CAUSES OF DETERIORATION. 47 



growth and late fruiting-, with the probable result of a smaller crop. 

 American cotton planters are familiar with the fact that too nuich 

 rain often cuts clown the crop by inducing additional growth near the 

 beginning of the fruiting period. A whole crop of buds or young 

 bolls may be shed that Avould have groAvn to maturity if the weather 

 had continued dry. 



Cotton growing on lands along permanent watercourses in the 

 Zagazig district, where the water table must have been kept within a 

 few feet of the surface, did not show any serious imi>airment except 

 for a few rows along ditches or ponds that supplied water practi- 

 cally on the surface. The small size and pale color of one or two rows 

 along the dikes often indicated serious injury by the close proximity 

 to water, but usually there was a rapid improvement farther back. 

 A recent publication gives the results of many investigations of 

 water level in wells and concludes that the modern system of irriga- 

 tion has had no serious general effect in raising the level of the sub- 

 soil water. On the other hand, it is pointed out that a secondary 

 artificial water table may be formed when superfluous irrigation water 

 collects over an impervious subsoil layer." 



Disease also may play a part in the decline of production. As 

 pointed out by Mr. Fletcher, in the vicinity of Gizeh some of the 

 fields of cotton show irregular patches of very inferior plants, with 



" Ferrar. H. T. On the Creation of an Artificial Water Table in Egyiit, Cairo 

 Scientific Jonrnal, vol. 4. p. 153, Jul5% 1910. 



The conclusions of this pai^er are stated as follows : 



" It is reasonable to suppose that a small quantity of water has been retained 

 by the alluvium each succeeding year, for it is not likely that a great augmenta- 

 tion of subsoil water would take place in a year or two, and in the absence of 

 substantiated evidence we must assume that by degrees water has been accumu- 

 lating in the soil since the introduction of perennial irrigation. Observations 

 made in the provinces of Menufla and Gharl>ia have shown that at the present 

 time (May 1) a layer of saturation may be found which is seldom more than 

 two meters below the soil surface. The upper surface of this artificially 

 saturated layer has been called the artificial water table. 



" Some misapprehension exists with regard to the water which is found in 

 the Nile alluvium and it will be of interest, therefore, to state tentatively two 

 main conclusions drawn from observations made at more than 150 experi- 

 mental tube wells which have been under observation during the past year. 

 The observations made at these wells in T>ower Egypt all suiiport the view 

 that there are two water tables : 



"1. A natural water tabic which is independent of the works of man. except 

 locally where extra permeability allows a constant supply of irrigation water 

 to he added. 



"2. An artificial aater table uhich was created by the act of tlic introduction 

 of perennial irrigation by Mohammed Aly Pasha. It is thought that this arti- 

 ficial water table has gradually become higher, oiring mainly to excessive 

 watering of crops, until at the pi'esent day it has a deleterious effect upon the 

 fertility of the soil." 



77267°— Bui. 210—11 4 



