H2O2and ABA signaling are responsible for the increased Na+efflux and water uptake inGossypium hirsutumL. roots in the non-saline side under non-uniform root zone salinity

Water scarcity and quality degradation represent real threats to economic, social, and environmental development of arid and semi-arid regions. Drip irrigation associated to Deficit Irrigation (DI) has been investigated as a water saving technique. Yet its environmental impacts on soil and groundwater need to be gone into in depth especially when using brackish irrigation water. Soil water content and salinity were monitored in a fully drip irrigated potato plot with brackish water (4.45 dSm−1) in semi-arid Tunisia. The HYDRUS-1D model was used to investigate the effects of different irrigation regimes (deficit irrigation (T1R, 70% ETc), full irrigation (T2R, 100% ETc), and farmer’s schedule (T3R, 237% ETc) on root water uptake, root zone salinity, and solute return flows to groundwater. The simulated values of soil water content (θ) and electrical conductivity of soil solution (ECsw) were in good agreement with the observation values, as indicated by mean RMSE values (≤0.008 m3·m−3, and ≤0.28 dSm−1 for soil water content and ECsw respectively). The results of the different simulation treatments showed that relative yield accounted for 54%, 70%, and 85.5% of the potential maximal value when both water and solute stress were considered for deficit, full. and farmer’s irrigation, respectively. Root zone salinity was the lowest and root water uptake was the same with and without solute stress for the treatment corresponding to the farmer’s irrigation schedule (273% ETc). Solute return flows reaching the groundwater were the highest for T3R after two subsequent rainfall seasons. Beyond the water efficiency of DI with brackish water, long term studies need to focus on its impact on soil and groundwater salinization risks under changing climate conditions.

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Water and salt transport in daily irrigated root zone.

Netherlands Journal of Agricultural Science ◽

10.18174/njas.v35i3.16734 ◽

1987 ◽

Vol 35 (3) ◽

pp. 395-406

Author(s):

C. Dirksen

Keyword(s):

Soil Water ◽

Water Uptake ◽

Gamma Ray ◽

Root Zone ◽

Root Water Uptake ◽

Salt Transport ◽

Soil Water Retention ◽

Transport Models ◽

Leaching Fraction ◽

Water Contents

With closed, high-frequency irrigation systems, the water supply can be tailored to the instant needs of plants. To be able to do this optimally, it is necessary to understand how plants interact with their environment. To study water uptake under a variety of non-uniform conditions in the root zone, lucerne was grown in laboratory soil columns with automated gamma ray attenuation, tensiometer and salinity sensor equipment to measure soil water contents, pressure potentials and osmotic potentials, respectively. The columns were irrigated with water of different salinity at various frequencies and leaching fractions. This paper presents results obtained in a column irrigated daily with water of conductivity 0.33 S/m (h0 = -13.2 m) at a target leaching fraction of 0.08. This includes the drying and wetting patterns under daily irrigations in deficit and excess of evapotranspiration, respectively. After 230 days the salination of the column had still not reached a steady state. Salinity increased rapidly with depth and root water uptake was shallow for the deep-rooting lucerne. Water and salt transport under daily irrigation cannot be described without taking hysteresis of soil water retention into account. The data presented are suitable for testing various water uptake models, once numerical water and salt transport models of the required complexity are operational. (Abstract retrieved from CAB Abstracts by CABI’s permission)

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Effects of non-uniform root zone salinity on growth, ion regulation, and antioxidant defense system in two alfalfa cultivars

Plant Physiology and Biochemistry ◽

10.1016/j.plaphy.2018.09.028 ◽

2018 ◽

Vol 132 ◽

pp. 434-444 ◽

Cited By ~ 6

Author(s):

Xue Xiong ◽

Nan Liu ◽

Yu-qi Wei ◽

Yi-xian Bi ◽

Jian-chuan Luo ◽

...

Keyword(s):

Antioxidant Defense ◽

Root Zone ◽

Antioxidant Defense System ◽

Defense System ◽

Ion Regulation ◽

Root Zone Salinity

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Towards understanding tree root profiles: simulating hydrologically optimal strategies for root distribution

Hydrology and Earth System Sciences ◽

10.5194/hess-5-629-2001 ◽

2001 ◽

Vol 5 (4) ◽

pp. 629-644 ◽

Cited By ~ 45

Author(s):

M. T. van Wijk ◽

W. Bouten

Keyword(s):

Water Uptake ◽

Root Distribution ◽

Root Zone ◽

Evolutionary Game ◽

Optimal Strategies ◽

Single Root ◽

Root Interactions ◽

Model Configuration ◽

The One ◽

Root Distributions

Abstract. In this modelling study differences in vertical root distributions measured in four contrasting forest locations in the Netherlands were investigated. Root distributions are seen as a reflection of the plant’s optimisation strategy, based on hydrological grounds. The "optimal" root distribution is defined as the one that maximises the water uptake from the root zone over a period of ten years. The optimal root distributions of four forest locations with completely different soil physical characteristics are calculated using the soil hydrological model SWIF. Two different model configurations for root interactions were tested: the standard model configuration in which one single root profile was used (SWIF-NC), and a model configuration in which two root profiles compete for the same available water (SWIF-C). The root profiles were parameterised with genetic algorithms. The fitness of a certain root profile was defined as the amount of water uptake over a simulation period of ten years. The root profiles of SWIF-C were optimised using an evolutionary game. The results showed clear differences in optimal root distributions between the various sites and also between the two model configurations. Optimisation with SWIF-C resulted in root profiles that were easier to interpret in terms of feasible biological strategies. Preferential water uptake in wetter soil regions was an important factor for interpretation of the simulated root distributions. As the optimised root profiles still showed differences with measured profiles, this analysis is presented, not as the final solution for explaining differences in root profiles of vegetation but as a first step using an optimisation theory to increase understanding of the root profiles of trees. Keywords: forest hydrology, optimisation, roots

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Policy-Driven Sustainable Saline Drainage Disposal and Forage Production in the Western San Joaquin Valley of California

Sustainability ◽

10.3390/su12166362 ◽

2020 ◽

Vol 12 (16) ◽

pp. 6362

Author(s):

Amninder Singh ◽

Nigel W. T. Quinn ◽

Sharon E. Benes ◽

Florence Cassel

Keyword(s):

Root Zone ◽

Subsurface Drainage ◽

Drainage Water ◽

Agricultural Drainage ◽

Forage Production ◽

Tall Wheatgrass ◽

San Joaquin River ◽

Agricultural Drainage Water ◽

Irrigation Drainage ◽

Root Zone Salinity

Environmental policies to address water quality impairments in the San Joaquin River of California have focused on the reduction of salinity and selenium-contaminated subsurface agricultural drainage loads from westside sources. On 31 December 2019, all of the agricultural drainage from a 44,000 ha subarea on the western side of the San Joaquin River basin was curtailed. This policy requires the on-site disposal of all of the agricultural drainage water in perpetuity, except during flooding events, when emergency drainage to the River is sanctioned. The reuse of this saline agricultural drainage water to irrigate forage crops, such as ‘Jose’ tall wheatgrass and alfalfa, in a 2428 ha reuse facility provides an economic return on this pollutant disposal option. Irrigation with brackish water requires careful management to prevent salt accumulation in the crop root zone, which can impact forage yields. The objective of this study was to optimize the sustainability of this reuse facility by maximizing the evaporation potential while achieving cost recovery. This was achieved by assessing the spatial and temporal distribution of the root zone salinity in selected fields of ‘Jose’ tall wheatgrass and alfalfa in the drainage reuse facility, some of which have been irrigated with brackish subsurface drainage water for over fifteen years. Electromagnetic soil surveys using an EM-38 instrument were used to measure the spatial variability of the salinity in the soil profile. The tall wheatgrass fields were irrigated with higher salinity water (1.2–9.3 dS m−1) compared to the fields of alfalfa (0.5–6.5 dS m−1). Correspondingly, the soil salinity in the tall wheatgrass fields was higher (12.5 dS m−1–19.3 dS m−1) compared to the alfalfa fields (8.97 dS m−1–14.4 dS m−1) for the years 2016 and 2017. Better leaching of salts was observed in the fields with a subsurface drainage system installed (13–1 and 13–2). The depth-averaged root zone salinity data sets are being used for the calibration of the transient hydro-salinity computer model CSUID-ID (a one-dimensional version of the Colorado State University Irrigation Drainage Model). This user-friendly decision support tool currently provides a useful framework for the data collection needed to make credible, field-scale salinity budgets. In time, it will provide guidance for appropriate leaching requirements and potential blending decisions for sustainable forage production. This paper shows the tie between environmental drainage policy and the role of local governance in the development of sustainable irrigation practices, and how well-directed collaborative field research can guide future resource management.

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Fertilizer location modifies root zone salinity, root morphology, and water-stress resistance of tree seedlings according to the watering regime in a dryland reforestation

Journal of Plant Nutrition and Soil Science ◽

10.1002/jpln.201500181 ◽

2016 ◽

Vol 179 (2) ◽

pp. 223-233 ◽

Cited By ~ 4

Author(s):

Juan F. Ovalle ◽

Eduardo C. Arellano ◽

Rosanna Ginocchio ◽

Pablo Becerra

Keyword(s):

Water Stress ◽

Stress Resistance ◽

Root Morphology ◽

Root Zone ◽

Tree Seedlings ◽

Root Zone Salinity

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Root-Zone Salinity Alters Raffinose Oligosaccharide Metabolism and Transport in Coleus

PLANT PHYSIOLOGY ◽

10.1104/pp.115.3.1267 ◽

1997 ◽

Vol 115 (3) ◽

pp. 1267-1276 ◽

Cited By ~ 25

Author(s):

G. A. Gilbert ◽

C. Wilson ◽

M. A. Madore

Keyword(s):

Root Zone ◽

Root Zone Salinity

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Water drawdown by radish (Raphanus sativus L.) multiple-root systems evaluated using computed tomography

Soil Research ◽

10.1071/sr07116 ◽

2008 ◽

Vol 46 (3) ◽

pp. 228

Author(s):

M. A. Hamza ◽

S. H. Anderson ◽

L. A. G. Aylmore

Keyword(s):

Computed Tomography ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Water Uptake ◽

Root Zone ◽

Multiple Root ◽

Root Systems ◽

Bulk Soil ◽

Water Drawdown

Although measurements of water drawdown by single radish root systems have been previously published by the authors, further research is needed to evaluate water drawdown patterns in multiple-root systems. The objective of this study was to compare water transpiration patterns estimated using X-ray computed tomography (CT) with the traditional gravimetric method and to evaluate the effects of variably spaced multiple root systems on soil water content and corresponding water content gradients. Water drawdown showed a dual pattern in which it increased rapidly when soil water content was high at the beginning of transpiration, then slowed down to an almost constant level with time as water content decreased. These results contrast with the single-root system wherein transpiration rates initially increased rapidly and then slowly increased with time. Water uptake estimated using the CT method was observed to be 27–38% lower than the gravimetrically estimated water uptake; this difference was attributed to lower water uptake for the upper 30 mm layer (CT measured) than lower layers due to differences in root density. However, good correlation (r = 0.97) was found between both measurement methods. The drawdown patterns for multiple root systems showed a convex shape from the root surface to the bulk soil, compared with a nearly linear shape for single roots. The water content drawdown areas and the drawdown distances for multiple root systems were found to be much larger than those corresponding to single radish roots. Differential water content gradients were observed for roots spaced at 15-mm distances compared with 3–4-mm distances. These differential gradients from the bulk soil towards the root-zone occurred probably creating localised water potential gradients within the root-zone, which moved water from between roots to root surfaces. The lowest water content values were located in the inter-root areas. The CT-scanned layer probably acted as one drawdown area with particularly higher water drawdown from the inter-root areas.

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