230 Nitrification in Egyptian Soils 



The above results indicate very clearly that the sowing of maize on 

 ridges results in the waste of a considerable quantity of nitrate. The 

 very high values obtained for the tops of the ridges show the effect of 

 capillarity in the accumulation of soluble salts in the surface soil under 

 arid conditions of agriculture. The high value for the sodium chloride 

 and for the total salts is also an index of this factor. 



As would be expected from the above considerations, the maize 

 crop in Egypt responds readily to nitrogenous manuring, particularly 

 to nitrate of soda. 



The question of the relationship between the cultivation and 

 manuring of the maize crop is illustrated by two series of experiments 

 conducted at Bahtini during 1917 and 1918. In 1917 each treatment 

 was repeated on five plots and the maize was grown on ridges; the 

 results in Table XIII relate to this series. In 1918, each treatment 

 was repeated on four plots and the maize was grown on the flat at two 

 different spacings. The waste of nitrate on the ridges indicated in 

 Table XIII is bi'ought out in the yields obtaijied at the end of the season. 



Table XV. 

 Yields of maize. Bushels per acre. 



1917 Crop: cultivation on ridges 



Unmanurcd ... ... ... ... ... 311 ± 1-4 



Nitrate of soda (.333 lbs) applied before sowing ... ... ... 43-5 ± 0-9 



Nitrate of soda (333 lbs) applied half before sowing and half at first 



irrigation 47-7 ± 2-1 



Nitrate of soda (333 lbs) applied lialt at tlie first irrigation and half at 



the .second 50-8 ± 3-1 



Nitrate of soda applied at the first irrigation ... 49-2 ± 1-9 



Ammonium sulphate (equivalent) applied before sowing 39-0 ± 1-1 



1918 Crop: cultivation on the flat 



Unmanured 370 ± 1-9 



Nitrate of soda (333 lbs), half at first irrigation and half at second 



irrigation. Close planting ... 62-8 ± 0-8 



Nitrate of soda (333 lbs) applied before sowing. Clo.se planting ... 60-2 ±1-2 



Ammonium sulphate (equivalent) before sowing. Close planting ... fil-2 ±0-8 

 Nitrate of soda (333 lbs), half at first irrigation and half at second 



irrigation. Wide planting ... ... ... ... SS-S ± 0-7 



Nitrate of soda (333 lbs) applied before sowing. Wide planting ... .'i8-9 ± 0-5 



Ammonium sulphate (equivalent) before sowing. Wide planting ... 59-8 ± 0-7 



Close planting at 35 em. Wide planting at 55 cm. 



