CO_2浓度升高对不同施氮水平棉田土壤养分含量及酶活性的影响

Effects of Elevated Atmospheric CO_2 Level on Soil Nutrient and Enzyme Activities in Cotton Fields with Different Levels of Nitrogen

通过田间小区试验研究不同CO2浓度(CK:360μmol/mol,C540:540μmol/mol,C720:720μmol/mol)对不同施氮水平(N0:0kg/hm2,N150:150kg/hm2,N300:300kg/hm2,N450:450kg/hm2)下棉田土壤养分及酶活性的影响。结果显示:随着大气CO2浓度增加,土壤中有机碳含量总体表现下降趋势,速效磷含量总体呈增加趋势;CO2浓度增加后,N150处理土壤pH值与N300、N450处理间差异显著,速效钾含量随施氮量的增加先增后降再增加。CO2浓度增加后,土壤碱性磷酸酶活性增加、脲酶活性降低;N0和N300处理下,过氧化氢酶活性随CO2浓度增加先增后降,N150和N450处理降低了过氧化氢酶活性。CO2处理×氮处理交互作用对pH值,碱解氮、速效磷、速效钾含量及脲酶、碱性磷酸酶、过氧化氢酶活性的影响均达极显著水平。土壤脲酶活性与土壤有机碳、速效钾含量显著正相关,与速效磷含量显著负相关;碱性磷酸酶活性与碱解氮、速效磷含量极显著正相关;过氧化氢酶活性与有机碳含量、pH值极显著正相关,与速效磷含量显著负相关。

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 withnbsp;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 ＆#215; 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.