BULLETIN 018, U. S. DEPARTMENT OF AGRICULTURE. 





JON. 



FEB. 



mr/t/f. 



ap/t. 



WAY JUNE JULY flUG. 



SEPT. 



OCT. NOf. D 



110 



100 



so 



eo 



70 

 60 



so 



4-0 



30 



1916 

















































f 















\ 





















































aun^. 





















































































The Laguna district is an irregularly shaped valley of about 2,000 

 square miles, almost completely surrounded by mountains. It is 

 situated about 250 miles south of the Rio Grande, on the boundary- 

 line of the States of Durango and Coahuila, Mexico. It derives its 

 name from the fact that it was formerly a lake (laguna) serving as 

 an outlet of the Rio Nazas. As recently as 1837 a part of the Tla- 



hualilo property was 

 under water and at 

 present there are con- 

 siderable areas near 

 San Pedro, Coahuila, 

 which are filled with 

 water when the river 

 is at a flood stage. 

 The soil is a deep al- 

 luvial deposit, very 

 rich, and well adapted 

 to the culture of 

 cotton. 



CLIMATIC CONDITIONS. 



Torreon, the prin- 

 cipal city of the Lagu- 

 na, has an elevation 

 of about 4,000 feet. 

 Generally speaking, 

 this section of the 

 country receives an 

 average of 6 to 8 in- 

 ches rainfall annually, 

 but in 1919 the pre- 

 cipitation was very 

 close to 15 inches. 



In the months of 

 May, June, July, and 

 August temperatures 

 range from 95 °to 100° 

 F. during the day 

 down to about 64° (average) at night. In the winter months 

 of December, January, and February the thermometer registers from 

 69° (average maximum) to as low as 24° F. 



Figure 1 gives a graphic record of the thermometer readings taken 

 at the station in Ciudad Lerdo, Durango. 



It must be kept in mind that the above charts represent the aver- 

 age of the daily readings for each month and not the extremes which 



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Fig. 1. 



-Average mean temperature for 1918 and 1919 at 

 Ciudad Lerdo, Durango, Mexico. 



