荒漠森林开垦成农田前后土壤呼吸速率的变化及其影响因素

[目的]分析干旱区荒漠森林开垦前后土壤呼吸的变化及其影响因素,为该区社会发展和生态安全维护提供理论参考。[方法]测定新疆艾比湖地区连续种植30 a,16 a和3 a的农田以及未开垦荒漠森林的土壤呼吸速率和影响其变化的因子,利用单因素方差和多元逐步回归方法进行数据分析。[结果]①土壤呼吸速率随农田耕作年限显著增加(p<0.05);②所有农田的土壤呼吸速率显著高于荒漠森林(p<0.05);③土壤有机质、含水量、微生物菌落总数、细根生物量、总盐和pH值在不同耕作年限农田、荒漠森林间差异显著(p<0.05)。土壤温度、空气相对湿度和气温的变化与以上因子不同;④水盐是多元逐步回归方程中仅剩的因子,标准系数分别为0.67和-0.42。[结论]在干旱区荒漠,将荒漠开垦为农田后,农业活动增加了土壤含水量而减小了含盐量,导致土壤碳释放量随农田种植年限不断增加。

Differences in Soil Respiration Rate and Its Influencing Factors Between Natural Desert Forest and Farmlands

[Objective]The differences in soil respiration and its influencing factors between natural desert forest and farmlands were studied,in order to provide theoretical reference for the social development and ecological security maintenance in arid desert region.[Methods]Soil respiration rate and its influencing factors were investigated at three farmlands with different cultivation years(i.e.,30,16,3 years),and a natural desert forest in Ebinur Lake basin in the Xinjiang Uygur Autonomous Region.One-way ANOVA and multiple stepwise regressions were used for data analysis.[Results]①Soil respiration rate increased significantly along the cultivation years(p<0.05).②Soil respiration rate in three farmlands were signifiantly higher than that in natural desert forest(p<0.05).③Soil organic matter,soil moisture,total colony number,fine root biomass,soil salinity and pH value were significantly different between farmlands and natural desert forest(p<0.05),whereas there was no significant difference between soil temperature,air relative humidity and air temperature(p>0.05).④Soil moisture and salinity to soil respiration rate were the only remaining factores in the multiple stepwise regressions,and the standard coefficients were 0.67 and-0.42,respectively.[Conclusion]Agricultural activities increased soil moisture while decreased salinity in the reclaiming of natural desert forest into farmlands,and as a consequence,increased soil respiration rate along cultivation years.