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
The North China Plain （NCP） is one of the most important agricultural re- gions in China, but it is experiencing a serious water-resource crisis due to exces- sive exploitation of groundwater reserves. Improving wat...The North China Plain （NCP） is one of the most important agricultural re- gions in China, but it is experiencing a serious water-resource crisis due to exces- sive exploitation of groundwater reserves. Improving water-use efficiency （WUE） of crops is thought to have good potential for conserving groundwater and in maintain- ing high crop production in the region, In this paper, firstly, strategies for improving WUE of crop cultivars in the NCP were discussed. According to studies on key factors affecting cultivar WUE, stomatal conductance, which has large genotypic variability and differs among cultivars in response to drought, is an important physio- logical trait associating closely with the performance of cultivars in WUE and yield. Higher WUE and higher yield may be obtained through strategies of cultivar adop- tion with appropriate stomatal characteristics suitable to different conditions of water availability. Secondly, irrigation scheduling in the North China Plain was further dis- cussed. The irrigation frequency currently employed in this area could be reduced by at least one application （from four to three applications） to obtain higher produc- tion and also higher WUE. Finally, straw mulching and the use of early vigor culti- vats were suggested as two practices that had the potential to be effective in in- creasing crop WUE.展开更多
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.
基金Supported by Grants from the Ministry of Science and Technology of China(2011AA100501)the National Natural Science Foundation of China(30871447)~~
文摘The North China Plain （NCP） is one of the most important agricultural re- gions in China, but it is experiencing a serious water-resource crisis due to exces- sive exploitation of groundwater reserves. Improving water-use efficiency （WUE） of crops is thought to have good potential for conserving groundwater and in maintain- ing high crop production in the region, In this paper, firstly, strategies for improving WUE of crop cultivars in the NCP were discussed. According to studies on key factors affecting cultivar WUE, stomatal conductance, which has large genotypic variability and differs among cultivars in response to drought, is an important physio- logical trait associating closely with the performance of cultivars in WUE and yield. Higher WUE and higher yield may be obtained through strategies of cultivar adop- tion with appropriate stomatal characteristics suitable to different conditions of water availability. Secondly, irrigation scheduling in the North China Plain was further dis- cussed. The irrigation frequency currently employed in this area could be reduced by at least one application （from four to three applications） to obtain higher produc- tion and also higher WUE. Finally, straw mulching and the use of early vigor culti- vats were suggested as two practices that had the potential to be effective in in- creasing crop WUE.
