采用LICOR-6400便携式光合作用仪连接6400-09土壤叶室,对山西大学校园内的三种绿地（黑麦草、紫叶小檗和日本黄杨）的土壤呼吸进行了一年的测定。结果表明：土壤呼吸速率具有较明显的季节变化,冬春季较低,盛夏秋初较高,最大值出现在8月...采用LICOR-6400便携式光合作用仪连接6400-09土壤叶室,对山西大学校园内的三种绿地（黑麦草、紫叶小檗和日本黄杨）的土壤呼吸进行了一年的测定。结果表明：土壤呼吸速率具有较明显的季节变化,冬春季较低,盛夏秋初较高,最大值出现在8月,最低值出现在12月。土壤呼吸速率与0-10 cm深度的土壤温度关系显著,黑麦草、紫叶小檗和日本黄杨土壤温度变化分别解释土壤呼吸季节变化的57.3%、65.4%、46.6%（线性函数）和60.6%、71.3%、50.7%（指数函数）;黑麦草地土壤呼吸与土壤水分的关系均为极显著（p〈0.01）;用土壤温度和土壤水分的复合方程可以解释土壤呼吸变化的52%-84%。黑麦草、紫叶小檗和日本黄杨的年土壤呼吸总量分别为1.246 kg C.m^-2、1.822 kg C.m^-2、1.806 kg C.m^-2。展开更多
Crop water stress index(CWSI)is widely used for efficient irrigation management.Precise canopy temperature(T_(c))measurement is necessary to derive a reliable CWSI.The objective of this research was to investigate the...Crop water stress index(CWSI)is widely used for efficient irrigation management.Precise canopy temperature(T_(c))measurement is necessary to derive a reliable CWSI.The objective of this research was to investigate the influences of atmospheric conditions,settled height,view angle of infrared thermography,and investigating time of temperature measuring on the performance of the CWSI.Three irrigation treatments were used to create different soil water conditions during the 2020-2021 and 2021-2022 winter wheat-growing seasons.The CWSI was calculated using the CWSI-E(an empirical approach)and CWSI-T(a theoretical approach)based on the T_(c).Weather conditions were recorded continuously throughout the experimental period.The results showed that atmospheric conditions influenced the estimation of the CWSI;when the vapor pressure deficit(VPD)was>2000 Pa,the estimated CWSI was related to soil water conditions.The height of the installed infrared thermograph influenced the T_(c)values,and the differences among the T_(c)values measured at height of 3,5,and 10 m was smaller in the afternoon than in the morning.However,the lens of the thermometer facing south recorded a higher T_(c)than those facing east or north,especially at a low height,indicating that the direction of the thermometer had a significant influence on T_(c).There was a large variation in CWSI derived at different times of the day,and the midday measurements(12:00-15:00)were the most reliable for estimating CWSI.Negative linear relationships were found between the transpiration rate and CWSI-E(R^(2)of 0.3646-0.5725)and CWSI-T(R^(2)of 0.5407-0.7213).The relations between fraction of available soil water(FASW)with CWSI-T was higher than that with CWSI-E,indicating CWSI-T was more accurate for predicting crop water status.In addition,The R^(2)between CWSI-T and FASW at 14:00 was higher than that at other times,indicating that 14:00 was the optimal time for using the CWSI for crop water status monitoring.Relative higher yield of winter wheat was obtained with average seasonal values of CWSI-E and CWSI-T around 0.23 and 0.25-0.26,respectively.The CWSI-E values were more easily influenced by meteorological factors and the timing of the measurements,and using the theoretical approach to derive the CWSI was recommended for precise irrigation water management.展开更多
文摘采用LICOR-6400便携式光合作用仪连接6400-09土壤叶室,对山西大学校园内的三种绿地（黑麦草、紫叶小檗和日本黄杨）的土壤呼吸进行了一年的测定。结果表明：土壤呼吸速率具有较明显的季节变化,冬春季较低,盛夏秋初较高,最大值出现在8月,最低值出现在12月。土壤呼吸速率与0-10 cm深度的土壤温度关系显著,黑麦草、紫叶小檗和日本黄杨土壤温度变化分别解释土壤呼吸季节变化的57.3%、65.4%、46.6%（线性函数）和60.6%、71.3%、50.7%（指数函数）;黑麦草地土壤呼吸与土壤水分的关系均为极显著（p〈0.01）;用土壤温度和土壤水分的复合方程可以解释土壤呼吸变化的52%-84%。黑麦草、紫叶小檗和日本黄杨的年土壤呼吸总量分别为1.246 kg C.m^-2、1.822 kg C.m^-2、1.806 kg C.m^-2。
基金supported by the Project of State Grid Hebei Electric Power Co.,Ltd.(SGHEYX00SCJS2100077).
文摘Crop water stress index(CWSI)is widely used for efficient irrigation management.Precise canopy temperature(T_(c))measurement is necessary to derive a reliable CWSI.The objective of this research was to investigate the influences of atmospheric conditions,settled height,view angle of infrared thermography,and investigating time of temperature measuring on the performance of the CWSI.Three irrigation treatments were used to create different soil water conditions during the 2020-2021 and 2021-2022 winter wheat-growing seasons.The CWSI was calculated using the CWSI-E(an empirical approach)and CWSI-T(a theoretical approach)based on the T_(c).Weather conditions were recorded continuously throughout the experimental period.The results showed that atmospheric conditions influenced the estimation of the CWSI;when the vapor pressure deficit(VPD)was>2000 Pa,the estimated CWSI was related to soil water conditions.The height of the installed infrared thermograph influenced the T_(c)values,and the differences among the T_(c)values measured at height of 3,5,and 10 m was smaller in the afternoon than in the morning.However,the lens of the thermometer facing south recorded a higher T_(c)than those facing east or north,especially at a low height,indicating that the direction of the thermometer had a significant influence on T_(c).There was a large variation in CWSI derived at different times of the day,and the midday measurements(12:00-15:00)were the most reliable for estimating CWSI.Negative linear relationships were found between the transpiration rate and CWSI-E(R^(2)of 0.3646-0.5725)and CWSI-T(R^(2)of 0.5407-0.7213).The relations between fraction of available soil water(FASW)with CWSI-T was higher than that with CWSI-E,indicating CWSI-T was more accurate for predicting crop water status.In addition,The R^(2)between CWSI-T and FASW at 14:00 was higher than that at other times,indicating that 14:00 was the optimal time for using the CWSI for crop water status monitoring.Relative higher yield of winter wheat was obtained with average seasonal values of CWSI-E and CWSI-T around 0.23 and 0.25-0.26,respectively.The CWSI-E values were more easily influenced by meteorological factors and the timing of the measurements,and using the theoretical approach to derive the CWSI was recommended for precise irrigation water management.
