J. A. Prescott 



225 



Table VII. 



Amounts of nitrate found in the surface soil of a cotton field. 



Temperature „_ 



at the time of Parts per million Moisture 



sai^jling 



IV-O" C. 

 19-9° C. 



19]7. 



Date 

 Mar. 6 

 Mar. 22 

 Apr. 30 

 May 26 

 Jun. 17 

 Jun. 22 

 Jun. 26 

 Jul. 10 

 Aug. 1 

 Sep. 4 

 Sep. 15 

 Oct. 24 



290° C. 

 26-5° C. 

 31-4° C. 



27-6^ C. 

 280° C. 

 270° C. 

 25-5° C. 

 24-8° C. 

 20-5° C. 



Nitric nitrogen. 



Parts per million 



of dry soil 



210 

 35-5 

 28-3 

 22-5 

 16-8 

 26-2 

 22-7 

 30-2 

 33-3 

 21-4 

 181 

 15-8 



16-2 

 20-0 

 19-9 

 16-8 

 15-6 

 28-4 

 22-4 

 14-3 

 16-5 

 210 

 16-7 

 i7-3 



Ayricultural operations. 



March 6. Seed sowing. 

 March 8. Irrigation. 

 Other irrigations: March 22, April 28, May 25, June 21, July 12, July 31, August 19, 



October 2. 

 October 28. Plants removed from the ground. 



The cotton field of 1918. 

 The characteristics of the observations made in 1918 are quite 

 similar to those observed in 1917. The results are given in Table VIII. 



1918. 



Agricultural operations. 



Seed sowing: March 5. 



Irrigations: March 5, April 13, May 23, June 16. July 4. July 22, .'Vugust6, Septembers, 

 October 5. 



