The 19th ICID Congress, Beijing, Sept. 2005 Q52. IMPROVING WATER AND LAND MANAGEMENT FOR INCREASING EFFICIENCY IN IRRIGATED AGRICULTURE IMPROVING WATER AND LAND MANAGEMENT FOR EFFICIENT WATER USE Q52.1: On-farm water and management; IN IRRIGATED AGRICULTURE Q52.2: Performance evaluation and integrated management of and systems; Luis S. Pereira Q52.3: Conjunctive use of water to optimize food production; Vice-president Hon., ICID Q52.4: Policy options for water saving in irrigation; President, CIGR Q52.5: Management transfer and participatory irrigation and drainage management; Technical University of Lisbon Q52.6: Application of information technology in irrigation and drainage management.

For millennia, civilisations developed in water scarce environments. The respective cultural skills are an essential heritage of those nations and peoples, and the humanity as well. A water economic culture is now following a technical one, imposed when the large irrigation schemes were built. Both are generally imported from different cultural and instituttional environments.

Management faces therefore difficult challenges due to the fact that irrigators have a perception of problems, practices and objectives different from the non-farmer managers. However, progress in XX century questioned the traditional know-how, which has been often replaced by modern technologies and management Tozeur imported from different environments and cultures.

Pressures about water use in irrigation are coming from a ever A turn in viewing traditional growing urban society that understands less and less the rural irrigation is starting in the world and, mainly, the peasants. Most common include: non-technical media ¾“decrease water consumption” - when it should be said “control water demand” Farmers may not have access to other and better technologies, and may do not know how to improve those they are using after centuries

But we need to help providing our know-how accepting Oasis of Turpan, farmers cultures and perception Xinjiang

1 Reducing the demand for supplemental irrigation of cereals may However for crops having a high demand for water such as summer crops, be feasible if to decreasing Gross Margins per unit land (GM/ha) including if they have a favourable ratio between yield price and water cost, correspond increased GM per unit water. e.g. tomato in Tunisia, when GM/ha decreases due to less water application The farmer incomes then reduces but, when water is lacking, that the GM/m3 do not increase. It is then questionable to adopt deficit irrigation income is higher than reducing the cropped area. More knowledge about water-yield-revenues is required before adocating deficit irrigation for demand reduction

5000 0.8 GM/ha 3

) GM/m ) 3 4000 0.6 ha /

D 3000 S 0.4 U ( 2000 M GM (USD / m

G 0.2 1000

0 0.0 240 320 400 480 560 640 720 800 880 240 320 400 480 560 640 720 800 880 (6) (8) (10) (12) (14) (16) (18) (20) (22) (6) (8) (10) (12) (14) (16) (18) (20) (22) Season irrigation (mm) Season irrigation (mm) Number of Number of irrigations Zairi et al., 2003 r average ( ), high ( ) and very high ( ) demand conditions Zairi et al., 2003

¾“pay the full costs of water”, but, … Impacts of water prices on water demand (and irrigated cropped area) at system level what about yield prices and farmers revenues?

what about the externalities of irrigation such as Traditional irrigation, Duero Modern irrigation, Guadalquivir aquifer recharge and flood control?

Paddies in the Po Valley, courtesy by M. Greppi

Impacts of water prices on If multifunctions of irrigated water demand, cropping agriculture are recognized, pattern and income at farm the water is “fully” valued level, Alentejo, Portugal and farmers will pay what is socially and economically acceptable

Japan. Inst. Irrig. Drain., 2003 Mitsubishi Res. Inst., 2001

If water is to be paid in full as an economic good the demand will decrease together with the irrigated area and farm income Pinheiro and Saraiva, 2002

2 The depth of applied water D depends upon the technologies ¾ “improve irrigation efficiency”, but available. Improving them to achieve an high uniformity UC that provides for making D close to Dopt relates to the relationship farmers generally know they need to apply water in excess to leach salts, to store water in the soil when deliveries are not between the price of the yield commodity (PY) and the cost of reliable, or to overcome the distribution uniformity of the system the water (PW)

New developed oasis near Tozeur, Tunisia Mantovani, 1993

Maximing Yields or maximizing WP follow different objectives which relate to the socio economic farming conditions ¾“more crop per drop”, or “increase water productivity”. However, this may be achieved by improving agronomic practices not decreasing water use

Moreover, a peasant farmer, having 0.5 ha/family, do not understand the water productivity concept: he needs to increase land not water productivity, because it relates to the revenue he may get from his land

Qingtongxia, Ningxia Molden at al., 2003

There is a contradiction between water and land productivity A key issue is to know the relationship between “applied water” that is solved differently by and “costs” and “revenues”, maily these ones! a water manager Max(WP) a farmer Max(LP)

English et al., 2002

3 The farm’s socio economic Where this water goes? To irrigation only? conditions dictate options that may be different of those of water managers May be it is worthwhile to adopt new water use concepts

Max net income for commercial farming Is below max Yield (near max WP)

Max total income for small (family) farmers Is near max Yield (far from max WP) Tank irrigation in Sigirya, Sri Lanka

WATER USE WATER USE = Diverted for any purpose

CONSUMED NON- FRACTION CONSUMED FRACTION CONSUMED NON- Preserved Degraded FRACTION CONSUMED Quality Quality FRACTION NON- REUSABLE Preserved Degraded REUSABLE Quality Quality Beneficial

NON- Non-beneficial (waste) Non-beneficial REUSABLE REUSABLE

Non- LOSSES beneficial

A new approach looking the Basin and not the irrigated fields Pathways to improve water use alone has been developed by IWMI along these lines

WATER USE ¾Identify the water pathways

CONSUMED NON- FRACTION CONSUMED FRACTION Preserved Degraded Quality Quality ¾Maximize beneficial uses NON- REUSABLE REUSABLE Beneficial Waste ¾Minimize non-beneficial uses Non- LOSSES beneficial ¾Control, avoid water losses

4 Effective rain WATER DIVERSION Effective rain WATER DIVERSION

Environment Agriculture Agriculture Domestic Industry and other and landscape

Conveyance + Seepage + Classical transport & Conveyance + Seepage + distribution runoff distribution runoff distribution efficiency Total WP Irrig WP reuse Non-crop ET reuse Non-crop ET Classical application Application to Percolation + efficiency Application to Percolation + cropped field runoff cropped field runoff Farm WP Transpiration Soil evapor Transpiration Soil evapor WUE YIELD YIELD

WATER DIVERSION WATER DIVERSION AGRICULTURE AGRICULTURE

Reservoir Evaporation Reservoir Evaporation System Seepage + runoff System Seepage + runoff N-BWU BWU Percolation + Field N-BWU runoff Percolation + Leaching BWU Field runoff Non-crop ET Leaching Crop ET

Non-crop ET YIELD Crop ET NCF CF CF NCNRF NCRF YIELD

WATER DIVERSION Pathways to improve water use

WATER USE Agriculture Environment Urban Industry (and landscape) and other ¾Identify the water pathways CONSUMED NON- FRACTION CONSUMED treatment FRACTION Preserved Degraded Quality Network Non-consum Non-consum Consump Quality NON- Seepage + runoff Reusable Non-reusable use REUSABLE REUSABLE Beneficial Non-beneficial use Reuse Waste

Field Non- LOSSES Beneficial + non-benef. use beneficial Runoff + percol Maximized beneficial uses Non-reuse Reusable Wastes Losses Cons.use Minimized non-beneficial uses Wild ET Crop ET Leaching Controlled, avoided water losses Efficient water use Losses Wastes Beneficial use High water productivity

5 On farm water management for efficient water use Modern sprinklers may produce excellent performances in set Objective Technology systems, ... Reduce demand • Select low demand crop varieties/crop patterns • Adopt deficit irrigation if design is adequate Water saving • Improve irrigation systems and the selected system uniformity and management is appropriate for the • Reuse water spills and runoff local environmental Water conservation • Soil management/surface constraints and farming mulch conditions Higher yields per unit of • Adopt best farming practices water • Avoid crop stress at critical periods Higher farmer income • Select cash crops • Adopt appropriate irrigation technologies

The same applies When micro-irrigation – drip, SDI, micro-sprinkling - to moving gun are well designed and managed, performances can sprinklers under be excellent, but … non-windy conditions ... these are not achievable without appropriate support to farmers

... and to the modern sprinklers in moving laterals. They produce excellent performances with low energy when design and management fit the environmental constraints

Excellent performances may be achieved with when land levelling and irrigation technologies are appropriate

The challenge is to pay adequate attention and provide incentives to support farmers in improving their systems

Adopting zigzag furrowing, shortening the basin strips and using a PE pipe and valved tubing available in the market, this farmer reduced the demand from about 1500 to near 1000 mm. But DU still is very low because land is unlevelled!

6 With poor nozzling The reality is far from ideal: without design, without techical assistance, this farmer was assistance, what unable to adequately use drip can this farmer do to irrigation – he was using more water get an uniform crop? and expecting less yield than for his surface irrigated field, ...

In betwwen the towers, a less developed crop Near a tower, a well developed crop

...but Services in his region were just advising to move from surface to drip

1st case: basin Present: irrigation in the excess water Yellow River diversion Basin causes high watertable and salinity, making Huinong inadequate the Irrigation typical irrigation System schedules

This is an arid Irrigations Season Deep Crop GWc ETc ETc after irrigation percolation adj region, with very (mm) (mm) (mm) cold winter and rain planting (mm) (mm) generally < 200 mm Intercrop 6 630 386 471 810 816 Main crops are Wheat 4 422 213 297 546 554 wheat and maize, often intercropped, Maize 5 521 266 383 747 780 and rice

Present Irrigation Performances Pre-conditions for farm water savings and increased productivity: Irrigation q D Zreq Ea DUlq Percolation 1st: cut to about half the number (l s-1 m-1) (mm) (mm) (%) (%) (mm) diversions from the river 1st 1.0 - 1.4 107 - 109 92 77.8 - 85.9 61.4 - 90.9 15 - 24 2nd 0.7 - 1.3 90 - 136 30 22.0 - 33.5 56.8 - 95.6 64 - 106 rd nd 3 0.4 - 0.9 94 - 114 51 44.8 - 54.4 82.9 – 87.3 43 - 63 2 : rehabilitate the drainage th th system (without great 4 and 5 1.2 105 - 157 50 25.6 - 35.2 84.4 - 92.7 12 - 77 th 0.7 - 0.9 97 - 141 14 9.9 - 14.4 99.3 - 94.3 83 - 127 investments) 6

3rd: reduce percolation Uniformity DU is acceptable to very good Efficiencies Ea (to the level required for are very low because leaching, upland crops) •Irrigations after the first are applied when there is too much water in the soil (lack of watertable control) •Applied depths are much above required •Percolation very high

7 Irrigation depths may be optimized according to pre-defined Adopting low paddy water depths, objectives. If yields are to be improved the total water application improved delivery and irrigation may have to increase but percolation is controlled. scheduling, demand reduces by 50% and yields increase by 10% Season irrigation volumes Zero level Irrigation (mm) 700 basins are 3500 600 required if 500 3000 400 such 300 2500 Depth (mm) 200 results are 2000 250

Volumes (mm) Volumes 100 0 intended 1500

Intercrop wheat maize 200 1000 700 Deep percolation 500 Actual 600 150 0 Foreseen 500 GIRFARM(mm) 400 100 GIDSUPPLY(mm) 300 200 50 100 Volumes (mm) Volumes 0 0 Intercrop wheat maize 1 2 3 4 Actual 5 6 ET+Percolation Present Improved Salt control Salt control with water savings 7 8 9

Improved Irrigation Performances Gross margin per unit water use, Huinong ¾improved schedule

¾controlled Yuan/m3 ¾zero levelling 2.5 ¾higher inflow rates

2 Irrigation q D Zlq Ea DUlq Percolation number (l s-1 m-1) (mm) (mm) (%) (%) (mm) st 1 1 130 112.0 84.3 75 20.4 1.5 3 113 106.9 97.0 93 3.2 2nd 1 123 110.3 89.5 85 12.9 1 3 113 108.3 97.4 95 2.9 3rd 1 119 108.2 92.1 88 9.3 0.5 3 111 106.7 98.5 95 1.5 th 0 4 1 119 109.7 92.3 93 9.0 t en d es e m GM/Vol_Farm r ch ar st 3 113 109.0 97.5 97 2.7 P +s f y in p s rm GM/Vol_Deliv ra Im p fa ce th D % Im v+ ri ov 40 % eli o pr p. 5 1 120 110.5 91.4 92 10.2 50 d n m im p. p i h m Im gh ig i Hi H ax 3 112 108.5 97.4 96 2.8 V. M field length of 48m

Total water use, TWU Present Present conditions Combined Non-beneficial WU, farm Using a DSS 20 90000 farm demand Non-beneficial WU, delivery farm consumptive use Improvements in delivery mulyicriteria 80000 system demand /ha/year) simulated demand

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m conditions, drainage, 3 70000 model applied 15 farm irrigation to the system 60000 10 to analyse the 50000 scheduling and basin foreseen 40000 irrigation systems lead to 5 30000 improvements. (10 volumes Water reduce the demand

20000 results relative water volume (1000 m3/year) Improved 4 0 Improved to level 4 to water use 0 1 2 3 4 5 6 7 8 9 10 10000 90000

0 farm demand 1.00 Time implementation (years) 80000 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 farm consumptive use 0.90 decade 70000 simulatedsystem demand demand 0.80 and to utilities show 0.70 60000 that more stringent 0.60 at system and farm 50000 0.50 improvements levels, and to 40000 Utility 0.40 (after level 4) have increase the 0.30 30000 farm gross margin relatively reduced 0.20 20000 delivery cost consumptive use water volume (1000 m3/year) 0.10 water use impacts delivery 10000 0.00 0 1 2 3 4 5 6 7 8 9 10 0 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 Time implementation decade

8 Present Present conditions Improvements at farm 90000 farm demand farm consumptive use – land levelling, inflow 2nd case: 80000 farm percolation Fergana Valley farm runoff rates, irrigation furrow 70000 scheduling – reduce irrigation in 60000 the Aral Sea 50000 the non-consumed Basin 40000 and non-reusable Basin

30000 fraction (percolation),

20000 water volume (1000 m3/year) ImprovedImproved 4 to level 4 10000 90000 farm demand 0 farm consumptive use 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 80000 farm percolation decade farm runoff 70000

60000 Arid climate where excessive 50000 water use produced and the non-consumable 40000 enormous changes in Aral Sea but reusable fraction 30000 and river ecosystems 20000 (runoff), mainly relative water volume (1000 m3/year)

10000 to paddies Main crops are wheat and 0 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 decade cotton, furrow irrigation

Furrow irrigation with continuous flow to alternate or every furrow Comparing continuous and surge flow, the later tends to provide for better performances 100 90 Efficiencies (Ea) are low % 80 except for alternate 100 70 furrow irrigation due to 90 80 60 excessive time of 70 50 application. 60 40 Uniformities (DU) are 50 30 good/very good 40 20 30 20 10 DU (adj tco) 10 0 DU 0 2.39 Ea (adj tco) Ea 2.36 2.4/1.2 2.4/1.2 2.4 2.4 3.0/1.5 3.0/1.5 2.4/1.2 2.4/1.2 2.4 2.4 3.0/1.5 3.0/1.5 1.79 1.78 Ea Reducing cutoff DU 1.79 Inflow rate (l/s) Inflow rate (l/s) 1.78 1.21 times the irrigation depth D reduces, Best performances are for Ea improve, and alternate furrow irrigation DU decreases

Water use is less for alternate furrows (A) than for every furrow Every furrow continuous flow provides for maximizing yields irrigation (E) and also decrease from continuous to surge flow (Ya/Ymax) but to minimal water use ratios. Opposite,

3 D Yield alternate surge irrigation do not achieve maximal yields but 10 m3/ha or kg/ha highest WP(irrig) and highest beneficial water use fraction 9

8 1 7 0.9 6 However, if prices of 0.8

5 production factors are 0.7

4 high and those of 0.6

3 commodities are low 0.5

2 the farmer option is to 0.4

1 maximise Ya/Ymax 0.3

0.2 0 Ya/Ymax EC ES AC AS Ave rage EC ES AC AS Average 0.1 BWUF(field) treatments 0 WCF(field)

However, the highest land/farm productivity is EC WP (irrig) kg/m3 ES AC for continuous flow in every furrow AS

9 Using a DSS in a GIS environment to evaluate alternative Comparing alternative improvements through multi-criteria improvements operating analysis, for the actual farming conditions in Fergana, the best aletrnatives are the present one – no changes - or Sched + AC: The price of products do not compensate for improving farm irrigation. Surge flow has not enough economic return

0.8

Irrigation network layer 0.7

0.6

y 0.5

Fields layer 0.4

Global Utilit 0.3

0.2 Satellite image 0.1 0 Water saving nt Uniform se Ev v re ff- -E lt P to ed -A Ev t Economics Application to Cu ch ed f- Al v S ch De f- -E lt S De ge -A v ur ge f-E lt Fergana, Uzbekistan S ur De f-A S r- De Su r- Su

Concluding: Knowledge and technologies exist that allow to Knowledge and technologies that exist to provide for a more make a more efficient the use of water in irrigation efficient use of water in irrigation need that appropriate quality control of equipments and management tools be enforced to support farmers in modernizing the systems These should mean capability to transfer into practice and to improve the existing irrigation, both at farm and system levels. The constraints imposed to farmers, which they know well, However, knowledge and technologies progress much faster need to be recognized, such as than technology transfer in case of small family and peasants ¾inappropriate delivery conditions farms ¾high costs of production factors, of irrigation equipments, Technologies are easily available when manufacturers have an ¾low prices of commodities, low incomes easy market, as it is for a variety of irrigation scheduling ¾lack of technical assistance and poor systems design equipment adopted by commercial farms and for sprinkler and Using indicators need to be carefully done and taking into micro-irrigation equipment, the so-called “modern irrigation”. consideration the irrigator constraints, not to be used to But when the markets have no quality exigences and control, describe environmental and managerial objectives the farmers may be purchasing less good equipment, poorly designed and demanding too much energy. Incentives that compensate for the upgrading costs, society In case of surface irrigation such market is generally not existing responsibilities, recognition of cultural skills, farmers decision and surface irrigation becomes synonimous of “old fashion” making and not only PIM, need innovative approaches.

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