MANURES. 2M 



To attach a money value to the above ingredients would 

 be a very difficult matter, and in any case the actual 

 manurial value would not represent the total benefit derived 

 by the application of these amounts of valuable ingredients 

 to the soil by means of an inundation. As already men- 

 tioned, the mechanical effect on certain soils and the fact 

 that injurious salts are washed down beyond the reach of 

 plants, attaches a value to warping on certain soils which 

 may be in excess of the manurial gain. It must not be 

 lost sight of, however, that very considerable quantities of 

 soluble nitrogen must be lost to the soil by leaching. 

 If we value the ingredients above at their present prices 

 in ordinary commercial manures in Egypt viz: potash 

 and phosphoric acid at 2d. (8ms.) per lb., and nitrogen at 

 7d. (28ms.) per lb., we have the following result: 



.<'. s. d. P.T. 



99 Ibs. potash at 2d. per lb. 16 6 = 80 i 



30^ ,. phos. ac. at 2d. per lb. = 5 1 = 24^ 



m ., nitrogen 7d. .. = 10 2^ = 49^ 



= 1 11 9i or 154* P.T. 



Consequently, at soluble commercial fertilizer rates, the 

 value of the mud deposited on a feddan is approximately 

 equal to P.T. 150. We have now, however, to take into 

 consideration, not only the fact that the various basins do 

 not receive an equal amount of silt for the reasons already 

 given, but also that its manurial ingredients are not in 

 those available forms in which they exist in the manures 

 with which we have compared it viz : sulphate of po- 

 tash, superphosphate and nitrate of soda, while on the 

 other hand to estimate the real value of such a system of 



