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

2011 ◽  
Vol 47 (1) ◽  
pp. 1-25 ◽  
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.

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

2013 ◽  
Vol 49 (4) ◽  
pp. 597-639 ◽  
Author(s):  
M. K. V. CARR
Keyword(s):  
Water Relations ◽  
Deficit Irrigation ◽  
Root Zone ◽  
Eastern Mediterranean ◽  
Stomatal Closure ◽  
Irrigation Scheduling ◽  
Convincing Evidence ◽  
Background Information ◽  
Evaporative Demand ◽  
Biennial Bearing

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.

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

2011 ◽  
Vol 48 (2) ◽  
pp. 176-193 ◽  
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.

THE WATER RELATIONS AND IRRIGATION REQUIREMENTS OF OIL PALM (ELAEIS GUINEENSIS): A REVIEW

2011 ◽  
Vol 47 (4) ◽  
pp. 629-652 ◽  
Author(s):  
M. K. V. CARR
Keyword(s):  
West Africa ◽  
Soil Water ◽  
Water Use ◽  
Water Relations ◽  
Oil Palm ◽  
Water Productivity ◽  
Background Information ◽  
Flower Initiation ◽  
Irrigation Interval ◽  
Best Estimates

SUMMARYThe results of research on the water relations and irrigation need of oil palm are collated and summarized in an attempt to link fundamental studies on crop physiology to drought mitigation and irrigation practices. Background information is given on the centres of origin (West Africa) and of production of oil palm (Malaysia and Indonesia), but the crop is now moving into drier regions. The effects of water stress on the development processes of the crop are summarized followed by reviews of its water relations, water use and water productivity. The majority of the recent research published in the international literature has been conducted in Malaysia and in Francophone West Africa. The unique vegetative structure of the palm (stem and leaves) together with the long interval between flower initiation and the harvesting of the mature fruit (ca. three years) means that causal links between environmental factors (especially water) and yield are difficult to establish. The majority of roots are found in the 0–0.6 m soil horizons, but roots can reach depths greater than 5 m and spread laterally up to 25 m from the trunk. The stomata are a sensitive indicator of plant water status and play an important role in controlling water loss. Stomatal conductance and photosynthesis are negatively correlated with the saturation deficit of the air. It is not easy to measure the actual water use of oil palm, the best estimates for mature palms suggesting crop evapotranspiration (ETc) rates of 4–5 mm d−1 in the monsoon months (equivalent to 280–350 l palm−1 d−1). For well-watered mature palms, crop coefficient (Kc) values are in the range 0.8–1.0. Although the susceptibility of oil palm to drought is well recognized, there is a limited amount of reliable data on actual yield responses to irrigation. The best estimates are 20–25 kg fresh fruit bunches ha−1 mm−1 (or a yield loss of about 10% for every 100 mm increase in the soil water deficit). These increases are only realized in the third and subsequent years after the introduction of irrigation and follow an increase in the number of fruit bunches as a result of an improvement in the sex ratio (female/total inflorescence production) and a reduction in the abortion of immature inflorescences. There is no agreement on the allowable depletion of the available soil water, or on the associated optimum irrigation interval. Drip irrigation has been used successfully on oil palm.

UNRAVELLING CROP WATER PRODUCTIVITY OF TEF (ERAGROSTIS TEF (ZUCC.) TROTTER) THROUGH AQUACROP IN NORTHERN ETHIOPIA

2011 ◽  
Vol 48 (2) ◽  
pp. 222-237 ◽  
Author(s):  
ALEMTSEHAY TSEGAY ◽  
DIRK RAES ◽  
SAM GEERTS ◽  
ELINE VANUYTRECHT ◽  
BERHANU ABRAHA ◽  
...  
Keyword(s):  
Water Stress ◽  
Goodness Of Fit ◽  
Field Experiments ◽  
Root Zone ◽  
Water Productivity ◽  
Eragrostis Tef ◽  
Coefficient Of Determination ◽  
Northern Ethiopia ◽  
Statistical Parameters ◽  
Canopy Development

SUMMARYAt various locations in North Ethiopia (Tigray), field experiments were conducted from 2006 to 2009 to assess the crop response to water stress of tef (Eragrostis tef (Zucc.) Trotter) under rainfed, fully irrigated and deficit irrigation conditions. Observed soil water content (SWC), canopy cover (CC), biomass production (B) and final grain yield (Y) were used to calibrate and validate AquaCrop for tef. Data from an experiment in a controlled environment in 2008 were also considered in the calibration process. Simulations of SWC, CC, B and Y were evaluated by determining the index of agreement, the root mean square error, the coefficient of determination and the Nash–Sutcliffe efficiency. The statistical parameters showed an adequate fit between observations and simulations. The model was able to simulate for tef growing under rainfed condition the observed fast drop in SWC and CC when the rains ceased. The overall goodness of fit between the observed and simulated CC and SWC indicated that the thresholds for root zone depletion at which water stress (i) affects canopy development, (ii) induces stomata closure and (iii) triggers early canopy senescence were well selected. The normalised biomass water productivity (WP*) for tef was 14 g m−2 for the local variety and 21 g m−2 for the improved variety, which is a lot smaller than the WP* expected for C4 plants (30–35 g m−2). The results revealed an increase of 27% in reference harvest index (HIo) of tef in response to mild water stress during the yield formation of up to 33%. However, severe water stress causing stomata closure had a negative effect on HIo. Once it is properly calibrated, AquaCrop can provide room to improve the water productivity of tef by developing guidelines for good agricultural management strategies.

THE WATER RELATIONS AND IRRIGATION REQUIREMENTS OF PASSION FRUIT (PASSIFLORA EDULIS SIMS): A REVIEW

2013 ◽  
Vol 49 (4) ◽  
pp. 585-596 ◽  
Author(s):  
M. K. V. CARR
Keyword(s):  
Water Stress ◽  
Water Relations ◽  
Potential Evapotranspiration ◽  
Crop Coefficient ◽  
Heavy Rain ◽  
Passion Fruit ◽  
Flower Bud ◽  
Leaf Production ◽  
Passiflora Edulis ◽  
Bud Initiation

SUMMARYIt is generally accepted that the two forms of Passiflora edulis, the golden and the purple, originated on the edges of tropical rainforests in Brazil. Extensive hybridisation has since taken place between these two forms and their hybrids. The passion fruit (a vine) is now grown throughout the tropics and subtropics. A limited amount of basic, fundamental research has been published on the water relations of passion fruit. Leaf production and expansion are both sensitive to water deficits, while water stress reduces leaf and floral bud initiation. A single axillary flower bud forms at each leaf node of new growth along with a tendril. Flower bud development and fruit set are less sensitive to water stress than leaf initiation. Heavy rain during pollination prevents fertilization. Unevenness in crop distribution during the year is possibly linked to water stress and temperature variation. Potential evapotranspiration rates in Brazil varied between 3.5 mm d−1 and 5.8 mm d−1. The value for the crop coefficient increases from about 0.6 during apical vegetative growth up to about 1.25 during flowering and fruiting. Water productivities still need to be determined. Micro-sprinklers and drip are the most effective ways of applying irrigation water with precision to passion fruit. Opportunities exist for international cooperation in research projects of mutual interest on passion fruit water relations.

scholarly journals Integration of vegetation indices into a water balance model to estimate evapotranspiration of wheat and corn

2010 ◽  
Vol 7 (5) ◽  
pp. 8631-8659
Author(s):  
F. L. M. Padilla ◽  
M. P. González-Dugo ◽  
P. Gavilán ◽  
J. Domínguez
Keyword(s):  
Water Stress ◽  
Water Balance ◽  
Root Zone ◽  
Vegetation Indices ◽  
Crop Coefficient ◽  
Grain Filling ◽  
Sensor Data ◽  
Balance Model ◽  
Plant Canopies ◽  
Negative Effect

Abstract. Vegetation indices (VIs) have been traditionally used for quantitative monitoring of vegetation. Remotely sensed radiometric measurements of visible and infrared solar energy, which is reflected or emitted by plant canopies, can be used to obtain rapid, non-destructive estimates of certain canopy attributes and parameters. One parameter of special interest for water management applications, is the crop coefficient employed by the FAO-56 model to derive actual crop evapotranspiration (ET). The aim of this study was to evaluate a methodology that combines the basal crop coefficient derived from VIs with a daily soil water balance in the root zone to estimate daily evapotranspiration rates for corn and wheat crops at field scale. The ability of the model to trace water stress in these crops was also assessed. Vegetation indices were first retrieved from field hand-held radiometer measurements and then from Landsat 5 and 7 satellite images. The results of the model were validated using two independent measurement systems for ET and regular soil moisture monitoring, in order to evaluate the behavior of the soil and atmosphere components of the model. ET estimates were compared with latent heat flux measured by an eddy covariance system and with weighing lysimeter measurements. Average overestimates of daily ET of 8 and 11% were obtained for corn and wheat, respectively, with good agreement between the estimated and measured root-zone water deficit for both crops when field radiometry was employed. Satellite remote-sensing inputs overestimated ET by 4 to 9%, showing a non-significant lost of accuracy when the satellite sensor data replaced the field radiometry data. The model was also used to monitor the water stress during the 2009 growing season, detecting several periods of water stress in both crops. Some of these stresses occurred during stages like grain filling, when the water stress is know to have a negative effect on yield. This fact could explain the lower yield reached compared to local yield statistics for wheat and corn. The results showed that the model can be used to calculate the water requirements of these crops in irrigated areas and that its ability to monitor water stress deserves further research.

scholarly journals Integration of vegetation indices into a water balance model to estimate evapotranspiration of wheat and corn

2011 ◽  
Vol 15 (4) ◽  
pp. 1213-1225 ◽  
Author(s):  
F. L. M. Padilla ◽  
M. P. González-Dugo ◽  
P. Gavilán ◽  
J. Domínguez
Keyword(s):  
Water Stress ◽  
Water Balance ◽  
Root Zone ◽  
Vegetation Indices ◽  
Crop Coefficient ◽  
Grain Filling ◽  
Sensor Data ◽  
Balance Model ◽  
Plant Canopies ◽  
Negative Effect

Abstract. Vegetation indices (VIs) have been traditionally used for quantitative monitoring of vegetation. Remotely sensed radiometric measurements of visible and infrared solar energy, which is reflected or emitted by plant canopies, can be used to obtain rapid, non-destructive estimates of certain canopy attributes and parameters. One parameter of special interest for water management applications, is the crop coefficient employed by the FAO-56 model to derive actual crop evapotranspiration (ET). The aim of this study was to evaluate a methodology that combines the basal crop coefficient derived from VIs with a daily soil water balance in the root zone to estimate daily evapotranspiration rates for corn and wheat crops at field scale. The ability of the model to trace water stress in these crops was also assessed. Vegetation indices were first retrieved from field hand-held radiometer measurements and then from Landsat 5 and 7 satellite images. The results of the model were validated using two independent measurement systems for ET and regular soil moisture monitoring, in order to evaluate the behavior of the soil and atmosphere components of the model. ET estimates were compared with latent heat flux measured by an eddy covariance system and with weighing lysimeter measurements. Average overestimates of daily ET of 8 and 11% were obtained for corn and wheat, respectively, with good agreement between the estimated and measured root-zone water deficit for both crops when field radiometry was employed. When the satellite sensor data replaced the field radiometry data the overestimation figures slightly changed to 9 and 6% for the same two crops. The model was also used to monitor the water stress during the 2009 growing season, detecting several periods of water stress in both crops. Some of these stresses occurred during stages like grain filling, when the water stress is know to have a negative effect on yield. This fact could explain the lower yield reached compared to local yield statistics for wheat and corn. The results showed that the model can be used to calculate the water requirements of these crops in irrigated areas and that its ability to monitor water stress deserves further research.

Modeling Evapotranspiration and Crop Growth of Irrigated and Non-Irrigated Corn in the Texas High Plains Using RZWQM

2018 ◽  
Vol 61 (5) ◽  
pp. 1653-1666 ◽  
Author(s):  
Huihui Zhang ◽  
Robert Wayne Malone ◽  
Liwang Ma ◽  
Lajpat R. Ahuja ◽  
Saseendran S. Anapalli ◽  
...  
Keyword(s):  
Water Stress ◽  
Soil Water ◽  
Crop Production ◽  
Root Zone ◽  
Potential Evapotranspiration ◽  
Water Productivity ◽  
Stress Factors ◽  
Irrigated Agriculture ◽  
High Plains ◽  
Area Index

Abstract. Accurate quantification and management of crop evapotranspiration (ET) are critical to optimizing crop water productivity for both dryland and irrigated agriculture, especially in the semiarid regions of the world. In this study, four weighing lysimeters in Bushland, Texas, were planted to maize in 1994 with two fully irrigated and two non-irrigated for measuring crop ET. The Root Zone Water Quality Model (RZWQM2) was used to evaluate soil water balance and crop production with potential evapotranspiration (PET) estimated from either the Shuttleworth-Wallace method (PTSW) or the ASCE standardized alfalfa reference ET multiplied by crop coefficients (PTASCE). As a result, two water stress factors were defined from actual transpiration (AT) and were tested in the model against the lysimeter data, i.e., AT/PTSW and AT/PTASCE. For both water stress factors, the simulated daily ET values were reasonably close to the measured values, with underestimated ET during mid-growing stage in both non-irrigated lysimeters. Root mean squared deviations (RMSDs) and relative RMSDs (RMSD/observed mean) values for leaf area index, biomass, soil water content, and daily ET were within simulation errors reported earlier in the literature. For example, the RMSDs of simulated daily ET were less than 1.52 mm for all irrigated and non-irrigated lysimeters. Overall, ET was simulated within 3% of the measured data for both fully irrigated lysimeters and undersimulated by less than 11% using both stress factors for the non-irrigated lysimeters. Our results suggest that both methods are promising for simulating crop production and ET under irrigated conditions, but the methods need to be improved for dryland and non-irrigated conditions. Keywords: ET, RZWQM modeling, Stress factor, Weighing lysimeter.

THE WATER RELATIONS AND IRRIGATION REQUIREMENTS OF AVOCADO (Persea americana Mill.): A REVIEW

2013 ◽  
Vol 49 (2) ◽  
pp. 256-278 ◽  
Author(s):  
M. K. V. CARR
Keyword(s):  
South Africa ◽  
Water Stress ◽  
Water Use ◽  
Water Relations ◽  
Water Productivity ◽  
Chloride Ions ◽  
Persea Americana ◽  
Mature Trees ◽  
Water Deficits ◽  
Eastern Australia

SUMMARYThe results of research on the water relations and irrigation need of avocado are collated and reviewed in an attempt to link fundamental studies on crop physiology to irrigation practices. Background information is given on the centre of origin (Mexico and Central America) and the three distinct ecological areas where avocados are grown commercially: (1) Cool, semi-arid climates with winter-dominant rainfall (e.g. Southern California, Chile, Israel); (2) Humid, subtropical climates with summer-dominant rainfall (e.g. eastern Australia, Mexico, South Africa); and (3) Tropical or semi-tropical climates also with summer-dominant rainfall (e.g. Brazil, Florida and Indonesia). Most of the research reported has been done in Australia, California, Israel and South Africa. There are three ecological races that are given varietal status within the species: Persea americana var. drymifolia (Mexican race), P. americana var. guatemalensis (Guatemalan race) and P. americana var. americana (Antillean, West Indian or Lowland race). Interracial crossing has taken place. This paper summarises the effects of water deficits on the development processes of the crop and then reviews plant–water relations, crop water requirements, water productivity and irrigation systems. Shoot growth in mature trees is synchronised into flushes. Flower initiation occurs in the autumn, with flowering in late winter and spring. Flowers form on the ends of the branches. A large heavily flowering tree may have over a million flowers, but only produce 200–300 fruits. Fruit load adjustment occurs by shedding during the first three to four weeks after fruit set and again in early summer. Water deficits during critical stages of fruit ontogeny have been linked to fruit disorders such as ring-neck. Reproductive growth is very resistant to water stress (compared with vegetative growth). Avocado is conventionally considered to be shallow rooted, although roots extend to depths greater than 1.5 m. The majority of feeder roots are found in the top 0.60 m of soil and root extension can continue throughout the year. Leaves develop a waxy cuticle on both surfaces, which is interrupted by stomata on the abaxial surface (350–510 mm−2), many of which are blocked by wax. Stomata are also present on the sepals and petals at low densities (and on young fruit). During flowering, the canopy surface area available for water loss is considerably increased. Stomatal closure is an early indicator of water stress, which together with associated changes in leaf anatomy, restricts CO2 diffusion. There have only been a few attempts to measure the actual water use of avocado trees. In Mediterranean-type climates, peak rates of water use (in summer) appear to be between 3 and 5 mm d−1. For mature trees, the crop coefficient (Kc) is usually within the range 0.4–0.6. The best estimate of water productivity is between 1 and 2 kg fruit m−3. Soil flooding and the resultant reduction in oxygen level can damage roots even in the absence of root rot. Avocado is particularly sensitive to salinity, notably that caused by chloride ions. Rootstocks vary in their sensitivity. Both drip and under-tree microsprinklers have been/are successfully used to irrigate avocado trees. Mulching of young trees is a recommended water conservation measure and has other benefits. A large proportion of the research reviewed has been published in the ‘grey’ literature as conference papers and annual reports. Sometimes, this is at the expense of reporting the science on which the recommendations are based in peer-reviewed papers. The pressures on irrigators to improve water productivity are considered.

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