Water management is a critical aspect of successful grape production in Egypt
(Beaumont, 1993; Hassan et al.,
1999). In new vineyards of reclaimed areas in Egypt and especially where
irrigation water is scarce, trickle irrigation is increasingly being introduced.
Water applied via trickle irrigation at the proper time and quantity can influence
grape yields and fruit quality (El-Hady and Abd El-Kader,
2003). In addition, water can be a scarce resource in many areas and its
efficient use must be a high priority (De Oliveira et al.,
Thus, methods for scheduling irrigation are an important aspect of good vineyard
management (De la Hera et al., 2007). One of
the main advantages of drip irrigation is the opportunity to obtain high system
uniformity. In general, drip irrigation systems often achieve over 90 % uniformity
with proper design, installation and maintenance. This is in contrast to typical
uniformities of 40-60 for gravity systems and 50-75% for sprinkler systems (Caswel
and Zilbernian, 1985). Moreover (Zhang et al.,
2004) noted that under China conditions and maize crop field, the drip Irrigation
systems was more efficient than sprinkler irrigation and sprinkler irrigation
was more efficient than border/furrow irrigation.
Wetting patterns are primarily dictated by soil texture, soil tilth, structure
including soil compaction and chemistry. In general, water from an emitter exhibit
more laterals, horizontal movement in heavier clay soils with more vertical,
downward movement in lighter sandy soils (Gal et al.,
The use of closely spaced emitters is rapidly gaining popularity thus, the
ability to achieve superior wetting patterns more quickly than with wider spaced
emitters (Gal et al., 2004). In this respect,
the wetting patterns of emitters spaced at 12 and 8 inches, so, "wetted corridor
of moisture" achieved down and across the bed after 30 h of irrigation with
the 8 inches spacing. Therefore, "blackening of the beds" is highly desirable
by many growers under modern irrigation systems, especially when setting transplants
or germinating seeds, it was possible to increase soil water availability to
enhanced vegetative growth.
In general, irrigation management should focus in the adoption of practices
that enhance the efficient use of water so that other sectors can have more
water for economic use (CAWMA, 2007).
Previous studies showed that saving irrigation water, increasing water utilization
efficiency as well as controlling irrigation was accompanied with enhancing
growth and fruiting of grapevines and other fruit crops. (REF) Using modern
methods of irrigation is considered an important target for achieving the benefits
of water. Caswel and Zilbernian (1985), Hepner
et al. (1985), Araujo et al. (1995),
McCarthy et al. (1997) and Gal
et al. (2004).
Weather parameters, crop characteristics, management and environmental aspects
are factors affecting evaporation and transpiration (Allen
et al., 1998). At the same time a better management of water in irrigated
agriculture it is necessary to enhance crop production and preserve soil and
water quality (CAWMA, 2007).
The increment of water use from February until July may be attributed to the
development of shoots, leaf area and clusters, as well as to the increase of
evaporative demand. In addition the optimum water use of grapevine was 20, 35
and 23 L/vine/day from pruning to fruit set, fruit set to veraison and veraison
to fruit maturation, respectively (Araujo et al.,
1995). On other hand, Serman et al. (2004)
observed that under different irrigation rates 100, 80, 70 and 60% of ETo, the
amounts of water applied were 1060, 877, 763 and 649 mm year-1, respectively.
On 3 year old Superior vines with trickle irrigation. At the same time, Ferreyra
et al. (2004) studied the response of Cabernet Sauvignon grapes to
four irrigation treatments. The first at 100% of crop evapotranspiration (ETc)
throughout the second at 40% ETc throughout the season but the third with no
irrigation until veraison and 100% ETc applied throughout the rest of the season
and the fourth treatment at 100% ETc from bud burst until veraison and no irrigation
throughout the rest of the season. The amount of water use were 4447, 1769,
1711 and 2700 m3 ha-1. for treatments numbers 1,2,3 and
4, respectively. Furthermore, Seif et al. (2007)
noted that water consumptive use were 936.50, 749.16, 561.88 and 374.60 mm season-1.
Whereas crop coefficient were 0.75, 0.61, 0.50 and 0.43 when vines were irrigated
at 125, 100, 75 and 50% ETpan, respectively.
The objective of this study was therefore, to maximize water use efficiency
through elucidating the effect of trickle irrigation system treatments on enhancing
growth, yield and water utilization efficiency in Superior vineyard orchards
under Qena conditions.
MATERIALS AND METHODS
Experimental site description: This investigation was carried out during
2009 and 2010 seasons on 75 vigor of uniforms eight year's old Superior grapevines
in vineyard located at a private orchard in ELQenwia Qena Governorate. The selected
vines were trained according to cane pruning system (66 eyes for each vine at
6 fruiting canesx9 eyes+6 renewal spursx2 eyes) using shape supporting gable
system. The vines were planted at 1.75x2.75 meters apart which gave (831 vines
fed.-1) Irrigation source was Nile water and its salinity was 0.36
(dS m-1) pH = 7.4 where, the soil is saline and Loamy sand. Mechanical,
Physical and chemical characters of the tested soil were determined according
to Richards (1954).
The successful production of grapes depended on irrigation management and irrigation
water utilization efficiency (Kang and Zhang, 2004;
Loveys et al., 2005; Stevens
et al., 2008). Until now there is no recommended water requirement
and irrigation scheduling in the new reclaimed land under drip irrigation system.
Therefore, a preliminary study was conducted during 2006 to 2008 seasons to
calculate the average irrigation requirement for grape vines grown in this area.
So this study was designed to determine the best system of increasing water
efficiency under drip irrigation system in the grape vine. The ability to estimate
crop water use is important in semiarid areas such as Qena region where the
production of crops are dependent upon the availability of irrigation water.
In the present study it was favorably that to implement this work should be
definite amount of water use through the average of the three previous study
years from 2006 to 2008.
Crop water requirements: Applied water per vine and per feddan was calculated
from ETo avg, according to equation of Doorenbos and Pruitt
||Applied irrigation water (liter/tree/day)
|| Potential evapotranspiration (mm/day)
||Crop coefficient from FAO56. and AgriMet Crop Coefficients (http://www.usbr.gov/pn/agrimet/cropcurves/WGRPcc.html)
The crop coefficient is dependent upon stage of crop growth, canopy height,
cover and architecture (Allen et al., 1998)
||Canopy cover represented by the shadow area average which ranged between
0.32 in Feb. to 0.70 from May till Sept
Canopy size measured by the amount of shade cast on the ground beneath grapevines
growing areas (Walker and Stevens, 2004):
Plant area = 2.75x1.75. Ea = Irrigation system efficiency
(%) = 85 % for drip irrigation
Pe = Effective rainfall (mm) = 0.30 rainfall
Leaching requirement (LR) = 0.36/2x12 = 0.015
The crop coefficient (Kc) values were 0.15 (Feb.), 0.45, 0.75, 0.45 and 0.35
in April, July and Oct. Nov., respectively under Qena conditions eight year
old Superior grapevines and gable system supporting the results indicated that
total applied water during the growing period was 10428.3 L/vine/year, while
in unit of m it was 10.5 m3/vine per year. When using unit of area
as Feddan (4200 m2) the one feddan contains 831 vine and crop water
requirements was 8665.7 m3 fed-1.
Experimental treatments and design: Irrigation was done by drip system.
All the selected vines received the usual horticultural practices that normally
applies in vineyards except those dealing with irrigation.
The present experiment included the following five treatments:
T1: One lateral and two emitters/vine
T2: One lateral and three emitters/vine
T3: Double laterals and two emitters/vine
T4: Double laterals and four emitters/vine
T5: Double laterals and six emitters/vine
Each treatment was replaced three times, five vines per each. All the selected
vines received the same irrigation water amount namely 10. 5 m3/vine/year.
The distance between laterals and vines were 2.75 and 1.75 meters, respectively.
Emitters discharge was four L h-1. Operating times (hrs) in the present
five treatments are shown in Table 1.
Emitter discharge was 4 L h-1. Irrigation water amount was 9.4 m3/year/vine
for all treatments. Complete randomized block design was adopted for statistical
analysis of the present results. Main shoot length (cm.) was measured at the
middle of May in the two of the eight main shoots in all directions of the vines.
Leaf area (cm2) was estimated in twenty leaves per vine from those
leaves opposite to the first clusters on each shoot (middle of May) and leaf
area (cm2) was recorded according to the following equations reported
by Ahmed and Morsy (1999):
Leaf area (cm2) = 0.45 (0.79xW2)
Where, W is the maximum diameter (cm2).
Petioles of these leaves were saved, oven dried and grounded then 0.5 g weight
of each sample was digested using H2SO4 and H2O
until clear solution was obtained. The digested solution was quantitatively
transferred to 100 mL volumetric flask and completed to 100 mL by distilled
water. Therefore, leaf content of N, P, K, Mg and S (as percentages) and Zn,
Fe and Mn (as ppm) in the samples were determined according to the methods that
outlined in Wilde et al. (1985).
Berry set % was calculated by dividing the number of attached berries in the
caged clusters by the total number of flowers/ cluster and multiplying the product
Harvesting was conducted (middle June) when TSS/acid reached at least 24-26
(Weaver, 1976). The yield per vine was recorded in terms
of weight (kg) and the number of clusters per vine. Five clusters were taken
at random from the yield of each vine for the determination of cluster weight
(g) as well as the following physical and chemical characteristics of the grapes.
|| Operating times (h) in the five trickle irrigation system
during the period 2009 and 2010
||Percentage of shot berries by dividing number of small berries
by total number of berries per cluster and multiplying the productx100
||Percentage of total soluble solids in the juice
||Percentage of total acidity (expressed as g. of tartaric acid/100 mL of
juice) by titration against 0.1 N NaOH using phenolphthalein as indicator
||Total soluble solids/acid
||Percentage of total sugars in the juice (AOAC, 1995)
Water utilization efficiency (WUE) yield kg m-3 water was estimated
by dividing total yield per vine by applied water (m3/vine/year).
Statistical analysis: All the obtained data were tabulated and subjected
to the proper statistical analysis according to Mead et
al. (1993) using new LSD test at 5% for comparing between means of all
RESULTS AND DISCUSSION
Meteorological data: Qena Governorate located in South Egypt (Longitude
32.44, latitude 26.11 and 74.2 meter above sea level). Meteorological data were
collected for a period of three years (2006-2008) of the studied area in order
to detect the effect of different laterals and emitters frequencies on growth
or yield, leaf contents of representative macro and micro nutrients,
berry setting % and phonological characteristics of Superior vineyards.
The soil of the studied area has loamy texture, some other physicochemical properties
of studied area are given in Table 2 and 3.
Table 4 shows the average three years of climatic data from
2006 to 2008 belonged to Qena area which collected from the meteorological station
of South Valley Uni., reference evapotranspiration (ETO).
Data in Table 5 indicated that in Qena region the Mean of
three years ETo (mm month-1) registered highest ETo of 636 mm in
June, but the lowest in December, 186 mm, while the total mean for the three
years (2006 to 2008) recorded 4969.4 mm year-1. In the 2009 and 2010
seasons this average for the three years of ETo was used as a basis for water
use during the two seasons.
|| Meteorological data of Qena region average of three years
(2006 to 2008)
|| Average evapotranspiration ETo for Qena region during 2006
to 2008 seasons
The data (Table 6) represented the average water consumptive
recorded 10.5 m3/year/vine under Qena conditions in 2009 and 2010
seasons, the mean of evapotranspiration of the three years prior to this study
were used. Data in Table 3 showed that the highest value of
evapotranspiration in June was 21.2 mm day-1 which resulted in water
consumptive of 64.8 L/day/vine, the lowest values of evapotranspiration were
recorded in Jan, and Dec (6.2 and 6.0 mm day-1, respectively) without
irrigation. Meanwhile, water consumptive recorded 11.1, 27.48, 49.7, 56.42,
51.24, 36.1, 22.7 and 11.2 L day-1 in Mar., Apr., May, Jul., Aug.,
Sep., Oct. and Nov., respectively. As a result, Grapevine water use and Kc started
from Feb. to Nov. This findings were in agreement with that of http://www.usbr.gov/pn/agrimet/cropcurves/WGRPcc.html
and Seif et al. (2007) who noted that the amount
of irrigation water of 5, 11, 19, 33, 37, 34, 30, 26, 18 and 13 L/day/vine can
be applied during February up to November, respectively. So the previous results
were in agreed with Serman et al. (2004), Ferreyra
et al. (2004) and Teixeira et al. (2007).
In general, under arid climates evapotranspiration is above 200 mm year¯1,
so the total amount of water required for irrigation varies from climate to
climate (De Oliveira et al., 2009). furthermore,
crop growth and second yield are not possible without irrigation after the final
grape product (Martin and Gilley, 1993; Williams
and Matthews, 1990). Meanwhile Saayman and Lambrechts
(1995) observed that WUE can be improved by drip irrigation system which
was more effective than sprinkler irrigation. Moreover, saving of WUE of about
25% may be due to a reduced wetted soil volume under sandy soil. The optimum
response was obtained when irrigation of about 90 mm at veraison in Barlinka
grapes. Also Caswel and Zilbernian (1985), Zhang
et al. (2004) and De la Hera et al. (2007)
noted that drip irrigation systems often achieve over 90% uniformity with proper
design, installation and maintenance. This is in contrast to typical uniformities
of 40-60 for gravity systems and 50-75% for sprinkler systems. In this respect
Teixeira et al. (2007) they revealed that the
accumulated actual Evapotranspiration (ET) from pruning to harvest in wine grape
was 438 and 517 mm for the first and second Growing cycles, respectively. In
addition, table grape consumed less water than wine grape (393 and 352 mm) for
the first and second growing seasons, respectively. This result was due to the
shorter crop stages.
|| Average vineyard evapotranspiration ETo and water use for
Qena region from 2006 to 2008
On the other hand, these results were not in agreement with those obtained
by Cuevas et al. (2007) which observed that flowering
was advancement under low water irrigation. This result may be due to modifications
in the plant hormonal balance due to root signal which eventually led to earlier
According to these results, using drip irrigation system were studied using
amount of water of 8665.7 m3 year-1 on eight year's old
Superior grapevines grown at 1.75x2.75 m apart in sandy loam soil under Qena
conditions. The number of laterals and emitters per vine ranged from one to
two and from two to six/vine, respectively. The merit was enhancing irrigation
water utilization efficiency in Superior vineyards.
Leaf area and its content from N, P, K, Mg, S, Zn, Fe and Mn in the leaves:
Data in Table 7 clearly show that leaf area significant differs
with respect to number of laterals and emitters per vine and its content of
N, P, K, Mg, S, Zn, Fe and Mn. Increasing frequencies of laterals from one to
two and at the same time number of emitters from two to four significantly affect
the leaf area. In this respect, the highest value was observed in (T5)
using irrigation treatment, double laterals and six emitters/vine with 87.0
and 79.5 cm2 in the first and second seasons, respectively. At the
same time (T4) of Double laterals and four emitters/vine were less
effective but not significantly different from (T5) during the successive
seasons. Meanwhile the lowest values in leaf area were obtained in (T1)
with One lateral and two emitters/vine which recorded 71.1 and 72.2 cm2
in the first and second seasons, respectively. However, T3 recorded the intermediate
value of 74.5 and 77.5 cm2 under drip irrigation with Double laterals
and two emitters/vine it recorded during the first and second seasons, respectively.
From the above mentioned results it could be concluded that the optimum release
of water under wetted area that saved their surely reflected on supplying the
vines with their requirements from water and nutrients at different stages of
growth and grape development and these explain the present effects of increasing
number of laterals and emitters for each vine (Caswel and
Zilbernian, 1985). These results are in agreement with those obtained by
Hepner et al. (1985), McCarthy
et al. (1997), Zhang et al. (2004),
El-Hady and Abd El-Kader (2003), De
la Hera et al. (2007), Teixeira et al.
(2007), Stevens et al. (2008) and De
Oliveira et al. (2009).
Also the data in Table 7 shows considerable differences in
main shoot length as well as leaf content of N, P, K, Mg, S, Zn, Fe and Mn.
Considering the number of laterals and emitters per vine. The results reveal
that main shoot length gradually increased by increasing the laterals and emitters
||Influence of laterals and emitters frequency on the leaf area,
main shoot length and mineral content of Superior grapevines during 2009
and 2010 seasons
Therefore, the best result was observed when Superior vineyards irrigated by
using Double laterals and six emitters/vine (T5) the values are 107.2
and 108.1 cm during the first and second seasons respectively. Under these conditions
main shoot length was less than (T5) and no significant under drip
irrigation by using (T4) Double laterals and four emitters/vine.
Meanwhile the lowest value of main shoot length was observed with (T1)
were 69.0 and 98.0 (cm) as well as (T2) which gives 99.5 and 101.1
(cm) in the first and second seasons. Intermediate main shoot length 103.3 and
104 (cm) was recorded in the Double laterals and two emitters/ vine (T3)
during both seasons.
The leaf content of N, P, K, Mg, S, Zn, Fe and Mn. Table 7
Gave the same trend as in the leaf area and main shoot length. Thus, the use
of double laterals with two emitters significantly enhance these parameters
when compared to the application of one lateral with two emitter. Increasing
the number of emitters from four to six on double laterals did not show significant
effect on growth characters and the nutrients. The least values were recorded
on the vines that received water as one lateral with two emitters/vine (T1).
It gives the lowest macro nutrients (N%, P% and K%) in leaf (1.92 and 1.94%
N), (0.16 and 0.18% P) and (1.81 and 1.89% K) during the first and second seasons,
respectively, was also observed under this treatment. However, using double
laterals and six emitters/vine(T6) gave the highest values of leaf
mineral content which were 2.17 and 2.18% N, 0.25 and 0.29% P) and (2.14 and
2.23% K), for the two seasons, respectively. On the other hand, the immediate
values were recorded in the same trend was also observed in the (Mg, S, Zn,
Fe and Mn).
The differences between treatments may be attributed to increasing the number
of laterals and emitters per vine which increased the wetted area, that helps
on supplying the vines with their requirements from water and different nutrients
elements by rooting system consequently, increased macro and micro elements
and plant hormone accumulation during growth and grape development (Caswel
and Zilbernian, 1985).
||Influence of laterals and emitters frequency on berry
setting, yield, cluster weight, shoot berries as well as some physical and
chemical characteristics of berries of Superior grapevines during 2009 and
The present results agree with those of (Peacock et
al., 1977; Hepner et al., 1985; McCarthy
et al., 1997; Teixeira et al., 2007;
Stevens et al., 2008).
Berry setting: The percentage berry settings is presented in Table
8. which showed that there was a gradual and significant increase in berry
setting (%) of Superior grapevines with increase in number of laterals from
one to two as well as increase in the frequency of emitters per vine from two
to six. Berry setting (%) was significantly maximized with the use of two emitters
per vine on double laterals as compared with using the same number of emitters
with one lateral. The results varied significantly (LEVEL OF PROBABILITY) among
treatments except the last two (Table 8) (four or six emitters
situated on double laterals). In this study, the maximum values were recorded
on vines that were irrigated drip using double laterals with six emitters (T5)
conversely, using one lateral and two emitters/vine (T1) gave the
lowest values of 11.0% and 11.5%) berry setting during the first and second
seasons respectively, while the treatment T3 gave intermediate berry
setting of Superior grapevines under Double laterals and two emitters/vine (13.9
The beneficial effect of adjusting drip irrigation (selecting two laterals
and four to six emitters/vine) on berry setting might be attributed to its positive
effect on stimulating growth and vine nutritional status in favour of producing
more berry on each cluster. Similar results were recorded by Hepner
et al. (1985), Martin and Gilley (1993), Williams
and Matthews (1990) and Stevens et al. (2008).
Number of clusters/vine: Response of the number of clusters/vine to
the number of laterals and emitters per vine ranged from one to two and from
two to six/vine, respectively. In Table 8 no significant differences
on number of cluster/vine were observed among the five drip irrigation treatments
during the first seasons. However, the two treatments (T4) and (T5)
(four or six emitters situated on double laterals) recorded the highest values
in this respect (23 and 23) clusters/vine in the first seasons. While the same
comparison in the second season the significant clearly showed between laterals.
The positive effective response was recorded in (T5), (T4)
and (T3) they recorded (24 cluster/vine) per each treatments. On
the other hand the lowest response was observed on in (T1) One lateral
and two emitters/vine (21 cluster/vine). It would appear that the positive effect
of increasing laterals and emitters per vine was more effective in increasing
the supplying vines with their requirements from water and different nutrients
elements observation lead to increased macro and micro elements and plant hormone
accumulation during growth and grape development (Caswel
and Zilbernian, 1985).
These results corroborated the findings of Hepner et
al. (1985), Martin and Gilley (1993), Williams
and Matthews (1990) and Stevens et al. (2008).
Yield and cluster weight: Varying the number of laterals and emitters
per vine in drip irrigation system had significant effect on yield as expressed
in yield/vine and cluster weight (Table 8). Increasing the
number of laterals (from one to two) and emitters per vine (from two to six)
had a significant and gradual increase on yield and cluster weight. Thus, the
best results were observed in (T5) with double laterals and six emitters
(10.6 kg vine-1) in both seasons. This was followed but (not significantly
different) by (T4) with double laterals with four emitters (10.0
and 10.5 kg vine-1) during the first and second seasons, respectively.
In this respect, the intermediate effect on yield and significant differences
were noticed with (T3) double laterals with two emitters per vine
(8.9 and 9.1 kg vine-1) during the first and second seasons, respectively.
So, using double laterals/vine was preferable than using one lateral which recorded
(6.9 and 6.9 kg vine-1) and (7.8 and 8.0 kg vine-1) under
two and three emitters per vine during the first and second seasons, respectively.
Increasing the number of emitters per vine from four to six on double laterals
did not give appreciable increase in yield and cluster weight.
Cluster weight (g) in Table 8 presented that the application
of double laterals with four emitters/vine (T4) reached (434.8 and
437.5 g cluster-1) during the two studied seasons, respectively.
However, the best results was noticed in (T5) double laterals with
six emitters reached (460.9 and 441.7 g cluster-1). In this respect,
vines subjected to drip irrigation through one lateral and two emitters/vine
(T1) gave significantly minimum cluster weight (g) of 313.6 and 328.6
during the two studied seasons, respectively intermediate values of 404.5 and
397.2 were recorded in T3 while T2 and three emitters/vine
gave the highest values of 354.5 and 347.8 and significantly cluster weight
(g) was noticed in (T3) Double laterals and two emitters/vine ()followed
by (T2) One lateral and three emitters/vine (354.5 and 347.8) during
the first and second seasons, respectively.
These results can be attributed to the positive action of adjusting drip irrigation
system on berry setting, cluster weight and cluster number previously mentioned.
This is supported by many earlier research findings Peacock
et al. (1977), Hepner et al. (1985),
Martin and Gilley (1993), Williams
and Matthews (1990), Teixeira et al. (2007),
Donaire et al. (1977), Stevens
et al. (2008) and McCarthy et al. (1997).
Also Glenn (2000) reported that when only a portion
of the root zone is wetted, the water absorption by the wetted roots increases
relative to the amount absorbed by the portion when the whole root systems is
wetted thereby increasing the efficiency of water uptake. Conversely, these
results are not in agreement with those obtained by Cuevas
et al. (2007) which stated that flowering was advanced under low
water irrigation. The result may be due to modifications in the plant.
Percent shoot berries: Percentage shoot berries gradually reduced with
increasing laterals and emitters frequency. Using double laterals with six emitters
per vine (T5) gave the lowest values in Shoot berries (3.9 and 3.5)
while there was no significant reduction in %shoot berries when the number of
emitters per vine increased from four (T4) to six (T5)
on Table 8. These results were consistent in both seasons.
In this respect, the highest values in shoot berries were recorded in one lateral
and two emitters/vine (T1) with 8.1 and 8.3 during the first and
second studied seasons, respectively. The enhancement in %shoot berries had
a moderate but non-significant reduction in (T3) with double laterals
and two emitters/vine. This was followed by (T2) (one lateral and
three emitters/vine) during the two seasons.
The benefit of selecting the best system of drip irrigation on the availability
of water to all plant organs at specific stage of berries development surely
reflected on the reduction of shoot berries phenomenon. The findings of Weaver
(1976), Williams and Matthews (1990), McCarthy
et al. (1997), Glenn (2000) and Stevens
et al. (2008) supported these results.
Physical and chemical characteristics of the berries: It is clear from
the data in Table 8 that carrying out drip irrigation by increasing
number of laterals from one to two as well as number of emitters from two to
six per vine was significantly accompanied by higher quality of berries in terms
of increase in berry weight (g). However, there was no significant response
to influence of emitters frequency on the berry weight on (T5) and
(T4) in descending order they recorded (3.16 and 3.26) and (3.15
and 3.25 g) in both treatments during the first and second seasons, respectively.
In contrast statistical significant response was found in single lateral (T1
and T2) in ascending order which recorded (2.81 and 2.82 g) and (2.95
and 2.96 g) in both treatments during the tow studied seasons, respectively.
On the other hand, a moderate effect was noticed in (T3) which registered
(3.05 and 3/1 g) during the two studied seasons.
A look at total soluble solids, TSS/acid, total sugars and decreasing total
acidity shows a slight insignificant promotion of both physical and chemical
characteristics of the grapes with increasing number of emitters from four to
six at double laterals. Thus, the carrying out of drip irrigation by using (T4)
double laterals and four emitters per vine was the best treatments for total
soluble solids. Furthermore, intermediate values in total soluble solids was
recorded in (T5) and (T3) with (19.0 and 20.0) and (19.7
and 20.0) during the first and second seasons, respectively. In all the treatments,
(T2) and (T1) recorded the lowest values in descending
order both for 2009 and 2010 seasons.
The TSS/acid, total sugars and decreasing total acidity data are presented
in Table 7. The best results of the TSS/acid and total sugars
and decreasing total acidity, in Superior grapevines obtained by using drip
irrigation with four emitters per vine on double laterals (T4) comparing
with using any other treatments. At the same time, the total acidity was higher
under (T1) followed by (T2) in descending order. Medium
effects on total acidity were observed in (T3) and (T5)
in ascending order. Similar trend was also observed in TSS/acid. On the other
hand, total sugars recorded the average effects using (T3) and (T5)
in descending order. In this regard, the lowest value was obtained in T1
followed by T2 in decreasing order. The results may be due to the
beneficial effect of adjusting the method of drip irrigation by enhancing the
availability of water especially during critical levels of plant development
thereby enhancing the biosynthesis of carbohydrates and encouraging cell division
(Winkler et al., 1974).
The results were in agreement with those by Weaver (1976),
Williams and Matthews (1990), McCarthy
et al. (1997), Glenn (2000) and Stevens
et al. (2008).
||Effects of laterals and emitters frequency on water
utilization efficiency (WUE) in Superior vineyards during 2009 and 2010
Water utilization efficiency (WUE) on yield (kg m-3) water:
Table 9 shows that WUE significantly increased with the increase
of laterals from one to two and emitters from two to six per vine. Using (T2)
which is one lateral with three emitters/vine significantly improved WUE over
using (T1), one lateral with two emitters per vine. No significant
promotion on WUE was observed when number of emitters was increased from four
to six or double laterals. Therefore, the application of two laterals with six
emitters/vine (T5) gave optimum results where WUE reached 1.01 kg
yield m-3. The lowest WUE was observed by using (T1) one
lateral with two emitters which registered only 0.66 kg yield m-3.
Similar results were observed in the two seasons.
The great promotion on the yield and the same time for the reduction of water
consumption obtained by (T5) followed by (T4) they leading
to the enhance of WUE.
Similar results were reported by Araujo et al. (1995),
McCarthy et al. (1997), El-Hady
and Abd El-Kader (2003), Gal et al. (2004),
De la Hera et al. (2007) and Stevens
et al. (2008). In this respect Teixeira et
al. (2007) observed that the accumulated actual evapotranspiration (ET)
from pruning to harvest in wine grape was 438 and 517 mm for the first and second
growing cycles, respectively. In addition, table grape consumed less water than
wine grape with 393 and 352 mm for the first and second growing seasons, respectively.
These results were however not in agreement with that obtained by Cuevas
et al. (2007) which observed that flowering was advanced under low
water irrigation. This result may be due to the modifications in the plant hormonal
balance due to root signal which eventually led to earlier flower induction.
In conclusion, for the promotion of irrigation water utilization efficiency
in Superior vineyards and at the same time improve yield quantitatively and
qualitatively, it is suggested to use drip irrigation of double laterals and
four or six emitters/vine.