48 THE DATE PALM. 



Irrigation by menus of flooding is sometimes practiced in Egypt for 

 the date palm, as has been done for all sorts of crops since remote 

 antiquity. The water covers the land to a depth ranging from a few 

 inches to several feet (see PI. XI), and remains on the soil for about 

 six weeks. a This method of irrigation is riot likely to prove desirable 

 anywhere in this country unless it be in the flood-plain of the Colorado 

 River in California and Arizona (see p. 131). It may be desirable to 

 use this method of flooding in order to wash the alkali out of the sur- 

 face layer of the soil where the accumulation of alkali in the upper 

 layers of the soil is so great as to prevent the best growth of the date 

 palm. It is of interest in this connection to note that the Egyptian 

 date palms are able to endure having their roots submerged for long 

 periods without appreciable in j ury . 



Mr. D. G. Fairchild has described a very interesting system of com- 

 bined irrigation and drainage practiced in the date plantations along 

 the Shat-el-Arab River at the head of the Persian Gulf, which are 

 doubtless the most extensive in the world. The level valley land 

 along the river is cut up into small rectangles, 10 to 15 by 20 to 30 feet 

 on a side, by irrigation ditches, through which, twice a day, water 

 flows when the river is backed up by the tide. As the tide recedes 

 the water flows out of the ditches, preventing stagnation and caus- 

 ing a lowering of the water level in the soil. The soil is doubtless 

 thoroughly aerated by this alternate rise and fall of the level of the 

 ground water. By this interesting system of tidal irrigation, which, 

 without any trouble beyond the first labor of digging the ditches pro- 

 vides for very perfect watering, drainage, and aeration of the soil, date 

 palms thrive in this region where the soil is as pure an adobe as the 

 clay of a brickyard. 6 



Such a system of combined irrigation and drainage can, of course, be 

 applied only where a river is backed up by high tides. No such con- 

 ditions occur, or at least not on any considerable scale, within the date 

 regions of the United States, since the region along the Sacramento 

 River in California where tidal irrigation can be practiced is so cooled 

 in summer by the cold winds and fogs from the Pacific that none but 

 the very earliest sorts of dates could mature. Along the Colorado 

 River, near its mouth in Mexico, it is possible that tidal irrigation 

 could be used in date culture, since the tides in the Gulf of California 

 are very high and the climate and soil in this region are favorable to 

 the culture of early and midseason dates/ 



a Kearney, Thos. H., and Means, Thos. H. Crops used in the reclamation of 

 alkali lands in Egypt, Yearbook, Department of Agriculture, 1902, p. 504. 



& Fairchild, D. G. Persian Gulf Dates and Their Introduction into America. Bui. 

 No. 54, Bureau of Plant Industry, U. S. Department of Agriculture, 1903, p. 14. 



c However, the head of tide water is only about fifteen miles above the mouth of 

 the river (as may be seen on fig. 10, p. 102), and consequently there is not room for 

 such immense date plantations as those described by Fairchild around Bassorah. 



