Seedlings of drought-tolerance rice varieties Han 501and Han A03,and the drought sensitive varietiesNanjing 11 and Yanjing 2 were raised in a paddyfield and transplanted into pots at the age of 8leaves.Water stress st...Seedlings of drought-tolerance rice varieties Han 501and Han A03,and the drought sensitive varietiesNanjing 11 and Yanjing 2 were raised in a paddyfield and transplanted into pots at the age of 8leaves.Water stress started at the tillering stage byholding water from 0 MPa of the soil water potentialin pots till the leaves showed seriously wilting.展开更多
Recent studies have focused on the improvement of rice productivity under aerobic conditions for times when water resources and food production are limited. This study aimed to evaluate the adaptability of high-yieldi...Recent studies have focused on the improvement of rice productivity under aerobic conditions for times when water resources and food production are limited. This study aimed to evaluate the adaptability of high-yielding rice cultivars to moderately water-stressed upland conditions in order to contribute breeding. A three-year field experiment in the temperate climate of Kyoto, Japan, indicated that the decrease in yield was mainly derived from a decrease in above-ground total dry matter (TDM) rather than a decrease in harvest index (HI). Although the decrease in TDM was mostly caused by a decrease in radiation use efficiency (RUE), we determined that the key to adapting high-yielding cultivars to upland conditions is intercepted radiation per day (IRPD), governed by leaf area index (LAI). Although the effect was not robust, LAI growth under upland conditions was associated with root length density. RUE was dependent on leaf water potential (LWP), indicating that a plant’s ability to maintain LWP under water-stressed conditions is important. The results also suggest the necessity of a canopy analyzer to evaluate LAI, as well as an infrared radiation thermometer to evaluate RUE. Performing such measurements during breeding efforts allows us to select for genotypes that are suitable for less stressed aerobic conditions.展开更多
In arid and semi-arid areas,the profitability of irrigated agriculture mainly depends on the availability of water resources and optimal cropping patterns of irrigation districts.In this study,an integrated agricultur...In arid and semi-arid areas,the profitability of irrigated agriculture mainly depends on the availability of water resources and optimal cropping patterns of irrigation districts.In this study,an integrated agricultural cropping pattern optimization model was developed with considering the uncertainty of water availability and water saving potential in the future,aiming to maximize agricultural net benefit per unit of irrigation water.The available water which was based on the uncertainty of runoff was divided into five scenarios.The irrigation water-saving potential in the future was quantified by assuming an increase in the rate irrigation water-saving of 10% and 20%.The model was applied to the middle reaches of Heihe River basin,in Gansu Province,China.Results showed that if the irrigation water-saving rate was assumed to increase by 10%,then the net water-saving quantity would increase by 21.5-22.5 million m3 and the gross water-saving quantity would increase by 275.7-303.0 million m3.Similarly,if the irrigation water-saving rate increased by 20%,then the net water-saving quantity would increase by 43.0-45.1 million m3 and the gross water-saving quantity would increase by 331.7-383.2 million m3.If the agricultural cropping pattern was optimized,the optimal water and cultivated area allocation for maize would be greater than those for other crops.Under the premise that similar volume of irrigation water quantity was available in different scenarios,results showed differences in system benefit and net benefit per unit of irrigation water,for the distribution of available irrigation water was diverse in different irrigation districts.展开更多
为了给以作物高效灌溉制度提供理论依据,对不同供水条件下冬小麦冠层温度进行了多年田间观测,模拟了以土壤水分条件为主导的冠气温差、叶水势、水分亏缺指数等的变化规律及其对影响因素的响应。结果表明,冬小麦各生育阶段不同供水处理...为了给以作物高效灌溉制度提供理论依据,对不同供水条件下冬小麦冠层温度进行了多年田间观测,模拟了以土壤水分条件为主导的冠气温差、叶水势、水分亏缺指数等的变化规律及其对影响因素的响应。结果表明,冬小麦各生育阶段不同供水处理冠层温度(T c)受土壤水分影响明显,处理间冠气温差(ΔT)差异极显著。叶水势(LW P)与ΔT、作物水分胁迫指数(CW S I)相关显著。LW P=-1.8M Pa,CW S I=0.40是指示冬小麦发生水分胁迫的关键性指标。综合各指标,为了达到节水目的,使ΔT维持在0^-4℃,可获得冬小麦产量最优值,此时冬小麦灌溉量下限应使土壤相对含水量达到58.7%。展开更多
文摘Seedlings of drought-tolerance rice varieties Han 501and Han A03,and the drought sensitive varietiesNanjing 11 and Yanjing 2 were raised in a paddyfield and transplanted into pots at the age of 8leaves.Water stress started at the tillering stage byholding water from 0 MPa of the soil water potentialin pots till the leaves showed seriously wilting.
文摘Recent studies have focused on the improvement of rice productivity under aerobic conditions for times when water resources and food production are limited. This study aimed to evaluate the adaptability of high-yielding rice cultivars to moderately water-stressed upland conditions in order to contribute breeding. A three-year field experiment in the temperate climate of Kyoto, Japan, indicated that the decrease in yield was mainly derived from a decrease in above-ground total dry matter (TDM) rather than a decrease in harvest index (HI). Although the decrease in TDM was mostly caused by a decrease in radiation use efficiency (RUE), we determined that the key to adapting high-yielding cultivars to upland conditions is intercepted radiation per day (IRPD), governed by leaf area index (LAI). Although the effect was not robust, LAI growth under upland conditions was associated with root length density. RUE was dependent on leaf water potential (LWP), indicating that a plant’s ability to maintain LWP under water-stressed conditions is important. The results also suggest the necessity of a canopy analyzer to evaluate LAI, as well as an infrared radiation thermometer to evaluate RUE. Performing such measurements during breeding efforts allows us to select for genotypes that are suitable for less stressed aerobic conditions.
基金We acknowledge that this work was financially supported by the National Natural Science Fund in China(Grant No.91425302,91325201)National Key Research and Development Program during the 13th Five-year Plan in China(Grant No.2016YFC0401306).
文摘In arid and semi-arid areas,the profitability of irrigated agriculture mainly depends on the availability of water resources and optimal cropping patterns of irrigation districts.In this study,an integrated agricultural cropping pattern optimization model was developed with considering the uncertainty of water availability and water saving potential in the future,aiming to maximize agricultural net benefit per unit of irrigation water.The available water which was based on the uncertainty of runoff was divided into five scenarios.The irrigation water-saving potential in the future was quantified by assuming an increase in the rate irrigation water-saving of 10% and 20%.The model was applied to the middle reaches of Heihe River basin,in Gansu Province,China.Results showed that if the irrigation water-saving rate was assumed to increase by 10%,then the net water-saving quantity would increase by 21.5-22.5 million m3 and the gross water-saving quantity would increase by 275.7-303.0 million m3.Similarly,if the irrigation water-saving rate increased by 20%,then the net water-saving quantity would increase by 43.0-45.1 million m3 and the gross water-saving quantity would increase by 331.7-383.2 million m3.If the agricultural cropping pattern was optimized,the optimal water and cultivated area allocation for maize would be greater than those for other crops.Under the premise that similar volume of irrigation water quantity was available in different scenarios,results showed differences in system benefit and net benefit per unit of irrigation water,for the distribution of available irrigation water was diverse in different irrigation districts.
文摘为了给以作物高效灌溉制度提供理论依据,对不同供水条件下冬小麦冠层温度进行了多年田间观测,模拟了以土壤水分条件为主导的冠气温差、叶水势、水分亏缺指数等的变化规律及其对影响因素的响应。结果表明,冬小麦各生育阶段不同供水处理冠层温度(T c)受土壤水分影响明显,处理间冠气温差(ΔT)差异极显著。叶水势(LW P)与ΔT、作物水分胁迫指数(CW S I)相关显著。LW P=-1.8M Pa,CW S I=0.40是指示冬小麦发生水分胁迫的关键性指标。综合各指标,为了达到节水目的,使ΔT维持在0^-4℃,可获得冬小麦产量最优值,此时冬小麦灌溉量下限应使土壤相对含水量达到58.7%。
