126 



FORESTRY AND IRRIGATION 



March 



21OO Metres 



5 *1 



150ft 



PrCi\ 



3 



Get n ct,L 



Dr-ivt-n 



FIG. I. FIRST PLAN OF DRAIN ARRANGEMENT. 



FLOODING THE LANDS. 



After the canals and drains are dug 

 and the land is sufficiently level to per- 

 mit uniform flooding, water is turned 

 into each gata to a depth of 4 inches. 

 When possible this depth is maintained 

 until the land is ready for a crop, but 

 during the season of low water in the 

 Nile the use of water for reclamation 

 purposes is not permitted, so that there 

 are times during the year when this 

 land has to remain dry. 



During the time the water remains 

 upon the land the salt which the soil 

 contains is dissolved and carried away 

 by the drainage w^ater. The drainage 

 water is very salt and is said to contain 

 at times over 10 per cent of sodium 

 chloride. 



On some of the land one season's 

 washing is sufficient, but as a rule the 



land is washed two years before the soil 

 is sweetened sufficiently to permit crop 

 growth. If the first season's washing 

 has not sufficiently sweetened the land, 

 it is plowed during the summer months, 

 when water is not abundant, in order 

 to reduce the surface evaporation to a 

 minimum. 



At the end of the second year the 

 land is usually sufficiently sweetened 

 for some crop. Samples of the soil are 

 examined for the percentage of sodium 

 chloride content, as experience has 

 shown that this is an indicator of the 

 condition of the land as regards crop 

 growth. The first crop to be grown 

 is barnyard grass (Panicum crus-galli), 

 called by the natives "dineba." The 

 seed of this plant is obtained from the 

 screenings from the rice mills, and as 

 it is a by-product it is very cheap. If 

 the growth of this grass is good, the 



21OO 



s 



o 

 5 

 5 



i.a.1 



Dr-aCrc 



FIG. 2. SECOND PLAN OF DRAIN ARRANGEMENT. 



