夏闲期耕作下旱地土壤有机碳库与温度和含水量季节变化及关系研究OA

This study aimed to understand the variations in soil organic carbon(SOC)pools,soil temperature and water content and their relationships to mitigate climate change.Therefore,a field experiment was conducted to investigate the seasonal dynamics of SOC,permanganate oxidizable organic carbon(POxC)concentrations,as well as their relationships with soil temperature and water content under different tillage practices during the summer fallow in the drylands of the Loess Plateau in China.The experiment included three tillage practices,i.e.,no tillage,plough tillage and subsoiling tillage during the summer fallow.Results showed that the seasonal changes in the SOC concentrations increased and then decreased at both 0-5 and 5-10 cm depths under plough tillage and subsoiling tillage treatments during the growth period of winter wheat.While the seasonal changes in POxC concentration,soil water content and soil temperature fluctuated.Regression analysis revealed that the soil water content at the 5-10 cm depth had a linear relationship with the SOC concentrations and a quadratic polynomial relationship with the POxC concentrations(P＜0.05),with a better fit under the plough tillage treatment compared to the no tillage and subsoiling tillage treatments.The SOC concentrations showed no significant response to variations in soil temperature at both the 0-5 and 5-10 cm depths.In contrast,the POxC concentrations demonstrated a negative correlation with daily maximum temperature,daily mean temperature and daily minimum temperature.In summary,the findings of our study demonstrated that the seasonal changes in the POxC concentration at 0-10 cm depth were closely related to variations in soil temperature and water content,while seasonal changes in the SOC concentrations were less sensitive to soil temperature under summer fallow tillage treatments in the drylands.This study provides a theoretical basis for the scientific management of SOC pools in dryland wheat fields.