THE WATER RELATIONS AND IRRIGATION REQUIREMENTS OF OLIVE (Olea europaea L.): A REVIEW

SUMMARYThe results of research on the water relations and irrigation needs of olive are collated and summarised in an attempt to link fundamental studies on crop physiology to irrigation practices. Background information on the ecology of the olive (it is native to the coastal areas of the eastern Mediterranean) and on crop development processes are presented, followed by reviews of the influence of water stress on gas exchange (stomatal conductance, photosynthesis and transpiration), crop water requirements, water productivities and irrigation systems. The olive has many attributes that help to protect it against drought, including the morphology of the leaf, and the capacity to conserve water under conditions of high evaporative demand through stomatal closure, osmotic regulation and resistance to cavitation. The concept of ‘deficit irrigation’ has been the subject of much research. Although vegetative growth is restricted, there is no convincing evidence that ‘sustained deficit irrigation’ or ‘regulated deficit irrigation’ or ‘partial root zone drying’ offer any advantages over conventional practices. Water productivities are very variable and difficult to reconcile due, in part, to biennial bearing, tree-to-tree variability and differences in tree population densities. Similarly, no clear consensus has emerged on how best to exploit the sensitivity of trunk expansion to water availability in irrigation scheduling. As production methods for this historical crop are intensified (high-density hedgerows, irrigated and mechanized orchards), so will the need to understand the role that water plays in the production processes become ever more critical.

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THE WATER RELATIONS AND IRRIGATION REQUIREMENTS OF SUGAR CANE (SACCHARUM OFFICINARUM): A REVIEW

Experimental Agriculture ◽

10.1017/s0014479710000645 ◽

2011 ◽

Vol 47 (1) ◽

pp. 1-25 ◽

Cited By ~ 47

Author(s):

M. K. V. CARR ◽

J. W. KNOX

Keyword(s):

Water Stress ◽

Water Relations ◽

Sugar Cane ◽

Root Zone ◽

Water Productivity ◽

Crop Coefficient ◽

Saccharum Officinarum ◽

Irrigation Scheduling ◽

Background Information ◽

Technology Choice

SUMMARYThe results of research on the water relations and irrigation needs of sugar cane are collated and summarized in an attempt to link fundamental studies on crop physiology to irrigation practices. Background information on the centres of production of sugar cane is followed by reviews of (1) crop development, including roots; (2) plant water relations; (3) crop water requirements; (4) water productivity; (5) irrigation systems and (6) irrigation scheduling. The majority of the recent research published in the international literature has been conducted in Australia and southern Africa. Leaf/stem extension is a more sensitive indicator of the onset of water stress than stomatal conductance or photosynthesis. Possible mechanisms by which cultivars differ in their responses to drought have been described. Roots extend in depth at rates of 5–18 mm d−1 reaching maximum depths of > 4 m in ca. 300 d providing there are no physical restrictions. The Penman-Monteith equation and the USWB Class A pan both give good estimates of reference crop evapotranspiration (ETo). The corresponding values for the crop coefficient (Kc) are 0.4 (initial stage), 1.25 (peak season) and 0.75 (drying off phase). On an annual basis, the total water-use (ETc) is in the range 1100–1800 mm, with peak daily rates of 6–15 mm d−1. There is a linear relationship between cane/sucrose yields and actual evapotranspiration (ETc) over the season, with slopes of about 100 (cane) and 13 (sugar) kg (ha mm)−1 (but variable). Water stress during tillering need not result in a loss in yield because of compensatory growth on re-watering. Water can be withheld prior to harvest for periods of time up to the equivalent of twice the depth of available water in the root zone. As alternatives to traditional furrow irrigation, drag-line sprinklers and centre pivots have several advantages, such as allowing the application of small quantities of water at frequent intervals. Drip irrigation should only be contemplated when there are well-organized management systems in place. Methods for scheduling irrigation are summarized and the reasons for their limited uptake considered. In conclusion, the ‘drivers for change’, including the need for improved environmental protection, influencing technology choice if irrigated sugar cane production is to be sustainable are summarized.

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Productivity and water relations of field-grown cashew: a comparison of sprinkler and drip irrigation

Australian Journal of Experimental Agriculture ◽

10.1071/ea00158 ◽

2001 ◽

Vol 41 (5) ◽

pp. 663 ◽

Cited By ~ 6

Author(s):

S. J. Blaikie ◽

E. K. Chacko ◽

P. Lu ◽

W. J. Müller

Keyword(s):

Linear Relationship ◽

Surface Area ◽

Drip Irrigation ◽

Root Zone ◽

Leaf Gas Exchange ◽

Stomatal Closure ◽

Dry Season ◽

Water Application ◽

Evaporative Demand ◽

Tropical Regions

Cashew is an emerging crop in the seasonally ‘wet–dry’ tropical regions of northern Australia. In North Queensland flowering and fruiting of cashew coincides with the dry season (May–November). During this period growers sprinkler irrigate at 500 L/tree.week. A 3-year (1996–98) experiment compared this strategy with alternatives, including no irrigation or drip irrigation in which 115 or 230 L/tree.week was applied by drippers placed near the tree trunk and near the canopy drip line throughout the dry season. Measurements of soil water to 1.3 m, leaf gas exchange, chlorophyll fluorescence, tree sap flow and yield were made. Data collected in the first 2 years showed that the water requirement of the trees increased progressively as the crop load and evaporative demand increased during the dry season. During the final year of the study, additional sprinkler and drip treatments, in which water applications were progressively increased during the dry season, were introduced. The productivity of cashew in this experiment was strongly influenced by irrigation treatments, ranging (over all years) from 42 to 160 g nut/m 2 canopy surface area. Depletion of plant-available water in the root zone was associated with a reduction in photosynthesis mediated by partial stomatal closure. These effects of soil drying were evident in all irrigated treatments during the mid and late stages of the dry season but were more severe in treatments receiving the least water. When irrigation was withheld until the mid-stage of the dry season the trees had similar yields to those that were irrigated throughout, emphasising the importance of providing adequate irrigation between nut set and harvest. When rainfall from January to September in each year of the study was taken into account, there was a strong linear relationship between nut yield and water applied (rainfall + irrigation), with each extra kilolitre of water applied resulting in about 6 extra g nut/m 2 canopy surface area. This linear relationship was based on water application in the range 25–50 kL per season. It is possible that if the seasonal water application had exceeded 50 kL the marginal response to extra water may have diminished. Using drippers was slightly more efficient than sprinklers, with drip-irrigated trees requiring about 5% less water applied to achieve a given nut yield. In years when rainfall is average, and subject to other economic factors, growers in North Queensland should aim to irrigate about 500 L/tree.week. In years of low rainfall between January and September it is likely that yield will be improved by applying more irrigation water; high rainfall during these months of the year may reduce the irrigation requirement. In all cases growers should be careful to accurately monitor water applications, particularly when the total (from rainfall + irrigation) exceeds 40 kL/tree for the season.

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THE WATER RELATIONS OF RUBBER (HEVEA BRASILIENSIS): A REVIEW

Experimental Agriculture ◽

10.1017/s0014479711000901 ◽

2011 ◽

Vol 48 (2) ◽

pp. 176-193 ◽

Cited By ~ 29

Author(s):

M. K. V. CARR

Keyword(s):

East Asia ◽

Water Relations ◽

Leaf Growth ◽

Water Productivity ◽

Stomatal Closure ◽

Rubber Tree ◽

Background Information ◽

South East Asia ◽

Water Requirements ◽

Water Potentials

SUMMARYThe results of research done on water relations of rubber are collated and summarised in an attempt to link fundamental studies on crop physiology to crop management practices. Background information is given on the centres of origin (Amazon Basin) and production of rubber (humid tropics; south-east Asia), but the crop is now being grown in drier regions. The effects of water stress on the development processes of the crop are summarised, followed by reviews of its water relations, water requirements and water productivity. The majority of the recent research published in the international literature has been conducted in south-east Asia. The rubber tree has a single straight trunk, the growth of which is restricted by ‘tapping’ for latex. Increase in stem height is discontinuous, a period of elongation being followed by a ‘rest’ period during which emergence of leaves takes place. Leaves are produced in tiers separated by lengths of bare stem. Trees older than three to four years shed senescent leaves (a process known as ‘wintering’). ‘Wintering’ is induced by dry, or less wet, weather; trees may remain (nearly) leafless for up to four weeks. The more pronounced the dry season the shorter the period of defoliation. Re-foliation begins before the rains start. The supply of latex is dependent on the pressure potential in the latex vessels, whereas the rate of flow is negatively correlated with the saturation deficit of the air. Radial growth of the stem declines in tapped trees relative to untapped trees within two weeks of the start of tapping. Roots can extend in depth to more than 4 m and laterally more than 9 m from the trunk. The majority of roots are found within 0.3 m of the soil surface. Root elongation is depressed during leaf growth, while root branching is enhanced. Stomata are only found on the lower surface of the leaf, at densities from 280 to 700 mm−2. The xylem vessels of rubber trees under drought stress are vulnerable to cavitation, particularly in the leaf petiole. By closing, the stomata play an essential role in limiting cavitation. Clones differ in their susceptibility to cavitation, which occurs at xylem water potentials in the range of −1.8 to −2.0 MPa. Clone RRII 105 is capable of maintaining higher leaf water potentials than other clones because of stomatal closure, supporting its reputation for drought tolerance. Clones differ in their photosynthetic rates. Light inhibition of photosynthesis can occur, particularly in young plants, when shade can be beneficial. Girth measurements have been used to identify drought-tolerant clones. Very little research on the water requirements of rubber has been reported, and it is difficult to judge the validity of the assumptions made in some of the methodologies described. The actual evapotranspiration rates reported are generally lower than might be expected for a tree crop growing in the tropics (<3 mm d−1). Virtually no research on the yield responses to water has been reported and, with the crop now being grown in drier regions, this is surprising. In these areas, irrigation can reduce the immaturity period from more than 10 years to six years. The important role that rubber plays in the livelihoods of smallholders, and in the integrated farming systems practised in south-east Asia, is summarized.

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Yield and water productivity response of quinoa to various deficit irrigation regimes applied with surface and subsurface drip systems

The Journal of Agricultural Science ◽

10.1017/s0021859621000265 ◽

2021 ◽

pp. 1-12

Author(s):

Y. Bozkurt Çolak ◽

A. Yazar ◽

A. Alghory ◽

S. Tekin

Keyword(s):

Deficit Irrigation ◽

Mediterranean Region ◽

Root Zone ◽

Eastern Mediterranean ◽

Water Productivity ◽

Eastern Mediterranean Region ◽

First Year ◽

Regulated Deficit Irrigation ◽

Significant Difference ◽

Subsurface Drip

Abstract This study evaluated the yield and water productiivty response of quinoa to regulated deficit irrigation (RDI), partial root-zone drying (PRD) and conventional deficit irrigation (DI) and full irrigation (FI) using surface ( SD ) and subsurface drip ( SSD ) systems in 2016 and 2017 in the eastern Mediterranean region of Turkey. The treatments consisted of RDI, PRD50, DI50, DI75 and FI. A rainfed treatment (RF) was also included in the study. The experimental design was split plots with four replications. DI75 and DI50 received 75 and 50% of FI, respectively. PRD50 received 50% of FI, but from alternative laterals. RDI received 50% of FI during vegetative stage until flowering, and then received 100% of water requirement. The results showed that quinoa under SD used slightly more water than SSD due to reduced surface evaporation. RDI resulted in water saving of 23 and 21% for SD and SSD , respectively, compared to FI; and RDI produced statistically similar grain yields to FI. DI75 treatment resulted in water savings of 16% for both drip methods in the first year and 10 and 25% for SD and SSD systems, respectively, in the second year. PRD50 produced greater yield than DI50 eventhough they received the same amount of irrigation water. RF and PRD50 treatments resulted in significantly greater water productivity (WP) values than other treatments. There was no significant difference between SD and SSD regarding the grain and dry matter yields and WP values. Thus, RDI and DI75 appear to be good alternatives to FI for sustainable quinoa production in the Mediterranean region.

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Water Relations of Well-watered Citrus Exposed to Cold-acclimating Temperatures

HortScience ◽

10.21273/hortsci.48.10.1309 ◽

2013 ◽

Vol 48 (10) ◽

pp. 1309-1312 ◽

Cited By ~ 2

Author(s):

Smita Barkataky ◽

Robert C. Ebel ◽

Kelly T. Morgan ◽

Keri Dansereau

Keyword(s):

Drought Stress ◽

Cold Acclimation ◽

Water Relations ◽

Water Status ◽

Stomatal Closure ◽

Irrigation Scheduling ◽

Stem Water Potential ◽

Cold Temperatures ◽

Relative Water ◽

Leaf Relative Water Content

This study was conducted on well-watered citrus to determine changes in water relations during cold acclimation independent of drought stress. Potted sweet orange and Satsuma mandarin trees were exposed to progressively lower, non-freezing temperatures down to 10/4 °C, light/dark temperatures, respectively, for 9 weeks in environmental growth chambers to promote cold acclimation. The trees were watered twice daily and three times on the day water relations data were collected to minimize drought stress. Although soil moisture was higher and non-limiting for plants in the cold than in the warm chamber, cold temperatures promoted stomatal closure, higher root resistance, lower stem water potential (Ψstem), lower transpiration, and lower leaf ψS. Leaf relative water content (RWC) was not different for cold-acclimated trees compared with the controls. Cold acclimation promoted stomatal closure at levels only observed in severely drought-stressed plants exposed to warm temperatures and where Ψstem and RWC are typically much lower than what was found in this study. Ψstem continued to decline the last 4 weeks of the experiment although air temperature, leaf ψS, RWC, stomatal conductance (gS), and transpiration were constant. The results of this experiment indicate that water relations of citrus during cold acclimation vary from those known to occur as a result of drought stress, which have implications for using traditional measures of plant water status in irrigation scheduling during winter.

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THE WATER RELATIONS AND IRRIGATION REQUIREMENTS OF COCOA (THEOBROMA CACAO L.): A REVIEW

Experimental Agriculture ◽

10.1017/s0014479711000421 ◽

2011 ◽

Vol 47 (4) ◽

pp. 653-676 ◽

Cited By ~ 52

Author(s):

M. K. V. CARR ◽

G. LOCKWOOD

Keyword(s):

Water Stress ◽

Stomatal Conductance ◽

Water Use ◽

Water Relations ◽

Stomatal Closure ◽

Dry Season ◽

Leaf Water ◽

Background Information ◽

Published Data ◽

Rhythmic Pattern

SUMMARYThe results of research into the water relations of cocoa are reviewed in the context of drought mitigation and irrigation need. Background information on the centres of production of the cocoa tree, and the role of water in crop development and growth processes, is followed by reviews of the effects of water stress on stomatal conductance, leaf water status and gas exchange, together with drought tolerance, crop water use and water productivity. Leaf and shoot growth occur in a series of flushes, which are synchronized by the start of the rains following a dry season (or an increase in temperature), alternating with periods of ‘dormancy’. Flowering is inhibited by water stress but synchronous flowering occurs soon after the dry season ends. Roots too grow in a rhythmic pattern similar to that of leaf flushes. Roots can reach depths of 1.5–2.0 m, but with a mass of roots in the top 0.2–0.4 m, and spread laterally >5 m from the stem. Stomata open in low light intensities and remain fully open in full sunlight in well-watered plants. Partial stomatal closure begins at a leaf water potential of about −1.5 MPa. Stomatal conductance is sensitive to dry air, declining as the saturation deficit increases from about 1.0 up to 3.5 kPa. Net photosynthesis and transpiration both consequently decline over a similar range of values. Little has been published on the actual water use of cocoa in the field. Measured ETc values equate to <2 mm d−1 only, whereas computed ETc rates of 3–6 mm d−1 in the rains and <2 mm d−1 in the dry season have also been reported. Despite its sensitivity to water stress, there is too a paucity of reliable, field-based published data of practical value on the yield responses of cocoa to drought or to irrigation. With the threat of climate change leading to less, or more erratic, rainfall in the tropics, uncertainty in yield forecasting as a result of water stress will increase. Social, technical and economic issues influencing the research agenda are discussed.

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Vine Water Relations and Quality of ‘Muscat of Alexandria’ Table Grapes Subjected to Partial Root-zone Drying and Regulated Deficit Irrigation

Engei Gakkai zasshi ◽

10.2503/jjshs.76.13 ◽

2007 ◽

Vol 76 (1) ◽

pp. 13-19 ◽

Cited By ~ 10

Author(s):

Diaa Osama El-Ansary ◽

Goro Okamoto

Keyword(s):

Water Relations ◽

Deficit Irrigation ◽

Root Zone ◽

Regulated Deficit Irrigation ◽

Table Grapes

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Field Measurements and Simulation of Nitrogen Fate under Citrus Production

HortScience ◽

10.21273/hortsci.33.3.498c ◽

1998 ◽

Vol 33 (3) ◽

pp. 498c-498

Author(s):

A. Fares ◽

A.K. Alva ◽

S. Paramasivam

Keyword(s):

Mass Balance ◽

Best Management Practices ◽

Rainy Season ◽

Crop Production ◽

Management Practices ◽

Root Zone ◽

Field Measurements ◽

Irrigation Scheduling ◽

N Leaching ◽

Citrus Production

Water and nitrogen (N) are important inputs for most crop production. The main objectives of nitrogen best management practices (NBMP) are to improve N and water management to maximize the uptake efficiency and minimize the leaching losses. This require a complete understanding of fate of N and water mass balance within and below the root zone of the crop in question. The fate of nitrogen applied for citrus production in sandy soils (>95% sand) was simulated using a mathematical model LEACHM (Leaching Estimation And Chemistry Model). Nitrogen removal in harvested fruits and storage in the tree accounted the major portion of the applied N. Nitrogen volatilization mainly as ammonia and N leaching below the root zone were the next two major components of the N mass balance. A proper irrigation scheduling based on continuous monitoring of the soil water content in the rooting was used as a part of the NBMP. More than 50% of the total annual leached water below the root zone was predicted to occur in the the rainy season. Since this would contribute to nitrate leaching, it is recomended to avoid N application during the rainy season.

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Combined simulation and optimization framework for irrigation scheduling in agriculture fields

Irrigation Science ◽

10.1007/s00271-021-00746-y ◽

2021 ◽

Author(s):

Mireia Fontanet ◽

Daniel Fernàndez-Garcia ◽

Gema Rodrigo ◽

Francesc Ferrer ◽

Josep Maria Villar

Keyword(s):

Crop Yields ◽

Root Zone ◽

Growing Season ◽

Irrigation Scheduling ◽

Irrigated Agriculture ◽

Traditional Methods ◽

Simulation And Optimization ◽

Optimization Framework ◽

Net Margin ◽

Combined Simulation

AbstractIn the context of growing evidence of climate change and the fact that agriculture uses about 70% of all the water available for irrigation in semi-arid areas, there is an increasing probability of water scarcity scenarios. Water irrigation optimization is, therefore, one of the main goals of researchers and stakeholders involved in irrigated agriculture. Irrigation scheduling is often conducted based on simple water requirement calculations without accounting for the strong link between water movement in the root zone, soil–water–crop productivity and irrigation expenses. In this work, we present a combined simulation and optimization framework aimed at estimating irrigation parameters that maximize the crop net margin. The simulation component couples the movement of water in a variably saturated porous media driven by irrigation with crop water uptake and crop yields. The optimization component assures maximum gain with minimum cost of crop production during a growing season. An application of the method demonstrates that an optimal solution exists and substantially differs from traditional methods. In contrast to traditional methods, results show that the optimal irrigation scheduling solution prevents water logging and provides a more constant value of water content during the entire growing season within the root zone. As a result, in this case, the crop net margin cost exhibits a substantial increase with respect to the traditional method. The optimal irrigation scheduling solution is also shown to strongly depend on the particular soil hydraulic properties of the given field site.

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