Estimation of Spring Wheat Water Use Efficiency by Remote Sensing in the Yingke Oasis of Heihe Drainage Area

2010 ◽  
Vol 8 (1) ◽  
pp. 6-10 ◽  
Author(s):  
G. J. Yang ◽  
Z. R. Xing ◽  
Y. G. Feng ◽  
W. J. Huang
2021 ◽  
Vol 13 (12) ◽  
pp. 2393
Author(s):  
Wanyuan Cai ◽  
Sana Ullah ◽  
Lei Yan ◽  
Yi Lin

Water use efficiency (WUE) is a key index for understanding the ecosystem of carbon–water coupling. The undistinguishable carbon–water coupling mechanism and uncertainties of indirect methods by remote sensing products and process models render challenges for WUE remote sensing. In this paper, current progress in direct and indirect methods of WUE estimation by remote sensing is reviewed. Indirect methods based on gross primary production (GPP)/evapotranspiration (ET) from ground observation, processed models and remote sensing are the main ways to estimate WUE in which carbon and water cycles are independent processes. Various empirical models based on meteorological variables and remote sensed vegetation indices to estimate WUE proved the ability of remotely sensed data for WUE estimating. The analytical model provides a mechanistic opportunity for WUE estimation on an ecosystem scale, while the hypothesis has yet to be validated and applied for the shorter time scales. An optimized response of canopy conductance to atmospheric vapor pressure deficit (VPD) in an analytical model inverted from the conductance model has been also challenged. Partitioning transpiration (T) and evaporation (E) is a more complex phenomenon than that stated in the analytic model and needs a more precise remote sensing retrieval algorithm as well as ground validation, which is an opportunity for remote sensing to extrapolate WUE estimation from sites to a regional scale. Although studies on controlling the mechanism of environmental factors have provided an opportunity to improve WUE remote sensing, the mismatch in the spatial and temporal resolution of meteorological products and remote sensing data, as well as the uncertainty of meteorological reanalysis data, add further challenges. Therefore, improving the remote sensing-based methods of GPP and ET, developing high-quality meteorological forcing datasets and building mechanistic remote sensing models directly acting on carbon–water cycle coupling are possible ways to improve WUE remote sensing. Improvement in direct WUE remote sensing methods or remote sensing-driven ecosystem analysis methods can promote a better understanding of the global ecosystem carbon–water coupling mechanisms and vegetation functions–climate feedbacks to serve for the future global carbon neutrality.


2014 ◽  
Vol 94 (2) ◽  
pp. 223-235 ◽  
Author(s):  
R. Kröbel ◽  
R. Lemke ◽  
C. A. Campbell ◽  
R. Zentner ◽  
B. McConkey ◽  
...  

Kröbel, R., Lemke, R., Campbell, C. A., Zentner, R., McConkey, B., Steppuhn, H., De Jong, R. and Wang, H. 2014. Water use efficiency of spring wheat in the semi-arid Canadian prairies: Effect of legume green manure, type of spring wheat, and cropping frequency. Can. J. Soil Sci. 94: 223–235. In the semi-arid Canadian prairie, water is the main determinant of crop production; thus its efficient use is of major agronomic interest. Previous research in this region has demonstrated that the most meaningful way to measure water use efficiency (WUE) is to use either precipitation use efficiency (PUE) or a modified WUE that accounts for the inefficient use of water in cropping systems that include summer fallow. In this paper, we use these efficiency measures to determine how cropping frequency, inclusion of a legume green manure, and the type of spring wheat [high-yielding Canada Prairie Spring (CPS) vs. Canada Western Red Spring (CWRS)] influence WUE using 25 yr of data (1987–2011) from the “New Rotation” experiment conducted at Swift Current, Saskatchewan. This is a well-fertilized study that uses minimum and no-tillage techniques and snow management to enhance soil water capture. We compare these results to those from a 39-yr “Old Rotation” experiment, also at Swift Current, which uses conventional tillage management. Our results confirmed the positive effect on WUE of cropping intensity, and of CPS wheat compared with CWRS wheat, while demonstrating the negative effect on WUE of a green manure crop in wheat-based rotations in semiarid conditions. Furthermore, we identified a likely advantage of using reduced tillage coupled with water conserving snow management techniques for enhancing the efficiency of water use.


2010 ◽  
Vol 52 (2) ◽  
pp. 263-269 ◽  
Author(s):  
Beibei Zhang ◽  
Wenzhao Liu ◽  
Scott X. Chang ◽  
Anthony O. Anyia

Soil Research ◽  
2008 ◽  
Vol 46 (8) ◽  
pp. 659 ◽  
Author(s):  
Jin He ◽  
Hongwen Li ◽  
A. D. McHugh ◽  
Zhongmin Ma ◽  
Xinhui Cao ◽  
...  

Permanent raised beds have been proposed as a more productive and water-efficient alternative to the conventional system of flat, flood-irrigated bays for planting narrow-spaced crops in arid north-west China. Data from a field experiment (2005–2007) conducted in the Hexi Corridor at Zhangye, Gansu Province, China, were used to compared the effects of traditional tillage (TT), zero tillage (ZT), and permanent raised beds (PRB) on crop growth, yield, and water use in a spring wheat monoculture. The results show that PRB significantly (P < 0.05) increased soil water content to 0.30 m depth by 7.2–10.7% and soil temperature to 0.05 m depth by 0.2–0.9°C during the wheat-growing period relative to TT and ZT treatments. Bulk density in 0–0.10 m soil layer under PRB was also 5.8% less than for flat planting treatments. Mean wheat yields over 3 years on PRB plots were slightly greater and furrow irrigation in permanent beds was particularly effective in increasing irrigation water use efficiency (~18%), compared with TT and ZT treatments. This increase in water use efficiency is of considerable importance for these arid areas where irrigation water resources are scarce.


2005 ◽  
Vol 85 (4) ◽  
pp. 877-888 ◽  
Author(s):  
Paul G. Jefferson ◽  
Herb W. Cutforth

Crested wheatgrass (Agropyron cristatum L. Gaertn.) and alfalfa (Medicago sativa L.) are introduced forage species used for hay and grazing by cattle across western Canada. These species are well adapted to the semiarid region but their long-term responses to water stress have not been previously compared. Two alfalfa cultivars with contrasting root morphology (tap-rooted vs. creeping-rooted) and two crested wheatgrass (CWG) cultivars with different ploidy level (diploid vs. tetraploid) were compared with continuously cropped spring wheat (Triticum aestivum L.) for 6 yr at a semiarid location in western Canada. Soil water depletion, forage yield, water use efficiency, leaf water potential, osmotic potential and turgor were compared. There were no consistent differences between cultivars within alfalfa or CWG for variables measured. However, these two species exhibit different water stress response strategies. Leaf water potential of CWG was lower during midday stress period than that of alfalfa or wheat. Alfalfa apparently had greater capacity to osmotically adjust to avoid midday water stress and maintain higher turgor. Soil water use patterns changed as the stands aged. In the initial years of the trial, forage crops used soil water from upper layers of the profile. In later years, soil water was depleted down to 3 m by alfalfa and to 2 m by crested wheatgrass. Alfalfa was able to deplete soil water to lower concentrations than crested wheatgrass or wheat. Soil water depletion by wheat during the non-active growth season (after harvest to fall freeze-up) was much less than for CWG or alfalfa as expected for annual vs. perennial crops. As a result, more soil water was available to wheat during its active growth period. In the last 3 yr, the three species depleted all available soil water. Forage yield responses also changed over time. In the initial 3 yr, crested wheatgrass yielded as much as or more than alfalfa. For the last 3 yr of the experiment, alfalfa yielded more forage than crested wheatgrass. Forage crops deplete much more soil water during periods of aboveground growth dormancy than wheat. Water use efficiency of crested wheatgrass declined with stand age compared with fertilized continuous spring wheat. Alfalfa exhibited deep soil water extraction and apparent osmotic adjustment in response to water stress while CWG exhibited tolerance of low water potential during stress. Key words: forage yield, soil water, water potential, water use, water use efficiency, drought


2013 ◽  
Vol 93 (2) ◽  
pp. 287-289
Author(s):  
Herb Cutforth

Cutforth, H. 2013. Yield of spring wheat and field pea seeded into standing and cultivated canola stubble on the semiarid Canadian prairie. Can. J. Plant Sci. 93: 287–289. Previous research in the semiarid prairie showed that crop yields increased as the height of standing cereal stubble increased to ≥45 cm. A 3-yr (2008–2010) study was conducted at Swift Current, SK, to determine how seeding field pea and spring wheat into cultivated and tall (≥45 cm high) canola stubble affected crop yield. Similar to cereal stubble, crop yield and water use efficiency were significantly greater for crops grown in the tall standing canola stubble compared to the cultivated stubble. Water use by each crop was independent of stubble management.


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