A crop water stress index and time threshold for automatic irrigation scheduling of grain sorghum

A two-year field experiment was conducted to determine the effect of water stress, including Crop Water Stress Index (CWSI), on seed, protein and oil yields, for two hybrids of drip-irrigated soybean in Central Greece. The experiment was set up as a split plot design with four replicates, five main plots (irrigation treatments) and two sub-plots (soybean hybrids, ‘PR91M10’ and ‘PR92B63’). Irrigation was applied to provide 100, 75, 50 and 25% of the crop evapotranspiration needs and 0% non-irrigated. Biomass weight, seed yield, oil and protein concentration were measured after harvest. To compute CWSI, lower and upper baselines were developed based on the canopy temperature measurements of I100 and I0 treatments, respectively. Deficit irrigation had a significant effect on biomass, seed, protein and oil yields. Hybrid PR92B63 was more responsive to irrigation and showed higher biomass, seed protein and oil yields, while the more sensitive hybrid PR91M10 had the ability to maintain productivity with increasing degrees of water stress. The rain-fed treatments significantly reduced biomass production and seed yield compared with the fully-irrigated ones. The highest and the lowest protein and oil yields were obtained in the I100 and I0 treatments respectively in both years and cultivars. Statistically significant exponential relationships were determined between CWSI and biomass, seed, protein and oil yields. Generally, CWSI could be used to measure crop water status and to improve irrigation scheduling of the crop and 0.10 for PR92B63 and 0.19 for PR91M10 could be offered as threshold values under the climatic conditions of the region.

Download Full-text

Evaluation of yield, quality and crop water stress index of sugar beet under different irrigation regimes

Water Science & Technology Water Supply ◽

10.2166/ws.2016.163 ◽

2016 ◽

Vol 17 (2) ◽

pp. 571-578 ◽

Cited By ~ 1

Author(s):

Omid Bahmani ◽

Ali Akbar Sabziparvar ◽

Rezvan Khosravi

Keyword(s):

Water Stress ◽

Sugar Beet ◽

Irrigation Scheduling ◽

Sugar Yield ◽

Stress Index ◽

Crop Water ◽

Crop Water Stress Index ◽

Water Stress Index ◽

Yield Quality ◽

Crop Water Stress

This study was carried out to evaluate the use of the crop water stress index (CWSI) for irrigation scheduling of sugar beet for two years under the semi arid climate of Iran. Statistical relationships between CWSI and yield, quality parameters and irrigation water use efficiency (IWUE) were investigated. Irrigations were scheduled based on 100 (I100), 85 (I85), 70 (I50) and 0% (I0) of plant water requirement. CWSI values were calculated from the measurements of canopy temperatures by infrared thermometer, air temperatures and vapor pressure deficit values for all the irrigated treatments. The highest IWUE was found in I70 with 9.16 and 1.66 kg m−3 for the root and sugar yield, respectively, in 2013. A non-water stressed baseline (lower line) equation for sugar beet was measured from full irrigated plots as (Tc − Ta)ll = −0.832VPD + 2.1811; R2 = 0.6508. There was a high determination coefficient between CWSI with the root and sugar yield and IWUE. The CWSI could be used to determine the irrigation time of sugar beet, and 0.3 could be offered as a threshold value. Results indicated that the CWSI can be used to evaluate crop water stress and improve irrigation scheduling for sugar beet under semiarid conditions.

Download Full-text

A satellite based crop water stress index for irrigation scheduling in sugarcane fields

Agricultural Water Management ◽

10.1016/j.agwat.2017.04.016 ◽

2017 ◽

Vol 189 ◽

pp. 70-86 ◽

Cited By ~ 34

Author(s):

Shadman Veysi ◽

Abd Ali Naseri ◽

Saeid Hamzeh ◽

Harm Bartholomeus

Keyword(s):

Water Stress ◽

Irrigation Scheduling ◽

Stress Index ◽

Crop Water ◽

Crop Water Stress Index ◽

Water Stress Index ◽

Crop Water Stress

Download Full-text

Automatic irrigation scheduling of apple trees using theoretical crop water stress index with an innovative dynamic threshold

Computers and Electronics in Agriculture ◽

10.1016/j.compag.2015.09.006 ◽

2015 ◽

Vol 118 ◽

pp. 193-203 ◽

Cited By ~ 30

Author(s):

Yasin Osroosh ◽

R. Troy Peters ◽

Colin S. Campbell ◽

Qin Zhang

Keyword(s):

Water Stress ◽

Irrigation Scheduling ◽

Stress Index ◽

Dynamic Threshold ◽

Crop Water ◽

Crop Water Stress Index ◽

Apple Trees ◽

Water Stress Index ◽

Crop Water Stress

Download Full-text

Application of a Daily Crop Water Stress Index to Deficit Irrigate Malbec Grapevine under Semi-Arid Conditions

Agriculture ◽

10.3390/agriculture10110492 ◽

2020 ◽

Vol 10 (11) ◽

pp. 492

Author(s):

Krista C. Shellie ◽

Bradley A. King

Keyword(s):

Water Stress ◽

Water Status ◽

Irrigation Scheduling ◽

Stress Index ◽

Crop Water ◽

Crop Water Stress Index ◽

Irrigation Amount ◽

Water Stress Index ◽

Arid Conditions ◽

Crop Water Stress

Precision irrigation of wine grape is hindered by the lack of an automated method for monitoring vine water status. The objectives of this study were to: Validate an automated model for remote calculation of a daily crop water stress index (CWSI) for the wine grape (Vitis vinifera L.) cultivar Malbec and evaluate its suitability for use in irrigation scheduling. Vines were supplied weekly with different percentages of evapotranspiration-based estimated water demand (ETc) over four growing seasons. In the fifth growing season, different daily CWSI threshold values were used to trigger an irrigation event that supplied 28 mm of water. All three indicators of vine water status (CWSI, midday leaf water potential (Ψlmd), and juice carbon isotope ratio (δ13C)) detected an increase in stress severity as the irrigation amount decreased. When the irrigation amount decreased from 100% to 50% ETc, 70% to 35% ETc, or the daily CWSI threshold value increased from 0.4 to 0.6, berry fresh weight and juice titratable acidity decreased, juice δ13C increased, the weekly CWSI increased, and Ψlmd decreased. Under the semi-arid conditions of this study, utilizing a daily CWSI threshold for irrigation scheduling reduced the irrigation amount without compromising the yield or changes in berry composition and remotely provided automated decision support for managing water stress severity in grapevine.

Download Full-text

Evaluation of Infrared Canopy Temperature Data in Relation to Soil Water-Based Irrigation Scheduling in a Humid Subtropical Climate

Transactions of the ASABE ◽

10.13031/trans.13912 ◽

2020 ◽

Vol 63 (5) ◽

pp. 1217-1231

Author(s):

Bruno P. Lena ◽

Brenda V. Ortiz ◽

Andres F. Jiménez-Lópe ◽

Álvaro Sanz-Sáez ◽

Susan A. O’Shaughnessy ◽

...

Keyword(s):

Water Stress ◽

Soil Water ◽

Irrigation Scheduling ◽

Stress Index ◽

Crop Water ◽

Crop Water Stress Index ◽

Time Threshold ◽

Irrigation Treatments ◽

Temperature Time ◽

Crop Water Stress

HighlightsCorn response to irrigation was influenced by the precipitation distribution in 2018 and 2019, and that impacted the response of CWSI as an irrigation scheduling signaling method.CWSI was sensitive to changes in soil water storage, increasing due to crop evapotranspiration and decreasing after a precipitation or irrigation event.In 2018, both seasonal CWSI and yield were not different among the irrigation treatments, while in 2019, seasonal CWSI and yield were all statistically different among the treatments evaluated.Post analysis of canopy and air temperature indicated that the temperature-time threshold (TTT) method might not appropriately signal crop water stress in a humid environment.Abstract. Irrigation scheduling based on the crop water stress index (CWSI) and temperature-time threshold (TTT) methods is promising for semi-arid and arid climates. The objective of this study was to investigate if CWSI and TTT methods could be used as irrigation signaling tools for a humid environment in the southeastern U.S. Corn canopy temperature data were collected in Alabama in 2018 and 2019 using infrared leaf temperature sensors on a fully irrigated treatment and on two limited irrigation treatments. A set of three soil water sensors installed at 0.15, 0.3, and 0.6 m soil depth were used to prescribe irrigation time and amount. CWSI was sensitive to precipitation, irrigation, and plant water uptake. No statistical differences in CWSI or yield among the three irrigation levels were found in 2018 when precipitation was well distributed during the season. In contrast, during 2019 both CWSI and yield differed significantly among the three irrigation treatments. Precipitation events in 2019 were sparse compared to 2018; therefore, irrigation promoted greater differences in water availability between treatments. Inconsistencies observed in potential irrigation signaling using the TTT method with or without the inclusion of a limiting relative humidity algorithm indicate that the TTT method may not be a reliable irrigation signaling tool for humid environments. Keywords: Corn yield, Crop water stress index, Irrigation scheduling, Limiting relative humidity, Soil water depletion, Temperature-time threshold.

Download Full-text

Data-Driven Models for Canopy Temperature-Based Irrigation Scheduling

Transactions of the ASABE ◽

10.13031/trans.13901 ◽

2020 ◽

Vol 63 (5) ◽

pp. 1579-1592

Author(s):

Bradely A. King ◽

Krista C. Shellie ◽

David D. Tarkalson ◽

Alexander D. Levin ◽

Vivek Sharma ◽

...

Keyword(s):

Water Stress ◽

Canopy Temperature ◽

Irrigation Scheduling ◽

Data Driven ◽

Stress Index ◽

Wine Grape ◽

Crop Water ◽

Crop Water Stress Index ◽

Water Stress Index ◽

Crop Water Stress

HighlightsArtificial neural network modeling was used to predict crop water stress index lower reference canopy temperature.Root mean square error of predicted lower reference temperatures was <1.1°C for sugarbeet and Pinot noir wine grape.Energy balance model was used to dynamically predict crop water stress index upper reference canopy temperature.Crop water stress index for sugarbeet was well correlated with irrigation and soil water status.Crop water stress idex was well correlated with midday leaf water potential of wine grape.Abstract. Normalized crop canopy temperature, termed crop water stress index (CWSI), was proposed over 40 years ago as an irrigation management tool but has experienced limited adoption in production agriculture. Development of generalized crop-specific upper and lower reference temperatures is critical for implementation of CWSI-based irrigation scheduling. The objective of this study was to develop and evaluate data-driven models for predicting the reference canopy temperatures needed to compute CWSI for sugarbeet and wine grape. Reference canopy temperatures for sugarbeet and wine grape were predicted using machine learning and regression models developed from measured canopy temperatures of sugarbeet, grown in Idaho and Wyoming, and wine grape, grown in Idaho and Oregon, over five years under full and severe deficit irrigation. Lower reference temperatures (TLL) were estimated using neural network models with Nash-Sutcliffe model efficiencies exceeding 0.88 and root mean square error less than 1.1°C. The relationship between TLL minus ambient air temperature and vapor pressure deficit was represented with a linear model that maximized the regression coefficient rather than minimized the sum of squared error. The linear models were used to estimate upper reference temperatures that were nearly double the values reported in previous studies. A daily CWSI, calculated as the average of 15 min CWSI values between 13:00 and 16:00 MDT for sugarbeet and between 13:00 and 15:00 local time for wine grape, were well correlated with irrigation events and amounts. There was a significant (p < 0.001) linear relationship between the daily CWSI and midday leaf water potential of Malbec and Syrah wine grapes, with an R2 of 0.53. The data-driven models developed in this study to estimate reference temperatures enable automated calculation of the CWSI for effective assessment of crop water stress. However, measurements taken under conditions of wet canopy or low solar radiation should be disregarded as they can result in irrational values of the CWSI. Keywords: Canopy temperature, Crop water stress index, Irrigation scheduling, Leaf water potential, Sugarbeet, Wine grape.

Download Full-text