Water use in Italian agriculture: analysis of rainfall patterns, water storage capacity and irrigation systems Simone Orlandini, Anna Dalla Marta, Francesca Natali Department of Agronomy and Land Management University of Florence (Italy) E-mail: [email protected]

Aims • To analyse the availability and use of water in Italy • To consider several aspects concerning irrigation and water storage methods

Outline • Introduction • Analysis of rainfall pattern • The problem of soil water storage and erosion • Irrigation methods • The role of farm pond • Examples for Tuscany Region

Climatic limitations and vulnerabilities in Europe

Winter wheat

Grassland

Spring barley

Grapevine

Grain maize

Source: Survey of agrometeorological practices and applications in Europe regarding climate change impacts_ COST 734

Impacts of drought in Europe Winter wheat Alpine North

Spring barley

Grain Maize

Grassland

0.0

0.0 0.5

Grapevine

Boreal

0.5

1.0

Nemoral

1.0

1.8

1.0

1.0

Atlantic North

0.8

0.8

0.3

1.0

0.5

Alpine South

1.0

1.5

1.7

1.8

2.0

Continental

0.4

1.0

1.2

1.2

0.6

Atlantic Central

0.3

0.0

0.7

0.5

0.7

Pannonian

0.7

1.3

2.0

1.3

0.4

Lusitanian

1.0

1.0

2.0

1.0

0.0

Mediterranean Montains

-1.0

-1.0

-1.0

1.0

-1.0

Mediterranean North

0.8

0.7

1.3

0.8

1.0

Mediterranean South

0.8

0.0

0.3

0.8

0.6

Source: Survey of agrometeorological practices and applications in Europe regarding climate change impacts_COST 734

Observed adaptation measures in Europe

Source: Survey of agrometeorological practices and applications in Europe regarding climate change impacts_COST 734

ANALYSIS OF RAINFALL PATTERN

Precipitations in Italy • The average yearly precipitations are 300 billion of m3 corrisponding to about 1000 mm/year. • The average precipitations in Italy are higher than European value that is about 650 mm/year • Only 53 (about 18%) of the 300 billion m3/year of precipitations are used for civil, agricultural or industry needs.

Average precipitations in Italy (years 1961-1990) mm/month

The rainfall decreases from North to South.

Source: GPCC Visualizer

Precipitation anomalies in Italy (years 1997-2007)

Anomalies are negative in the North and positive in the South

Source: NOAA

Precipitation anomalies in the last years (2003-2007) 2003

2004

2005

The figures show the negative anomalies in 2003, 2006 and 2007

+400% +150% +67% +25% Mean value -20% -40% -60% -80%

2006

2007 Source: GPCC Visualizer

Seasonal precipitation anomalies Winter 2003

2004

2005

+400% +150% +67% +25% Mean value -20% -40% -60% -80%

2006

2007

2008

The anomalies are positive in the South and negative in the North during 2003, 2005 and 2006. In 2007 and 2008 the winter was very dry. Source: GPCC Visualizer

Seasonal precipitation anomalies Spring 2003

2004

2005

The anomalies are negative in the North. In the South the precipitations of 2004, 2007 and 2008 are higher than mean value.

+400% +150% +67% +25% Mean value -20% -40% -60% -80%

2006

2007

2008 Source: GPCC Visualizer

Seasonal precipitation anomalies Summer 2003

2004

2005

The anomalies are negative in the North and positive in the South.

+400% +150% +67% +25% Mean value -20% -40% -60% -80%

2006

2007 Source: GPCC Visualizer

Seasonal precipitation anomalies Autumn 2003

2004

+400%

2005

In the last years the autumn was dry.

+150%

The autumn precipitations are important to increase water storage in the soil.

+67% +25% Mean value -20% -40% -60% -80%

2006

2007 Source: GPCC Visualizer

Trend of snowfall in Italy (1982- 2004) Trend (%) of Alpine Stations

Trend (%) of Apennine Stations

-1.5

-3.3

-1.9

-1.5

-1.5

-0.1

-2.7

-3.9

-2.2

-11.1

-2.0

-8.0

-1.8

-0.4

0.3

-5.9

-2.5

6.7 4.2 2.4 -7.7 -0.5 1.7 -4.3

AVG

-1.8

-2.1

Source: Nevosità in Italia, ultimi 20 anni

Change precipitation distribution Rainy days and daily rainfall intensity from 1880 to 2006 Intensity

According to Brunetti et al. (2006), rainy days are reduced of 10% in a century and intensity is increased of 5%.

N° days

mm/rainy day

Rainy days

Years

Years

North West North Est (north) North est (south) Center South

Source: Climate changes meeting 2007

Convective energy in Mediterranean area

1980

1990

2000-2005

Variation rate (%)

Variation of rainfall intensity in Arno river basin (1960-1970 versus 1990-2000 average)

Intensity of daily rainfall (mm)

Frequency of landslide events

1961-70

1971-80

1981-90

1991-00

THE PROBLEM OF SOIL WATER STORAGE AND EROSION

Water availability in the soil Infiltration rate and field capacity are two hydrological variables depending on soil texture. Texture

important

Infiltation (mm/h)

Total porosity %

Field Capacity %

Wilting point %

Water availability %

50 (25-250)

38 (32-42)

9 (6-12)

4 (2-6)

5 (4-6)

Loamsandy

25 (12-75)

43 (40-47)

14 (10-18)

6 (4-8)

8 (6-10)

Slow

Loam

12.5 (8-20)

47 (43-49)

22 (18-26)

10 (8-12)

12 (10-14)

Moderately slow

Loamclayey

8 (3-15)

49 (47-51)

27 (23-31)

13 (11-15)

14 (12-16)

Moderate

20-63

Slime clayey

2.5 (0.3-5)

51 (49-53)

31 (27-35)

15 (13-17)

16 (14-18)

Moderately rapid

63-127

Clayey

0.5 (0.1-10)

53 (51-55)

35 (31-39)

17 (15-19)

18 (16-20)

Sand

Infiltration rate (mm/h) Very slow

Rapid

127

The effect of irrigation efficiency LOW EFFICIENCY

8 Water drawing

10 Water table storage 2 Residual water

6 Water drawing

table storage

4 Crop use

4 Water loss

6 Final water table storage

HIGH EFFICIENCY

5 Crop use

4 Residual water table storage

1 Water loss

5 Final water table storage Protecting Water Resources in Biofuels Production, Huffaker R., ESA 2008 Bologna

The effect of land use and setting

No land setting

Rice cultivation

Forestry

Tsukuba Agricultural Research Station (Japan)

RUN OFF

No land setting

Rice cultivation

Forestry

Tsukuba Agricultural Research Station (Japan)

Effect of land setting

The instruments

The results

• Average concentration of runoff (g/l): ¾ 0.72 linked terraces vineyard ¾ 4.18 up and down slope vineyard • ¾ ¾ ¾

Average soil erosion by erosive event (kg/ha): 221.9 linked terraces vineyard with bare fallow inter-row 230.2 up and down slope vineyard with turfed inter-row 395.3 up and down slope vineyard with bare fallow inter-row

• ¾ ¾ ¾

Maximum soil erosion by erosive event (kg/ha): 2581.7 linked terraces vineyard with bare fallow inter-row 7783.9 up and down slope vineyard with turfed inter-row 8588.9 up and down slope vineyard with bare fallow inter-row

Effective rainfall in agriculture Effective rainfall (ER): part of precipitation utilizable to the plant. It can be determined reducing total rainfall by the following water amounts: • fallen on vegetation • lost for surface runoff; • percolated in the soil; • soil moisture uptake by the crop. ER changes owing to: • precipitations; • intensity of precipitation; • soil characteristic (texture) In FAO Paper n. 25 empirical and semi-empirical methods are explained to estimate effective rainfall.

Relative merits of different methods Methods

Factors taken into account Run -off

Soil

Aridity

Crop

Field studies of soil moisture

+

+

+

+

Daily soil water budget with Eta

-

+

+

Integrating gauge

-

+

+

Ramdas apparatus

-

+

Lysimeters

-

Drum technique (rice)

Special equipment

Accuracy

Relative costs

Remarks

+

Very high

Medium

Good for verifying other met hods; cumbersome practicability low

+

Very high

Medium

Practicability medium

+

+

Medium

Medium

Needs careful standardization

+

+

+

High

Medium

Practicability good

+

+

+

+

Very high

Very high

Practicability medium, good as a check on other methods

+

+

+

+

+

Very high

Low

Practicability high

Renfro equation

-

B

+

-

+

Low

Negligible

Too empirical

U.S. Bureau of Reclamation method

+

-

-

-

-

Low

Negligible

Not suitable for wide use

Ratio of ETp to precipitation

B

B

+

-

-

Medium

Low

Satisfactory for very preliminary planning purposes

USDA, SCS method

-

B

+

B

-

Medium

Low

Good for areas with low intensity of rainfall and high soil infiltration rate

Empirical methods (other than rice)

B

B

B

B

-

Low to high

Negligible

Practicability very high

Empirical methods (rice)

B

B

B

B

-

Medium

Negligible

Needs verification; practicability high

+ = positive; - = negative; B = first approximation

Examples to calculate effective rainfall Inputs - Meteorological station of Mondeggi (Florence) April 2004: Monthly rainfall: 92 mm

Empirical method: ER= 53.6 mm USBR method ER= 78.5 mm Chaptal method ER= 70.4 mm USDA method ER= 67.7 mm

IRRIGATION METHODS

Water and agriculture The Italian agriculture uses about 26 billion of m3 of water in one year. This value represents the 49% of total water needs in Italy. The 40% of agricultural production comes from irrigated crop. The total irrigated area is 2.613.419 ha that is 20.4% of total cultivated area.

Distribution of irrigated surface in Italy

29.1%

North Center South 7.4%

63.5%

Source: ISTAT - Relazioni tra agricoltura e ambiente: dalle statistiche agli indicatori Anno 2005 – INEA 2006

Orographical distribution Percentage of irrigated on cultivated surface 50% 40% 30% 20% 10% 0% Montain

Hill

Plain Altimetry of irrigated surface in Italy

6.0% 23.6%

Montain Hill Plain

70.4%

Source: ISTAT - Relazioni tra agricoltura e ambiente: dalle statistiche agli indicatori Anno 2005 – INEA 2006

Irrigation methods in Italy In 2005 the main irrigation methods are sprinkler irrigation (37.5% of irrigated surface), followed to surface irrigation (30.2%), drip irrigation (20.6%), flooding (8.8%) and others method (3.8%). 80% 70% 60% 50% South 40%

Center North

30% 20% 10% 0% sprinkler irrigation

surface irrigation

drip irrigation

flooding

others method

The drip irrigation is more diffused in hot areas to save water. Source. ISTAT - Relazioni tra agricoltura e ambiente: dalle statistiche agli indicatori Anno 2005

Supplying water methods The 45.4% of farms take water from wells, for an area of 1.452.335 ha (52.6%), the 40.4%, for an area of 733.775 ha, is irrigated from land-reclamation authority. 80% 70% 60% 50% North Center

40%

South 30% 20% 10% 0% self-supplyng

land-reclamation authority

other method

more method

Home > Servizi > IrriSMS

IrriSMS

www.irriweb.it

IrriWeb

www.arsia.toscana.it/VeProLGs

THE ROLE OF FARM POND

The importance of small reservoirs Water reservoirs (farm pond) are built to accumulate precipitation. The classification is: Volume (m3)

High (m)

Big dams

>1.000.000

>15

Small dams