scholarly journals Using sap flow data to assess variations in water use and water status of apple orchards of varying age groups in the Western Cape Province of South Africa

Water SA ◽  
2020 ◽  
Vol 46 (2 April) ◽  
Author(s):  
NT Mobe ◽  
S Dzikiti ◽  
T Volschenk ◽  
SF Zirebwa ◽  
Z Ntshidi ◽  
...  
Keyword(s):  
South Africa ◽  
Water Use ◽  
Sap Flow ◽  
Water Status ◽  
Canopy Cover ◽  
Western Cape ◽  
Stem Water Potential ◽  
Sap Flux Density ◽  
Growing Season Length ◽  
Golden Delicious

No accurate quantitative information currently exists on how water use of apple (Malus domestica) orchards varies from planting to full-bearing age, leading to poor irrigation and water allocation decision making. This study sought to address this knowledge gap by investigating how the water use and tree water status vary with canopy cover, cultivar, and climatic conditions in 12 orchards growing in prime apple-producing regions in South Africa. The orchards were planted to the Golden Delicious/Golden Delicious Reinders cultivars which are widely planted in South Africa and the Cripps’ Pink/Cripps’ Red/Rosy Glow which are high-value late-season cultivars. The performance of two transpiration reduction coefficients, one based on sap flow (Ksf) and the other based on soil water depletion (Ks) (FAO approach) were evaluated against the midday stem water potential (MSWP) in all the orchards. While canopy cover had a clear effect on the whole-tree sap flow rates, there were no significant differences in the transpiration per unit leaf area among the cultivars. The daily average sap flux density under unstressed conditions was highest (~284 cm3∙cm-2) in the medium canopy cover orchards (30–44% fractional cover), followed by the mature orchards (~226 cm3∙cm-2), and was lowest in the young orchards (~137 cm3∙cm-2). Canopy cover rather than growing season length had a greater effect on seasonal total water use. Peak daily orchard transpiration ranged from 1.7 mm for young Golden Delicious Reinders trees to 5.0 mm in mature Golden Delicious trees that were maintained with large canopies to reduce sunburn damage to the fruit. For the red cultivars, the peak daily transpiration ranged from 2.0 to 3.9 mm, and the mature trees were maintained with less dense canopies to facilitate the development of the red fruit colour. The less dense canopies on the red cultivars had water-saving benefits since the seasonal total transpiration was lower relative to the Golden Delicious cultivar. The sap flow derived stress coefficient was strongly correlated to the MSWP (R2 ~ 0.60–0.97) in all the orchards while Ks was not able to detect plant stress due to over-irrigation.

scholarly journals Using sap flow data to assess variations in water use and water status of apple orchards of varying age groups in the Western Cape Province of South Africa

Water SA ◽  
2020 ◽  
Vol 46 (2 April) ◽  
Author(s):  
NT Mobe ◽  
S Dzikiti ◽  
T Volschenk ◽  
SF Zirebwa ◽  
Z Ntshidi ◽  
...  
Keyword(s):  
South Africa ◽  
Water Use ◽  
Sap Flow ◽  
Water Status ◽  
Canopy Cover ◽  
Western Cape ◽  
Stem Water Potential ◽  
Sap Flux Density ◽  
Growing Season Length ◽  
Golden Delicious

No accurate quantitative information currently exists on how water use of apple (Malus domestica) orchards varies from planting to full-bearing age, leading to poor irrigation and water allocation decision making. This study sought to address this knowledge gap by investigating how the water use and tree water status vary with canopy cover, cultivar, and climatic conditions in 12 orchards growing in prime apple-producing regions in South Africa. The orchards were planted to the Golden Delicious/Golden Delicious Reinders cultivars which are widely planted in South Africa and the Cripps’ Pink/Cripps’ Red/Rosy Glow which are high-value late-season cultivars. The performance of two transpiration reduction coefficients, one based on sap flow (Ksf) and the other based on soil water depletion (Ks) (FAO approach) were evaluated against the midday stem water potential (MSWP) in all the orchards. While canopy cover had a clear effect on the whole-tree sap flow rates, there were no significant differences in the transpiration per unit leaf area among the cultivars. The daily average sap flux density under unstressed conditions was highest (~284 cm3∙cm-2) in the medium canopy cover orchards (30–44% fractional cover), followed by the mature orchards (~226 cm3∙cm-2), and was lowest in the young orchards (~137 cm3∙cm-2). Canopy cover rather than growing season length had a greater effect on seasonal total water use. Peak daily orchard transpiration ranged from 1.7 mm for young Golden Delicious Reinders trees to 5.0 mm in mature Golden Delicious trees that were maintained with large canopies to reduce sunburn damage to the fruit. For the red cultivars, the peak daily transpiration ranged from 2.0 to 3.9 mm, and the mature trees were maintained with less dense canopies to facilitate the development of the red fruit colour. The less dense canopies on the red cultivars had water-saving benefits since the seasonal total transpiration was lower relative to the Golden Delicious cultivar. The sap flow derived stress coefficient was strongly correlated to the MSWP (R2 ~ 0.60–0.97) in all the orchards while Ks was not able to detect plant stress due to over-irrigation.

scholarly journals Water-use dynamics of an alien-invaded riparian forest within the Mediterranean climate zone of the Western Cape, South Africa

2017 ◽  
Vol 21 (9) ◽  
pp. 4551-4562 ◽  
Author(s):  
Bruce C. Scott-Shaw ◽  
Colin S. Everson ◽  
Alistair D. Clulow
Keyword(s):  
South Africa ◽  
Water Use ◽  
Sap Flow ◽  
Riparian Forest ◽  
Riparian Forests ◽  
Ratio Method ◽  
Natural State ◽  
Indigenous Species ◽  
Western Cape ◽  
Selection Of

Abstract. In South Africa, the invasion of riparian forests by alien trees has the potential to affect the country's limited water resources. Tree water-use measurements have therefore become an important component of recent hydrological studies. It is difficult for South African government initiatives, such as the Working for Water (WfW) alien clearing program, to justify alien tree removal and implement rehabilitation unless hydrological benefits are known. Consequently, water use within a riparian forest along the Buffeljags River in the Western Cape of South Africa was monitored over a 3-year period. The site consisted of an indigenous stand of Western Cape afrotemperate forest adjacent to a large stand of introduced Acacia mearnsii. The heat ratio method of the heat pulse velocity sap flow technique was used to measure the sap flow of a selection of indigenous species in the indigenous stand, a selection of A. mearnsii trees in the alien stand and two clusters of indigenous species within the alien stand. The indigenous trees in the alien stand at Buffeljags River showed significant intraspecific differences in the daily sap flow rates varying from 15 to 32 L day−1 in summer (sap flow being directly proportional to tree size). In winter (June), this was reduced to only 7 L day−1 when limited energy was available to drive the transpiration process. The water use in the A. mearnsii trees showed peaks in transpiration during the months of March 2012, September 2012 and February 2013. These periods had high average temperatures, rainfall and high daily vapor pressure deficits (VPDs – average of 1.26 kPa). The average daily sap flow ranged from 25 to 35 L in summer and approximately 10 L in the winter. The combined accumulated daily sap flow per year for the three Vepris lanceolata and three A. mearnsii trees was 5700 and 9200 L, respectively, clearly demonstrating the higher water use of the introduced Acacia trees during the winter months. After spatially upscaling the findings, it was concluded that, annually, the alien stand used nearly 6 times more water per unit area than the indigenous stand (585 mm a−1 compared to 101 mm a−1). This finding indicates that there would be a gain in groundwater recharge and/or streamflow if the alien species are removed from riparian forests and rehabilitated back to their natural state.

Seasonal variation in canopy reflectance and its application to determine the water status and water use by citrus trees in the Western Cape, South Africa

2011 ◽  
Vol 151 (8) ◽  
pp. 1035-1044 ◽  
Author(s):  
Sebinasi Dzikiti ◽  
Stephan J. Verreynne ◽  
Jan Stuckens ◽  
Albert Strever ◽  
Willem W. Verstraeten ◽  
...  
Keyword(s):  
South Africa ◽  
Seasonal Variation ◽  
Water Use ◽  
Water Status ◽  
Canopy Reflectance ◽  
Western Cape ◽  
Citrus Trees

scholarly journals Water-use dynamics of an alien invaded riparian forest within the mediterannean climate zone of the Western Cape, South Africa

2017 ◽  
Author(s):  
Bruce C. Scott-Shaw ◽  
Colin S. Everson ◽  
Alistair D. Clulow
Keyword(s):  
South Africa ◽  
Water Use ◽  
Sap Flow ◽  
Riparian Forest ◽  
Riparian Forests ◽  
Ratio Method ◽  
Natural State ◽  
Indigenous Species ◽  
Western Cape ◽  
Selection Of

Abstract. In South Africa the invasion of riparian forests by alien trees has the potential to affect the country's limited water resources. Tree water-use measurements have therefore become an important component of recent hydrological studies. It is difficult for government initiatives, such as the Working for Water (WfW) alien clearing programmes, to justify alien tree removal and implement rehabilitation unless a known hydrological benefit can be seen. Consequently water-use within a riparian forest along the Buffeljags river in the Western Cape of South Africa was monitored over a three year period. The site consisted of an indigenous stand of Western Cape afrotemperate forest adjacent to a large stand of introduced Acacia mearnsii. The heat ratio method was used to measure the water-use of a selection of representative indigenous species in the indigenous stand, a selection of A. mearnsii trees in the alien stand and two clusters of indigenous species within the alien stand. The indigenous trees in the alien stand at Buffeljags river showed significant intraspecific differences in the daily sap flow rates varying from 15 to 32 L day−1 in summer (sap flow being directly proportional to tree size). In winter (June) this was reduced to only 7 L day−1 when less energy was available to drive the transpiration process. The water-use in the A. mearnsii trees showed peaks in transpiration during the months of March 2012, September 2012 and February 2013. These periods corresponded to favourable climatic conditions of high average temperatures, rainfall and high daily vapour pressure deficits (VPD – average of 1.26 kPa). The average daily sap flow ranged from 25 L to 35 L in summer and approximately 10 L in the winter. The combined accumulated daily sap flow per year for the three Vepris lanceolata and three A. mearnsii trees was 5700 and 9200 L respectively, clearly demonstrating the higher water-use of the introduced Acacia trees during the winter months. After spatially upscaling the findings, it was concluded that, annually, the alien stand used nearly six times more water per unit area than the indigenous stand. This finding indicates that there would be a hydrological gain if the alien species are removed from riparian forests and rehabilitated back to their natural state.

An assessment of potato sap flow as affected by soil water status, solar radiation and vapour pressure deficit

1999 ◽  
Vol 79 (2) ◽  
pp. 245-253 ◽  
Author(s):  
R. Gordon ◽  
D. M. Brown ◽  
A. Madani ◽  
M. A. Dixon
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Vapour Pressure ◽  
Sap Flow ◽  
Water Status ◽  
Vapour Pressure Deficit ◽  
Potato Cultivars ◽  
Rapid Decline ◽  
Plant Variation ◽  
Flow Monitoring

Water-use of three field-grown potato cultivars (Atlantic, Monona and Norchip) was examined using a commercially available sap flow monitoring system over three consecutive growing seasons. The objectives of the investigation were to utilize the sap flow system to assess the water use of three field-grown potato cultivars. This included an assessment of the relationship between environmental conditions, water status and measured sap flow including the plant-to-plant variation in sap flow and an evaluation of relative transpiration in relation to the soil water status.Each cultivar maintained daily sap flow close to the atmospheric potential transpiration until approximately 70% of the available water was depleted. Under conditions where the soil was drier (>70% depleted), Monona potato plants exhibited a more rapid decline in transpiration than Norchip and Atlantic.Hourly sap flow rates were closely related to solar irradiance, especially under well-watered conditions, with no apparent light saturation point. Vapour pressure deficit effects on sap flow were less pronounced, although maximum vapour pressure deficits encountered were only 2 kPa. Key words: Water use, sap flow, transpiration, potato

scholarly journals Water-efficient Urban Landscapes: Integrating Different Water Use Categorizations and Plant Types

HortScience ◽  
2012 ◽  
Vol 47 (2) ◽  
pp. 254-263 ◽  
Author(s):  
Hongyan Sun ◽  
Kelly Kopp ◽  
Roger Kjelgren
Keyword(s):  
Water Use ◽  
Woody Plants ◽  
Woody Plant ◽  
Water Status ◽  
Canopy Cover ◽  
Urban Landscapes ◽  
Herbaceous Perennials ◽  
Different Types ◽  
Herbaceous Perennial ◽  
Optimum Water

Little research has examined water requirements of entire irrigated urban landscapes integrating different types of plants. Three landscape treatments integrating different types of plants—woody, herbaceous perennial, turf—and putative water use classifications—mesic, mixed, xeric—were grown in large drainage lysimeters. Each landscape plot was divided into woody plant, turf, and perennial hydrozones and irrigated for optimum water status over 2 years and water use measured using a water balance approach. For woody plants and herbaceous perennials, canopy cover rather than plant type or water use classification was the key determinant of water use relative to reference evapotranspiration (ETo) under well-watered conditions. For turf, monthly evapotranspiration (ETa) followed a trend linearly related to ETo. Monthly plant factors (Kp) for woody plants, perennials, and turf species under well-watered conditions in this study ranged from 0.3 to 0.9, 0.2 to 0.5, and 0.5 to 1.2, respectively. Adjusted Kp for each hydrozone was calculated based on landscaped area covered by plant types as a percent of total area, and landscape factor (Kl) was calculated based on adjusted Kp for each landscape treatment. Overall, Kl relative to ETo ranged from 0.6 to 0.8 for three water use classifications.

scholarly journals The Effect of Huanglongbing on Young Citrus Tree Water Use

2017 ◽  
Vol 27 (5) ◽  
pp. 659-665 ◽  
Author(s):  
Said A. Hamido ◽  
Kelly T. Morgan ◽  
Davie M. Kadyampakeni
Keyword(s):  
Water Use ◽  
Sap Flow ◽  
Water Relation ◽  
Irrigation Scheduling ◽  
Stem Water Potential ◽  
Citrus Tree ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus ◽  
Citrus Orchards

Understanding the role of Huanglongbing (HLB) caused by Candidatus Liberibacter asiaticus on citrus (Citrus sp.) water use is critical for determining if changes in water management of commercial citrus orchards affected by this disease is necessary. Reference evapotranspiration (ETo) is the most used methodology for irrigation scheduling, particularly in light of reports that indicate the lack of water for irrigation will become a major problem in many places around the world including Florida. The objectives of this study were to determine citrus tree water relationship [water use, sap flow, and stem water potential (Ψ)] as affected by ETo and HLB. The study was initiated on Jan. 2014 on two sweet orange (Citrus sinensis) cultivars included Hamlin and Valencia grown in a fine sandy soil texture (sandy, siliceous, and hyberthermic Arenic Alaquods) in a greenhouse. Twelve weighing lysimeters of each cultivar (six HLB-affected and six nonaffected trees) were used to determine selected water relation parameters. Results indicated a significant reduction in water use, Ψ, and sap flow for affected trees when compared with nonaffected trees. Citrus water use of healthy trees during the 2-year study was 31% and 27% greater than HLB-affected trees for ‘Hamlin’ and ‘Valencia’, respectively. Lower water use of HLB-affected trees resulted in 10% and 15% greater available soil water content than healthy ‘Hamlin’ and ‘Valencia’ trees, respectively. Therefore, reducing the water supply for HLB-affected trees than healthy trees may be a desirable practice that would lead to significant water savings.

Sign in / Sign up

Export Citation Format

Share Document