Microlysimeters of different sizes(5 cm 10 cm and 15 cm in length)were used extensively in the present study for the measurements of soil evapondion in site in an extremely arid area in southern Israel.All of the data...Microlysimeters of different sizes(5 cm 10 cm and 15 cm in length)were used extensively in the present study for the measurements of soil evapondion in site in an extremely arid area in southern Israel.All of the data obtained from the microlysimeters were used to evaluate two conventional eVaporation models developed by Black et al.and Ritchie,respectively.Our results indicated that the models could overestimate total cumulative evaporation by about 30% in the extremely arid environment.Reducing the power factor of the conventional model by a faCtor of 0.1 produced good agreement between the measured and simulated cumulative evaporation.Microlysimeter method proved to be a simple and accurate approach for the evaluation of soil evaporstion.展开更多
Knowledge of evapotranspiration(ET)and energy partitioning is useful for optimizing water management,especially in areas where water is scarce.A study was undertaken in a furrow-irrigated vineyard(2015)and a drip-irri...Knowledge of evapotranspiration(ET)and energy partitioning is useful for optimizing water management,especially in areas where water is scarce.A study was undertaken in a furrow-irrigated vineyard(2015)and a drip-irrigated vineyard(2017)in an arid region of northwest China to compare vineyard ET and energy partitioning and their responses to soil water content(SWC)and leaf area index(LAI).ET and soil evaporation(E)and transpiration(T)were determined using eddy covariance,microlysimeters,and sap flow.Seasonal average E/ET,T/ET,crop coefficient(Kc),evaporation coefficient(Ke),and basal crop coefficient(Kcb)were 0.50,0.50,0.67,0.35,and 0.29,respectively,in the furrow-irrigated vineyard and 0.42,0.58,0.57,0.29,and 0.43 in the dripirrigated vineyard.The seasonal average partitioning of net radiation(Rn)into the latent heat flux(LE),sensible heat flux(H)and soil heat flux(G)(LE/Rn,H/Rn,and G/Rn),evaporative fraction(EF)and Bowen ratio(β)were 0.57,0.26,0.17,0.69 and 0.63,respectively,in the furrowirrigated vineyard and 0.46,0.36,0.17,0.57 and 0.97 in the drip-irrigated vineyard.The LE/Rn,H/Rn,EF,andβwere linearly correlated with LAI.The E,Kc,Ke,E/ET,LE/Rn,LEs/Rn(ratio of LE by soil E to Rn),H/Rn,EF andβwere closely correlated with topsoil SWC(10 cm depth).Responses of ET and energy partitioning to the LAI and SWC differed under the two irrigation methods.Drip irrigation reduced seasonal average E/ET and increased average T/ET.From the perspective of energy partitioning,seasonal average H/Rn increased whereas LE/Rn,especially LEs/Rn,decreased.Compared with furrow irrigation,drip irrigation decreased the proportion of unproductive water consumption thereby contributing to enhanced water use efficiency and accumulation of dry matter.展开更多
文摘Microlysimeters of different sizes(5 cm 10 cm and 15 cm in length)were used extensively in the present study for the measurements of soil evapondion in site in an extremely arid area in southern Israel.All of the data obtained from the microlysimeters were used to evaluate two conventional eVaporation models developed by Black et al.and Ritchie,respectively.Our results indicated that the models could overestimate total cumulative evaporation by about 30% in the extremely arid environment.Reducing the power factor of the conventional model by a faCtor of 0.1 produced good agreement between the measured and simulated cumulative evaporation.Microlysimeter method proved to be a simple and accurate approach for the evaluation of soil evaporstion.
基金This work was funded by the National Natural Science Foundation of China(91425302,51621061)by the 111 Program of Introducing Talents of Discipline to Universities(B14002).
文摘Knowledge of evapotranspiration(ET)and energy partitioning is useful for optimizing water management,especially in areas where water is scarce.A study was undertaken in a furrow-irrigated vineyard(2015)and a drip-irrigated vineyard(2017)in an arid region of northwest China to compare vineyard ET and energy partitioning and their responses to soil water content(SWC)and leaf area index(LAI).ET and soil evaporation(E)and transpiration(T)were determined using eddy covariance,microlysimeters,and sap flow.Seasonal average E/ET,T/ET,crop coefficient(Kc),evaporation coefficient(Ke),and basal crop coefficient(Kcb)were 0.50,0.50,0.67,0.35,and 0.29,respectively,in the furrow-irrigated vineyard and 0.42,0.58,0.57,0.29,and 0.43 in the dripirrigated vineyard.The seasonal average partitioning of net radiation(Rn)into the latent heat flux(LE),sensible heat flux(H)and soil heat flux(G)(LE/Rn,H/Rn,and G/Rn),evaporative fraction(EF)and Bowen ratio(β)were 0.57,0.26,0.17,0.69 and 0.63,respectively,in the furrowirrigated vineyard and 0.46,0.36,0.17,0.57 and 0.97 in the drip-irrigated vineyard.The LE/Rn,H/Rn,EF,andβwere linearly correlated with LAI.The E,Kc,Ke,E/ET,LE/Rn,LEs/Rn(ratio of LE by soil E to Rn),H/Rn,EF andβwere closely correlated with topsoil SWC(10 cm depth).Responses of ET and energy partitioning to the LAI and SWC differed under the two irrigation methods.Drip irrigation reduced seasonal average E/ET and increased average T/ET.From the perspective of energy partitioning,seasonal average H/Rn increased whereas LE/Rn,especially LEs/Rn,decreased.Compared with furrow irrigation,drip irrigation decreased the proportion of unproductive water consumption thereby contributing to enhanced water use efficiency and accumulation of dry matter.
