48 DATE VARIETIES AND DATE CULTURE IN TUNIS. 



November and December, after the harvest, the trees being at that 

 time particularly weak and in need of stimulation. Irrigation 

 throughout the winter is regarded as an excellent practice, as it stores 

 the soil with water and makes it possible to get along with a smaller 

 amount when the hot weather first begins. Land that is left en- 

 tirely without water during the winter is said to become so dry that 

 the first irrigations in summer can only wet the soil to a slight depth 

 and the trees suffer from lack of water at the very time they need it 

 most. In winter, however, irrigations are given much less frequently 

 than at other seasons. It is said to be customary in winter to flood 

 the whole garden at once, rather than to turn the water into small 

 basins one at a time. Nor is so large a quantity of water necessary at 

 each application, as it is not thought well to let the water stand on 

 the land for any considerable length of time in winter, and the evapo- 

 ration is naturally much less than in summer. Judging by the height 

 of the ground water in the gardens of Tozer in midwinter (February 

 5), it would appear that the soils of the oasis are always in a very 

 wet condition. Compare column 3 in Table 9, page 34. 



No water should be applied for two or three weeks after the polli- 

 nation of the female flower clusters in spring, as irrigation at that 

 season causes the newly set fruit to drop off. Nor is it advisable to 

 irrigate in the autumn for three or four weeks preceding the harvest, 

 as otherwise the ripening fruit falls or else becomes so juicy that it 

 molds easily and can not be preserved. .Many gardeners withhold 

 water from their palms from about the 1st of October until the dates 

 are gathered." 



It has been pointed out in discussing the character of the drainage 

 water (see p. 40) that this is not too saline for irrigation purposes. 

 As a matter of fact, some of the gardens at Tozer lying neare'st the 

 Shott Jerid, and hence in the lowest part of the oasis, are irrigated 

 solely with water from the drains. It is true that the palms are less 

 thrifty and the yields obtained are smaller than elsewhere, but this is 

 at least partly attributable to the poorer quality of the soils in that 

 quarter and to the fact that in summer, when water is most needed, 

 the drains are frequently empty. 



a Charlet (Bui. Soc. Geogr. d'Alger, 1905) mentions that the same rule 

 in regard to spring and fall irrigation obtains in the Mzab oases, where the 

 application of water ceases about September 15, to be resumed after the harvest 

 is completed. 



92 



