3. WATER DEFICITS MAPS

As for the ETo maps, also the calculation for the water deficit maps was made on a monthly basis, at a probability of non-exceedance of 75% and for a basic wind velocity of 150 km/d. The following equations were adopted:

Def = ETcrop - Peff
ETcrop = ETo ´ Kc

in which:

Def = water deficit (mm/annual or seasonal, peak month)
ETcrop = crop evapotranspiration in a not limited water water regime (mm/annual or seasonal, peak month)
Peff = effective precipitation (mm/annual or seasonal, peak month)
ETo = reference crop evapotranspiration (mm/annual or seasonal, peak month)
Kc = crop coefficient

Effective precipitation is that part of total precipitation that has been lost by evapotranspiration. The empirical equation used to calculate Peff is the one proposed by the Soil Conservation Service, U.S.D.A. (U.S.D.A., 1970):

Peff = f [1.253(P)0.824 - 2.935] ´ 10(0.001 ETo)

in which:
f = correction factor which depends on the depth of application; f equals 1 if the depth of application equals 75 mm (750 m3/ha), the value adopted in this study.
P = total precipitation measured by pluviometer

The data on the following maps are the deficits (Def), at a probability of non-exceedance of 75%, that have been estimated as described above.

The crops are the main crops grown in Southern Italy, according to ISTAT statistics (1998). Kc values have been established on the basis of various sources (Doorenbos and Pruitt, 1977; Snyder, 1999; Pereira and Allen, 1999) and the authors' personal experience. Kc data have only one decimal figure and the crops have been as far as possible grouped.


1. garlic, beet leaf, broccoli, carrots, cabbage, cauliflower, chickory, green onion, green beans, fennel, endive, lettuce, celery, spinach, radish
2. onion
3. broad beans, beans, peas
4.

broad beans, beans, lentils, peas, soybeans

5. eggplant, peppers, tomato
6. watermelon, melons, squash, zucchini
7. coton
8. sunflower, castor beans, sesame
9. oats, wheat, corn, millet, barley, sorghum

 

1. orange, mandarin orange, lemon, tangerine
2. apricot, cherry, persimmon, almond, hazelnut, apple, walnut, peach, pear, prune

The water deficits mapped refer to a selection of crops cultivated in the periods of the year typical of Southern Italy. Deficits may vary considerably according to different periods and cultivation criteria.

Click on the green button to open the relative water deficit map, i.e. the net irrigation requirements map

The inland areas of the peninsula and of the islands above 500 meters a.s.l. are indicated in white.
The maps were created in .SRF files (using Surfer-Golden Software) and then compressed in .GIF format for posting them on the Internet. The .GIF files can therefore be opened, saved in a directory and printed by using any graphic editor which also permits sizing for better reading. The Adapt to Page option in Microsoft Office Photo Editor permits the automatic re-sizing of the image in order to print it on A4 size paper. Best resolution is achieved when maps are printed by using the original Surfer software.



Crops



Type of harvest



Period

Water
deficit
maps
(seasonal or annual)

Water
deficit
maps
(peak months)

Alfalfa

 

jan-dec

Artichoke

 

jan-dec

Asparagus

 

jan-dec

Carrots

 

mar-jun

Citrus

 

jan-dec

Corn

fully ripe

may-sep

Corn

fully ripe

jul-oct

Deciduous fruit trees

 

jan-dec

Eggplant

 

may-aug

Festuca

standard crop

jan-dec

Grapes

 

jan-dec

Kiwi

 

jan-dec

Lettuce

 

feb-apr

Melon

 

apr-aug

Olive

 

jan-dec

Patato

fully ripe

mar-jul

Peas

fully ripe

 

Peas

fresh

mar-jun

Pepper

 

may-aug

Squash

 

apr-aug

Strawberry

 

jan-dec

Sugar beet

 

mar-aug

Sunflower

 

apr-aug

Tomato

 

may-aug

Watermelon

 

apr-aug

Zucchini

 

apr-aug

Below are given water deficit data of some crops in numerical form.

Annual or seasonal water deficit (mm/annual or seasonal)


For the complete list of stations see Ravelli and Rota, 1994, annex F, pag. 74.

Peak month water deficit (mm/day)


For the complete list of stations see Ravelli and Rota, 1994, annex F, pag. 74.


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