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Agricultural Water Management 117 (2013) 133– 144

Contents lists available at SciVerse ScienceDirect

Agricultural Water Management

j ourna l ho me page: www.elsev ier .com/ locate /agwat

valuation of furrow irrigation practices in Fergana Valley of Uzbekistan

. Mohan Reddy ∗, K. Jumaboev, B. Matyakubov, D. Eshmuratovnternational Water Management Institute (IWMI), Tashkent, Uzbekistan

r t i c l e i n f o

rticle history:eceived 1 April 2012ccepted 7 November 2012vailable online 17 December 2012

eywords:lternate furrow irrigationpplication efficiencyotton irrigationurrow irrigationrrigation in Fergana Valleyrrigation in Uzbekistan

a b s t r a c t

The performance of furrow irrigation systems in terms of application efficiency, runoff ratio, and waterrequirement efficiency were evaluated at nine different sites within the Provinces of Fergana (6 sites)and Andijon (3 sites) in Uzbekistan. A total of 46 irrigation events were evaluated during the year 2009,whereas only a total of 8 irrigation events (at 3 sites) were evaluated during the year 2010. Most of theselected fields have slopes greater than 0.005; hence, the average runoff volume from these fields was39% of the total volume of water applied to the fields, indicating problems with selection of appropri-ate furrow flow rates under the given set of field conditions. For several fields, the seasonal volume ofwater applied was significantly different than the irrigation norms specified for the site. Though someof the farmers followed the irrigation advisory service on when to irrigate, there was a large mismatchbetween the volume of water applied and the volume of water deficit within the crop root zone. Reli-ability, in terms of magnitude and duration of flow rate received at the fields, was a major issue at all

unoff ratioater requirement efficiency

the sites. Considerable fluctuations were observed in the flow rates received at all the field sites duringeach irrigation event. In addition, the average flow rate received at the field sites varied considerablybetween irrigation events making it difficult for farmers to manage irrigation water. Farmers that hadhigh watertable (less than 100 cm from the ground surface) still applied large volumes of water, result-ing in low application efficiency. Several recommendations for improving the performance of furrow

ekista

irrigation systems in Uzb

. Introduction

Furrow irrigation is the dominant method of irrigation in Uzbek-stan, and this method of irrigation is practiced over more than5% of the irrigated area. Recently, the area under drip irrigationas been slowly increasing, particularly for growing fruit and veg-table crops. The total irrigated area in Uzbekistan is close to 4illion hectares, most of which has been developed during the

ast century. In 1960 the total irrigated area in Uzbekistan was 2.5illion hectares. Starting from 1970, there was a rapid increase

n irrigated area, and by 1990s the total irrigated area reached aaximum of 4.3 million hectares. As early as late 1970s, the twin

roblems of waterlogging and salinity were spreading within therrigation schemes, indicating that there were problems with the

anagement of the irrigation schemes. By 1994, close to 50% of theotal irrigated area was affected by waterlogging and salinity. Theseroblems are unevenly distributed within irrigation schemes: only0% of the irrigated area is under waterlogging and saline condi-

ions in the upper reaches of the two river basins (Amu Darya andyr Darya), and close to 90% of the irrigated area is under waterlog-ing and salinity in the lower reaches of these two river basins.

∗ Corresponding author. Tel.: +998 71 237 0445; fax: +998 71 237 0317.E-mail address: m.junna@cgiar.org (J.M. Reddy).

378-3774/$ – see front matter © 2012 Elsevier B.V. All rights reserved.ttp://dx.doi.org/10.1016/j.agwat.2012.11.004

n are provided.© 2012 Elsevier B.V. All rights reserved.

The prevailing waterlogging and salinity conditions are a resultof excessive seepage and operational losses from canal networks(mostly earthen canals), and losses at field level combined withpoor performance of drainage systems.

In order to address the issues associated with irrigation systems,one has to understand the way the irrigation systems are operatedin Uzbekistan. With the collapse of the Soviet Union, the State Agri-cultural Cooperatives disintegrated, and the agricultural land wasdistributed to individuals. The agricultural land is still owned bythe Republic of Uzbekistan. The farmers lease the land, typically for50 years, from the Government. In year 2000, through an Agricul-tural Reform Act, Water User Associations (WUAs) were formed.Today, there are close to 66,000 farmers grouped into 1486 WUAs.On about 80% of the leased land, farmers are mandated to growonly cotton and winter wheat, and on the remaining 20% of theland, farmers grow fruit crops. On about less than 10% of the irri-gated area, farmers are given the freedom to grow ‘kitchen gardens’.At the beginning of the irrigation season, based upon the plannedcropping pattern, an operational plan for each irrigation system isprepared. Then, based upon the projected availability of water dur-ing the given irrigation season in any river basin, these operational

plans are adjusted, if necessary, and this information is communi-cated to farmers through Water Users Associations (WUAs). EveryWUA is expected to have a copy of the proposed operational plan forthe entire irrigation season. The operational plan is based upon the

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dom to decide whether they want to apply the specified monthlynorm during one, two or three irrigations. The source of irrigationwater is South Fergana Canal which draws its water from Andijon

34 J.M. Reddy et al. / Agricultural Wa

ropping pattern, historical average climatic data, soil conditionsincluding salinity), and groundwater conditions. The operationallan basically specifies the magnitude and duration of flow rateo be supplied to each farmer within each decadal period (10-dayeriod) during the irrigation season.

The Government provides bulk water supply to WUAs, and thent is the responsibility of WUAs to supply this water equitably tondividual farmers. Because of lack of adequate infrastructure toontrol water, and lack of skilled personnel to distribute waterithin each WUA, there are issues with equity in water distribu-

ion within WUAs. In addition to equity, the flow rates received atelds fluctuate considerably during each irrigation event, affectinghe performance of field application systems. Water is provided to

UAs and, subsequently, to farmers free of charge. The volume ofater delivered to each WUA is measured and recorded. However,UAs charge a service fee to supply irrigation water to farmers.

his charge is typically based upon area irrigated, and not basedpon the volume of water used by each farmer. Hence, farmers doot have any incentives to save water.

Furrow irrigation is the dominant method of irrigation used inzbekistan. The irrigation technology used at field level is very

imple and labor intensive (Fig. 1). Though there is no publishedata on average field application efficiency, field observations indi-ate that the efficiencies are low. Bos and Nugteren (1990), fromheir world-wide survey of data on irrigation efficiencies, reportedeld application efficiency values ranging from 17% to 88%. Theigher values of reported application efficiencies refer to drip andprinkler irrigation systems, whereas the application efficiencies ofurface irrigation systems in developing countries are reported toe, on average, less than 40%.

With a view to improve application efficiencies at field level, theovernment of Uzbekistan has been encouraging use of improvedethods of furrow irrigation such as alternate furrow irrigation,

ig-zag furrow irrigation, short furrow irrigation, and laser landeveling, etc. Alternate furrow irrigation has definite advantagesn terms of saving water on light to medium textured soils. Wateravings in alternate furrow irrigation result from reduced deep per-olation losses due to reduced wet surface area of furrows. Fieldtudies by Eisenhauer and Youth (1992), Graterol et al. (1993),han et al. (1999), Samadi and Sepaskhah (1984), Sepaskhah andamgar-Haghighi (1997), and Unlu et al. (2007) suggested wateravings of as much as 40% using alternate-furrow irrigation com-ared to every-furrow irrigation. Based upon experimental data,orst et al. (2005) reported on the potential for water savings in

urrow irrigation systems in the Fergana Valley of Central Asia,nd recommended the use of alternate-furrow irrigation ratherhan every-furrow irrigation. Alternate-furrow irrigation does notave any advantages in clay or heavy textured soils. Conversely,very-furrow irrigation, including zig-zag furrows, is more desir-ble in the case of heavy textured soils because every-furrowrrigation provides more wetted surface area for water to infiltratento the crop rootzone. Similarly, short-furrow irrigation has thedvantage of providing irrigation water more uniformly along theength of a field, particularly on light to medium textured soils.oday, alternate-furrow irrigation and short-furrow irrigation areidely practiced by farmers in Uzbekistan. However, there is no

eal field data on the performance of alternate-furrow and short-urrow irrigation systems under farmer-managed conditions inzbekistan. Therefore, during the summers of 2009 and 2010, field

tudies were undertaken to evaluate the performance of furrowrrigation systems in Uzbekistan. This kind of information is crucialor developing future strategies for improving irrigated agriculturen Uzbekistan. This paper presents the results of this study, androvides recommendations for improving performance of furrow

rrigation systems. These recommendations have wider implica-ions throughout Central Asia and beyond.

nagement 117 (2013) 133– 144

2. Description of the experimental sites

All sites selected for research are located in the command area ofSouth Fergana Canal, Uzbekistan. These sites are located in two dif-ferent Provinces – Andijan and Fergana – of Uzbekistan. Altogether,nine different field sites were selected for this research (Fig. 2). Thesame field sites were used in 2009 and 2010. Initially, as a part of theIntegrated Water Resources Management Project of Fergana Valley(IWRM-FV), several WUAs were selected for strengthening theircapacity to manage irrigation water. Subsequently, in some of theseWUAs, some farmers were selected based upon their willingness tohave the research conducted on their fields and the accessibility ofthe sites.

The physical characteristics such as area, slope, soil type, lengthof field, soil bulk density, soil-moisture content at field capacity, andfurrow lengths used at each site are presented in Table 1. The soiltypes varied from loamy sands to sandy clay loams, with apparentbulk density (soil bulk density (g/cm3)/density of water1 (g/cm3))values ranging from 1.2 to 1.75. The depth of watertable was mon-itored in all the fields using piezometers. Only one piezometerwas centrally located within each field. The measured depth ofwatertable in different fields ranged from 0.37 m to 3.5 m, as shownin Table 3.

Cotton is one of the two major crops grown in Uzbekistan. Theother major crop grown is winter wheat. Furrow irrigation is theonly method of irrigation used to grow cotton in Uzbekistan. Thefurrow slopes of the experimental sites ranged from 0.0027 to0.0072, and all of the furrow irrigation systems in the selectedresearch sites had runoff from the downstream-end of the field.In all the selected fields, farmers used alternate furrow irrigation(Fig. 1). As shown in Table 1, almost all the farmers divided theirfield length into 2–6 segments (tiers) to improve uniformity ofwater application. However, these segments were not of equallength even within each field.

As shown in Fig. 3, a typical short-furrow irrigation system hasone main distribution ditch (that runs parallel to the furrows), andseveral sub-distribution ditches. There is one sub-distribution ditchfor each tier of furrows. Runoff from the furrows in the first tierflows into the furrows in the second tier. The same process happensin the subsequent tiers. Finally, runoff from the last tier leaves thefield and contributes to inefficiency at field level. Depending uponthe flow rate available, a field is divided into several sets along thewidth direction. Each set is irrigated in sequence. The number offurrows irrigated in each set may or may not be the same.

Within each of the nine fields, soil-moisture samples were col-lected at three different locations. At each location, soil-moisturesamples were collected at three different depths: 15 cm, 45 cm, and75 cm from the ground surface. In addition, the soil-moisture con-tent at field capacity and the soil bulk density were calculated, usingstandard procedures, for each location.

The farmers are expected to irrigate the fields as per norms (bothseasonal as well as monthly) provided by the Ministry of Agricul-ture and Water Resources. These norms are provided in Table 2.Some of the specified norms, such as 80 m3/ha (8 mm of irrigationdepth) and 102 m3/ha (10.2 mm of irrigation depth) are unrealis-tic to accomplish efficiently using surface irrigation systems. Forirrigation purposes, each month is divided into three decades,and the farmers have the freedom to choose the decade(s) duringwhich they would like to irrigate. Also, the farmers have the free-

1 Density of water = 1 gram/cm3.

J.M. Reddy et al. / Agricultural Water Management 117 (2013) 133– 144 135

Fig. 1. Furrow irrigation practices in Uzbekistan.

Fig. 2. Location of field sites in the provinces of Fergana and Andijon.

Table 1Information on site characteristics.

Site # Total fieldlength (m)

Set length (m) Furrow slope Soil type Field area (ha) Field capacity,% by weight

Soil bulk density,�bd (g/cm3)

1 160 160 0.0054 Loamy sand 2.6 17 1.242 150 150 0.0059 Sandy loam 1.8 21 1.413 300 150, 150 0.0027 Silt loam 5 25 1.714 200 100, 100 0.0050 Silt loam 4 21 1.595 310 100, 90, 120 0.0056 Loamy sand 5.5 17 1.26 421 105, 210, 106 0.0041 Silt loam 5 21 1.477 280 150, 130 0.0066 Silt loam 9 25 1.758 410 130, 120, 160 0.0072 Sandy clay loam 4.8 21 1.419 780 160, 115, 125, 130, 115, 135 0.0067 Loam 10 21 1.48

136 J.M. Reddy et al. / Agricultural Water Management 117 (2013) 133– 144

Tier 1 Tier 2 Tier 3

Se

t 2

Se

t 1

Fie

ld w

idth

, B

InflowMain distribution ditch Sub-distribution ditches

Direction of

flow of water

Ditch

Runoff

Field Length, L

L1 L2 L3

Re

qu

irem

en

t

Runoff

Ro

ot

zo

ne

on in

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TS

Deep per colat ion

Fig. 3. Typical layout for water distributi

eservoir constructed on Kara Darya. The salinity level of water isess than 0.5 dS/m; hence, salinity is not a major issue in about 90%f the irrigated command area under South Fergana Canal. At eachf the nine experimental fields, a flow measurement structure wasonstructed of concrete to measure the flow rate and the volume of

ater applied per irrigation. The flow measurement structure used

s called the SANIIRI (Central Asian Scientific Institute for Irrigationesearch, based in Tashkent, Uzbekistan) flume and was developed

able 2easonal and monthly irrigation norms for the selected sites.

Demo field site # Seasonal irrigation norm (m3/ha) Irrigation period

1 5000 1.06–5.09

2 7000 16.05–15.09

3 4200 6.06–5.09

4 4200 6.06–5.09

5 4700 6.06–5.09

6 4200 6.06–5.09

7 4800 1.06–5.09

8 5200 26.05–10.09

9 3900 6.06–5.09

Deficit

furrow irrigation systems in Uzbekistan.

at this institute during the Soviet period. The geometry of the flumeis similar to a cut-throat flume without the diverging section. Theaccuracy of the flume is ±5%. Similarly, runoff from downstreamend of each experimental field was measured using a portable Cipo-letti weir. The accuracy of this weir is expected to be ±5% (Burton,

2010).

An irrigation agronomist was hired to advise farmers on agro-nomic practices and on when to irrigate. But no information was

Recommended monthly norms for cotton (m3/ha)

V VI VII VIII IX

1200 1950 1700 150560 1470 2310 2030 630

966 1680 1470 84966 1680 1470 84

1081 1880 1645 94966 1680 1470 84

1008 1920 1680 192104 1144 1924 1664 364

780 1599 1443 78

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J.M. Reddy et al. / Agricultural Wa

rovided to the farmers on how much water to apply during eachrrigation event. The farmers decided on how much water to applyased upon their experience. The farmers were not required totrictly follow the agronomist’s advice on when to irrigate.

. Methodolgy for irrigation performance evaluation ateld level

The performance of furrow irrigation systems was evaluated inerms of application efficiency of water applied to several selectedelds, where application efficiency is defined as (Jensen, 1980):

a = 100 × Vwsrz

Va(1)

n which Ea = application efficiency, in percent; Vwsrz = volume ofater stored in the rootzone (m3); Va = volume of water applied

o the field (m3). In addition to Ea, additional parameters such asater requirement efficiency (ER) and runoff ratio (RR) were used

o describe the performance of these irrigation systems. These per-ormance parameters are defined as follows:

R = 100 × Vwsrz

Vreq(2)

nd

R = Vrunoff

Va(3)

n which Vreq = volume of water required (or deficit) in the rootone (m3); and Vrunoff = volume of runoff from the field (m3). Theolume of runoff, Vrunoff, from the fields, for each irrigation event,as measured using portable Cipoletti weirs. The volume of water

tored within the crop root zone was related to the volume of waternfiltrated into the field as follows:

wsrz = Vinf if Vinf ≤ Vreq (4a)

r

wsrz = Vreq if Vinf > Vreq (4b)

n which Vinf = volume of water infiltrated into the field (m3); andreq = volume of water required (or deficit) in the field (m3). In thebove definition, it was assumed that the water was distributedniformly along the entire field length. Because of the short furrowssed, the above assumption was not expected to over-estimate theater requirement efficiency and application efficiency by a signif-

cant amount (not more than 5%). In Eq. (4), the volume of waternfiltrated into a field was calculated as follows:

inf = Va − Vrunoff (5)

he volume of water required (or water deficit) in the crop rootone, before each irrigation event, was calculated using the follow-ng equation:

req = 10 × Af × (�fc − �ave) × �bd × zr (6)

n which Af = area of the field, in hectares; �fc = soil-moisture con-ent at field capacity, in percent by weight; �ave = average actualoil-moisture content within the plant root zone before eachrrigation, in percent by weight; �bd = average bulk density of theoil; and zr(t) = crop rooting depth, in millimeters, which is a func-ion of time (FAO, 1979). All the nine fields grew cotton, which hasn average rooting depth of 160 cm. However, the active rootingepth was considered to be only 120 cm.

Within each field, soil-moisture samples were collected at three

ifferent locations, and at each location the soil-moisture samplesere collected from three different layers—0–30 cm, 30–60 cm, and

0–90 cm. Though the active rooting depth of cotton is 120 cm, theoil-moisture samples were only collected up to a depth of 90 cm.

nagement 117 (2013) 133– 144 137

Only a small amount of water, around 10%, is typically extractedfrom the soil layers that are below 90 cm. Therefore, the changein soil-moisture content below 90 cm was not monitored. Thisassumption was found to be because the soil-moisture content inthe 60–90 cm layer was close to field capacity at most of the sites(Fig. 4). The average soil-moisture content within each field beforeeach irrigation event was calculated as follows:

�ave =∑3

i=1�i

3(7)

where �i = average soil-moisture content, in percent, of layer i, andis calculated as follows:

�i =∑3

j=1�ij

3(8)

where �ij = soil-moisture content, in percent, of layer i at loca-tion j. In each field, soil-moisture samples were collected at threedifferent locations. The actual soil-moisture content before eachirrigation event, the bulk density of soils, and the soil-moisturecontent at field capacity and wilting point at all the field sites werecalculated using standard soil analysis procedures.

In most of the locations, the watertable was below 200 cm fromthe ground surface. There were three sites in which the watertablewas less than 100 cm from the ground surface. In one of thesesites, the watertable fluctuated between 30 cm and 60 cm duringthe growing season.

4. Results and discussion

Cotton is typically planted during the first decade of April, andharvested after mid-September. In a normal year, the first irrigationis not applied until the last decade of May. As shown in Table 2, theseasonal irrigation norms for cotton during the vegetation period(April–September) vary from 4000 m3/ha to 7000 m3/ha depend-ing upon the soil type and groundwater depth, and the farmers areexpected to apply an irrigation amount that is close to the specifiedwater requirement for each location. However, there are no flowmeasurement structures to measure the volume of water deliv-ered to each farmer’s field. Therefore, flow measurement structureswere installed at all the nine research sites to measure both theinflow into the field and the outflow (runoff) from the field. Datacollected from the nine research sites shows (Table 3) that theactual average amount of water applied was 7442 m3/ha which ismore than the recommended irrigation norm for most of the sites.Within the research sites, the volume of water applied ranged from3787 m3/ha to 11,607 m3/ha. The lowest volume of irrigation waterapplied corresponds to Site 3 which has a high watertable (30 cm to60 cm depth from the ground surface) during the growing season.

As shown in Table 3, the average application efficiency of thenine fields was 49%, whereas the actual range of application effi-ciencies achieved ranged from 7% (in Site 5) to 82% (in Site 6). Mostof the inefficiency was due to high runoff losses: the average runoffloss from the fields was 39% of the volume of water applied to thefields, and the range of runoff losses varied from a minimum of 17%to a maximum of 64%. It is very interesting to note that, on aver-age, the farmers slightly under-irrigated their fields, i.e. the averagewater requirement efficiency was 90%.

During year 2010, only three field sites were monitored, becauseon the other six sites the farmers grew winter wheat instead of cot-ton. Based upon our experience during 2009, it was decided not to

collect soil-moisture samples before each irrigation event on allthe three sites. Therefore, water requirement efficiencies were notcalculated for these fields, as shown in Table 4. It must be men-tioned here that the year 2010 was a wet year; hence, the number of

138J.M

. R

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Agricultural

Water

Managem

ent 117 (2013) 133– 144

Table 3Performance parameters of furrow irrigation systems at different sites in 2009.

Site # Ng Date of irrigation Area (ha) Va (m3) Vrunoff (m3) Vinf (m3) Zr (mm) WT (mm) Zave (m3/ha) Zinf (m3/ha) Zreq (m3/ha) ER (%) Ea (%) RR (%) Seasonal volume(m3/ha)

1 1 6/23–25/2009 2.6 4570 1820 2750 900 2583 1758 1058 760 100 43 40 11,6072 7/3–5/2009 2.6 4579 1937 2641 900 2583 1761 1016 557 100 32 423 7/19–21/2009 2.6 5162 2602 2560 900 2683 1985 985 581 100 29 504 7/30–31/2009 2.6 5009 2665 2344 900 2683 1927 902 537 100 28 535 8/9–14/2009 2.6 5598 2588 3010 900 2200 2153 1158 642 100 30 466 8/29–31/2009 2.6 5260 2838 2422 900 2200 2023 932 697 100 34 54

2 1 6/19–20/2009 1.8 2308 970 1338 900 3500 1282 743 1073 69 58 42 10,2432 7/1–2/2009 1.8 2564 952 1612 900 3500 1424 896 805 100 56 373 7/11–13/2009 1.8 2484 943 1541 900 3500 1380 856 920 93 62 384 7/21–23/2009 1.8 2358 938 1420 900 3500 1310 789 832 95 60 405 8/1–2/2009 1.8 2109 885 1224 900 3500 1172 680 1075 63 58 426 8/10–12/2009 1.8 2148 833 1315 900 3500 1194 731 988 74 61 397 8/22–24/2009 1.8 2198 1037 1161 900 3500 1221 645 607 100 50 478 8/30–31/2009 1.8 2269 1036 1233 900 3500 1260 685 1035 66 54 46

3 1 7/1–2/2009 5 6573 1377 5196 300 367 1315 1039 379 100 29 21 37872 8/3–5/2009 5 12,361 4952 7409 300 817 2472 1482 340 100 22 40

4 1 6/10–13/2009 4 6609 2907 3702 900 1113 1652 926 967 96 56 44 76322 6/25–27/2009 4 6755 2853 3902 900 1113 1689 976 1019 96 58 423 7/10–12/2009 4 6324 1962 4362 900 1130 1581 1091 1020 100 65 314 7/26–28/2009 4 3956 1437 2519 900 983 989 630 1042 60 64 365 8/16–19/2009 4 3545 1104 2441 850 857 886 610 923 66 69 316 9/5–7/2009 4 3340 1148 2192 850 857 835 548 841 65 66 34

5 1 6/20–22/2009 5.5 6124 2254 3870 900 1347 1113 704 205 100 18 37 95032 7/1–3/2009 5.5 6280 2170 4110 900 1347 1142 747 276 100 24 353 7/13–17/2009 5.5 5308 1761 3547 900 1207 965 645 154 100 16 334 7/25–28/2009 5.5 5444 1771 3674 900 1207 990 668 227 100 23 335 8/2–4/2009 5.5 8198 2874 5324 900 1130 1491 968 194 100 13 356 8/11–14/2009 5.5 8307 2886 5421 900 1130 1510 986 166 100 11 357 8/23–27/2009 5.5 6488 2269 4219 857 857 1180 767 85 100 7 358 9/3–5/2009 5.5 6118 2210 3908 857 857 1112 711 145 100 13 36

6 1 6/15–16/2009 5 5278 957 4321 900 1083 1056 864 900 96 82 18 65472 7/1–4/2009 5 5208 909 4298 900 1083 1042 860 852 100 82 173 7/16–19/2009 5 6297 1185 5112 900 1007 1259 1022 878 100 70 194 8/4–6/2009 5 5865 1107 4758 900 1007 1173 952 829 100 71 195 8/18–21/2009 5 5017 1977 3040 900 1130 1003 608 797 76 61 396 9/4–5/2009 5 5071 1078 3993 900 1130 1014 799 762 100 75 21

7 1 6/21–25/2009 9 17,466 8077 9389 900 1920 1941 1043 1637 64 54 46 85852 7/21–25/2009 9 19,768 10,522 9246 900 1930 2196 1027 1708 60 47 533 8/21–26/2009 9 20,056 10,937 9119 900 1910 2228 1013 1645 62 45 554 9/2–5/2009 9 19,978 10,787 9191 900 1920 2220 1021 1348 76 46 54

8 1 6/26–29/2009 4.8 10,116 4366 5750 900 1887 2108 1198 799 100 38 43 59002 7/28–31/2009 4.8 9318 4041 5277 900 2060 1941 1099 892 100 46 433 8/25–28/2009 4.8 8884 3645 5239 900 2200 1851 1091 790 100 43 41

9 1 6/24–28/2009 10 14,517 5027 9490 900 1957 1452 949 883 100 61 35 45482 7/25–29/2009 10 14,973 4914 10,059 900 2060 1497 1006 898 100 60 333 8/24–28/2009 10 15,993 5021 10,972 900 2127 1599 1097 924 100 58 31

Average values 90 47 39 7442

Va = volume of water applied to the fields; Vrunoff = volume of runoff from the fields; Vinf = volume of water infiltrated into the fields; Zr = crop rooting depth; WT = depth of watertable; Zave = average depth of water applied to field;Zinf = average depth of water infiltrated; Zreq = depth of water required in the field; ER = water requirement efficiency; Ea = application efficiency; and RR = runoff ratio.

J.M. Reddy et al. / Agricultural Water Management 117 (2013) 133– 144 139

ers be

it

4

t

Fig. 4. Measured average soil-moisture content of different soil lay

rrigations applied during the vegetation period was much less thanhe number of irrigations applied during year 2009.

.1. Site 1

The farmer applied six irrigations during the season with aotal volume of 11,607 m3/ha, which is more than twice the

fore each irrigation event in different farmers’ fields in Year 2009.

recommended irrigation norm of 5000 m3/ha for this field. Theaverage application efficiency of this field was around 35%, andthe average runoff from this site was 47%. The length of the field

was only 160 m, and the field slope was 0.0054. This indicates thatthe farmer was applying a high flow rate to individual furrows. Inaddition to runoff, the farmer over-irrigated his field most of thetime, indicating that the farmer was irrigating the field longer than

140 J.M. Reddy et al. / Agricultural Water Ma

Tab

le

4Pe

rfor

man

ce

par

amet

ers

of

furr

ow

irri

gati

on

syst

ems

at

dif

fere

nt

site

s

in

2010

.

Site

#

Ng

Dat

e

of

Irri

gati

on

Are

a

(ha)

Va

(m3)

Vru

nof

f(m

3)

Vin

f(m

3)

Z r(m

m)

WT

(mm

)

Z ave

(m3/h

a)

Z in

f(m

3/h

a)

Z req

(m3/h

a)

E R(%

)

E a(%

)

RR

(%)

Seas

onal

volu

me

(m3/h

a)

31

04.0

7.20

10

5

6573

2115

4458

900

1315

892

–

721

–

–

3228

192

3.08

.201

0

5

7521

3505

4017

900

1504

803

–

484

–

–

47

81

23.0

6.20

10

4.8

6981

1105

5876

900

1454

1224

–

1876

–

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nagement 117 (2013) 133– 144

required to fill the root zone completely. The depth of watertablein this field was more than 2.30 m from the ground surface. And,since it is a light textured soil, the contribution of groundwater tocrop water requirements was assumed to be negligible. The averageflow rate received during irrigation events 4 and 6 was signifi-cantly higher than the average flow rate received during the otherirrigation events, resulting in the highest runoff rates of 53% and54% for these two irrigation events.

4.2. Site 2

The length of this field was 150 m, the average application effi-ciency was around 57%, and the average runoff was 43%, indicatingthat the farmer was applying a higher flow rate than was requiredfor efficient irrigation. The slope of the field was 0.0059. This farmerapplied eight irrigations during the season with the total volumeof water applied equal to 10,243 m3/ha, as opposed to the rec-ommended value of 7000 m3/ha for this field. The farmer slightlyunder-irrigated his field during irrigation events 5–8. There seemedto be a problem with water supply during these specific irrigationevents.

4.3. Site 3

This farmer applied only two irrigations during the season, andthe total volume of water applied was only 2407 m3/ha. The lengthof the field was 300 m, and the farmer divided the field length intotwo equal segments of 150 m each. The first irrigation was appliedon July 1st, 3 months after planting, and the depth of watertablewas 37 cm below the ground surface the day before irrigation, indi-cating that the watertable must have been closer than 37 cm fromthe ground surface at the beginning of the season. The soil has abulk density of 1.71 g/cm3, indicating that it is a heavy soil with ahigh capillary rise. The soil-moisture deficit just before irrigationis shown in Fig. 4, which indicates that the soil-moisture con-tent was at or above the field capacity in the bottom two soillayers (layer 2–30 cm to 60 cm, and layer 3–60 cm to 90 cm). Thesecond irrigation was applied on August 3rd, almost one monthafter the first irrigation, and the soil-moisture content in layer 2and layer 3 were at or above field capacity (Fig. 4). Even thoughthe soil-moisture deficit was only 340 m3/ha, the farmer applied1538 m3/ha of water during this irrigation event resulting in a lowapplication efficiency of 22%. Most of this inefficiency was in theform of high runoff (64%) due to high soil-moisture content in theroot zone as well as the low infiltration rate of the heavy soil. Fromthe data it is clear that the farmer could have grown this crop with-out providing any irrigation water. In the summer of 2010, thisfarmer applied 2800 m3/ha during the vegetation period, and thewatertable condition and runoff volumes were similar to year 2009(Table 3).

4.4. Site 4

This farmer applied six irrigations during the irrigation sea-son. The total volume of water applied during the season was7632 m3/ha, which is 80% more than the recommended value of4200 m3/ha. The length of the field was 200 m, which was dividedinto two equal segments of 100 m each. The slope of the fieldwas 0.005. The average application efficiency of this field was63% with an average runoff value of 37% (Table 3). The depth ofwatertable varied from 111 cm at the beginning of the season to86 cm toward the end of the season. Soil-moisture data collected

before each irrigation event showed that the soil-moisture con-tent in layer 3 was below the field capacity for all irrigation eventsexcept for irrigation event six (Fig. 4) when the watertable wasonly 86 cm from the ground surface. This shows that the capillary

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J.M. Reddy et al. / Agricultural Wa

ise was not significant for this soil. The bulk density of the soil was.59 g/cm3. This farmer significantly under-irrigated during the lasthree irrigation events of the season. However, this seems to beue to shortage of water. The average volume of water receiveduring the first three irrigation events was more than 1650 m3/ha,hereas the average volume of water received during the last three

rrigation events was close to 900 m3/ha. The farmer could havemproved his application efficiency and water requirement effi-iency by using a lower flow rate per furrow.

.5. Site 5

The length of the field was 310 m, and this length was dividednto three unequal furrow segments—100 m, 90 m and 120 m. Thisarmer applied 8 irrigations totaling 9503 m3/ha during the sea-on, as against the recommended value of 4700 m3/ha for this fieldTable 2). The depth of watertable ranged from 86 cm to 135 cmrom the ground surface. The average application efficiency of thiseld was less than 20%, mostly due to over-irrigation and heavyunoff (Table 3). The average runoff from the field was 35%. Soil-oisture data from field (Fig. 4) indicates that the moisture content

n layer 3 (60–90 cm) was above field capacity, and the averageoil-moisture content in the top two layers of the rootzone wasuch higher before each irrigation, indicating that the watertableas contributing adequate quantity of water to the root zone. The

armer applied irrigation water during every decade in the monthsf July and August, whether the crop needed water or not.

.6. Site 6

This farmer applied a total of six irrigations during the sea-on, and the total volume of water applied was 6547 m3/ha. Theength of the field was 420 m, and the farmer divided the lengthnto three segments—105 m, 210 m, and 105 m. The average appli-ation efficiency of this field was more than 75%, without anynder-irrigation, except during irrigation event 5. The depth ofatertable ranged from 108 cm to 113 cm from the ground sur-

ace. Soil-moisture data before irrigation events showed that theoil-moisture content was below field capacity in layer 3, indicat-ng that the capillary rise was not very high. There was significantifference in the average flow rate received during the six irrigationvents (Fig. 5). In spite of that, this farmer has done a good job ofanaging his water.

.7. Site 7

This farmer applied four irrigations during the irrigation sea-on totaling 8585 m3/ha, as against the recommended quantity of800 m3/ha for this site. The total length of the field was 280 m,hich was divided into two unequal segments of 150 m and 130 m.

he average application efficiency of this field was 49% and theverage runoff was 52% (Table 3). This farmer under-irrigatedonsistently throughout the irrigation season. The average waterequirement efficiency satisfied was only 66%. The depth of theatertable was about 190 cm below the ground surface, and the

oil-moisture content in layer 3 was below field capacity beforeach irrigation event (Fig. 4). The soil bulk density was 1.75 g/cm3

ndicating that it is a heavy soil with low infiltration rate. The slopef the field was 0.0066. The low infiltration rate and high field slopeontributed to high runoff volume in this field. The farmer proba-

ly used a high inflow rate into his furrows. In addition, there waso need for dividing the field into two different segments alonghe field length. The average flow rate into the field was differenturing each irrigation event (Fig. 5).

nagement 117 (2013) 133– 144 141

4.8. Site 8

This farmer applied only three irrigations during the irrigationseason, and the total volume of water applied during the season was5900 m3/ha, as opposed to the recommended value of 5200 m3/ha.The length of the field was 410 m, and it was divided into threeunequal segments—130 m, 120 m, and 160 m. The soil is a mediumtextured soil with a bulk density of 1.41, and the depth of thewatertable varied from 189 cm to 220 cm from the ground sur-face during the irrigation season. The average application efficiencyachieved was only 42% with an average runoff value of 42% (Table 3).The remaining 16% was deep percolation beyond 90 cm rootingdepth. However, since the average rooting depth of cotton is about120 cm, this deep percolation is really not a loss. Therefore, theaverage adjusted application efficiency may be close to 55% in thiscase. The main issue in this field is the high runoff volume, which isbasically due to the steep slope (0.0072) and lack of proper design ofthe irrigation system. Even though 2010 was a wet year comparedto 2009, this farmer applied more water (6880 m3/ha) during the2010 irrigation season (Table 4) than the 2009 irrigation season(Table 3).

4.9. Site 9

This farmer applied only three irrigations during the irrigationseason. The total volume of water applied during the season was4548 m3/ha. The total length of the field was 780 m which was splitinto six unequal segments—160 m, 115 m, 125 m, 130 m, 115 m, and135 m. The soil is a medium textured soil with a bulk density of1.48 g/cm3. The slope of the field was 0.0067. The average appli-cation efficiency of the field was 60% with an average runoff valueof 33% (Table 3). The depth of the watertable varied from 196 cmto 213 cm during the growing season. Soil-moisture data collectedbefore each irrigation (Fig. 4) event indicated that the soil-moisturecontent in layer 3 was slightly below field capacity value which sug-gested that the groundwater capillary rise from the watertable wasnot reaching the bottom of layer 3. Therefore, any excess water per-colated beyond 90 cm was not really lost and, hence, the averageadjusted application efficiency would be higher than 60%. Thereis still scope for improving the application efficiency by reducingrunoff. The average inflow rate was not significantly different fromone irrigation event to the other at this site. Even though 2010was a wet year compared to 2009, this farmer applied more water(5788 m3/ha) during the 2010 irrigation season (Table 4) than the2009 irrigation season (Table 3).

It is evident from the above discussion that high runoff volumefrom these fields was contributing to the low application efficiency.The main reason for the high runoff was the steep slopes of theresearch plots: the field slopes ranged from 0.0027 to 0.0072, andseven fields out of the nine research fields had a field slope greaterthan 0.005. The furrow flow rates were not properly sized to suitthe soil type and soil slope. Today, no general guidelines are avail-able to the farmers for choosing appropriate furrow flow rate touse on a given slope and given type of soil. Guidelines, such as theonce provided by Booher (1974) and Marr (1967), on selection ofappropriate furrow flow rate would help the farmers in improv-ing the performance of irrigation systems. As mentioned earlier,irrigation agronomists have been advocating the use of alternatefurrows and short furrows for uniform and efficient application ofirrigation water. The farmers are very good at following appropri-ate recommendations. Five years ago, the number of farmers thatwere using short furrows to provide more uniform application of

irrigation water along furrows was very small, whereas today sev-eral farmers are practicing this technique to improve uniformity ofwater application along furrows. However, analysis of the field datashows that some of the recommendations such as using alternate

142 J.M. Reddy et al. / Agricultural Water Management 117 (2013) 133– 144

01020304050

Q (l

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Site-1

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10

20

30

40

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Site-2

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10

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Site-4

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01020304050

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Q(l/

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urrow irrigation and short furrows on heavy soils may have beenndiscriminately applied by some farmers. This clearly suggests theeed for a robust irrigation extension service in Uzbekistan andentral Asia. The average flow rate received at each field was dif-

erent for each irrigation event. The farmers do not know what flowate to expect at the field for any given irrigation event. It is veryifficult to plan (how many furrows to irrigate per set, etc.) for irri-ating a field without knowing the magnitude and the duration

te received at different field sites in year 2009.

of flow rate that will be available for any given irrigation event. Asshown in Fig. 5, at site 1, the average flow rate available at field var-ied from 12.8 �/s (for irrigation event 5) to 35.2 �/s (for irrigationevent 4), and the duration of water availability varied from 36 h

(for irrigation event 4) to 120 h (for irrigation event 5). And, at site6, the average flow rate available at field varied from 16.1 �/s (forirrigation event 5) to 45 �/s (for irrigation event 1), and the dura-tion of water availability varied from 30 h (for irrigation event 1) to

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J.M. Reddy et al. / Agricultural Wa

4 h (for irrigation event 5). Similar variations can be seen at otherites as well (Fig. 5). In addition, during each irrigation event theow rate available at fields varied considerably, sometimes twices much as the average flow rate. It is impossible to plan for effi-ient irrigation under unknown fluctuating flow rate conditions.hese fluctuations in flow rate were mainly due to fluctuations inow rate received by WUAs, and the way the WUAs distributedhe water within their irrigated command area. Therefore, in ordero improve water management at field level, water managementt main canal level and WUA level must be improved in order torovide reliable (with minimal fluctuations) and manageable flowates to all farmers within the command areas of irrigation projects.eliable water supply is a prerequisite (necessary but not sufficientondition) for improved performance of irrigation systems at fieldevel.

Comparing Tables 2 and 3, it is clear that the farmers wereot following the specified irrigation norms either because of non-vailability of this information to them or lack of strict enforcementrom irrigation authorities. In the absence of strict enforcement,here is no incentive for farmers to stick to the specified irrigationorms. Even if the information on norms was available, how canhe WUA enforce the norms in the absence of flow measurementtructures? As mentioned earlier, an agronomist provided advi-ory service to all the demo field farmers on when to irrigate. But,o advice was provided on how much water to be provided forach irrigation event. Table 3 indicates that some of the farmersid not follow the advice of the agronomist, and irrigated at theirwn will. In addition, there was considerable difference betweenhe volume of water required in the root zone and the volume ofater that was applied per irrigation event. Even if the farmers

ollowed the advice of the irrigation agronomist on the timing ofrrigations as well as the amount of irrigation water to apply forach irrigation event, it would still have been difficult to matchupply with demand because the farmers did not have any con-rol on the magnitude and duration of flow rate received at theeld.

The average runoff from fields was 49% of the volume of waterpplied to the field. This volume of water was clearly visible to thearmer as loss. However, the farmers did not pay any attention tohe runoff from their fields because there was no incentive for farm-rs to save water. In Uzbekistan, water is free of charge, and farmersay fixed service charge to WUAs based upon the area irrigatedather than the volume of irrigation water applied to their fields.he irrigation water charges range from 15,000 to 20,000 Uzbekums2 per season per hectare of cotton grown. It is clear from theata that unless there is a penalty for over-use of irrigation water,

t may be difficult to improve irrigation water management at fieldevel.

Finally, the average application efficiency of all the nine demon-tration field sites (with a total of 53 irrigation events) that usedlternate-furrow irrigation was 47%. This does not mean that theres no advantage to using an alternate-furrow irrigation system inlace of a traditional every-furrow irrigation system. On the con-rary, it indicates that, like any other type of irrigation system, anlternate-furrow irrigation systems must also be properly designednd operated in order to achieve improved performance, which wasot the case with the demonstration sites here.

. Summary and conclusions

The performance of furrow irrigation systems in terms of appli-ation efficiency, runoff ratio, and water requirement efficiency

2 1 US Dollar = 2650 Uzbek Sums.

nagement 117 (2013) 133– 144 143

were evaluated in nine different cotton fields covering a totalof 54 individual irrigation events during the growing seasons of2009 and 2010 in the Fergana Valley of Uzbekistan. Data showsthat the farmers did not follow the specified irrigation normsfor their locations. The average application efficiency of the 46irrigation events in 2009 was 48% with an average runoff lossof 39% from the fields. In general, the field slopes were steep(>0.005) and contributed to higher runoff losses from fields. Thefurrow inflow rates were not sized to suit the slope. Majority of thefarmers did follow the recommendation that short furrow lengthswould minimize deep percolation losses at the upstream-end ofthe furrow and would help in achieving a more uniform distri-bution of irrigation water along the length of the field. However,at majority of the sites there was a mismatch between the actualsoil-moisture deficit at the time of irrigation and the volume ofirrigation water applied. This mismatch may be due to farmers’inability to determine the quantity of irrigation water to be appliedand/or lack of their ability to regulate the flow received at theirfields.

Fluctuations in the magnitude and duration of flow rate receivedat the fields was significant; hence, even if the farmers knew howmuch water to apply per irrigation event, the farmers did not haveany control on the flow rate received at their fields. This unreli-ability in water supply partly contributed to the low applicationefficiencies that were realized at the demonstration sites. There-fore, to improve the performance of furrow irrigation systems, thereliability of water supply to farmers’ fields must be improved.Farmers should receive a flow rate that is appropriate for the siteconditions and manageable. The farmer should know the flow ratethat would be supplied so that he can plan his irrigation applicationaccordingly. In addition, the fluctuations in flow rate should be keptto a minimum. The performance of the furrow irrigation systemscan be further increased by providing irrigation scheduling servicesto farmers because South Fergana canal is capable of (with minimaladditional investment) delivering water to WUAs on an arrangeddelivery schedule. In addition, some guidance to the farmers onselection of an appropriate furrow flow rate based upon their indi-vidual site conditions would help them in reducing runoff fromfields.

Acknowledgement

The funding for this research was provided by the SwissAgency for Development and Cooperation (SDC) Tashkent office,Uzbekistan, as part of the Water Productivity Improvement atPlot Level (WPI-PL) project. Their financial support is highlyappreciated.

References

Booher, L.J., 1974. Surface Irrigation. FAO Agricultural Development Paper 95, Rome,Italy.

Bos, M.G., Nugteren, J., 1990. On Irrigation Efficiencies. International Institute forLand Reclamation and Improvement, Wageningen, The Netherlands.

Burton, M., 2010. Irrigation Management Principles and Practices. CABI Publishers,Oxfordshire, United Kingdom.

Eisenhauer, D.E., Youth, C.D., 1992. Managing furrow irrigation system. In:Proceedings of Central Plains Irrigation Symposium, February 5–6, Lincoln,Nebraska, United States of America.

Food and Agriculture Organization, 1979. Yield Response to Water. FAO Irrigationand Drainage Paper 33, Rome, Italy.

Graterol, Y.E., Eisenhauer, D.E., Elmore, R.W., 1993. Alternate furrow irrigation forsoybean production. Agricultural Water Management 24, 113–145.

Horst, M.G., Shamutalov, S.S., Pereira, L.S., Goncalves, J.M., 2005. Field assessment

of the water saving potential with furrow irrigation in Fergana, Aral Sea Basin.Agricultural Water Management 77, 210–231.

Jensen, M.E. (Ed.), 1980. Design and Operation of Farm Irrigation Systems. ASAEMonograph 3. Published by the American Society of Agricultural Engineers, St.Joseph, Michigan, United States of America.

1 ter Ma

K

M

S

44 J.M. Reddy et al. / Agricultural Wa

han, K.H., Rana, M.A., Arshad, M., 1999. Alternate furrow irrigation for enhanc-ing water use efficiency in cotton. Pakistan Journal of Agricultural Sciences 36,

175–178.

arr, J.C., 1967. Furrow Irrigation. Manual 37. California Agricultural ExperimentStation Extension Service. University of California-Davis, California.

amadi, A., Sepaskhah, A.R., 1984. Effects of alternate furrow irrigation on yield andwater use efficiency of dry beans. Iran Agricultural Research 3, 95–115.

nagement 117 (2013) 133– 144

Sepaskhah, A.R., Kamgar-Haghighi, A.A., 1997. Water use and yields of sugarbeetgrown under every-other-furrow irrigation with different irrigation regimes.

Agricultural Water Management 34, 71–79.

Unlu, M., Kanber, R., Onder, S., Sezen, M., Diker, K., Ozekici, B., Oylu, M., 2007.Cotton yields under different furrow irrigation management techniques inthe Southeastern Anatolia Project (GAP) area, Turkey. Irrigation Science 26,35–48.