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:

in which:

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.

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.