COMPOSITION OF NILE MUD DURING FLOOD. V 



sediment per acre, or between G and 7 tons. The soil thus receives 

 annually this coating of mud, the chemical nature of which has given 

 rise to very divergent views on the part of chemists, chiefly owing, it 

 is believed, to the manner in which samples for analysis have been 

 taken. The analyses made by Doctor Mackenzie at the Scliool of 

 Agriculture are considered the most reliable obtainable and are the 

 average of many determinations. 



COMPOSITION OF NILE MTJD DURING FLOOD. 



The addition of 15,000 pounds per acre per annum of sediment con- 

 sisting of nitrogen, 0.12 per cent, phosphoric acid, 0.21 per cent, and 

 potash, 0.G8 per cent, would give to tlie soil 18 pounds of nitrogen, 31^ 

 pounds of phosphoric acid, and 102 pounds of potash. These <iuan- 

 tities, when compared with the general composition of Egyptian soils 

 and with the results which have been obtained by actual manurial 

 experiments, are quite consistent. Egj'ptian clover, as is well known, 

 is very extensively grown in Egypt, and the deficiency of Nile mud 

 in nitrogen has, no doubt, to a very great extent been comi3ensated 

 for in this manner. Roughly speaking, cultivation in the basins means 

 one crop yearly, the flood providing sufficient water and raanui*e for 

 the raising of this crop under a system of rotation. In tlie basins, 

 where the chief crops are cereals, beans, and clover, this is true as 

 regards the matter of manure supply, but when irrigation is practiced 

 by means of wells or from the Nile the need for manure at once 

 becomes pressing. In fact, this interdependence of manure and water 

 is always most prominently brought out in any irrigated country. 



An examination of the manurial ingredients added to the soil dur- 

 ing the inundation of the basins will at once indicate that while suffi- 

 cient phosphoric acid and potash are added to grow an ordinary crop 

 of wheat or barley, this is not true as regards nitrogen, and were it 

 not for the alternation of clover and beans with the cereal crops the 

 growth of the latter without nitrogenous manures would be impossible. 

 The fact that it is found imi)ossible to grow two wheat crops satisfac- 

 torily in succession is an indication that so far as nitrogen is concerned 

 the Nile mud does not supply a sufficient quantity. A bean crop, 

 which removes more phosphoric acid and more potash, but which 

 obtains its nitrogen largely from the air, is successfully alternated 

 with it. 



IRRIGATION AND FERTILIZERS. 



As the crops in the basins are generally grown without irrigation, 

 manures, as already mentioned, are but seldom used. The wheat crop 

 under such circumstances will average some 30 or 35 bushels per acre, 

 and often grows to the height of a man's shoulder. The bean crop is 

 a most important one in Upper Egypt, providing, as it does, the staple 

 food during the summer and flood months, not only for Upper Egypt, 

 but to a considerable extent also for Lower Egypt, while the export 



