不同灌水下限设施番茄土壤CO2排放特征及其影响因素研究

【目的】探讨不同灌水下限设施土壤CO2排放特征及其影响因素,为调控设施土壤水分和碳排放提供理论依据。【方法】在番茄生育期内采用LI-8100A土壤碳通量自动测定仪观测不同灌水下限20 kPa(D20)、30 kPa(D30)、40 kPa(D40)]下的土壤CO2排放速率,并分析其影响因素。【结果】在番茄生育期内,不同灌水下限设施土壤CO2排放速率变化趋势基本一致,D20处理最高,平均速率为2.759μmol/(m2·s),其次是D30处理,为2.601μmol/(m2·s),D40处理最低,为2.559μmol/(m2·s)。在土壤CO2累积排放量方面,D20处理显著高于其他2个处理,而D30和D40处理之间无显著差异。就单因素模型而言,不同灌水下限处理的土壤CO2排放速率与15 cm土壤温度呈指数回归关系,且均达显著水平(P<0.05);不同灌水下限处理的土壤CO2排放速率与15 cm土壤含水率均呈显著二次回归关系(P<0.05);与单因素模型相比,土壤温度和土壤含水率的双因素复合模型(68.5%~83.8%)可以更好地解释土壤CO2排放的变化。土壤温度敏感系数Q10值在1.442~1.498之间,其中D20处理最敏感,D40处理最不敏感。相关分析结果表明,土壤CO2累积排放量与0~20 cm土层土壤有机质量、pH值、全氮量、速效磷量、速效钾量、碱解氮量和微生物量碳呈显著相关关系。采用PCA分析提取出的2个主成分累积贡献率为85.79%。【结论】灌水下限影响设施土壤CO2的排放,其中D20处理促进了设施土壤CO2的排放。

The Characteristics of Soil CO2 Emission and Its Impact Factors of Greenhouse Potato Soil under Different Controlled Irrigation Low Limits

【Objective】In order to provide theoretical basis for regulating soil moisture and CO2 emission, the dynamic changes of soil CO2 emission and its impact factors of greenhouse soil under different controlled irrigation lower limits were investigated.【Method】During the growth period of tomato, adopting LI-8100 A automatic determination of soil carbon flux, soil CO2 emission rate and environment factors under 3 controlled irrigation lower limits(D20, D30, D40) were observed.【Result】Soil CO2 emission rates under different controlled irrigation low limits were found to have similar variability during the growth period of tomato. The meansoil CO2 emission rate in the D20 treatment(2.759 μmol/(m2·s)) was the highest, followed by D30 treatment(2.601 μmol/(m2·s)) and the lowest was D40 treatment(2.559 μmol/(m2·s)). The total amount of soil CO2 emission in the D20 treatment was significantly higher than the other two treatments, while D30 and D40 treatments had no significant difference. The relationship between soil CO2 emission and soil temperature at 15 cm depth under different controlled irrigation lower limits was explained by exponential functions(P<0.05). The relationship between soil CO2 emission and soil water content at 15 cm depth(P<0.05) under different controlled irrigation lower limits was explained by quadratic curve functions. Compared with the single-factor model, the changes of soil CO2 emission were better explained by the two-factor model of soil temperature and soil water content(P<0.01, R2=0.685~0.838). The temperature sensitivity coefficient(Q10) of soil CO2 emission was 1.442~1.498. The most temperature sensitive treatment was the D20 treatment, while the least sensitive one was the D40 treatment. According to the study by the method of correlation analysis, the relationship between the total amount of soil CO2 emission and soil organic matter, pH, total nitrogen, available P, available K, available N, microbial biomass carbon was significantly correlated. The cumulative contribution rate of the two principal components extracted by PCA analysis was 85.79%.【Conclusion】The CO2 emission of greenhouse soil is affected by the controlled irrigation lower limit, and the CO2 emission of greenhouse soil is promoted by the D20 treatment.