scholarly journals Diurnal and Seasonal Mapping of Water Deficit Index and Evapotranspiration by an Unmanned Aerial System: A Case Study for Winter Wheat in Denmark

2021 ◽  
Vol 13 (15) ◽  
pp. 2998
Author(s):  
Vita Antoniuk ◽  
Kiril Manevski ◽  
Kirsten Kørup ◽  
Rene Larsen ◽  
Inge Sandholt ◽  
...  

Precision irrigation is a promising method to mitigate the impacts of drought stress on crop production with the optimal use of water resources. However, the reliable assessment of plant water status has not been adequately demonstrated, and unmanned aerial systems (UAS) offer great potential for spatiotemporal improvements. This study utilized UAS equipped with multispectral and thermal sensors to detect and quantify drought stress in winter wheat (Triticum aestivum L.) using the Water Deficit Index (WDI). Biennial field experiments were conducted on coarse sand soil in Denmark and analyses were performed at both diurnal and seasonal timescales. The WDI was significantly correlated with leaf stomatal conductance (R2 = 0.61–0.73), and the correlation was weaker with leaf water potential (R2 = 0.39–0.56) and topsoil water status (the highest R2 of 0.68). A semi-physical model depicting the relationship between WDI and fraction of transpirable soil water (FTSW) in the root zone was derived with R2 = 0.74. Moreover, WDI estimates were improved using an energy balance model with an iterative scheme to estimate the net radiation and land surface temperature, as well as the dual crop coefficient. The diurnal variation in WDI revealed a pattern of the ratio of actual to potential evapotranspiration, being higher in the morning, decreasing at noon hours and ‘recovering’ in the afternoon. Future work should investigate the temporal upscaling of evapotranspiration, which may be used to develop methods for site-specific irrigation recommendations.

2016 ◽  
Vol 54 (2) ◽  
pp. 257-272 ◽  
Author(s):  
XIAOYU ZHANG ◽  
XIYING ZHANG ◽  
SUYING CHEN ◽  
HONGYONG SUN ◽  
LIWEI SHAO ◽  
...  

SUMMARYSelecting high-yielding cultivars under drought is an important practice to improve crop production. Canopy temperature (T) shows a relative reliable association with grain yield. In this study, we compared the suitability of canopy T and other agronomic as well as physiological traits associated with grain yield under different water regimes. Field experiments over two seasons (2011–2012 and 2012–2013) were carried out under three water regimes, represented about 64, 76 and 89% of potential evapotranspiration, with 16 local winter wheat (Triticum aestivum L.) cultivars in each season. Results showed that cultivars with higher yield usually performed consistently lower canopy T under three water regimes, while the relationships of grain yield with other agronomic or physiological traits were more influenced by soil moisture. In addition, the relationship between canopy T and grain yield varied with different growth stages: From the time of heading to early grain filling stages, a more significant negative linear relationship (p < 0.001) existed under the three irrigation levels.


1997 ◽  
Vol 24 (1) ◽  
pp. 19-24 ◽  
Author(s):  
P. J. Sexton ◽  
J. M. Bennett ◽  
K. J. Boote

Abstract Peanut (Arachis hypogaea L.) fruit growth is sensitive to surface soil (0-5 cm) conditions due to its subterranean fruiting habit. This study was conducted to determine the effect of soil water content in the pegging zone (0-5 cm) on peanut pod growth rate and development. A pegging-pan-root-tube apparatus was used to separately control soil water content in the pegging and root zone for greenhouse trials. A field study also was conducted using portable rainout shelters to create a soil water deficit. Pod phenology, pod and seed growth rates, and final pod and seed dry weights were determined. In greenhouse studies, dry pegging zone soil delayed pod and seed development. In the field, soil water deficits in the pegging and root zone decreased pod and seed growth rates by approximately 30% and decreased weight per seed from 563 to 428 mg. Pegs initiating growth during drought stress demonstrated an ability to suspend development during the period of soil water deficit and to re-initiate pod development after the drought stress was relieved.


2008 ◽  
Vol 88 (4) ◽  
pp. 451-460 ◽  
Author(s):  
M A Bolinder ◽  
O. Andrén ◽  
T. Kätterer ◽  
L -E Parent

The potential for storage of atmospheric CO2-C as soil organic C (SOC) in agroecosystems depends largely on soil biological activity and the quantity and quality of annual C inputs to soil. In this study we used the Introductory Carbon Balance Model (ICBM) approach driven by daily standard weather station data, specific soil properties and crop characteristics at the scale of Canadian agricultural ecoregions. The objectives were to calculate a climate-dependent soil biological activity parameter representative for annual agricultural crop production systems (re_crop) and to estimate the effect of fallow (re_fallow). These parameters are based on the daily product of soil temperature and stored water that influence biological activity in the arable layer, and are used to adjust the decomposition rates of the ICBM SOC pools. We also tested re_crop and re_fallow on SOC stock change data for different site and treatment combinations from long-term field experiments located in some of the ecoregions. An re_crop value of 0.95 for western ecoregions was on average 0.23 units lower than that of the eastern ecoregions, indicating a lower decomposition rate of SOC. Although the estimated annual C inputs to soil for small-grain cereals were on average ≈7.5% higher in the eastern ecoregions (305 vs. 285 g C m-2 yr-1), the overall results suggest that the western ecoregions would have a greater potential to maintain high SOC levels in the long term. However, these parameters varied between ecoregions and, consequently, the SOC sequestration potential was not always higher for the western ecoregions. The effect of fallow was on average ≈0.04, i.e., SOC decomposed slightly faster under fallow. Predictions for 24 out of 33 site and treatment combinations across Canada were significantly improved (P = 0.003), compared with a previous application with the ICBM that did not differentiate between crops and fallow. The methodology used here enabled us to examine regional differences in the potential for SOC sequestration as a balance between annual C inputs to soil and soil biological activity. Key words: Annual C inputs, climate, fallow, soil biological activity, agroecosystems


2020 ◽  
Author(s):  
Bouchra Ait Hssaine ◽  
Olivier Merlin ◽  
Jamal Ezzahar ◽  
Salah Er-raki ◽  
Saïd Khabba ◽  
...  

&lt;p&gt;Over semi-arid agricultural regions, detecting the crop water need at the onset of water stress is of paramount importance for optimizing the use of irrigation water. Evapotranspiration (ET) is a crucial component of the water cycle, it strongly impacts the water resource management, drought monitoring, and climate. Remote sensing observations provide very relevant information to feed ET models. In particular, the microwave-derived surface (0-5 cm) soil moisture (SM), which is the main controlling factor of soil evaporation, the visible/near-infratred-derived vegetation cover fraction (fc), which provides an essential structural constraint on the fractioning between vegetation transpiration and soil evaporation, and - thermal-derived land surface temperature (LST), which is a signature of both available energy and evapotranspiration (ET) rate. The aim of this work is to integrate those independent and complementary information on total ET within an energy balance model. As a state-of-the-art and commonly used model, we chose the TSEB modelling as a basis for developments. An innovative calibration procedure is proposed to retrieve the main parameters of soil evaporation (soil resistance, r&lt;sub&gt;ss&lt;/sub&gt;) and plant transpiration (Priestly Taylor coefficient, &amp;#945;&lt;sub&gt;PT&lt;/sub&gt;) based on a threshold on fc. The procedure is applied over an irrigated wheat field in the Tensift basin, central Morocco. Overall, the coupling of the soil resistance formulation with the TSEB formalism improves the estimation of soil evaporation, and consequently, improves the partitioning of ET. Analysis of the retrieved time series indicates that the daily &amp;#945;&lt;sub&gt;PT&lt;/sub&gt; mainly follows the phenology of winter wheat crop with a maximum value coincident with the full development of green biomass and a minimum value reached at harvest. The temporal variations of &amp;#945;&lt;sub&gt;PT&lt;/sub&gt; before senescence are attributed to the dynamics of both the root zone soil moisture and the amount of green biomass.&lt;/p&gt;


OENO One ◽  
2014 ◽  
Vol 48 (4) ◽  
pp. 269
Author(s):  
Gabriel Balint ◽  
Andrew G. Reynolds

<p style="text-align: justify;"><strong>Aim</strong>: The efficacy of partial root zone drying (PRD) and regulated deficit irrigation (RDI) on vine physiology, yield components, fruit composition and wine sensory profiles of ‘Cabernet-Sauvignon’ was investigated in a cool climate region in Ontario, Canada.</p><p style="text-align: justify;"><strong>Methods and results</strong>: Field experiments were conducted in a Cabernet-Sauvignon block in Niagara-on-the-Lake, ON Canada between 2006 and 2008. There were five treatments : non-irrigated control, PRD, full irrigation [100 % of crop evapotranspiration (ET<sub>c</sub>)] and two levels of RDI (50 and 25 % ET<sub>c</sub>). Treatments started immediately after fruit set and continued until post-veraison. Soil and vine water status were apparently controlled not only by the amount of water but also by the irrigation strategy used. In the PRD treatments, soil moisture, leaf water potential, and transpiration rate were generally lower than in 100 % ET<sub>c</sub> but higher than non-irrigated and RDI treatments. Almost all treatments were different than in non-irrigated vines in fruit composition and wine sensory attributes. Wine sensory attributes differed considerably due to the amount of irrigation water applied in 2007. RDI strategies were more consistent than the PRD treatments in their effect on vine water status, grape composition and wine sensory profiles. Inconsistent patterns across seasons for some variables indicated that besides soil and vine water status, there were other factors that impacted vine physiology, yield components and berry composition.</p><p style="text-align: justify;"><strong>Conclusions</strong>: RDI treatments improved wine quality when compared with full or either non-irrigated treatments. Overall, use of RDI irrigation or PRD during dry and warm years can improve grape composition in cool climates.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: To the best of our knowledge, this is the first evaluation of PRD and RDI on Cabernet-Sauvignon in a cool humid climate. It suggests that although RDI strategies are more effective, PRD also has value, particularly in dry seasons.</p>


HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 511f-511
Author(s):  
D. Richard Loero ◽  
Kent D. Kobayashi ◽  
H. C. Bittenbender

Coffee (Coffea arabica L.) is grown mainly as an uninigated crop in the Kona district of Hawaii (Big Island). Previous research has shown that water status and crop load are major components of annual yield fluctuations exhibited by coffee in Kona. The need for a quantitative method to estimate yield has led to the development of a yield model. Seven years of historical yield, meteorological, and soil data were utilized. Meteorological and soil data were used in a soil water balance model developed with the simulation language Stella® (High Performance Systems Inc.) to generate a daily soil water status value. Then, values for the number of days and mm of deficit (duration and magnitude) were grouped in trimesters and used to estimate yield: Yn = 17425 - 6.3(T2)n-1 - 181(T3)n-1 + 0.26(Y)n-1 where Yn, is the current year's yield (kg/ha); T2 is the water deficit during April-June of the previous year (days-mm); T3 is the water deficit during July-September of the previous year (days-mm); Yn-1 is the previous year's yield (kg/ha); and n is the current year. The use of this model permitted yield estimation three months before anthesis and nine months before the start of harvest with a mean prediction error of 17% or 3,154 kg/ha of coffee cherry.


Horticulturae ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 424
Author(s):  
Will Wheeler ◽  
Brent Black ◽  
Bruce Bugbee

Cherry orchards are transitioning to high-density plantings and dwarfing rootstocks to maximize production, but the response of these rootstocks to drought stress is poorly characterized. We used a 16-container, automated lysimeter system to apply repeated water stress to ungrafted Krymsk® 5 and 6 rootstocks during two growing cycles. Drought stress was imposed by withholding irrigation until the daily transpiration rate of each tree was 25% and 30% of the unstressed rate during the first trial and second trial, respectively. After this point was reached, the root-zone water status was restored to field capacity. Whole-tree transpiration measurements were supplemented with leaf-level gas-exchange measurements. Krymsk® 6 had a higher rate of photosynthesis, more vigorous vegetative growth and less conservative stomatal regulation during incipient drought than Krymsk® 5. At harvest, carbon partitioning to roots was greater in Krymsk® 6 than Krymsk® 5. The conservative rate of water use in Krymsk® 5 could be a function of greater stomatal control or reduced carbon partitioning to roots, which thereby limited transpiration rates. Further studies are needed to confirm that these results are applicable to trees grown using a common grafted scion under field conditions.


HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 779D-779
Author(s):  
David C. Percival ◽  
John T.A. Proctor ◽  
J. Alan Sullivan

Field experiments consisting of trickle irrigation (TI), IRT-76 plastic film (PF), and straw mulch were initiated to determine the influence of soil temperature and water status on carbon partitioning during the establishment of Rubus idaeus L. `Heritage' (1993, 1994), `Autumn Bliss' (1994), and `Summit' (1994) micropropagated raspberries. Environmental, vegetative, reproductive, and nutrition data were collected. Photosynthesis (Pn) measurements were recorded under field conditions using a Li-Cor LI-6200 portable photosynthesis system. Neither node number nor shoot: root ratio was influenced by TI, PF, or straw mulch. PF, however, increased root and shoot weight, total flowers produced, total berries harvested, and foliar N and P. Although differences existed among cultivars, field Pn measurements indicated that, regardless of groundcover treatment or cultivar examined, the maximum Pn rate occurred at a root-zone temperature of 25C. Hence, results from this study indicate that conditions in both the air and root zone physical environment regulate carbon assimilation and partitioning.


OENO One ◽  
2013 ◽  
Vol 47 (3) ◽  
pp. 159 ◽  
Author(s):  
Gabriel Balint ◽  
Andrew G. Reynolds

<p style="text-align: justify;"><strong>Aim</strong>: The impacts of partial root zone drying (PRD) and regulated deficit irrigation (RDI) on soil moisture, vine water status, yield components, fruit composition and wine sensory profile of Sauvignon blanc were studied in a cool climate region.</p><p style="text-align: justify;"><strong>Methods and results</strong>: Field experiments were conducted in a commercial Sauvignon blanc block in Ontario, Canada between 2006 and 2008. Treatments were: non-irrigated control, PRD, full irrigation [100% of crop evapotranspiration (ET<sub>c</sub>)] and one level of RDI (25% ET<sub>c</sub>). Treatments began immediately after fruit set and continued until the beginning of September. Reference evapotranspiration (ET<sub>o</sub>) was calculated using the Penman–Monteith equation. Soil moisture and vine water status (leaf water potential and transpiration rate) in the PRD treatments were generally less than in 100% ET<sub>c</sub> but higher than in non-irrigated and 25% ET<sub>c</sub> treatments. Almost all treatments were different than non-irrigated vines in fruit composition and wine sensory attributes. RDI strategies were more consistent across vintages than the PRD treatments in their effect on vine water status, grape composition and sensory profiles.</p><p style="text-align: justify;"><strong>Conclusions</strong>: Use of RDI or PRD in cool climates during dry and warm years can improve grape composition. In very dry and hot seasons, like that of 2007, irrigation improved grape composition and wine aroma typicity. RDI enhanced fruity aroma attributes, which suggests that this could be a viable strategy to improve grape and wine quality in cool areas. However, due to high climatic variation over the period studied, no consistent pattern of irrigation effects was found for berry composition, suggesting that plant water status was not the only factor that controlled fruit and wine quality.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: To the best of our knowledge, this study is the first evaluation of PRD in a cool, humid climate, and highlights the potential value of both RDI and PRD irrigation techniques in cool climate regions, particularly during dry growing seasons.</p>


Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3299
Author(s):  
Minseok Kang ◽  
Chulsang Yoo ◽  
Wooyoung Na

This study evaluated the contribution of small agricultural reservoirs (the mool-tongs) to crop production on Udo, and the role they play. Agricultural water demand and deficit, water storage in the mool-tongs, and the amount of irrigation water were analyzed by applying the water balance model. In particular, the Blaney-Criddle method was used to estimate the agricultural water for crop growth. In this study, four typical crops of garlic, spring onion, peanut, and barley were considered, whose growing seasons were somewhat different from each other. A total of 47 years (1973–2019) of rainfall, temperature, and evaporation data were used in this study. As a result, it was confirmed that the crop coefficient, growing period of a crop, share of the cultivated area, and the seasonal distribution of rainfall affect the role of the mool-tongs. Comparison of the frequencies of occurrence of agricultural water deficit and irrigation interval before and after introducing the mool-tongs also confirms their usefulness. After the introduction of the mool-tongs for irrigation, the frequency of occurrence of agricultural water deficits changed significantly, from almost 30% of the entire simulation period to less than 20%. Even though the water supply capacity of the mool-tongs on Udo is insufficient to offset the entire agricultural water deficit, the water stored in the mool-tongs was found to considerably aid the survival of the crops and increase crop production. The results in this study can help to determine the capacity of rainwater collecting systems, especially on a small island where the available water resources are limited.


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