scholarly journals Canopy-Air Temperature Differences and Soil Water as Predictors of Water Stress of Apple Trees Grown in a Humid, Temperate Climate

1992 ◽  
Vol 117 (3) ◽  
pp. 453-458 ◽  
Author(s):  
Preston K. Andrews ◽  
David J. Chalmers ◽  
Mapasaka Moremong
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Soil Water ◽  
Stress Index ◽  
Temperate Climate ◽  
Full Irrigation ◽  
Plastic Mulch ◽  
Crop Water Stress Index ◽  
Water Stress Index ◽  
Floor System

Temperature differences between tree canopies and air (Tc - Ta) and between leaves and air (T1 - Ta) of apples (Malus domestics Borkh. `Royal Gala') grown in New Zealand were measured with infrared (IR) thermometry. Treatments included three orchard-floor management systems and irrigation withheld (WI) for part of the growing season. Measurements of soil moisture indicated that, under full irrigation (FI), an alfalfa orchard-floor system apparently had higher soil water content than herbicide-strip (H) or plastic-mulch systems, whereas under the drought stress of WI, the H system retained the most water. The Tc - Ta and T1 - Ta of the WI treatment were significantly greater than those of the FI treatment after a soil-moisture differential was established. Linear regression between Tc - Ta, or T1 - Ta, and vapor pressure deficit (VPD) exhibited variable responses among dates. A crop water stress index (CWSI) was calculated from environmental measurements. The calculated CWSIS were not related to soil-moisture measurements. Even 35 days after full irrigation had been reinstated on the WI plots, the Tc - Ta, T1 - Ta, and CWSI of the WI plots were still significantly greater than those of the FI plots. These discrepancies in IR thermometry-based water-stress indices may be due to increased errors in the calculation of minimum CWSI at low VPDS and to fluctuating solar radiation and evapotranspiration, which are prevalent in humid, temperate climates.

scholarly journals Estimating Soil Moisture Under Low Frequency Surface Irrigation Using Crop Water Stress Index

2003 ◽  
Vol 129 (1) ◽  
pp. 27-35 ◽  
Author(s):  
Paul D. Colaizzi ◽  
Edward M. Barnes ◽  
Thomas R. Clarke ◽  
Christopher Y. Choi ◽  
Peter M. Waller
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Low Frequency ◽  
Stress Index ◽  
Crop Water ◽  
Surface Irrigation ◽  
Crop Water Stress Index ◽  
Water Stress Index ◽  
Crop Water Stress

scholarly journals Application of AquaCrop in processing tomato growing and calculation of irrigation water

2018 ◽  
pp. 183-187
Author(s):  
Sándor Takács ◽  
Tibor Molnár ◽  
Erzsébet Csengeri ◽  
Tuan Anh Le
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Irrigation Water ◽  
Stomatal Closure ◽  
Stress Factors ◽  
Stress Index ◽  
Crop Water Stress Index ◽  
Tomato Production ◽  
Processing Tomato ◽  
Water Stress Index

The area and volume of processing tomato production is increasing in Hungary. Irrigation is crucial for processing tomato growing. To save water and energy, it is important to know exactly how much water is needed to reach the desirable quality and quantity. AquaCrop is a complex software, developed by FAO, which is able to calculate irrigation water needs, several stress factors and to predict yields. A field experiment was conducted in Szarvas in processing tomato stands, under different irrigation treatments. These were the following: fully irrigated plot with 100% of evapotranspiration (ET) (calculated by AquaCrop), deficit irrigated plot with 50% of ET (D) and control (K) plot with basic water supply was also examined. Dry yield, crop water stress index and soil moisture were compared to modelled data. The yields in the plots with different access to water were not outstanding in the experiment. The model overestimated the yields in every case, but the actual and modelled yields showed good correlation. AquaCrop detected stomatal closure percentages only in the unirrigated plot. These values were compared to CWSI – computed from leaf surface temperature data, collected by a thermal cam in July – and showed moderately strong correlation. This result suggests that Aquacrop simulates water stress not precisely and it is only applicable in the case of water scarcity. Soil moisture data of the three plots were only compared by means. The measured and modeled data did not differ in the case of K and ET plots, but difference appeared in the D plot. The obtained results suggest that the use of AquaCrop for monitoring soil moisture and water stress has its limits when we apply the examined variables. In the case of dry yield prediction overestimation needs to be considered.

scholarly journals Irrigation Scheduling of Kohlrabi (Brassica oleracea var. gongylodes) Using Crop Water Stress Index

HortScience ◽  
2004 ◽  
Vol 39 (2) ◽  
pp. 276-279 ◽  
Author(s):  
Maria Victoria Cremona ◽  
Hartmut Stützel ◽  
Henning Kage
Keyword(s):  
Water Stress ◽  
Brassica Oleracea ◽  
Soil Water ◽  
Irrigation Water ◽  
Irrigation Scheduling ◽  
Stress Index ◽  
Crop Water ◽  
Crop Water Stress Index ◽  
Water Stress Index ◽  
Crop Water Stress

Two-year field experiments were carried out to evaluate the suitability of crop water stress index (CWSI) as a basis for irrigation scheduling of kohlrabi (Brassica oleracea L. var. gongylodes) by comparison with irrigation scheduling based on total soil water content (SWC). In the first year, irrigation scheduling when CWSI exceeded 0.3 resulted in more frequent water applications, but the total amount of irrigation water given was lower compared to irrigation when SWC fell below 70%. Kohlrabi tuber fresh weight at harvest was similar in both scheduling treatments, leading to 25% higher irrigation water use efficiency in the CWSI-scheduled plots. In the second year, three threshold levels, i.e., 0.2 and 80%, 0.4 and 60%, and 0.6 and 40% of CWSI and SWC, respectively, were investigated. At the level of highest water supply (CWSI = 0.2 and SWC = 80%), the total amount of water supplied was less in the CWSI but the number of irrigations was higher than in the SWC plots. The CWSI-based approach may be a method for irrigation scheduling of vegetables under temperate conditions. The higher irrigation frequency required would make this method particularly suitable in combination with irrigation system that allow frequent applications, i.e., in drip irrigation. To improve the method, a coupling with a soil water balance model seems promising.

scholarly journals Determination of Irrigation Time Using Plant Water Stress Index Values of Second Crop Sunflower in Semi-Arid Climate Conditions

2021 ◽  
Vol 9 (12) ◽  
pp. 2289-2295
Author(s):  
Ali Beyhan Uçak ◽  
Halis Seçme
Keyword(s):  
Water Stress ◽  
Seed Yield ◽  
Stress Index ◽  
Full Irrigation ◽  
Crop Water ◽  
Crop Water Stress Index ◽  
Climate Conditions ◽  
Water Stress Index ◽  
Irrigation Time ◽  
Crop Water Stress

This study was carried out in 2020 to determine crop water stress index (CWSI) by using infrared thermometer (IRT) data calculated by leaf canopy temperature measurements of the second crop sunflower genotype in semi-arid climate conditions, and to determine the relationships between irrigation time, seed yield of sunflower plant and CWSI by using these index values. Irrigation program consisted of a full irrigation and 2 different levels of stress, which were 100% (I100), 70% (I70), 35% (I35) of water losses within the effective root depth of 90 cm every 7 days. A total of 644 mm of irrigation water was applied to I100 (control) irrigation. The water consumption for full irrigation was 721 mm and the yield was 3516.00 kg/ha. Lower limit (LL) value without water stress required to determine plant water stress index was Tc-Ta=-2.528×VPD +0.749 (R2=0.814) and upper limit (UL) value, where the plant is completely under water stress, was determined as +3.27℃. Crop water stress index value threshold at which sunflower seed yield started to decrease was calculated as 0.33 using the infrared thermometer measurements at the time of irrigation. In addition, a negative correlation was obtained between sunflower seed yield and CWSI values. The results revealed that the yield tends to decrease as the CWSI increases.

Monitoring Crop Water Status and Irrigation Needs Using Multispectral Airborne Sensors

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 905D-905
Author(s):  
Thomas R. Clarke ◽  
M. Susan Moran
Keyword(s):  
Water Stress ◽  
Near Infrared ◽  
Water Status ◽  
Canopy Cover ◽  
Stress Index ◽  
Crop Water ◽  
Vegetative Cover ◽  
Crop Water Stress Index ◽  
Water Stress Index ◽  
Subsurface Drip

Water application efficiency can be improved by directly monitoring plant water status rather than depending on soil moisture measurements or modeled ET estimates. Plants receiving sufficient water through their roots have cooler leaves than those that are water-stressed, leading to the development of the Crop Water Stress Index based on hand-held infrared thermometry. Substantial error can occur in partial canopies, however, as exposed hot soil contributes to deceptively warm temperature readings. Mathematically comparing red and near-infrared reflectances provides a measure of vegetative cover, and this information was combined with thermal radiance to give a two-dimensional index capable of detecting water stress even with a low percentage of canopy cover. Thermal, red, and near-infrared images acquired over subsurface drip-irrigated cantaloupe fields demonstrated the method's ability to detect areas with clogged emitters, insufficient irrigation rate, and system water leaks.

An insight to the performance of crop water stress index for olive trees

2013 ◽  
Vol 118 ◽  
pp. 79-86 ◽  
Author(s):  
N. Agam ◽  
Y. Cohen ◽  
J.A.J. Berni ◽  
V. Alchanatis ◽  
D. Kool ◽  
...  
Keyword(s):  
Water Stress ◽  
Stress Index ◽  
Crop Water ◽  
Crop Water Stress Index ◽  
Water Stress Index ◽  
Olive Trees ◽  
Crop Water Stress

scholarly journals Practical Applications of a Multisensor UAV Platform Based on Multispectral, Thermal and RGB High Resolution Images in Precision Viticulture

Agriculture ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 116 ◽  
Author(s):  
Alessandro Matese ◽  
Salvatore Di Gennaro
Keyword(s):  
Water Stress ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Stress Index ◽  
Crop Water Stress Index ◽  
Practical Applications ◽  
Water Stress Index ◽  
Sensing Applications ◽  
Wide Range ◽  
Precision Viticulture

High spatial ground resolution and highly flexible and timely control due to reduced planning time are the strengths of unmanned aerial vehicle (UAV) platforms for remote sensing applications. These characteristics make them ideal especially in the medium–small agricultural systems typical of many Italian viticulture areas of excellence. UAV can be equipped with a wide range of sensors useful for several applications. Numerous assessments have been made using several imaging sensors with different flight times. This paper describes the implementation of a multisensor UAV system capable of flying with three sensors simultaneously to perform different monitoring options. The intra-vineyard variability was assessed in terms of characterization of the state of vines vigor using a multispectral camera, leaf temperature with a thermal camera and an innovative approach of missing plants analysis with a high spatial resolution RGB camera. The normalized difference vegetation index (NDVI) values detected in different vigor blocks were compared with shoot weights, obtaining a good regression (R2 = 0.69). The crop water stress index (CWSI) map, produced after canopy pure pixel filtering, highlighted the homogeneous water stress areas. The performance index developed from RGB images shows that the method identified 80% of total missing plants. The applicability of a UAV platform to use RGB, multispectral and thermal sensors was tested for specific purposes in precision viticulture and was demonstrated to be a valuable tool for fast multipurpose monitoring in a vineyard.

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