IRRIGATION OP DATE PALMS. 47 



The cost of planting a palm is about 2^ cents, but in already estab- 

 lished gardens the work of replacing old or diseased palms is part of 

 the regular duties of the khammes, or tenant, for which he receives 

 no extra compensation. 



The young palm is usually sheltered by a tentlike covering of date 

 palm leaves (PI. II, fig. 2), until it is strong enough to face without 

 protection the summer sun and the cold winds of winter. The shelter 

 is generally left in place for a year, i. e., until the spring after the 

 planting. Where palms are planted on the edge of an oasis, and 

 hence beyond the shelter of older trees, " tabias," or palisades, to 

 break the force of the sand-bearing winds (see p. 14), are often 

 erected at intervals of 30 to 50 feet in the young plantation. It is 

 estimated in the Jerid that from 10 to 15 per cent of the suckers 

 planted fail to grow. 



IRRIGATING. 



As soon as the offshoot is planted a shallow basin is made around 

 its base, in order to hold the irrigating water. Care is taken to con- 

 struct this so that the water can not come in contact with the terminal 

 bud, or " heart," of the young palm. During the first forty days 

 after planting, many of the natives consider it preferable to water 

 palms by hand from a water jar, at the rate of 4 gallons for each 

 palm daily, rather than by flooding. It costs about 20 cents to water 

 30 palms daily in this way. After forty days two waterings a week 

 are generally sufficient. At Nefta the growers told the writer that 

 the practice is to water palms, until they are one year old, every day 

 in summer, every four days in spring, and every eight days in autumn. 

 If irrigated by flooding, two irrigations a week are generally suffi- 

 cient, at least after the first few weeks, and two a month in rainy 

 seasons, e. g., in autumn. 



For older palms irrigation by flooding small basins, each containing 

 several palms, is the only method practiced. One irrigation a 

 week is generally sufficient, although a marked increase in yield 

 is -said to be obtained by irrigating twice a week. But many 

 proprietors of gardens at Tozer, having disposed of part of their 

 water right, get water only once or twice a month. According to an 

 estimate made by M. Minangoin, water is ordinarily put on the land 

 to a depth of about 2-| inches, of which nearly 1 inch is almost imme- 

 diately absorbed by the soil. M. Masselot, however, states that the 

 " lands " are flooded to a depth of about 4 inches at each irrigation. 

 The amount of water theoretically available for each palm in the 

 oasis of Tozer is variously estimated at from 42 to 62^ gallons daily. 

 (Compare p. 29.) 



Irrigation is most urgently required during the hot, dry months of 

 June, July, and August, when the fruit is developing, and again in 



92 



