滴灌水量和土壤温度对桶栽棉花土壤剖面CO2浓度影响的试验研究

为探究膜下滴灌条件下灌水量和土壤温度对新疆不同深度土壤CO2浓度的影响。采用桶栽试验,通过气相色谱仪监测,研究不同滴灌水量〔充分灌溉(CK,100%);轻度水分亏缺(W1,80%);重度水分亏缺(W2,60%)〕处理下(植棉和裸土) 10~50 cm土层土壤CO2浓度变化规律。结果表明:灌水量对土壤剖面CO2浓度影响显著。在植棉或裸土条件下,随着灌水量的增加,不同深度处土壤CO2浓度均呈上升趋势,土壤剖面CO2浓度均呈上低下高的分布特征,50 cm处CO2浓度是表层10 cm处CO2浓度的2倍左右,植棉土壤CO2浓度是裸土土壤CO2浓度的2倍左右。土壤剖面CO2浓度变化有着明显的日变化和季节性变化规律。在一天内,土壤温度和土壤剖面CO2浓度随气温升高而增加,呈现出"单峰"曲线变化规律,峰值出现在16:00;棉花生育期内土壤剖面CO2浓度在花铃期达到最大值。灌水量和土壤温度均与土壤剖面CO2浓度呈显著正相关(P <0. 01)。这一结果可为干旱区棉花种植节水减排提供理论参考。

Experimental study on the effect of drip irrigation water volume and soil temperature on CO2 concentration in the soil profile of barrel-planted cotton

This study aimed to explore the effects of irrigation volume and soil temperature on soil CO2 concentrations at different depths under drip irrigation in Xinjiang. The barrel test was used with different amounts of drip irrigation: full irrigation (CK) of 100% irrigation,mild water deficit (W1) of 80% irrigation,and severe water deficit (W2) of 60% irrigation. The variation in CO2 concentrations in the 10-50 cm soil layer were monitored and studied using gas chromatography in planted cotton and bare soil. The results showed that the amount of irrigation had a significant effect on the soil profile CO2 concentration. Under the condition of cotton planting or bare soil,with an increase in the amount of irrigation,the soil CO2 concentration increased at different depths,and the soil profile CO2 concentration was characterized by an upper,lower,and higher distribution. The CO2 concentration at a depth of 50 cm was about twice that at a depth of 10 cm in the surface layer,and the concentration of CO2 in the cotton-planted soil was about twice the concentration of CO2 in bare soil. The change in CO2 concentration in the soil profile showed evident diurnal and seasonal variation. In one day,the soil temperature and soil profile CO2 concentration increased with the increase in temperature,showing a"single peak"curve,with the peak appearing at 16: 00. The soil profile CO2 concentration during the cotton growth period reached a maximum during the flowering period. Irrigation quantity and soil temperature were positively correlated with the soil profile CO2 concentration (P < 0. 01). This result provides a theoretical reference for water saving and emission reduction in cotton planting in arid areas.