Water uptake by crop roots is influenced by many factors. In this study, on the basis of previous studies, root water uptake models were established with the root weight as a dependent variable from the perspective of...Water uptake by crop roots is influenced by many factors. In this study, on the basis of previous studies, root water uptake models were established with the root weight as a dependent variable from the perspective of root biomass changes according to the theory of soil water dynamics. The established models were verified and evaluated using two indicators: root-mean-square error (RMSE) and mean absolute percentage error (MAPE). The results indicated that the annual variation range of root-mean-square error (RMSE) was 0.477-1.231, with an aver- age of 0.810; the annual variation range of mean absolute percentage error (MAPE) was 1.082%-4.052%, with an average of 2.520%, suggesting that the simulation accuracy basically met the requirements. The established numerical models of root water uptake and the compiled program exhibit high simulation accuracy, which can perfectly simulate soil water dynamics during the growth period of crops under nat- ural conditions.展开更多
Water storage pit irrigation is a new method suitable for apple trees.It comes with advantages such as water saving,water retention and drought resistance.A precise study of soil water movement and root water uptake i...Water storage pit irrigation is a new method suitable for apple trees.It comes with advantages such as water saving,water retention and drought resistance.A precise study of soil water movement and root water uptake is essential to analyse and show the advantages of the method.In this study,a mathematical model(WSPI-WR model)for 3D soil water movement and root water uptake under water storage pit irrigation was established based on soil water dynamics and soil moisture and root distributions.Moreover,this model also considers the soil evaporation,pit wall evaporation and water level variation in the pit.The finite element method was used to solve the model,and the law of mass conservation was used to analyse the water level variation.The model was validated by experimental data of the sap flow of apple trees and soil moisture in the orchard.Results showed that the WSPI-WR model is highly accurate in simulating the root water uptake and soil water distributions.The WSPI-WR model can be used to simulate root water uptake and soil water movement under water storage pit irrigation.The simulation showed that orchard soil water content and root water uptake rate centers on the storage pit with an ellipsoid distribution.The maximum distribution region of soil water and root water uptake rate was near the bottom of the pit.Distribution can reduce soil evaporation in the orchard and improve the soil water use efficiency in the middle-deep soil.展开更多
As root water uptake(RWU)is an important link in the water and heat exchange between plants and ambient air,improving its parameterization is key to enhancing the performance of land surface model simulations.Althou...As root water uptake(RWU)is an important link in the water and heat exchange between plants and ambient air,improving its parameterization is key to enhancing the performance of land surface model simulations.Although different types of RWU functions have been adopted in land surface models,there is no evidence as to which scheme most applicable to maize farmland ecosystems.Based on the 2007–09 data collected at the farmland ecosystem field station in Jinzhou,the RWU function in the Common Land Model(Co LM)was optimized with scheme options in light of factors determining whether roots absorb water from a certain soil layer(W_x)and whether the baseline cumulative root efficiency required for maximum plant transpiration(W_c)is reached.The sensibility of the parameters of the optimization scheme was investigated,and then the effects of the optimized RWU function on water and heat flux simulation were evaluated.The results indicate that the model simulation was not sensitive to W_x but was significantly impacted by W_c.With the original model,soil humidity was somewhat underestimated for precipitation-free days;soil temperature was simulated with obvious interannual and seasonal differences and remarkable underestimations for the maize late-growth stage;and sensible and latent heat fluxes were overestimated and underestimated,respectively,for years with relatively less precipitation,and both were simulated with high accuracy for years with relatively more precipitation.The optimized RWU process resulted in a significant improvement of Co LM’s performance in simulating soil humidity,temperature,sensible heat,and latent heat,for dry years.In conclusion,the optimized RWU scheme available for the Co LM model is applicable to the simulation of water and heat flux for maize farmland ecosystems in arid areas.展开更多
Reducing irrigation water use by improving water use ef ficiency(WUE) in grain production is critical for the development of sustainable agriculture in the North China Plain(NCP). This article summarizes the research ...Reducing irrigation water use by improving water use ef ficiency(WUE) in grain production is critical for the development of sustainable agriculture in the North China Plain(NCP). This article summarizes the research progresses in WUE improvement carried out at the Luancheng station located in the Northern part of NCP for the past three decades. Progresses in four aspects of yield and WUE improvement are presented, including yield and WUE improvement associated with cultivar selection, irrigation management for improving yield and WUE under limited water supply, managing root system for ef ficient soil water use and reducing soil evaporation by straw mulch. The results showed that annual average increase of 0.014 kg$m^(–3)for winter wheat and 0.02 kg$m^(–3)in WUE were observed for the past three decades, and this increase was largely associated with the improvement in harvest index related to cultivar renewal and an increase in chemical fertilizer use and soil fertility. The results also indicated that de ficit irrigation for winter wheat could signi ficantly reduce the irrigation water use, whereas the seasonal yield showed a smaller reduction rate and WUE was signi ficantly improved. Straw mulching of summer maize using the straw from winter wheat could reduce seasonal soil evaporation by 30–40 mm. With new cultivars and improved management practices it was possible to further increase grain production without much increase in water use. Future strategies to further improve WUE are also discussed.展开更多
The matching relationship between the spatial structure of cotton cluster root systems and soil-wetting patterns under mulched drip irrigation forms the theoretical basis for the technical design of mulched drip irrig...The matching relationship between the spatial structure of cotton cluster root systems and soil-wetting patterns under mulched drip irrigation forms the theoretical basis for the technical design of mulched drip irrigation.A 2-year field experiment was conducted,in which different soil-wetting patterns were produced by setting different emitter discharge rates.The envelopes of cotton cluster root length densities were derived using the topological methodology and used to examine the effects of different soil-wetting patterns on the spatial structure of root systems and water uptake capacity within row spaces.The results showed that the root systems in rows of cotton grown under narrower and deeper soil-wetting patterns exhibited a single-peak distribution,while those under wider and shallower soil-wetting patterns exhibited a two-peak distribution.Furthermore,cotton rows grown near mulch edges experienced lower moisture stress,and wider and shallower soil-wetting patterns contributed to greater root growth rates in the vertical direction and resulted in more even potential water uptake capacities.The findings of this study revealed that wider and shallower soil-wetting patterns were more desirable for mulched drip irrigation of cotton and should be considered in the technical design of drip irrigation systems.展开更多
文摘Water uptake by crop roots is influenced by many factors. In this study, on the basis of previous studies, root water uptake models were established with the root weight as a dependent variable from the perspective of root biomass changes according to the theory of soil water dynamics. The established models were verified and evaluated using two indicators: root-mean-square error (RMSE) and mean absolute percentage error (MAPE). The results indicated that the annual variation range of root-mean-square error (RMSE) was 0.477-1.231, with an aver- age of 0.810; the annual variation range of mean absolute percentage error (MAPE) was 1.082%-4.052%, with an average of 2.520%, suggesting that the simulation accuracy basically met the requirements. The established numerical models of root water uptake and the compiled program exhibit high simulation accuracy, which can perfectly simulate soil water dynamics during the growth period of crops under nat- ural conditions.
基金supported by the Chinese National Natural Science Foundation(grant numbers 51109154,51579168,U1803112)the Shanxi Province National Natural Science Foundation(grant number 201601D011053).
文摘Water storage pit irrigation is a new method suitable for apple trees.It comes with advantages such as water saving,water retention and drought resistance.A precise study of soil water movement and root water uptake is essential to analyse and show the advantages of the method.In this study,a mathematical model(WSPI-WR model)for 3D soil water movement and root water uptake under water storage pit irrigation was established based on soil water dynamics and soil moisture and root distributions.Moreover,this model also considers the soil evaporation,pit wall evaporation and water level variation in the pit.The finite element method was used to solve the model,and the law of mass conservation was used to analyse the water level variation.The model was validated by experimental data of the sap flow of apple trees and soil moisture in the orchard.Results showed that the WSPI-WR model is highly accurate in simulating the root water uptake and soil water distributions.The WSPI-WR model can be used to simulate root water uptake and soil water movement under water storage pit irrigation.The simulation showed that orchard soil water content and root water uptake rate centers on the storage pit with an ellipsoid distribution.The maximum distribution region of soil water and root water uptake rate was near the bottom of the pit.Distribution can reduce soil evaporation in the orchard and improve the soil water use efficiency in the middle-deep soil.
基金Supported by the National Natural Science Foundation of China(41305058)Cultivation Plan for Young Agricultural Science and Technology Talents of Liaoning Province(2015060 and 2014060)Key Agricultural Science and Industrialization Project of the Science and Technology Department of Liaoning Province(2014210003)
文摘As root water uptake(RWU)is an important link in the water and heat exchange between plants and ambient air,improving its parameterization is key to enhancing the performance of land surface model simulations.Although different types of RWU functions have been adopted in land surface models,there is no evidence as to which scheme most applicable to maize farmland ecosystems.Based on the 2007–09 data collected at the farmland ecosystem field station in Jinzhou,the RWU function in the Common Land Model(Co LM)was optimized with scheme options in light of factors determining whether roots absorb water from a certain soil layer(W_x)and whether the baseline cumulative root efficiency required for maximum plant transpiration(W_c)is reached.The sensibility of the parameters of the optimization scheme was investigated,and then the effects of the optimized RWU function on water and heat flux simulation were evaluated.The results indicate that the model simulation was not sensitive to W_x but was significantly impacted by W_c.With the original model,soil humidity was somewhat underestimated for precipitation-free days;soil temperature was simulated with obvious interannual and seasonal differences and remarkable underestimations for the maize late-growth stage;and sensible and latent heat fluxes were overestimated and underestimated,respectively,for years with relatively less precipitation,and both were simulated with high accuracy for years with relatively more precipitation.The optimized RWU process resulted in a significant improvement of Co LM’s performance in simulating soil humidity,temperature,sensible heat,and latent heat,for dry years.In conclusion,the optimized RWU scheme available for the Co LM model is applicable to the simulation of water and heat flux for maize farmland ecosystems in arid areas.
基金supported by the Hebei S&T Project (14227007D)National Scientific Supporting Project (2013BAD05B02,2013BAD05B05)
文摘Reducing irrigation water use by improving water use ef ficiency(WUE) in grain production is critical for the development of sustainable agriculture in the North China Plain(NCP). This article summarizes the research progresses in WUE improvement carried out at the Luancheng station located in the Northern part of NCP for the past three decades. Progresses in four aspects of yield and WUE improvement are presented, including yield and WUE improvement associated with cultivar selection, irrigation management for improving yield and WUE under limited water supply, managing root system for ef ficient soil water use and reducing soil evaporation by straw mulch. The results showed that annual average increase of 0.014 kg$m^(–3)for winter wheat and 0.02 kg$m^(–3)in WUE were observed for the past three decades, and this increase was largely associated with the improvement in harvest index related to cultivar renewal and an increase in chemical fertilizer use and soil fertility. The results also indicated that de ficit irrigation for winter wheat could signi ficantly reduce the irrigation water use, whereas the seasonal yield showed a smaller reduction rate and WUE was signi ficantly improved. Straw mulching of summer maize using the straw from winter wheat could reduce seasonal soil evaporation by 30–40 mm. With new cultivars and improved management practices it was possible to further increase grain production without much increase in water use. Future strategies to further improve WUE are also discussed.
基金This study was supported by the National Natural Science Foundation of China(Grant No.51790533(a major project)and No.51709266)the National Key Research and Development Program of China(Grant No.2017YFC0403303)the Central Public-interest Scientific Institution Basal Research Fund(Farmland Irrigation Research Institute,CAAS)(FIRI2016-19 and FIRI2016-16).
文摘The matching relationship between the spatial structure of cotton cluster root systems and soil-wetting patterns under mulched drip irrigation forms the theoretical basis for the technical design of mulched drip irrigation.A 2-year field experiment was conducted,in which different soil-wetting patterns were produced by setting different emitter discharge rates.The envelopes of cotton cluster root length densities were derived using the topological methodology and used to examine the effects of different soil-wetting patterns on the spatial structure of root systems and water uptake capacity within row spaces.The results showed that the root systems in rows of cotton grown under narrower and deeper soil-wetting patterns exhibited a single-peak distribution,while those under wider and shallower soil-wetting patterns exhibited a two-peak distribution.Furthermore,cotton rows grown near mulch edges experienced lower moisture stress,and wider and shallower soil-wetting patterns contributed to greater root growth rates in the vertical direction and resulted in more even potential water uptake capacities.The findings of this study revealed that wider and shallower soil-wetting patterns were more desirable for mulched drip irrigation of cotton and should be considered in the technical design of drip irrigation systems.