APPENDIX. 



POT EXPERIMENT WITH VARIOUS NITROGENOUS MANURES. 



The very extensive and growing use of artificial nitrogenous fertilizers in 

 Egypt renders the introduction of the new manures, prepared from atmospheric 

 nitrogen, a matter of no little interest. The production of these fertilizers bids 

 fair to increase very rapidly, especially should the new processes of Ostwald prove 

 successful on the large commercial scale. The interest is made even greater by 

 the possibility of these substances being produced in this country should the 

 Aswan Power Scheme become an accomplished fact. 



While there is no doubt that the final test of any fertilizer must always be 

 made on the large scale in the field, still there is always a great deal of information 

 to be obtained from experiments in pots, if these are carried out with sufficient 

 care. In this country, in summer, one's choice of crops which are at all suitable 

 for cultivation under these conditions is extremely limited, and indeed maize 

 appears to be the only plant available. Owing to its very rapid growth it is 

 evident that only those fertilizers which are of almost immediate availability 

 will prove of value. This fact must be borne in mind wnen considering the 

 results of the experiment now to be described. 



In comparing fertilizers which provide the same ingredient two courses 

 are open. Either equal money values of the various manures may be applied 

 and the increases in yield over a control plot compared, or equal weights of the 

 particular constituent (e.g. nitrogen) may be employed and the relative efficiency 

 calculated from the results by comparing the increases brought about by the 

 different manures with that obtained by some standard material, in this case 

 nitrate of soda. In the present instance the latter course was adopted. 



The pots used for this experiment each contained twenty-two kilos, of soil, 

 taken from the Nile bank. This had been thoroughly mixed and was consequently 

 uniform in character. The following table shows the quantity of the various manures 

 employed. These quantities are so calculated as to supply the same amount of 

 nitrogen as that contained in ten grammes of nitrate of soda (ninety-six per cent). 

 All the manures were applied in two equal dressings. The first hal f of the cyanamide 

 in Nos. 7 and 8 was applied before sowing, that in Nos. 11 and 12 after sowing, 

 at the same time as the remaining manures. Six grammes of sodium phosphate 

 and four grammes of potassium chloride were also applied to each pot. This also 



