300 ,N450 treatments and N150 treatment,the available potassium content first increased and then decreased finally increased with the increase of nitrogen application amount.When the CO2 concentration increased,the alkaline phosphatase activity in soil increased,urease activity decreased;catalase activity of N300 and N0 treatments first increased and then decreased with the increase of atmospheric CO2 concentration, catalase activity of N150 and N450 treatments decreased under the increased CO2 concentration.The effects of CO2 treatment × nitrogen treatment interactions on soil pH value,alkali-hydrolyzale nitrogen content,available phosphorus content,available potassium content,urease activity, alkaline phosphatase activity,catalase activity were significant.Soil urease activity was significantly positively related with soil organic carbon content and available potassium content, and significantly negatively related with the available phosphorus content;alkaline phosphatase activity was significantly positively related with alkali-hydrolyzale nitrogen content and available phosphorus content;catalase activity was significantly positively related with organic carbon content and pH value,and significantly negatively related with the available phosphorus content.