Abstract
All commercial apple fruit (Malus Domestica (Borkh) exported from semi-arid regions are grown under irrigation with drip and micro sprinkler systems being the most widely used. Few studies have directly compared the physiological responses of fruit trees to these systems in detail leading to uncertainties around their performance. This study investigated variations in transpiration rates, tree water status, growth, water use partitioning, fruit yield and quality for trees growing on deep sandy soils under these two systems. Data were collected in a mature Royal Gala orchard in South Africa over three growing seasons. Tree transpiration was quantified using the heat ratio method of monitoring sap flow while the soil water balance approach was used to derive the evapotranspiration (ET) rates. Leaf level results showed that one day after irrigation on hot dry days, the stomatal conductance was, on average, almost double for trees under micro than those under drip irrigation. There was more stress under drip with the minimum midday leaf water potential dropping to under -1.80 MPa compared to only around -1.20 MPa under micro sprinklers. Consequently, the tree transpiration per unit leaf area was substantially higher under micro sprinkler (2.9 L/m2/d) compared to 2.3 L/m2/d under drip (P ≤ 0.05). Canopy growth was slower under drip with peak leaf area index (LAI) around 2.1 compared to 2.7 under the micro sprinkler system. The micro sprinkler system had a more active ground cover than the drip. At peak canopy cover in summer, up to 28% of ET was derived from the orchard floor under micro compared to only 15% under drip. However, fruit size and fruit quality were lower under drip compared to micro sprinkler irrigated trees. The study highlights that while water savings are high under drip irrigated orchards on sandy soils, trees tend to experience considerable water stress culminating in smaller fruit of compromised quality.
Abstract from the paper’s OpenAlex record; open copy licensed cc-by-nc-nd. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 9
Claim · model-written summary
Stomatal conductance was almost double under micro sprinklers one day after irrigation.
- Taxon
- apple trees
Malus domesticat0 - Treatment
- microe0
- Outcome
- stomatal conductancee0
- Direction
- almost doublee0
- Qualifier
- one day after irrigation on hot dry dayse0
- Comparator
- drip irrigatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“one day after irrigation on hot dry days, the stomatal conductance was, on average, almost double for trees under micro than those under drip irrigation”
t0“apple trees”
Claim · model-written summary
Minimum midday leaf water potential was below -1.80 MPa under drip versus around -1.20 MPa under micro sprinklers.
- Taxon
- apple treesMalus domesticat0
- Treatment
- dripe0
- Outcome
- minimum midday leaf water potentiale0
- Direction
- droppinge0
- Value
- -1.80 MPae0
- Qualifier
- -1.20 MPae0
- Comparator
- micro sprinklerse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was more stress under drip with the minimum midday leaf water potential dropping to under -1.80 MPa compared to only around -1.20 MPa under micro sprinklers”
t0“apple trees”
Claim · model-written summary
Transpiration per leaf area was 2.9 under micro sprinklers versus 2.3 L/m2/d under drip.
- Taxon
- apple treesMalus domesticat0
- Treatment
- micro sprinklere0
- Outcome
- tree transpiration per unit leaf areae0
- Direction
- highere0
- Value
- 2.9 L/m2/de0
- Qualifier
- 2.3 L/m2/de0
- Comparator
- dripe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tree transpiration per unit leaf area was substantially higher under micro sprinkler (2.9 L/m2/d) compared to 2.3 L/m2/d under drip (P ≤ 0.05)”
t0“apple trees”
Claim · model-written summary
Canopy growth was slower under drip, with peak LAI 2.1 versus 2.7 under micro sprinklers.
- Taxon
- apple treesMalus domesticat0
- Treatment
- dripe0
- Outcome
- Canopy growthe0
- Direction
- slowere0
- Value
- 2.1e0
- Qualifier
- 2.7e0
- Comparator
- micro sprinkler systeme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Canopy growth was slower under drip with peak leaf area index (LAI) around 2.1 compared to 2.7 under the micro sprinkler system”
t0“apple trees”
Claim · model-written summary
Micro sprinkler irrigation had more active ground cover.
- Taxon
- apple treesMalus domesticat0
- Treatment
- micro sprinkler systeme0
- Outcome
- ground covere0
- Direction
- more activee0
- Comparator
- dripe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The micro sprinkler system had a more active ground cover than the drip”
t0“apple trees”
Claim · model-written summary
Orchard floor ET share reached 28% under micro sprinklers versus 15% under drip.
- Taxon
- apple treesMalus domesticat0
- Treatment
- microe0
- Outcome
- ET was derived from the orchard floore0
- Value
- 28%e0
- Qualifier
- 15%e0
- Comparator
- dripe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“up to 28% of ET was derived from the orchard floor under micro compared to only 15% under drip”
t0“apple trees”
Claim · model-written summary
Fruit size was lower under drip than micro sprinklers.
- Taxon
- apple treesMalus domesticat0
- Treatment
- dripe0
- Outcome
- fruit sizee0
- Direction
- lowere0
- Comparator
- micro sprinklere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“fruit size and fruit quality were lower under drip compared to micro sprinkler irrigated trees”
t0“apple trees”
Claim · model-written summary
Fruit quality was lower under drip than micro sprinklers.
- Taxon
- apple treesMalus domesticat0
- Treatment
- dripe0
- Outcome
- fruit qualitye0
- Direction
- lowere0
- Comparator
- micro sprinklere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“fruit size and fruit quality were lower under drip compared to micro sprinkler irrigated trees”
t0“apple trees”
Claim · model-written summary
Drip irrigation yielded high water savings but considerable tree water stress.
- Taxon
- apple treesMalus domesticat0
- Outcome
- water savingse0
- Direction
- highe0
- Qualifier
- considerable water stresse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“water savings are high under drip irrigated orchards on sandy soils, trees tend to experience considerable water stress”
t0“apple trees”
The same questions in other papers
irrigation · growth · Malus domestica (apple)Results differ
14 papers in the same direction as this paper · 52 in the opposite direction
- positive
- positive
- positive
63 papers more in this group
See all 67 papers →irrigation · quality: grain · Malus domestica (apple)Positive and negative results
2 papers in the same direction as this paper · 3 in the opposite direction
- no effect
- positive
- positive
2 papers more in this group
See all 6 papers →irrigation · physiology: gas exchange · Malus domestica (apple)Positive and negative results
6 papers in the same direction as this paper · 3 in the opposite direction
- negative
- negative
- negative
6 papers more in this group
See all 10 papers →irrigation · physiology: water · Malus domestica (apple)Positive and negative results
11 papers in the same direction as this paper · 26 in the opposite direction
- positive
- positive
- positive
34 papers more in this group
See all 38 papers →irrigation · yield · Malus domestica (apple)Positive and negative results
20 papers in the same direction as this paper · 63 in the opposite direction
- positive
- positive
- negative
80 papers more in this group
See all 84 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.