The effective and efficient management of agricultural water use is crucial to enhance agricultural production to meet the demand of a rapidly growing population. The performance assessment studies are successfully us...The effective and efficient management of agricultural water use is crucial to enhance agricultural production to meet the demand of a rapidly growing population. The performance assessment studies are successfully used to describe the irrigation problems and provide remedial measures. In this study, the performance assessment of the twin main canals of the Gezira Scheme were examined and evaluated using a set of performance indicators. The analysis was made using 3 Landsat and 8 Modis data of 2001-2002, and results showed that the seasonal average values of water productivity, relative water supply, overall consumed ratio, depleted fraction and relative evapotranspiration were respectively 0.47, 0.72, 1.41, 0.75 and 0.57 kg·m^-3 for Gezira main canal, whereas the values for Managil main canal were 0.43, 0.54, 1.68, 0.71 and 0.50 kg·m^-3, respectively. The monthly average values of crop water deficit for Gezira and Managil were respectively 71 and 78 mm-month^-1. Considering the spatial variation in some indicators, the irrigation uniformity is deemed as poor according to Molden and Gates （1990）. The analysis also showed that the gap between water demand and supply during winter season was glaringly high （46%）.展开更多
Improving irrigation water management is a key concern for the agricultural sector,and it requires extensive and comprehensive tools that provide a complete knowledge of crop water use and requirements.This study pres...Improving irrigation water management is a key concern for the agricultural sector,and it requires extensive and comprehensive tools that provide a complete knowledge of crop water use and requirements.This study presents a novel methodology to explicitly estimate daily gross and net crop water requirements,actual crop water use,and irrigation efficiency of center pivot irrigation systems,by mainly utilizing the Sentinel-2 MultiSpectral Instrument(MSI)imagery at the farm scale.ETMonitor model is adapted to estimate actual water use(as the sum of canopy transpiration and evaporation of water intercepted by canopy and evaporation from soil)at daily/10-m resolution,benefiting from the high-resolution Sentinel-2 data and thus to assess the irrigation efficiency at the farm scale.The gross irrigation water requirement is estimated from the net crop water requirement and the water loss,including the water droplet evaporation directly into the air during application before droplets fall on the canopy and canopy interception loss.The method was applied to a pilot farmland with two major crops(wheat and potato)in the Inner Mongolia Autonomous Region of China,where modern equipment and appropriate irrigation methods are deployed for efficient water use.The estimated actual crop water use showed good agreement with the ground observations,e.g.the determination coefficients range from 0.67 to 0.81 and root mean square errors range from 0.56 mm/day to 1.24 mm/day for wheat and potato when comparing the estimated evapotranspiration with the measurement by the eddy covariance system.It also showed that the losses of total irrigated volume were 25.4%for wheat and 23.7%for potato,respectively,and found that the water allocation was insufficient to meet the water requirement in this irrigated area.This suggests that the amount of water applied was insufficient to meet the crop water requirement and the inherent water losses in the center pivot irrigation system,which imply the necessity to improve the irrigation practice to use the water more efficiently.展开更多
Field topography or microtopography plays an important role in achieving acceptable performance in border irrigation. Extension of conservation tillage across the North China Plain has resulted in change in field bott...Field topography or microtopography plays an important role in achieving acceptable performance in border irrigation. Extension of conservation tillage across the North China Plain has resulted in change in field bottom configuration. This study defined regular bottom configuration for border irrigation, and introduced three regular bottom configurations： border-strip irrigation （BSI）, border-furrow irrigation （BFI） and rill irrigation （RI）. The effects of regular bottom configuration on the hydraulic process and irrigation performance were evaluated by field experiments and a WinSRFR3.1 model. Results suggest that the WinSRFR3.1 model was capable of the simulation of BFI and RI, and that the hydraulic process and irrigation performance were diverse among BSI, BFI, and RI. BSI had the highest infiltration rate while BFI had the lowest infiltration rate; BSI took the most time to complete the water advance while BFI took the least time. As a result, BSI showed the worst irrigation performance while BFI gave the best irrigation performance. Different field bottom configurations mainly accounted for differences. We conclude that regular field bottom configuration is an important factor for acceptable performance in border irrigation.展开更多
Maintaining the homogeneity of soil nitrogen(N)and plant vigor across agricultural fields is a major concern for farmers and agricultural scheme planners,particularly fields that are irrigated through pressurized syst...Maintaining the homogeneity of soil nitrogen(N)and plant vigor across agricultural fields is a major concern for farmers and agricultural scheme planners,particularly fields that are irrigated through pressurized systems,such as center pivots.Therefore,this study was carried out on a 30 hm2 potato field located 650 km south of Riyadh,the capital city of the Kingdom of Saudi Arabia,to investigate the impacts of the center pivot irrigation distribution uniformity on the crop development and the spatial distribution of residual soil N.Irrigation performance test was designed to investigate water application rate and distribution uniformities.The overall water application uniformity coefficients(Cu),determined through Christiansen(Cud)and Heerman(CuH)methods,were determined at 81.29%and 80.64%,respectively.However,the overall water distribution uniformity(Du)was determined at 70%.A considerable variability in the distribution uniformity of irrigation water was observed across the experimental field(a Du value of 67%over the medium spans compared to a Du value of 88%over the inner spans).Results of this study showed a linear correlation between the irrigation water distribution uniformity and the soil N(R^(2)=0.88).On the other hand,the vegetation cover distribution,indicated by the Cumulative Normalized Difference Vegetation Index(CNDVI),was not found to be much responsive to the irrigation distribution uniformity(R^(2)=0.11).A time series of successive NDVI maps extracted throughout the potato crop growth stages showed a consistent trend in the distribution of NDVI across the field,with R2 values that ranged between 0.25-0.73.展开更多
文摘The effective and efficient management of agricultural water use is crucial to enhance agricultural production to meet the demand of a rapidly growing population. The performance assessment studies are successfully used to describe the irrigation problems and provide remedial measures. In this study, the performance assessment of the twin main canals of the Gezira Scheme were examined and evaluated using a set of performance indicators. The analysis was made using 3 Landsat and 8 Modis data of 2001-2002, and results showed that the seasonal average values of water productivity, relative water supply, overall consumed ratio, depleted fraction and relative evapotranspiration were respectively 0.47, 0.72, 1.41, 0.75 and 0.57 kg·m^-3 for Gezira main canal, whereas the values for Managil main canal were 0.43, 0.54, 1.68, 0.71 and 0.50 kg·m^-3, respectively. The monthly average values of crop water deficit for Gezira and Managil were respectively 71 and 78 mm-month^-1. Considering the spatial variation in some indicators, the irrigation uniformity is deemed as poor according to Molden and Gates （1990）. The analysis also showed that the gap between water demand and supply during winter season was glaringly high （46%）.
基金supported by the National Natural Science Foundation of China(NSFC)[Grant no.42090014,42171039,42271394]the Open Research Program of the International Research Center of Big Data for Sustainable Development Goals[Grant no.CBAS2023ORP05]+2 种基金ESA-NSRCC Dragon 5 Program[Grant no.59061]MOST High Level Foreign Expert program[Grant No.G2022055010L]the Chinese Academy of Sciences President’s International Fellowship Initiative[Grant No.2020VTA0001].
文摘Improving irrigation water management is a key concern for the agricultural sector,and it requires extensive and comprehensive tools that provide a complete knowledge of crop water use and requirements.This study presents a novel methodology to explicitly estimate daily gross and net crop water requirements,actual crop water use,and irrigation efficiency of center pivot irrigation systems,by mainly utilizing the Sentinel-2 MultiSpectral Instrument(MSI)imagery at the farm scale.ETMonitor model is adapted to estimate actual water use(as the sum of canopy transpiration and evaporation of water intercepted by canopy and evaporation from soil)at daily/10-m resolution,benefiting from the high-resolution Sentinel-2 data and thus to assess the irrigation efficiency at the farm scale.The gross irrigation water requirement is estimated from the net crop water requirement and the water loss,including the water droplet evaporation directly into the air during application before droplets fall on the canopy and canopy interception loss.The method was applied to a pilot farmland with two major crops(wheat and potato)in the Inner Mongolia Autonomous Region of China,where modern equipment and appropriate irrigation methods are deployed for efficient water use.The estimated actual crop water use showed good agreement with the ground observations,e.g.the determination coefficients range from 0.67 to 0.81 and root mean square errors range from 0.56 mm/day to 1.24 mm/day for wheat and potato when comparing the estimated evapotranspiration with the measurement by the eddy covariance system.It also showed that the losses of total irrigated volume were 25.4%for wheat and 23.7%for potato,respectively,and found that the water allocation was insufficient to meet the water requirement in this irrigated area.This suggests that the amount of water applied was insufficient to meet the crop water requirement and the inherent water losses in the center pivot irrigation system,which imply the necessity to improve the irrigation practice to use the water more efficiently.
基金the Knowledge Innovation Program,Chinese Academy of Sciences (No.KSCX2-EW-B-1andKSCX1-YW-09-06)
文摘Field topography or microtopography plays an important role in achieving acceptable performance in border irrigation. Extension of conservation tillage across the North China Plain has resulted in change in field bottom configuration. This study defined regular bottom configuration for border irrigation, and introduced three regular bottom configurations： border-strip irrigation （BSI）, border-furrow irrigation （BFI） and rill irrigation （RI）. The effects of regular bottom configuration on the hydraulic process and irrigation performance were evaluated by field experiments and a WinSRFR3.1 model. Results suggest that the WinSRFR3.1 model was capable of the simulation of BFI and RI, and that the hydraulic process and irrigation performance were diverse among BSI, BFI, and RI. BSI had the highest infiltration rate while BFI had the lowest infiltration rate; BSI took the most time to complete the water advance while BFI took the least time. As a result, BSI showed the worst irrigation performance while BFI gave the best irrigation performance. Different field bottom configurations mainly accounted for differences. We conclude that regular field bottom configuration is an important factor for acceptable performance in border irrigation.
文摘Maintaining the homogeneity of soil nitrogen(N)and plant vigor across agricultural fields is a major concern for farmers and agricultural scheme planners,particularly fields that are irrigated through pressurized systems,such as center pivots.Therefore,this study was carried out on a 30 hm2 potato field located 650 km south of Riyadh,the capital city of the Kingdom of Saudi Arabia,to investigate the impacts of the center pivot irrigation distribution uniformity on the crop development and the spatial distribution of residual soil N.Irrigation performance test was designed to investigate water application rate and distribution uniformities.The overall water application uniformity coefficients(Cu),determined through Christiansen(Cud)and Heerman(CuH)methods,were determined at 81.29%and 80.64%,respectively.However,the overall water distribution uniformity(Du)was determined at 70%.A considerable variability in the distribution uniformity of irrigation water was observed across the experimental field(a Du value of 67%over the medium spans compared to a Du value of 88%over the inner spans).Results of this study showed a linear correlation between the irrigation water distribution uniformity and the soil N(R^(2)=0.88).On the other hand,the vegetation cover distribution,indicated by the Cumulative Normalized Difference Vegetation Index(CNDVI),was not found to be much responsive to the irrigation distribution uniformity(R^(2)=0.11).A time series of successive NDVI maps extracted throughout the potato crop growth stages showed a consistent trend in the distribution of NDVI across the field,with R2 values that ranged between 0.25-0.73.
