Effect of Early-Stage Regulated Deficit Irrigation on Stem Lodging Resistance, Leaf Photosynthesis, Root Respiration and Yield Stability of Winter Wheat under Post-Anthesis Water Stress Conditions

In recent years, the area dedicated to modern irrigated almond plantations has increased significantly in Spain. However, the legal irrigation allocations are lower than the maximum water requirements of the crop in most cases. Therefore, almond growers are forced to implement regulated deficit irrigation strategies on their farms, applying water stress in certain resistant phenological periods and avoiding it in sensitive periods. Given the need to monitor the water status of the crop, especially in the most sensitive periods to water stress, the objective of this work was to evaluate the sensitivity of two UAV-based crop water status indicators to detect early water stress conditions in four almond cultivars. The field trial was conducted during 2020 in an experimental almond orchard, where two irrigation strategies were established: full irrigation (FI), which received 100% of irrigation requirements (IR), and regulated deficit irrigation (RDI), which received 70% of IR during the whole irrigation period except during the kernel-filling stage when received 40% IR. The UAV flights were performed on four selected dates of the irrigation season. The Crop Water Status Index (CWSI) and the Normalized Difference Vegetation Index (NDVI) were derived from thermal and multispectral images, respectively, and compared to classical water status indicators, i.e., stem water potential (Ψstem), stomatal conductance (gs), and photosynthetic rate (AN). Of the four flights performed, three corresponded to mild water stress conditions and a single flight was performed under moderate water stress conditions. Under mild water stress, CWSI was not able to capture the differences between FI and RDI trees that were observed with Ψstem. Under moderate stress conditions, CWSI was sensitive to the water deficit reached in the trees and showed significant differences among both irrigation treatments. No differences were observed in the CWSI and NVDI response to water stress among cultivars. Although NDVI and CWSI were sensitive to water stress, the low signal intensity observed in NDVI makes this index less robust than CWSI to monitor crop water stress. It can be concluded that UAV-based CWSI measurements are reliable to monitor almond water status, although for early (mild) levels of water stress, Ψstem seems to be the preferred option.

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Monitoring water stress and fruit quality in an orange orchard under regulated deficit irrigation using narrow-band structural and physiological remote sensing indices

ISPRS Journal of Photogrammetry and Remote Sensing ◽

10.1016/j.isprsjprs.2012.05.003 ◽

2012 ◽

Vol 71 ◽

pp. 47-61 ◽

Cited By ~ 63

Author(s):

S. Stagakis ◽

V. González-Dugo ◽

P. Cid ◽

M.L. Guillén-Climent ◽

P.J. Zarco-Tejada

Keyword(s):

Remote Sensing ◽

Water Stress ◽

Fruit Quality ◽

Deficit Irrigation ◽

Narrow Band ◽

Regulated Deficit Irrigation ◽

Orange Orchard ◽

Remote Sensing Indices

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Water stress thresholds for regulated deficit irrigation in pistachio trees: Rootstock influence and effects on yield quality

Agricultural Water Management ◽

10.1016/j.agwat.2015.08.006 ◽

2016 ◽

Vol 164 ◽

pp. 58-72 ◽

Cited By ~ 21

Author(s):

H. Memmi ◽

M.C. Gijón ◽

J.F. Couceiro ◽

D. Pérez-López

Keyword(s):

Water Stress ◽

Deficit Irrigation ◽

Regulated Deficit Irrigation ◽

Yield Quality ◽

Pistachio Trees

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Morphological, Physiological, and Biochemical Responses to Water Stress in Melon (Cucumis melo) Subjected to Regulated Deficit Irrigation (RDI) and Partial Rootzone Drying (PRD)

Journal of Crop Science and Biotechnology ◽

10.1007/s12892-018-0122-0 ◽

2018 ◽

Vol 21 (4) ◽

pp. 407-416

Author(s):

Mouna Lamaoui ◽

Abdelghani Chakhchar ◽

Youssef EL Kharrassi ◽

Said Wahbi ◽

Cherkaoui El Modafar

Keyword(s):

Water Stress ◽

Cucumis Melo ◽

Deficit Irrigation ◽

Regulated Deficit Irrigation ◽

Biochemical Responses ◽

Partial Rootzone Drying ◽

Physiological And Biochemical

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Regulated deficit irrigation in potted Dianthus plants: Effects of severe and moderate water stress on growth and physiological responses

Scientia Horticulturae ◽

10.1016/j.scienta.2009.06.030 ◽

2009 ◽

Vol 122 (4) ◽

pp. 579-585 ◽

Cited By ~ 45

Author(s):

Sara Álvarez ◽

Alejandra Navarro ◽

Sebastián Bañón ◽

M. Jesús Sánchez-Blanco

Keyword(s):

Water Stress ◽

Deficit Irrigation ◽

Physiological Responses ◽

Regulated Deficit Irrigation

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Moderate Water Stress from Regulated Deficit Irrigation Decreases Transpiration Similarly to Net Carbon Exchange in Grapevine Canopies

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.140.5.413 ◽

2015 ◽

Vol 140 (5) ◽

pp. 413-426 ◽

Cited By ~ 13

Author(s):

Julie M. Tarara ◽

Jorge E. Perez Peña

Keyword(s):

Water Stress ◽

Deficit Irrigation ◽

Photon Flux ◽

Canopy Conductance ◽

Carbon Exchange ◽

Regulated Deficit Irrigation ◽

Clear Cut ◽

Single Leaf ◽

Unit Leaf ◽

Net Carbon Exchange

To determine the effects of timing and extent of regulated deficit irrigation (RDI) on grapevine (Vitis vinifera) canopies, whole-canopy transpiration (TrV) and canopy conductance to water vapor (gc) were calculated from whole-vine gas exchange near key stages of fruit development. The vines were managed under three approaches to RDI: 1) standard industry practice (RDIS), or weekly replacement of 60% to 70% of estimated evapotranspiration (ET) for well-watered grapevines; 2) early additional deficit (RDIE), or one-half of RDIS applied between fruit set and veraison; and 3) late additional deficit (RDIL), or one-half of RDIS applied between veraison and harvest. Compared with RDIS, the additional deficits (RDIE, RDIL) reduced daily cumulative Trv by about 45% (RDIE) and about 48% [RDIL (57% by unit leaf area)]. Diurnal patterns of gc indicated consistent moderate water stress in all RDI regimens (gc ≈50–150 mmol·m−2·s−1). Under RDIE and RDIL, there were transient occurrences of severe water stress, indicated by gc declining below 50 mmol·m−2·s−1. Across the day, vines under RDIE and RDIL had lower gc than RDIS. Under all deficit regimens, TrV exhibited opposing hysteretic loops with solar radiation [photosynthetic photon flux (PPF)] and vapor pressure deficit (VPD), with less sensitivity to VPD in RDIE and RDIL. For a given value of VPD, TrV was higher in the morning than in the afternoon. For a given value of PPF, TrV was higher in the afternoon than in the morning. Single-leaf measurements of transpiration overestimated TrV by an average of 45%. Instantaneous water use efficiency (WUE) declined during midday at the pre- and postveraison measurements for all RDI regimens. Whole-canopy daily integrated WUE (WUEd) did not differ among regimens during the additional deficits because daily cumulative values of whole-vine net carbon exchange (NCEV) and TrV changed proportionally: by about 43% to 46% in RDIE relative to RDIS. The case was less clear-cut for RDIL, where NCEv declined by 33% and TrV by 48% relative to RDIS. However, WUEd did not differ significantly between the two. More substantial water deficits than those are currently practiced in the industry through RDI could be used for potential water savings in semiarid climates.

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Individual Phenolics and Enzymatic Changes in Response to Regulated Deficit Irrigation of Extra-early Nectarines

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.141.3.222 ◽

2016 ◽

Vol 141 (3) ◽

pp. 222-232 ◽

Cited By ~ 3

Author(s):

Natalia Falagán ◽

Francisco Artés ◽

Perla A. Gómez ◽

Francisco Artés-Hernández ◽

Alejandro Pérez-Pastor ◽

...

Keyword(s):

Water Stress ◽

Bioactive Compounds ◽

Deficit Irrigation ◽

Prunus Persica ◽

Dehydroascorbic Acid ◽

Total Phenolic ◽

White Pulp ◽

Anthocyanin Content ◽

Critical Periods ◽

Regulated Deficit Irrigation

The effect of long-term regulated deficit irrigation (RDI) strategies on bioactive compounds and enzymes at harvest, during cold storage [0 °C, 90% to 95% relative humidity (RH)] and after a simulated retail sale period (15 °C, 70% to 75% RH) of extra-early nectarine ‘VioWhite 5’ [Prunus persica (L.) Batsch] was evaluated for 3 consecutive years. RDI strategies were scheduled as follows: 1) control [irrigated at 110% of maximum crop evapotranspiration (ETc) during the whole season], 2) RDI1 (irrigated at 110% ETc during critical periods of growth and at 85% of control during the rest of the growing season), and 3) RDI2 (irrigated at 110% ETc during critical periods of growth and at 80% and 60% control during the second fruit growth stage in March and late postharvest, respectively). Results suggested the existence of water stress when RDI was applied on extra-early nectarine. The RDI effect induced a change on the activity of enzymes studied that depended on the intensity and duration of water stress. RDI fruit, especially RDI2, presented higher catalase (CAT), phenylalanine ammonia-lyase (PAL), and ascorbate peroxidase (APX) enzyme activity and, together with dehydroascorbic acid level, appeared as indicators of this abiotic stress. RDI nectarine fruit increased total phenolic and flavonoids contents improving the nutraceutical quality of the product. With storage, polyphenol oxidase (PPO) increased its activity through the reduction of flavonoids, particularly in pulp. In this study, RDI2 achieved the highest initial and stored antioxidant capacity values. Peel compared with pulp was the main tissue where bioactive compounds were found in ‘VioWhite 5’ nectarine fruit and the only tissue with anthocyanin content in this white pulp nectarine. The significant water savings were of 780 and 2050 m3·ha−1 per year for RDI1 and RDI2, respectively. RDI can be used as a field practice to enhance bioactive compounds on extra-early nectarine fruit and to contribute to reduce water demand.

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