Rapid assessment of seasonal in-field water management on micro irrigated annual and perennial crops in Central Italy.

Graziano Ghinassi and Stefano Cecchi

University of Florence – Italy

graziano.ghinassi@unifi.it

7th Asian Regional Conference June 27, 2012 – Adelaide, Australia

Triennial research project on irrigation sustainability (S.E.Agr.I.T.)

supported by the Regional Agency for Development and Innovation in the Agricultural and Forest Sector (ARSIA) of the Tuscan Region.

The project was carried out in the main irrigated areas of Tuscany.

the project

main irrigated areas in tuscany

investigated 1,200 ha of irrigated crops

Perennial Annual Horticultural

Investigate on-farm water use and management, in order to define guidelines for improving efficiency of irrigation water use at different scales

aim of the project

-University of Florence:

Department of Hydraulics

Department of Soil Sciences and Plant Nutrition

Department of Agricultural Economics

-University of Pisa:

National Laboratory of Irrigation, LNI (standard testing and certification of irrigation equipments)

project partners-universities

project partners-professional associations

-Professional Associations of Farmers:

ERATA

IRIPA

CIPA-AT

-Tuscan Regional Union of Water User Associations (URBAT)

Sample of 40 irrigated farms selected according to representative criteria:

size

cultivated crops

irrigation type

tenancy

labour

management

Selection supported by the professional Associations

farms sample

Composed of progressive steps on assessment and measurements of:

water withdrawals

crop water requirements

energy use

agronomical and economical evaluation of the farming practices

project arrangement

Intermediate step at irrigation unit level (on 18 farms):

measurement of working characteristics and performance of the irrigation system;

hydrological characterization of the soil;

monitoring of crop and climate evolution through the season.

project arrangement

1. system performance and irrigation management

Lab and field measurements (nominal to actual discharge);

Irrigation to avoid deficit irrigated zones.

Nominal discharge does not allow correct estimate of the average discharge of driplines

Nominal DRIPLINE MODEL discharge Average Max Min DUlq

(l/h·m) (l/h·m) (l/h·m) (l/h·m) (%)

Model 1 3.80From bench test at LNI 1.77 2.27 1.58 86.8

From field measure 1.84 2.50 1.50 82.2Modello 2 3.80

From bench test at LNI 2.30 2.45 2.24 95.8From field measure 2.26 2.50 2.01 90.5

Model 3 3.67From bench test at LNI 2.40 2.71 2.29 93.5

From field measure 2.27 2.71 2.00 88.7Model 4 3.67

From bench test at LNI 1.97 2.95 1.57 76.4From field measure 2.02 3.15 1.37 69.0

…………. …..…………… ….. …. ….. …..

Lab and field measurements (nominal to actual discharge)

Actual DUlq is below the potential as calculated according to the LNI bench results

Nominal DRIPLINE MODEL discharge Average Max Min DUlq

(l/h·m) (l/h·m) (l/h·m) (l/h·m) (%)

Model 1 3.80From bench test at LNI 1.77 2.27 1.58 86.8

From field measure 1.84 2.50 1.50 82.2Modello 2 3.80

From bench test at LNI 2.30 2.45 2.24 95.8From field measure 2.26 2.50 2.01 90.5

Model 3 3.67From bench test at LNI 2.40 2.71 2.29 93.5

From field measure 2.27 2.71 2.00 88.7Model 4 3.67

From bench test at LNI 1.97 2.95 1.57 76.4From field measure 2.02 3.15 1.37 69.0

…………. …..…………… ….. …. ….. …..

Lab and field measurements (nominal to actual discharge)

Dripline length (m)D

epth

(cm

)

Infiltrated water Active rootzone Average infiltration

Soil water infiltration along a dripline on flat ground

USED BY THE CROP

WASTED

Effective and inefficient irrigation

irrigation to avoid deficit irrigated zones

2. scope of the presentation

Describe an approach to investigate and assess in-field management of micro irrigation

3. materials & methods

Measurement and assessment on:

3.1 DUlq target

3.2 Seasonal Net Irrigation Requirement (NIR)

3.3 Seasonal Irrigation Supply (SIS)

3.4 Irrigation performance - relative surplus

3.1 DUlq target

DUlq target= reasonable minimal target threshold of DUlq, set equal to 90% for irrigation of both annual and perennial crops, taking into account average farming conditions, cropping patterns and farmers skills;

DUlq target compared to values measured in the irrigation units;

Assessment of water supplied by system operating at DUlq target (ISDU90).

3.2 Seasonal Net Irrigation Requirement (NIR)

Calculated through the daily water budget referred to the soil depths explored by the active root system during the season;

Crop evapotranspiration (ETc) calculated by using the Eto FAO-Penman-Monteith equation and site specific crop coefficients (kc);

Effective rainfall (ER) assumed to be ≥5mm;

On mulched crops, total ETc and ER were reduced;

Climatic data yielded by meteorological stations which are part of the Agrometeorological Service of ARSIA.

19

3.3 Seasonal Irrigation Supply (SIS)

Seasonal irrigation supply on each micro irrigated unit estimated according to: -actual discharge under average working conditions (e.g., operating pressure);-irrigation time during the season.

3.4 Irrigation performance - relative surplus

relative irrigation surplus, either positive or negative, depending on system performance:

where:TRS= Technical Relative Surplus (%);SIS= Seasonal Irrigation Supply (mm);ISDU90= Irrigation Supply under the target DUlq (mm).

3.4 Irrigation performance - relative surplus

relative irrigation surplus, either positive or negative, depending on on-farm management:

where:MRS= Management Relative Surplus (%);SIS= Seasonal Irrigation Supply (mm);NIR= Net Irrigation Requirement (mm).

3.5 simplified water balance

NIR/DUlq ratio is the traditional approach to represent Gross Irrigation Requirement (GIR) to apply;

Evaluation of the components that over the season enter and leave the field allows to assess:

Efficiency of irrigation practice (NIR/SIS); Effectiveness of Irrigation Management (SIS/GIR),

under actual conditions.

Fates of water applied

Fates of water applied under drip irrigation

4. results and discussion-annual crops

CROP DN

(l/h*m) DM

(l/h*m) DUlq

[/] SIS

(mm) ISDU90

(mm) NIR

(mm) NIR/SIS

(%) GIR

(mm) SIS/GIR

(%)

Tomatoes 3.33 3.00 0.90 320 321 219 68.4 243 132 Watermelon1 2.18 2.22 0.83 96 89 78 81.3 94 102 Courgette1 3.73 4.02 0.56 150 99 102 68.0 182 82 Tomatoes 3.40 2.90 0.81 420 383 298 71.0 367 114 Melon1 2.18 1.71 0.85 72 69 70 97.2 82 88 Tomatoes 3.80 4.21 0.89 420 418 298 71.0 333 126 Celery 3.40 0.86 0.82 390 360 219 56.2 265 147 Tomatoes 3.00 3.22 0.50 410 247 135 32.9 269 153 Melon1 3.67 3.12 0.80 165 149 67 40.6 83 199 Watermelon 3.40 2.98 0.81 500 453 295 59.0 367 136 Melon 3.40 2.27 0.56 600 395 295 49.2 529 113 AVERAGE 0.76 322 271 189 63.2 249 127 1Black polyethylene mulched

CROP DN

(l/h*m) DM

(l/h*m) DUlq

[/] SIS

(mm) ISDU90

(mm) NIR

(mm) NIR/SIS

(%) GIR

(mm) SIS/GIR

(%)

Tomatoes 3.33 3.00 0.90 320 321 219 68.4 243 132 Watermelon1 2.18 2.22 0.83 96 89 78 81.3 94 102 Courgette1 3.73 4.02 0.56 150 99 102 68.0 182 82 Tomatoes 3.40 2.90 0.81 420 383 298 71.0 367 114 Melon1 2.18 1.71 0.85 72 69 70 97.2 82 88 Tomatoes 3.80 4.21 0.89 420 418 298 71.0 333 126 Celery 3.40 0.86 0.82 390 360 219 56.2 265 147 Tomatoes 3.00 3.22 0.50 410 247 135 32.9 269 153 Melon1 3.67 3.12 0.80 165 149 67 40.6 83 199 Watermelon 3.40 2.98 0.81 500 453 295 59.0 367 136 Melon 3.40 2.27 0.56 600 395 295 49.2 529 113 AVERAGE 0.76 322 271 189 63.2 249 127 1Black polyethylene mulched

CROP DN

(l/h*m) DM

(l/h*m) DUlq

[/] SIS

(mm) ISDU90

(mm) NIR

(mm) SIS/NIR

(%) GIR

(mm) SIS/GIR

(%)

Tomatoes 3.33 3.00 0.90 320 321 219 146 243 132 Watermelon1 2.18 2.22 0.83 96 89 78 123 94 102 Courgette1 3.73 4.02 0.56 150 99 102 147 182 82 Tomatoes 3.40 2.90 0.81 420 383 298 141 367 114 Melon1 2.18 1.71 0.85 72 69 70 103 82 88 Tomatoes 3.80 4.21 0.89 420 418 298 141 333 126 Celery 3.40 0.86 0.82 390 360 219 178 265 147 Tomatoes 3.00 3.22 0.50 410 247 135 304 269 153 Melon1 3.67 3.12 0.80 165 149 67 246 83 199 Watermelon 3.40 2.98 0.81 500 453 295 169 367 136 Melon 3.40 2.27 0.56 600 395 295 203 529 113 AVERAGE

0.76 322 271 189 170 249 127

1Black polyethylene mulched

4. results and discussion-annual crops

CROP DUlq

[/] NIR/SIS

(%) SIS/GIR

(%)

Tomatoes 0.90 68.4 132 Watermelon 0.83 81.3 102 Courgette 0.56 68.0 82 Tomatoes 0.81 71.0 114 Melon 0.85 97.2 88 Tomatoes 0.89 71.0 126 Celery 0.82 56.2 147 Tomatoes 0.50 32.9 153 Melon 0.80 40.6 199 Watermelon 0.81 59.0 136 Melon 0.56 49.2 113

AVERAGE 0.76 63.2 127

4. results and discussion-perennial crops

CROP DN (l/h)

DM (l/h)

DUlq [/]

SIS (mm)

ISDU90

(mm) NIR

(mm) SIS/NIR

(%) GIR

(mm) SIS/GIR

(%) Vineyard1 2.3 2.13 0.80 - - 100 - 125 - Vineyard 1.6 1.73 0.93 100 103 100 100 108 93 Apple 3.8 3.07 0.93 425 438 452 94 486 87 Apple 3.8 2.93 0.76 425 366 336 126 442 96 Apple 3.8 2.62 0.80 100 90 336 30 420 24 Peach 8.0 8.27 0.60 180 126 164 110 273 66 Apple2 - 51.33 0.40 570 285 452 126 1130 50 AVERAGE

0.75 300 235 277 108 426 69

4. results and discussion-farmers’ self evaluation annual

CROP TRS(%)

MRS (%)

TSE MSE

Tomatoes 0 46 adequate adequate

Watermelon 8 24 adequate adequate

Courgette 52 48 adequate adequate

Tomatoes 10 41 adequate high

Melon 5 3 high adequate

Tomatoes 1 41 adequate adequate

Celery 8 78 adequate adequate

Tomatoes 66 203 high adequate

Melon 11 148 adequate adequate

Watermelon 10 69 adequate adequate

Melon 52 103 adequate adequate

AVERAGE 20 73

4. results and discussion-farmers’ self evaluation perennial

CROP TRS(%)

MRS (%)

TSE MSE

Vineyard -3 0 high high

Apple -3 -6 adequate adequate

Apple 16 26 adequate adequate

Apple 11 -70 adequate adequate

Peach 43 10 adequate adequate

Apple 100 26 adequate low

AVERAGE 27 -2

5. conclusions

Difference between nominal and actual discharge can affect irrigation efficiency and wastes of water, fertilizers and energy.

Farmers seem to pay little attention to system performance, especially when irrigating annual crops.

Poor technical performance not balanced by management in most cases, as indicated by the surplus indexes.

Farmers’ evaluation about on-farm irrigation seems to be based on yield response rather than on water use.

5. conclusions

Good technical and management performance on units adopting saving strategies, such as mulching, or devoted to typical crops such as Vineyard.

System DUlq is below the expected threshold.

Irrigation efficiency is far below the potential in the project areas.

Thank you for

your attention