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Copyright is owned by the Author of the thesis. Permission is given for a copy to be downloaded by an individual for the purpose of research and private study only. The thesis may not be reproduced elsewhere without the permission of the Author.
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EFFECTS OF RDI ON APPLE TREE (ev. Royal Gala) GROWTH, YIELD AND FRUIT
QUALITY IN A HUMID ENVIRONMENT
A thesis presented in partial
fulfilment of the requirements for the degree
of Doctor in Philosophy in Horticulture
at Massey University
Gladys Durand November, 1990
To my Beloved Son Kahlil who fills my life withjoy
and In Memory of my Husband.
ABSTRACT
The feasibility of using Regulated Deficit Irrigation in the humid environment of !\ ew
Zealand was evaluated on trees of apple cv. Royal Gala (Malus domestica Borkh.).
The study was carried out in a glasshouse experiment and a field experiment. In the
glasshouse experiment, it was evaluated the pattern of soil water extraction by the
winter mutant of lucerne (Medicago sativa sensu lato) ASR13R from a 'synthetic' soil
layered in the same way that it occurs in the research orchard, under trickle and
sprinkler irrigation. Results indicated that lucerne extracted soil water at a high rate
and explored deep areas of soil.
The field experiment was conducted during two consecutive seasons (1987-1989).
Lucerne as under tree cover and black polyethylene mulch were compared with
conventional herbicide strip to control excess of water in the root zone of the crop that
would otherwise promote vegetative growth. These treatments were applied in
combination with an irrigation schedule divided into three Phases. In Phase I, water
. was withheld, in Phase II RDI was compared with full irrigation, and during Phase ill
which coincided v,rith the rapid fruit growth, all treatments received the full irrigation
rate. During the first season, RDI and full irrigation treatments were based on 25% and
100% replacement EPS (evaporation in the planting square) respectively. In the second
season, after a 50% of the soil water content in the top 600 mm of soil, between
Drainage Upper Limit and the Lower Limit was reached, full irrigation treatments
were replenished to the DL'"L, while RDI treatments received 25% of that amount.
Results showed that under the conditions of this study evaluation of crop water
requirements based on soil moisture measurements was more reliable than those based
on pan evaporation.
The degree of reduction of summer pruning obtained under lucerne X RDI treatment,
reflected levels of soil and plant water deficit similar to those obtained in arid
environments. Results confirmed my hypothesis that by using lucerne as under tree
cover, a RDI strategy can be used in this environment. In contrast, black plastic mulch
appeared to maintain soil moisture rather than prevent its accumulation. Nevertheless,
effects were obtained which reflected positively in fruit growth and yield. Similar
results were obtained under the control treannent, although it was less effective for in
reducing tree vigour. The latter treatment, however, can be implemented in most
orchards at no cost and generate imponant savings.
Apple fruit growth proved to be relatively insensitive to water deficit imposed during
early stages of growth, whereas vegetative growth was checked. Restoring full
irrigation to coincide with rapid fruit growth stimulated growth of RDI fruits resulting
in higher yield under control and plastic X RDI. Lucerne showed higher rates of water
use that were not compensated by the irrigation which affected fruit growth and size.
Results showed that fruits from RDI treatments were fmner, accumulated higher T.S.S.
and had lower bruise susceptibility than fruits from fully irrigated rreatrnents. Fruit
quality remained higher after 10 weeks of cool storage.
ACKNOWLEDGMENTS
I am greatly indebted to Professor David Chalmers for the tremendous
effort and t ime he spent in guiding this work and preparing the
manuscript. Thanks for his constant moral support and the encouragement
to venture in the applied Plant Physiology field.
Gratitude is extended to Dr. Brent Clothier, DSIR for his invaluable
assistance with the soil data;
Thanks to the New Zealand Government, Ministry of External Relations
and Trade, Venezuelan Goverment and mainly to Massey University for
the scholarship grant;
Grateful acknowledgments are due to Dr. Hugo Varela for all the efforts in
solving the most complicated computer programming of this work and for
his "latin" friendship.
I am very grateful to the staff and postgraduate students, Deparnnent of
Horticultural Science at Massey University, for their help throughout this
study.
Special thanks are extended to Simon Cayzer and Andrew Saunders for
their assistance during the field work and to Bruce MacKay and Dr.
Preston Andrew for their constructive comments and suggestions.
Thanks to all the staff of Fruit Crop Unit for their enonnous help during
the experimental work.
Thanks to the Filipino and Singaporean communities and all my friends in
New Ze°aland, for "replacing" my family when far from home.
iii
My deep appreciation goes to my brothers and sisters for their great moral
support and love, and especially to my mother who extended her unfailing
love support to me and my work.
Finally, I give thanks to the Lord Jesus who guided my steps to the stage
where I am.
iv
TABLE OF CONTENTS
ABSTRACT ..................................................................................................... i
ACKJ.�OWLEDGMENTS .......................................... ............ .......... . . .. ........ .iii
LIST OF TABLES.: ....................................................................... ............ ... xiv
LIST OF FIGURES ............................ ............................ .......... ................... xvii
CHAPTER ONE. LITERATURE REVIE\V . . ...................................... ...... 1
1 . 1 .
1 .2.
1.2. 1 .
1.2.2.
1 .2.3.
1 .2.3. 1.
1 .2.3. 1 . 1 .
1.2.3. 1 .2.
1 .2.3 . 1 .3.
1.2.3. 1 .3. 1.
1.2.3. 1.3.2.
1 .2.3. 1 .3.3.
1 .2.3.2.
1.2.3.2. 1.
1.2.3.2. 1 . 1.
1.2.3.2.1.1.1.
1.2.3.2.1. 1.2.
1.2.3.2.1 .2.
1.2.3.2. 1.2. 1.
Introduction ..................................................................... ... 1
Irri . ., ganon . ...................................... . .................................... _
Introduction ............................................................. ..... . ..... 2
Irrigation Methods . .................................................. .......... 3 Crop Water Requirements . ............................................... .4
Methods of Estimating Evapotranspiration . ...................... 5
Water Balance Methods . .................................................... 6
Micrometeorological Methods . ......................................... 9
Plant Physiological Methods . ............................................ 9
Chamber Methods .................................. ............................ 9
Tracer Techniques . .......................................................... 10
Other Plant Physiological Methods . ................................ 1 1
Modelling of Evapotranspiration . .................................... 1 1
Models for Potential and Reference ET . ....... .................. 1 1
Process Oriented Models . ................................................ 1 1
Combination Equation Models . ....................................... 1 1
Net Radiation Models . ..................................................... 12
Correlation Based Models . .............................................. 13
Radiation Model. ..................................... ...... .................. 13
1.2.3.2. 1.2.2. Temperature Model. .............................. .......................... 14
1.2.3.2. 1.2.3. Humidity Models . .................................... ................................ 14
1.2.3.2. 1.2.4. Evaporation Models . . ............................................................... 15
1.2.3.2.2. Models for Actual Evapotranspiration . ........................... 15
1 .2.3.2.2. 1 . Correlation Based Models . .............................................. 15
1.2.3.2.2. 1 . 1 . :Models Based on Crop Coefficient . ........................................ 15
1.2.3.2.2. 1.2. �lodels Based on Soil Water Deficit . ...................................... 16
1.2.3.2.2.2. Process Oriented Models . ................................................ 17
1.2.3.2.2.2. 1 . Models Based on Surface Resistance . ............................. 17
1.2.3.2.2.2.2. Mode l s Based on t h e Root Extraction
1.2.3.3.
1.2.3.3.l.
1.2.3.3.2.
1 .2.3.3.3.
1.2.3.3.3. 1.
1 .2.3.3.3.2.
1.2.3.3.3.3.
1.2.3.3.3.4.
1 .2.3.3.3.5.
1 .2.3.4.
1.3.
1.3. 1.
1.3.2.
1.3.3.
1.3.4.
1 .3.5.
1.4.
1.4.1.
1.4. 1. 1.
1.4. 1.2.
1.4. 1.2. 1.
1.4.1.2.2.
Function . .......................................................................... 17
Estimation of Irrigation Requirements . ...... ..................... 18
Allowable Soil Water Depletion ...................................... 19
Allowable Evapotranspiration Deficit. ............................ 20
Plant Approach . ............................................................... 21
Allowable Leaf Water Potential Depression . .................. 21
Foliage-Air Temperature Difference . .............................. 22
Plants as Indicators of Water Stress . ............................... 22
Phenological Variation in Crop Sensitivity to
Water Stress . .................................................................... 23
Development of the Concept of Regulated
Deficit Irrigation . .............................. ............................... 25
Irrigation Timing . ............................................................ 30
Soil \Vater Regime ........................................................... 33
Introduction ...................................................................... 33
Soil Water Availability . ................................................... 33
Water Distribution in the Soil . ......................................... 35
Soil Water Storage and Water Extraction ........................ 36
Controlling the Soil Water Budget. ................................. 37
Plant Responses to Water Deficits ................................... 39
Leaf Water Potential . ....................................................... 39
Diurnal Pattern . ................................................................ 39
Seasonal Changes . ........................................................... 40
Pattern Related to Soil Moisture . .................................... .40
Pattern Related to Phenological Phase . .......................... .42
1 .4.2.
1 .4.3.
1 .4.4.
1 .4.4. 1 .
1 .4.4. 1 . 1 .
1 .4.4. 1 .2.
1 .4.4. 1 .3.
1 .4.4. 1 .3. 1 .
1 .4.4. 1 .3. 1 .
1 .4.5.
1 .4.5. 1 .
1 .4.5. 2.
1 .4.5.3.
1 .4.5.4.
1 .4.5.5.
1 .4.5.6.
1 .4.6.
1 .4.6. 1 .
1 .4.6.2.
1 .4.6.2. 1 .
1 .4.6.2.2.
1 .4.6.2.3.
1 .4.6.2.3. 1 .
1 .4.6.2.3.2.
1 .4.7.
1 .4.7. 1 .
1 .4.7.2.
Stomatal Resistance, Conduc tance and
Transpiration ....... . ................................... ......................... 43
Stem Water Potential . . .... . ............. .................... . .............. 45
Growth . . .. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. .. . . .. . . . . . . . . . . . . . . . . . . . . ....... 46
Vegetative Growth ......... .................................................. 46
Root. ................................................................................. 46
Stem and Shoot . ............................................................... 47
Reproductive Growth ........................... ............................ 48
Fruit Set . ............ ... . . . . . . .............. . ........... . . . . . ... ................... 48
Fruit Growth and yield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .. . . . . . . .... .... 49
Fruit Quality . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . 52
Total Soluble Solids and Acidity . . .. . . .. . . . . . . . . .. . . .. . . . . . . . . . . . . . . . 52
Fruit Size . .................................. ............. .......................... 53
Colour . ............................. ............ . . ..... . ....... . .................... 55
Firmness ............. ............... ................. .. . ....... . ................... 55
Bruise Resistance . . . . ..... . . . . . . . . . .. . . . . .. . . . . . . . . . . . . . . . . .. . . . . . . . . ......... 57
Keeping Quality and Incidence of Disorders . . . . .............. 57
Relative Sensitivity to Water Deficit. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . 58
Physiological Processes . .. .. . . .. . . . ... . ... ... . . . .. .. .. . ........ . .......... 58
Assimilate Partitioning . . .. . ..... . .......... . . . ....... . . ... . . ... ........... 59
Sink Growth ... . . . . . . . . . .. . . . . . . . . .. . . .. . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . .. . . . . . . . 59
Sink Metabolism .... . .. . . . ... . . .......... ... ....... . ..... .. ................... 60
Regulation of Growth and Assimila te
Partitioning in Fruit Trees .............. . . . . . . . . . . . ........... . ........... 61
Role of Root Growth in Control of Vegetative
Growth and Assimilate Partitioning . . . . . . . . . . . . . . . . . ... . . . . . . ...... 62
Role of Fruit in Assimilate Partitioning . . . . . .......... . .. ........ 64
Use of Water Deficit to Manipulate Plant
Growth . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .......... . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . 65
Manipulation of Root Growth . .... ... . ...... . . .. ... ............. . . . . . . 65
Different ial Sensi t ivi ty of Competing
Physiological Processes to Water Deficits . . . . .............. .... 67
1.5. This Study . ....................................................................... 68
CHAPTER TWO. GENERAL MATERIALS AND METHODS . . ......... 70
2. 1 .
2.2.
2.3.
2.3. 1 .
., ., ., _. -'._.
2.4.
2.4. 1 .
2.4. 1 . 1 .
2.4. 1 .2.
., -_ . .) .
2.5 . 1 .
2.5 . 1 . 1 .
2.5.1 .2.
., - ., _ . .) ._.
2.5 .2. 1 .
2.52.2.
2.5 .2.3 .
2.4.2.4.
2.4.2.5.
Introduction ......................................................... ............. 70
Plant :rvlaterial ................................................................ ... 70
Environment. ............................................... . . .......... . ....... 71
Climate . .......................... .................................................. 7 1
Soil. .................................................................................. 7 1
Field Trials .............................. ............................ ............. 73
Experimental Layout. ........ ............................................. 73
Soil Management Treatments . ..... .................................... 75
Irrigation Strategies . ........... . . ........................................ ... 75
Data Collection . .................... .......................... . .... ............ 76
Collection of Soil Moisture Data . ......... . ... . . . . . . ..... .... . ... . . . . 76
Field Calibration . ............................................................. 7 6
Field Data ......................................................................... 76
Collection of Plant Data ........................................... . ....... 79
Trunk Circumference ....................................................... 79
Shoot Length .................................................................... 79
Fruit Data . ........................................................................ 79
Plant Water Status Data . .................................................. 80
Data Analysis ................................................................... 8 1
CHAPTER THREE. GLASSHOUSE EXPERIMENT: INTERACTION
BE T W E E N IR R I G A TION M ETHO D A ND
LUCERNE ON SOIL WATER REGIME • ................. 82
3 . 1 .
3 .2.
3 .2. 1 .
3.2.2.
Introduction ...................................................................... 82
Materials and Methods . .............................................. ..... 83
The Soil Profile ................................................................ 83
Irrigation . ......................................................................... 83
v
3.2.2.1.
3.2.2.2.
3.3.
3.3.l.
3.3.1.l.
3.3.1.2.
3.3.1.3.
3.3.2.
3.3.2.1.
3.3.2.2.
3.3.2.3.
3.3.3.
3.3.l.
3.4.
Sprinkler Irrigation . .................................................... . . ... 83
Trickle Irrigation .............................................................. 84
Results . .......................................................... ................ ... 84
Soil ,\Vater Content. ...................................................... ... 84
Sprinkler Irrigation . ......................................................... 84
Trickle Irrigation .............................................................. 86
Comparison Between Irrigation Systems in
Relation to Drainage . ....................................................... 87
Soil Water Storage (W) . .................................................. 89
Sprinkler Irrigation . .................. ........................ ............... 89
Comparison Between Irrigation Systems in
Relation to Root Water Extraction . ................................. 92
Trickle Irrigation .............................................................. 92
Soil Water Balance .......................................................... 96
Water Use Efficiency ....................................................... 98
Discussion ........................................................................ 98
CHAPTER FOUR. SEASON 1987-1988 . ............... ................................. 101
4.1.
4.2.
4,3.
4.3.1.
4.3.2.
4.3.3.
4.3.4.
4.3.5.
4.3.6.
4.3.6.1.
4.3.6.2.
4.3.7.
4.3.7.1.
Introduction ....... ... . ........................................................ . 101
Objectives . ..................................................................... 102
Materials and Methods . ................................................. 102
Weather. ......................................................................... 102
Prediction of ET Crop by Pan Evaporation . .................. 103
Irrigation . .. ......... ............................................................ 104
Estimation of Net Water Input.. ..................................... 105
Predicted Water Deficit. ............. ................................... 105
Soils . .................................................. ............................ 106
Stored Soil Water ........................................................... 106
Soil \Vater Volume . ....................................................... 106
Collection of Plant Data .................. ............................... 107
Plant Water Status .......................................................... 1 07
4.3.7.2.
4.3.7.3.
4.3.7.4.
4.4.
4.4. 1 .
4.4. 1 . 1 .
4.4. 1 .2.
4.4. 1 .3.
4.4.3.
4.4.4.
4.4.4. 1 .
4.4.4. 1 . 1 .
4.4.4.2.
4.4.4.2. 1 .
4.4.4.2.2.
4.4.4.2.3.
4.4.4.3.
4.4.4.3. 1 .
4.4.4.3.2.
4.4.4.3.3.
4.4.4.3.4.
4.4.4.4.
4.4.4.4. 1 .
4.4.4.4.2.
4.4.5.
4.4.6.
P h o t o s y n t h e t i c R a t e a n d S to m a ta l
Conductance . ................................................................. 107
S hoot Data . .................................................................... 107
Fruit Data . .................................................................... .. 108
Results ............................................................................ 108
Weather Season 1987-1988 . . . . . . . . . . . . . . . . . . . . . . . . . . ............ ..... 108
Phase 1. ..... ...................................................................... 108
Phase II . ......................................................................... 108
Phase m . ........................................................................ 108
Accumulated Predicted Water Deficit . .......................... 1 10
Soil �loisture . ....... ...................... ................................... 1 10
Volumetric Water Content. . ... ........................................ 1 10
Volumetric Water Content in Phase 1.. .......................... 1 15
Effects of Treatments on Total S oil Water
Storage . ................................................................... ....... 1 16
Phase 1. . .................. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .. . . .. . . ................ 1 16
Phase II . ................................... .... . ........ .......... ............... 121
Phase m . .................................. . . .................................... 123
Accumulated Soil Water Deficit .... ................................ 123
Phase 1. .... ................. . . .. . . .. ........ . . . . . . . . . . . . . . .. .... . . . . . . ...... ...... 123
Phase II ............................................ . ............................. 124
Phase m . ........................................................................ 129
Relationship Between Cumulative Predicted
ET and Cumulative S oi l Water D eficit
Measured ................................... . .......... . ......................... 130
Effect of Treatments on Pattern of Wate r
Extraction .................................... ................................... 1 31
Pattern with Depth . ........................... ............................. 1 31
Pattern with Distance From the Tree . .................. .......... 1 31
Diurnal Pattern of Leaf Water Potential . ....................... 1 35
Effects of Treatments o n Diurnal Pattern of
Photosynthesis . .......................... .................................... 1 36
4.4.7.
4.4.8.
4.4.8.1.
4.4.8.2.
4.4.9.
4.4.9.1.
4.4.9.2.
4.4.9.3.
4.4.9.4.
4.4.9.4.1.
4.4.9.4.2.
4.4.9.4.3.
4.4.:>.4.4.
4.4.10.
E f f e c t s of T r e a tme nts o n S t oma t a l
Conductance . ................................................................. 138
E f f e c t s of Tr eatme n t s o n Vege t ativ e
Growth . .......................................................................... 138
Trunk Cross Sectional Area (TCSA) . .......... ........ .......... 138 Shoot Gro\vth ...... ........................................................... 140
•
Effects of Treatments on Fruit Growth .......................... 143
Phase I and II. ............ .................... .... _ ........................ . . 143
Phase III . ...... ............ ............................ .......................... 146 Yield . .......................................................... ................... 148
Effects on Fruit Quality . ...... .......................................... 1.+9
Fruit Size .................................................... .................... 149
Flesh Firmness ............... ............... . ........... . .................... 151
Total Soluble Solids . .................. ....... .............. . .............. 151
Bruise Susceptibility ... ................................. . ................. 153
Discussion ... ............ ....................................................... 153
CHAPTER FIVE. SEASON 19S5-1989 . .................................................. 159
5.1.
5.2.
5.3.
5.3.1.
5.3.2.
5.3.3.
5.3.4.
5.3.5.
5.3.5.1.
5.3.5.2.
5.3.5.3.
5.3.5.3.1.
5.3.5.3.2.
Introduction .................................. ........................... ....... 160 Objectives . ..................................................................... 160
Materials and Methods . ................................................. 160
The Weather .............................. ..................................... 160
Irrigation S rrategies . ..... ............. ............................... ..... 161
Estimation of Total Water Input. ................................... 163
Soils . .............................................................................. 163 Collection of Plant Data .................................... .. ........... 164
Shoot Growth . ......... .. ............................................ .... ..... 16 4
Fruit Gro\vth . ............. .......... .... : ..................................... 164
Plant \Vater Status ..... ................ ...... ....... ........................ 164 Leaf Water Potential ('l'L)' .................... .......... ........ ...... 164
S tern Water Potential ('l' s) .................................. ........... 165
,
5.4.
5.4. 1 .
5.4. 1 . 1 .
5.4. 1 . 2.
5.4. 1 .3.
5.4.2.
5.4.2. 1 .
5.4.2.2.
5.4.2.2. 1 .
5.4.2.2.2.
5 .4.2.2.3.
5.4.2. 3.
5.4.2.3.1 .
5.4.2.3.2.
5.4.2.3.3.
5.4.2.4.
5 .4.3.
5 .4.3.1 .
5.4.3.2.
5 .4.3.3.
5.4.4.
5.4.5.
5 .4.5 . 1 .
5.4.5. 2.
5.4.6.
5 .4.6. 1 .
5.4.6.2.
5.4.6.3.
5.4.6.4.
5.4.6.4. 1 .
Results ............................................................................ 1 65
Weather Season 1988- 1989 . .. ..... .......... . . . ... . . ............. . ... 1 65
Phase I. . . . . . . ............... ...... . . . . .. ........... ...... . . ....... . . . . . . .......... 1 65
Phase II . ........................................................ ... .............. 165
Phase III . .......... ........................ .......... ....... ..................... 1 67
Soil Moisture . ................... ....................... . .... ........ . ........ 1 67
Volumetric Water Content ....... ........ ..................... .... ..... 16 7
Effects of Treatments on Total S oil Water
S torage . . . ...................... . ................ ................................ . 168
Phase I. ............. .............................................................. 168
Phase II. ........ ........................................................... ..... . 173
Phase III . ..................................... ... ...... . ................... ...... 174
Accumulated Soil Water Deficit ........................ . . ... ....... 174
Phase I. . . . .. .. .... ............ . . . . . . . . . ... . . ..... . . . . . . . .. . . . ... .. . . . . . . . .... . . . . . 174
Phase II. .. .......................... .................... . . .... ...... ...... .. ..... 175
Phase m . ....................................... . ...... . . . . .. . ...... ............. 179
E ffe c t s o f Tre at m e n t s o n P a tt ern o f
Extraction with Depth . ....................... ........................... . 1 80
Effect of Treatments on Seasonal Pattern of
Leaf Water Potential . ............. . ....................................... 1 82
Phase I. . . ........................ .... ......... .... . . ................... . ...... .... 1 82
Phase II. ......................................................................... 1 82
Phase ill . .............................................. ......................... . 1 8 8
S tem Water Potential ('¥ s) ............................................. 1 89
Effe c t s o f Tre atmen t s o n V e g e t at ive
Growth . ............................. .......................... ................... 192
Trunk Cross Sectional Area (TCSA) . .. .......................... 192
S hoot Length .......................................................... .. ...... 194
Effects of Treatments on Fruit Growth ................ . . . ... . ... 194
Phase I and Phase II . ...................................................... 194
Phase Ill . . ................................................ . ..... ... . ... .......... 196
Yield . ............................................................................. 198
Effects on Fruit Quality . .... ... .......... . .............................. 202
Fruit Size .................................................... .................... 202
5.4.6.4.2.
5 .4.6.4.3.
5 .4.6.4.4.
5 .5.
Flesh Finnness . ................ .......................... .. . ................. 202
Solids Soluble . ...... ......................................................... 205
Bruise Resistance . ... ....................................................... 206
Discussion . ................................................................ ..... 207
CHAPTER SIX. GENERAL DISCUSSION . .................................. ....... 21 1
6.l.
6.2.
6.3.
6.3.
Soil Management . .......................................................... 21 1
Irrigation Scheduling . .................... ......................... . ...... 213
Sensitivity to Water Stress at Different Crop
Stages . ..... ....................................................................... 215
Regulated Deficit Irrigation Effects on Fruit
Quality. . ........................... ........ ...... .... .... ...................... 217
REFERENCES. . ..................................................................................... 21 8
xi.
Table 3 . 1 .
Table 3 .2.
Table 3.3.
Table 3.4.
Table 4. 1 .
Table 4.2.
Table 4.3.
Table.4.4.
Table.4.5.
Table.4.6.
Table.4.7.
Table.4.8.
Table 4.9.
xiv
LIST OF TABLES
Water content (9) proflle during a drying cycle after
irrigation with point emitters . . . . . . . .. . . . . . . . . . . . . .... ...... . . . . . . . . . . . . . . .. .. . . . . 87
Water content (9) profile at time drainage initiated
and ceased as measured with the neutron probe . . .. . . . . .. . . . . . . . . . . .... 88
S oi l w ater storage c hange between soil depth
intervals during extraction periods of sprinkler and
trickle irrigation . ... . . . . . . . .. . . . . . . . . . . . . . . . . .. . . . . . . . . . . ................................ 95
Comparison between regression lines for soil water
storage (W) over time after sprinkler and trickle
irrigation . .. .. . . . . . . ........ ........ . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Climatic data for Palmerston North during season
1987-88 (Summary by periods) . .. .. .......................................... 103
Irrigation treatments during season 1987- 1988 . ... . . . . . . . . . . . . . . . . . . . 105
Changes in soil water content (9) during Phase I. . . . . . . . . . . . . . . . . . . . 1 16
Changes in total soil water storage (W) during
Phase I. ..................................................................................... 120
Changes in total soil water storage (W) during
Phase ll . ........ . . ............................................................. ............ 121
Accumulated soil water deficit over the planting
square (6. W) during Phase I. .............................................. ...... 124
Accumulated soil water deficit (�W) over the
planting square during Phase ll . ................. ......... ................. ... 125
Accumulated soil water deficit (�W) over the
planting square during Phase ill . ....................................... ...... 129
Determination coefficients (r2) for cumulative
predicted ET to cumulative soil water deficit
measured . ..... ........ .................................... .... ............ ................ 1 30
Table 4.10. Effects o f treatments o n percentage of water
xv
extracted from different depths in the root zone ............ .......... 132
Table 4.11. Absolute and relative trunk cross sectional area
(TCSA) increase during season 1987-1988 ............................. 140
Table 4.12. Effect of treatments on fruit growth rate (cm3·day·l)
during Phase I. ......................................................................... 143
Table 4.13. Effect of treatments on fruit growth rate (cm3'day'1)
during selected periods of Phase ll . ..................... .................... 146
Table 4.14. Effect of treatments on fruit growth rate (cm3·day·l)
during selected periods of Phase ill ......................................... 147
Table 4.15. Effect of treatments on yield during the season
1987-1988 . ............................................................................... 148
Table 4.16. Effects of treatments on yield (kg/unit) by class size
of the season 1987-1988 . ......................................................... 150
Table 4.17. Effe c t s o f soi l and irr i g at ion management
treatments on fruit quality ........................................................ 152
Table 5. 1 . Climatic data for Palmerston North during 1988-89 season .. 161.
Table 5.2. Drainage upper limit (DUL) and lower limit (LL) of
Table 5.3.
Table.5A.
Table 5.5.
Table 5.6.
Table 5 .7.
Table 5 .8 .
Table 5.9.
volumetric soil water content (9)Z in Massey Orchard . ........... 162
Changes in soil water content (9) during P hase
1. ............................................. .................................................. 167
Changes in total soil water storage (W) during
Phase 1. .................................................................................... 169
Accumulated soil water deficit, /l W (mm) over the
planting square during Phase 1.. ............................................... 175
Effects of treatments on the percent of w ater
extracted from different depths in the root zone ...................... 18 1
Effects of treatments on leaf water potential during Phase ll .. 186
Midday leaf water potential ('l'Lm) during Phase ll1.. .............. 188
Absolute and re la tive growth of trunk cross
sectional area (TCSA) during season 1988- 1989 . ................... 192
Table 5.10. Total abs olute and relative growth of trunk cross
x· .. ·i
sectional area (TCSA) during the experiment . ........................ 193
Table 5.11. Effect of treatments on yield during the season
1988-1989 . ................................................... ............................ 200
Table 5.12. Effect of treatments on yield during the experiment
( 1987-1989) . ............................................................................ 201
Table 5.13. Effect of soil and irrigation management treatments
on fruit quality during the season 1988- 1989 . ......................... 203
Table 5.14. Effect of soil and irrigation management treatments
on fruit quality during the experiment 1987-1989 ................... 204
LIST OF FIGURES
2.1. Monthly water balance for Palmerston North, New
Zealand . ............ ............ � .................................................................... 72
2.2. (a) Retentivity curve for the three textural elements of
the Manawaru fme sandy loam and (b) field calibration
of neutron probe at Massey orchard . ................................................. 74
2.3. Layout of drip emmitters and access tubes for neutron
probe measure::nents . ......................................................... . ............... 77
3.1. Profiles of water content of a "synthetic" soil analogue -�
of Manawaru 5...."1e sandy loam under sprinkler irrigation . ................. 85
3.2. Changes in the amount of water stored between 0-350,
35 0 - 5 50, 5 5 0- 7 5 0 and 7 5 0-9 5 0 mm depths of a
"synthetic" soil profile during the extraction period
following irrigation by sprinkler ................................................... . .... 90
3.3. Changes in the amount of water stored between the
depths 0-350, 350-550, 550-750 and 750-950 mm depths
of a "synthetic" soil profIle during a drying cycle after
sprinkler irrigation . ............................................................................ 91
3.4 The proportion of water extracted from layers between
0-350, 350-550. 550-750 and 750-950 rom depth during
a drying cycle after sprinkler irrigation . ............................................ 93
3.5 . The proportion of water extracted from layers between
0-350, 350-550, 550-750 and 750-950 mm depth during
a drying cycle after trickle irrigation . ................................................ 94
4.1. Daily water balance during growing season 1987-1988 ................. 109
4.2. Cumulative water deficit/surplus predicted for plastic
treatments during the growing season 1987-1 988 . ............. ............. 1 1 1
4.3. Cumulative water deficit/surplus predicted for control
xvi
treatments during the growing seas on 1987-1988 . .......................... 112
4.4. Cumulative water deficit/surplus predicte d for lucerne
treatments during the growing season 1987-1988 . .......................... 113
4.5. Typical soil water content profiles obtained under (a)
p l as ti c , (b) c o n tr ol and ( c) l u c e rne t re a tments
respectively during Phase I (day 36 *, day 59 +) . ......................... 114
4.6. Seasonal pattern of soil water s tored (W) under plastic
treatments , estimated by the neutron probe . ................. ................... 11 7
4.7. Seasonal pattern of soil water s tored (W) under control
treatments , estimated by the neutron probe . ................. ................... 118
4.8. Seasonal pattern of soil water stored (W) under lucerne
treatments , estimated by the neutron probe . ............. ....................... 119
4.9. Cumulative s oi l water defici t ob tained under plastic
treatments during the growing seas on 1987-1988 . .......................... 126
4.10. Cumulative s oi l water deficit obtaine d under control
treatments during the growing seas on 1987-1988 . .......................... 127
4.11. Cumulative soil w ater deficit obtained under lucerne
treatments during the growing season 1987-1988 . .......................... 128
4.12. Pattern of s oil w ater extraction with distance from the
tree for treatments during a selected period ..................................... 133
4.13. Diurnal pattern of leaf water potential ('PrJ for all the
treatments during days 53, 82, 123 and 148 after full
bloom .. ............................................................................................. 135
4.14. Diurnal pattern of photosynthesis rate for all treatments
during days 53, 82, 123 and 148 after full bloom ............................ 137
4.15. Diurnal pattern of leaf conductance for all treatments
during days 53,82, 123 and 148 after full bloom ............................ 139
4.16. Accumulate d shoot growth for all the treatments from
day 48 to 106 after full bloom . ........................................................ 141
4.17. Ratio between fruit growth rate of RDI treatments to the
respective full irrigation treatment.. ................................................. I44
::CT::'
4. 1 8. Cubic fit for fruit growth rate during growing season
1987- 1988 . ....................................................................................... 145
5.1. Daily water balance during growing season 1 988- 1989 . ... ............. 166
5.2. Seasonal pattern of soil water stored ('IN) under plastic
treatments, estimated by the neutron probe . ........... .......... . .............. 170
5.3. Seasonal pattern of soil water stored ('IN) under control
treatments, estimated by the neutron probe . ................... ... . .. ........... 171
5.4. Seasonal pattern of soil water stored ('IN) under lucerne
treatments, estimated by the neutron probe . .................................... 172
5.5. Cumulative soil w ater deficit ob tained under plas tic
treatments during the growing season 1 988- 1989 .............. ... ...... .... 176
5.6. Cumulative soil w ater deficit ob tained under control
treatments during the growing season 1 988- 1989 . .......................... 177
5.7. Cumulative soil water deficit ob tained under lucerne
treatments during the growing season 1 988- 1 989 . .......................... 178
5.8. Seas onal pattern of predawn ('1' Lp) and midday ('¥ Lm) leaf water potential for plastic treatments ........................................ 1 83
5.9. Seas onal pattern of predawn ('1' Lp) and midday ('¥ Lm) leaf water potential for control treatments ................ ....................... 1 84
5.10. Seas onal pattern of predawn ('¥ Lp) and midday ('¥ Lm) leaf water potential for lucerne treatments . ..................................... 1 85
5.11. Seasonal pattern of predawn stem water potential ('¥ s) of
c o n tr o l X fu l l ir r i g a t i o n a n d l u c er n e X R DT
treatments . ........................................................................................ 1 90
5.12. Seasonal pattern of midday stem water potential ('¥ s) of
c o n tr o l X fu l l irrig a t i o n a n d l u ce r n e X R DT
treatments ......................................................................................... 19 1
5.13. Accumulated shoot growth for all the treatments from
day 47 to 104 after full bloom . ........................................................ 195
5.14. R atio fruit gr ow th rate of RDT treatments to the
respective full irrigation treatments . ................................................ 195
X"
5. 15. Chan ge in fruit volume of Royal Gala apple trees as
affected by treatments during the season 1988-1989 . . .. . .... . .. . . . ..... . . 199
treatments . ................ .................................................. ...................... 190
5 . 12 . Seasonal panem of midday stem water potential ('P s) of c o n trol X fu 11 irr i g at i o n a n d l u c e r n e X RD I
treatments . ........ ............................ .......................... ......... . ................ 191
5.13. Accumulated shoot growth for all the treatments from
day 47 to 1 04 after full bloom . ........................................................ 195
5. 14. Ratio fru i t growth rate of RDI treatments to the
respective full irrigation treatments . ............................ .................... 195
5.15. Change in fruit volume of Royal G ala apple trees as
affected by treatments during the season 1988-1989 . ......... ... ......... 199