Agricultural Water Management 173 (2016) 55–60

Contents lists available at ScienceDirect

Agricultural Water Management
journal homepage: www.elsevier.com/locate/agwat

Alternate furrow irrigation can radically improve water productivityof okraA.A. Siyal a,∗ , A.S. Mashori b , K.L. Bristow c , M.Th. van Genuchten daU.S.-Pakistan Center for Advanced Studies in Water (USPCAS-W), Mehran University of Engineering and Technology, Jamshoro, Sindh, Pakistan
Department of Farm Power and Machinery, Faculty of Agricultural Engineering, Sindh Agriculture University Tandojam, Pakistan
CSIRO Agriculture, PMB Aitkenvale, Townsville, QLD 4814, Australia and University of Pretoria Water Institute/Department of Plant Production and Soil
Science, University of Pretoria, Private Bag X20, Hatﬁeld 0028, South AfricadDepartment of Mechanical Engineering, Federal University of Rio de Janeiro, UFRJ, Rio de Janeiro, RJ, 21945-970, Brazilbca r t i c l e

i n f oArticle history:
Received 13 June 2015
Received in revised form 27 April 2016
Accepted 29 April 2016
Keywords:
Irrigation efﬁciency
Water use efﬁciency
Water savings
Deﬁcit irrigationa b s t r a c t
Alternate furrow irrigation (AFI) is gaining interest as a means of saving water while minimising loss
in crop production. Given the potential water savings of AFI, a ﬁeld experiment was conducted in theTandojam region of Pakistan by growing okra with AFI and conventional furrow irrigation (CFI) in which
every furrow is irrigated. Our results show that total irrigation water applied in the AFI treatment was
roughly half (248 ± 2.9 mm) that applied to the CFI treatment (497 ± 1.7 mm). Despite the very signiﬁcantreduction in irrigation water used with AFI there was a non-signiﬁcant (p > 0.05) reduction (7.3%) in okra
yield. As a result, we also obtained a signiﬁcantly (p < 0.001) higher crop water productivity (CWP) of
5.29 ± 0.1 kg m−3 with AFI, which was nearly double the 2.78 ± 0.04 kg m−3 obtained with CFI. While
this reduction in yield and/or potential income may appear small, it could be critical to the welfare ofindividual farmers, who may as a result hesitate to make changes from CFI to AFI if they are worse off thanfarmers who do not adopt AFI. This situation exists because current water charges are based on crop andland area rather than the volume of water being accessed for irrigation. Transitioning from the current
crop and land area based method of charging for water to a volumetric method may require investmentin irrigation system changes and may take time to accomplish. These are important lessons for othercountries, and particularly developing countries who are trying to improve the environmental, socialand economic performance of their irrigated systems. We recommend that further studies be carried out
using AFI to determine whether similar water savings and ﬂow-on beneﬁts can be achieved across a wide
range of cropping systems in arid and semi-arid environments.
© 2016 Elsevier B.V. All rights reserved.

1. Introduction
Pakistan’s economy is dependent on agricultural production. It
is estimated that 70–80% of the total area cultivated in Pakistan
is irrigated through a network of canals. About 93% of the available fresh water resources are currently utilized in the agricultural
sector (Bhangar and Saima, 2008). The increasing population has
resulted in demand for more food and ﬁber, which is met throughincreasing irrigated agriculture. This translates into increasingpressure on Pakistan’s water resources. It is critical therefore
that management and utilization of available water resources is∗ Corresponding author.
E-mail addresses: siyal@yahoo.com (A.A. Siyal), abdulsattar 03@yahoo.com(A.S. Mashori), Keith.Bristow@csiro.au (K.L. Bristow), rvangenuchten@hotmail.com(M.Th. van Genuchten).
http://dx.doi.org/10.1016/j.agwat.2016.04.026
0378-3774/© 2016 Elsevier B.V. All rights reserved.

improved at all scales; from catchment, to irrigated district, to farmand ﬁeld scale. Management of water at the macro level is generally
expensive, time consuming and difﬁcult. By comparison management of water at the ﬁeld scale is generally relatively inexpensive,
more feasible and practical, and it can be implemented in a shortperiod of time. It is therefore critical to improve water management
at the ﬁeld scale through adoption of more efﬁcient and effective
irrigation methods.
About 90% of the irrigated land of the world is irrigated using relatively inefﬁcient surface irrigation methods (Tiercelin and Vidal,
2006). As a result about 20–30 million ha of irrigated lands globallyare seriously damaged by the build-up of salts and it is estimatedthat the area of salt affected soils will increase by about 0.25–0.5
million ha per year (FAO, 2002). Similar trends are observed inPakistan where traditional surface irrigation methods (basin, border and furrow) are widely used to irrigate crops. These are however
inefﬁcient methods of irrigation and are considered one of the main

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A.A. Siyal et al. / Agricultural Water Management 173 (2016) 55–60

Table 1
Measurements of soil properties at four depths at the ﬁeld experimental site, including soil texture, soil bulk density and soil water content at saturation (0 kPa), ﬁeld capacity(33.34 kPa) and wilting point (1500 kPa).
S. No.

Soil depth(cm)

Sand %

Silt %

Clay %

Texturalclass

Dry bulk
density(g cm−3 )Saturation
Capacity(cm3 cm−3 )Field Capacity (cm3 cm−3 )Wilting point (cm3 cm−3 )

1
2
3
4

0–20
20–40
40–60
60–80

23 ± 0.31
30 ± 0.62
26 ± 0.46
28 ± 0.34

52 ± 0.47
46 ± 0.60
48 ± 0.43
45 ± 0.47

25 ± 0.62
24 ± 1.02
26 ± 0.57
27 ± 0.69

Silt Loam
Loam
Loam
Loam

1.32 ± 0.08
1.36 ± 0.07
1.33 ± 0.04
1.33 ± 0.02

0.41 ± 0.03
0.38 ± 0.04
0.39 ± 0.03
0.40 ± 0.02

0.33 ± 0.02
0.30 ± 0.04
0.31 ± 0.04
0.33 ± 0.03

0.16 ± 0.02
0.14 ± 0.02
0.16 ± 0.03
0.15 ± 0.02

±Denotes conﬁdence interval.
Table 2
A comparison of irrigation water used in alternate furrow irrigation (AFI), conventional furrow irrigation (CFI) and ﬂood irrigation under three different irrigation methods
and water savings with CFI and AFI methods.
Irrigation
methods

Irrigation water used
m subplot

m ha

mm

Compared with ﬂood irrigation

Compared with CFI

AFI
CFI
Flood

50.1 ± 0.36
100.4 ± 0.21–2480 ± 184970 ± 107200a

248 ± 2497 ± 1
720

66
–
–

50
–
–

3

−1

AFI water savings (%)
3−1± Denotes conﬁdence interval.
aLiterature values taken from Mashori (2013).

causes of waterlogging and salinisation (Burt et al., 1997). It isbecause of these sorts of problems that the use of modern, high-techand efﬁcient micro irrigation methods (drip, bubbler, sprinkler etc.)
are advocated worldwide. However, farmers are often reluctant toadopt these high-tech methods, especially in Pakistan and otherdeveloping countries, due to their high cost of installation, operation and maintenance. As a result these methods have not yet been
widely adopted by farming communities in developing countries.
There is a need therefore for more efﬁcient irrigation methods thatare economical, easy to install and operate, and which are readily
acceptable to the farming community.
Furrow irrigation, reported to be one of the least efﬁcient methods compared with other irrigation methods (Burt et al., 1997),
is still one of the most widely used forms of surface irrigation. It
involves water ﬂow through narrow channels (furrows) spaced regularly across the ﬁeld (with row spacing often between 1.0–2.0 m),
instead of ﬂooding water over the whole ﬁeld. Despite its application efﬁciency remaining relatively low (Ampas and Baltas, 2009),
not enough effort is being made to keep improving its management and efﬁciency. Because furrow irrigation is a well-known,
simple and economical method of irrigation, farmers are likely tobe ready adopters of new approaches that are practical improvements of their current practices and that result in improved water
use efﬁciency.
It has been suggested (Kang et al., 2000a; Du et al., 2010;
Horst et al., 2005) that the efﬁciency of conventional furrow irrigation (CFI), referred to by some as every furrow irrigation, can be
improved by converting it to alternate furrow irrigation (AFI). The
AFI method is essentially the same as CFI, except that instead of irrigating every furrow, irrigation is applied to alternate furrows, while
the in-between furrows remain dry. This means each ridge receives
water from only one side, and the side receiving irrigation water
could be changed with each irrigation if the ﬁeld is set up to facilitate this change. Irrigating just one side of the ridge means there issigniﬁcant potential to save irrigation water compared to CFI. Thereis however, also potential in some cases for a reduction in crop
yield (Samadi and Sepaskah, 1984; Crabtree et al., 1985; Mashori,2013). It has been observed that farmers prefer to stick with traditional ﬂood irrigation methods due to their simplicity, ease ofoperation and maintenance and low installation/construction cost.
If the conventional furrow irrigation method (CFI) is transformed
into alternate furrow irrigation (AFI) then it might be readily

accepted by farmers. However, before introducing and advocating
this method to local farmers for adoption, the method needs to beevaluated under soil and climatic conditions representative of theareas being targeted for its introduction.
The objective of this study is to report on an experiment in whichokra (Abelmoschus esculentus L.), also known as Lady’s ﬁnger, wasgrown using CFI and AFI. Okra is an important vegetable crop grownthroughout Pakistan, and the aim of the experiment was to assess
the water savings and water productivity improvements that could
be achieved with AFI compared with CFI. While we report on beneﬁts of AFI for growing okra in Pakistan, this paper provides lessons
for furrow irrigators in general, and particularly for irrigators indeveloping countries who do not have access to high tech irrigation
methods such as pressurised drip irrigation.

2. Materials and methods
An experiment with conventional furrow irrigation (CFI) andalternate furrow irrigation (AFI) methods was conducted at a ﬁeld
site with an experimental plot that was 1260 m2 (36.5 m × 34.5 m)
located in the district Hyderabad, Sindh, Pakistan, at Latitude of25◦ 25 28 N and Longitude of 68◦ 32 6 E. The elevation at the site isabout 26 m above mean sea level (Fig. 1).
The experimental plot was deep ploughed with a moldboard
plough and the resulting clods were pulverized with a disc harrow.
The whole plot was levelled before demarcation into six subplots,
each with a size of 202 m2 . The remaining area (48 m2 ) was used
for construction of the water supply canals and bunds between
the subplots. The selection of subplots for testing the CFI and AFI
methods was completely randomized. Furrows were manually constructed using spades. The furrow to furrow and ridge to ridge
distance were 0.8 m. The furrow depth was 0.2 m. The total length ofeach furrow was 18 m, and there were a total of 14 furrows in each
subplot. There were therefore 3 subplots and 42 furrows under eachtreatment. Subplots were irrigated through a ﬁeld channel passing
through the center of the plot.
Seventy two (72) soil samples were collected from 3 randomly
selected locations in each subplot at depths of 0–20, 20–40, 40–60
and 60–80 cm for determining soil texture and soil dry bulk density. Soil texture was determined using the hydrometer method(Bouyoucos, 1962). Soil bulk density was determined using thecore method (Grossman and Reinsch, 2002). Soil water contents

A.A. Siyal et al. / Agricultural Water Management 173 (2016) 55–60

57

Fig. 1. Schematic showing location of the ﬁeld experimental site in Pakistan.

at saturation (0 bar), ﬁeld capacity (33.34 kPa) and wilting point(1500 kPa) were also determined using pressure plate apparatus.
Two to three okra seeds were sown at a depth of 4–5 cm on bothsides of the ridge at a rate of 22 kg ha−1 (MINFAL, 1997) keeping
a 0.2 m plant to plant spacing along the row. The seedlings were
inspected once they started to emerge and plants that appearedvery weak and unlikely to survive were removed. A total of 2520
plants per treatment (3 subplots) were harvested at maturity.
Weeds in all four subplots were removed manually using a handhoe. Fertilizer was applied to all subplots using recommended
quantities (MINFAL, 1997), namely 124 kg Nitrogen ha−1 , 247 kg
Phosphorous ha−1 and 124 kg Potassium ha−1 .
Meteorological data including air temperature, pan evaporation,
daily and total rainfall for the entire growing season was obtained
from a nearby weather station.
The total crop water requirement of an okra crop under furrow
irrigation is reported to be around 500 mm per crop growth cycle(MINFAL, 1997). This was split into 8 separate irrigations (62 mm
per irrigation) with an interval of 6–8 days between irrigations.
Groundwater with an EC of 0.45 dS m−1 was diverted from a nearby
tubewell for irrigation. The capacity of the tubewell was 0.5 cusec(14.158 L s−1 ), however during irrigation to furrows, only half of
the water ﬂow was diverted while the rest ﬂowed to irrigate theneighboring agricultural land. The irrigation was applied subplotwise to furrows until the water in the furrows reached the blocked
end of the furrows. The water supply was switched off when thewater level in the furrows reached 3/4 of the furrow depth. The
quantity of water applied to the subplots was measured using cutthroat ﬂume (throat width = 15 cm). Before ﬁeld installation, it wascalibrated using a known discharge. The ﬂume was placed on a levelled surface in such a way that free ﬂow occurred. It was aligned
straight with the ﬁeld channel and levelled longitudinally and laterally. The depth of water applied to each subplot was determinedusing the following relationship:
D = Q × t/A(1)

where Q is discharge (m3 s−1 ), t is time (s), A is area of the subplot(m2 ) and D is depth of water (m).
The crop was sown on June 03, 2013. The ﬁrst picking of the okra
pods (fruit) started 46 days after sowing with the last picking car-

Table 3aANOVA of irrigation water used by CFI and AFI methods.
Source of Variation

df

SS

MS

Fcal

Ftab@0.1%

Between groups
With groups

1
43795.11.04

3795.10.26

14596.7

74.1

Total

5

3796.1

ried out on August 31, 2013. The harvested okra fruit was weighed
and recorded.
The water saving with AFI compared to CFI was calculated as:
Water Saving (%) =WC − WA
× 100
WC

(2)

where WC is total water used (mm) with the CFI method and WA is
total water used (mm) with the AFI method.
The okra fruit yield for each subplot was weighed and recorded
once the pods had been harvested. The increase/decrease in yield(%) compared to the AFI method was computed as:
Increase in yield (%) =(YA − YC )
× 100
YC

(3)

where YA and YC are yields (kg ha−1 ) obtained with the AFI and CFI
methods, respectively.
The crop water productivity (CWP), expressed as kg m−3 ofwater, of AFI and CFI was determined using the relationship (Talha
and Aziz, 1979):
CWP =

Y
Wt

(4)

where Y is total production of the crop obtained from all 3 subplots
under each treatment (kg treatment−1 ) and Wt is the total water
applied (m3 treatment−1 ). The total water included both rainfall
and irrigation.
The economic analysis comparing CFI and AFI was carried out by
accounting for all costs involved in growing, harvesting and sellingthe okra crop. The actual costs on a per hectare basis for growing okra in the Tandojam region of Pakistan at the time this study
was carried out included tillage, $150; furrow construction, $150;
okra seed, $20; fertilizer and pesticide, $300; labour for weeding,$60; labour for picking pods, $400; irrigation water, $25; and transportation to market, $100. The total cost of $1205 ha−1 for okra

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A.A. Siyal et al. / Agricultural Water Management 173 (2016) 55–60

Table 3b
ANOVA of the crop yield obtained with CFI and AFI methods.
Source of Variation

df

SS

MS

Fcal

Ftab@5%

Between groups
With groups

1
4

661.5
460.0

661.5
115.0

5.75

7.70

Total

5

1121.5

Table 5
Crop water productivity, deﬁned as kg of yield per cubic meter of water applied,obtained with alternate furrow irrigation (AFI), conventional furrow irrigation (CFI)
and ﬂood irrigation.
Irrigation Method

Crop water productivity (kg m−3 )

AFI
CFI
Flood

5.29 ± 0.10
2.78 ± 0.04
1.37aaCalculated from literature data with crop water requirement = 7200 m3 ha−1
(Mashori, 2013) and crop yield = 9900 kg ha−1 (Rahman et al., 2012).

Table 3c
ANOVA of the crop water productivity of CFI and AFI methods.
Source of Variation

df

SS

MS

Fcal

Ftab@0.1%

Between groups
With groups

1
4

8.9
0.80

8.9
0.20

445.6

74.1

Total

5

9.01

production is the same for both the CFI and AFI treatments. This isbecause water charges are based on land area and crop grown, andnot on the volumetric amount of water accessed for irrigation. The
okra yield determined the amount of product that could be used by
the farmer for household consumption or sold at the market. The
net return was obtained by deducting the input cost from the valueof the total marketable product.
3. Results and discussion
Table 1 shows the textural class and bulk density of the soilat the experimental ﬁeld site at four different depths. The proﬁle shows that the soil was medium textured with sand, silt andclay ranging from 23 to 30%, 45–52% and 25–27%, respectively.
The spatial and depth-wise variation of sand, silt and clay soil
fractions was non-signiﬁcant. The soil bulk density of the proﬁleranged from 1.32 g cm−3 to 1.36 g cm−3 , with an average value of
1.34 ± 0.01 g cm−3 . There were no signiﬁcant spatial and depthwise trends in the soil bulk density.
There was 1.5 mm of rainfall at the ﬁeld site during the entire
crop growth period (June to August). The average monthly temperatures for the months of June, July and August were 39.5 ◦ C, 38.2 ◦ C
and 36.8 ◦ C, respectively. The corresponding average daily evaporation rates were 9.11 mm, 8.43 mm and 6.75 mm, respectively.
The total volume of irrigation water applied to each of the
AFI subplots was 50.1 m3 (248 mm) while 100.7 m3 (497 mm) wasapplied to each of the CFI subplots (Table 2). This shows that the
subplots under AFI used roughly half the amount of water compared to the subplots under CFI. This decrease in AFI water was a
result of irrigating only alternate furrows, which would have also
decreased evaporation and deep drainage losses. Our results alignwith the 46–50% water savings obtained using AFI compared with
CFI as reported by Crabtree et al. (1985), Graterol et al. (1989),
Khalid et al. (1999), Kang et al. (2000b) and Slatni et al. (2011).
We have also compared our experimental results with data provided by Mashori (2013) who reported that the typical crop waterrequirement of okra is 720 mm when grown during the summer
season with ﬂood irrigation. Our results show that water savings
when irrigating okra with AFI and CFI can be as high as 66% and
31% compared to ﬂood irrigation. The statistical analysis (ANOVA)of the irrigation water use achieved in our experiment is presented
in Table 3a. It shows that the difference in irrigation water use
between the CFI and AFI methods for growing okra was highly
signiﬁcant (p < 0.001).
The total okra crop yield obtained with AFI and CFI is given in
Table 4. It shows that the okra yield under AFI was 265 kg subplot−1 ,which is equivalent to 13,118 kg ha−1 . Similarly, total okra crop
yield under CFI was 286 kg subplot−1 , equivalent to 14158 kg ha−1 .
Okra yield in Pakistan using ﬂood irrigation has been reported as
9900 kg ha−1 (Rahman et al., 2012). Yield obtained with AFI and
CFI in our experiment was roughly 33% and 43% higher than thatobtained by Rahman et al. (2012) with ﬂood irrigation. When compared to CFI, the yield obtained with AFI was about 7% less. The
statistical analysis (ANOVA) of the okra crop yield obtained in our
experiment is presented in Table 3b. It shows that the differencein okra crop yield obtained with CFI and AFI was non-signiﬁcant(p > 0.05). A slight reduction in crop yield with AFI compared to CFI
was also reported by Bakker et al. (1995), Sepaskhah and Ghasemi(2008), and Raﬁee and Shakarami (2010). Crabtree et al. (1985) also
found a yield reduction in sorghum and soybeans when using AFI.
This is also supported by Stone and Nofziger (1993) who found that
AFI may result in lower yields because too little water is applied,particularly when evaporative rates are very high.
Under the AFI method, the okra plant root system was partiallywetted which could result in reduced stomatal conductance anda reduction in plant transpiration. Photosynthesis and dry matteraccumulation can however be less affected by this partial stomatal closure (Kang et al., 2000a). Also, the roots on the irrigated sideof the furrow (wet soil) will continue to take up water to try andmeet the required water demand of the plant (Ahmadi et al., 2010).
Zhang et al. (1987) reported that plants with two halves of theirroot system under alternate drying and wetting cycles resulted in
reduced stomatal opening but without signiﬁcant increase in leaf
water deﬁcit. This could be part of the reason why there was a
non-signiﬁcant reduction in crop yield with AFI compared with CFI.
Kang et al. (2000a) also observed a high grain yield for corn whensubjected to a 50% reduction in the amount of irrigation applied.
Panigrahi et al. (2011) reported alternate partial root-zone irrigation as a productive and potential water saving technique for okra
cultivation in sandy loam soils. Sepaskhah and Ahmadi (2010) also
recommended partial root zone drying (similar to AFI) for better
fruit quality and increased crop water productivity in areas withlimited water resources.
Table 5 shows the crop water productivity (CWP) of AFI, CFI
and ﬂood irrigation methods for growing okra. The highest CWP of

Table 4
Okra yield and percentage increase/decrease in yield with AFI compared with CFI and ﬂood irrigation methods.
Irrigation
method
AFI
CFI
Flood
a

Crop yield (kg area−1 )Yield increase/decrease (%)

Per sub-plot

Per hectare

Compared to Flood irrigation method

Compared to CFI method

265 ± 6.80
286 ± 5.50––

13118 ± 337
14158 ± 272
9900a

33
43
––

-7
––
––

Literature values taken from Rahman et al. (2012).

A.A. Siyal et al. / Agricultural Water Management 173 (2016) 55–60
Table 6
Economic analysis demonstrating the difference in beneﬁts obtained between the
CFI and AFI treatments. The production costs are the same for both the CFI and AFI
treatments because water charges are based on land area and crop grown, and noton the volumetric amount of water accessed for irrigation.

Total cost of okra production ($ ha−1 )Cost of water ($ ha−1 )Water applied (m3 ha−1 )Okra production (kg ha−1 )Crop water productivity (kg m−3 )Okra selling price ($ kg−1 )Total return ($ ha−1 )Net return ($ ha−1 )

CFI

AFI

1205
25
4970 ± 10
14,1582.84 ± 0.1
0.40
5663
4458

1205
25
2480 ± 18
13,1185.29 ± 0.1
0.40
5247
4042

59

Easter and Liu (2005) demonstrated that introduction of volumetric pricing in the Yangtze Basin Water Resource Project in China
reduced irrigation costs as farmers used less water per hectare.
Losses associated with delivery of water also decreased. It is clearthat the volumetric method of charging for water is effective, buttransitioning from the current crop and land area based method
to a volumetric method may require investment in irrigation system changes and may take some time to accomplish (Hassan and
Chaudhry, 1998). These are important lessons for other countries,
and particularly developing countries, who are trying to improvethe environmental, social and economic performance of their irrigated systems.
4. Conclusions and recommendations

5.29 kg m−3 was obtained with AFI followed by CFI with 2.78 kg m−3
and then ﬂood irrigation, which had the lowest CWP. The statisticalanalysis (ANOVA) of CWP is given in Table 3c. It shows that the variation in CWP for both treatments was highly signiﬁcant (p < 0.001),
which highlights the effect the method of irrigation has on CWP.
Ibrahim and Emara (2010) reported that the AFI method had higher
CWP compared with the CFI method. Stone et al. (1982) and Slatni
et al. (2011) reported that AFI resulted in a slight decrease in crop
yield but an increased water productivity. Raﬁee and Shakarami(2010) also reported that AFI enables more efﬁcient use of irrigation water but with a lower crop yield associated with some water
stress compared to CFI.
Table 6 provides a summary of the economic analysis of CFI and
AFI. It shows that the input cost per hectare for growing okra using
CFI and AFI is the same ($1205/ha), because water charges are basedon the crop grown and the area of crop that is irrigated and not on
the volume of water accessed for irrigation. The per hectare crop
production for AFI and CFI is however different because of the different amounts of water available to the crop, with the net return
being $4458 for CFI and $4042 for AFI. This shows that the farmer
who accessed roughly 50% less water using AFI than the farmer who
used CFI, will have about 1040 kg ha−1 (or 7%) less edible productif they keep it to use, or will be $416 dollars (or 9%) worse off ifthey sell their total crop. While 7% less yield or 9% less income
may not seem like much to some people, it could be critical to
the welfare of individual farmers who might not have access toother off farm resources. And they will certainly question why theyshould change if they see a decrease in yield or income for adopting
improved water use efﬁciency practices compared with those who
retain their much less efﬁcient irrigation practices.
Pakistan is a water stressed country and the Government is urging farmers to improve their water use efﬁciency by adopting more
efﬁcient irrigation practices. Based on the results of this study thiswill be difﬁcult to achieve when famers who adopt new more efﬁcient irrigation practices like AFI that save large amounts of water,
are worse off than farmers who continue using CFI and do not invest
in improving their irrigation water use efﬁciency.
Given that AFI can reduce water use by as much as 50% comparedwith CFI, widespread adoption of AFI has the potential to produce
massive public beneﬁts as the water saved by using AFI could be
used to improve environmental ﬂows and/or to expand irrigation
downstream. Encouraging adoption of water use efﬁcient irrigation
practices like AFI will, however, require changes to the way farmers
pay for irrigation water. The best way to achieve this is to move fromcrop and land area based water charges to volumetric based water
charges (Nyberg and Rozelle, 1999). Paying for each litre of water
accessed for irrigation will serve as a real incentive for farmers to
adopt the most efﬁcient irrigation practices possible, and movingfrom CFI to AFI is not a difﬁcult or costly thing to do. Making thechange requires instead a mind shift so that water and irrigation
management decisions deliver the beneﬁts that AFI is capable of.

Results of our ﬁeld study on alternate furrow irrigation (AFI)
for okra production demonstrates that this method can (i) deliver
water savings in excess of 50% compared with conventional furrow irrigation (CFI), (ii) radically improve okra water productivity,and (iii) be used as a practical management tool to save water sothat it can be put to other uses. These other uses could include
improved groundwater levels, improved environmental ﬂows andhence improved river and estuary health and/or to expand irrigation downstream. Potential economic implications to individual
farmers may however result in hesitation to make changes from CFI
to AFI if they are worse off from a yield and/or ﬁnancial point of viewthan farmers who do not adopt AFI. This situation exists because
current water charges are based on crop and land area rather thanthe volume of water being accessed for irrigation. Transitioning
from the current crop and land area based method to a volumetricmethod may require government investment in irrigation systemchanges and may take time to accomplish. We recommend that further studies be carried out using AFI to determine whether similarwater savings and ﬂow on beneﬁts can be achieved across a wide
range of cropping systems in arid and semi-arid environments.
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