4 BULLETIN 1031, U. S. DEPARTMENT OF AGRICULTURE. 



Kange Eeserve ^ for a study of the problems involved. Investigations 

 started soon afterwards are still in progress. Preliminary results 

 were j)ublished in 1917.^ The object of this publication is to present 

 results to date, with special reference to the period of drought in 

 1916 to 1918, inclusive, and to outline the management and investi- 

 gations proposed for the reserve in future based upon results and 

 experience for 8 years, beginning in 1912. 



JORNADA RANGE RESERVE. 



The Jornada Range Reserve is an area of approximately 202,000 

 acres of typical semidesert range lying in a basin adjacent to the 

 Rio Grande Valley in Dona Ana County, N. Mex., about 50 miles 

 north of the Mexican boundary. The major portion of the area 

 is a fiat to slightly rolling plain varying in elevation from about 

 4,100 to 4,T00 feet, with a small mass of igneous mountains, the 

 Dona Anas, at the southwest corner. The eastern portion of the re- 

 serve, about one-fourth of the total, includes the western slope of the 

 San Andres Mountains. 



The locality is one of the most arid in the Southwest. Records 

 for 57 years, at State College, N. Mex., about 15 miles south of the 

 reserve, show an average annual precipitation of 8.60 inches, with 

 precipitation for individual years as high as 17 inches and as low 

 as 3.50 inches. The main rainy season occurs in July, August, and 

 September, with an average of 4.50 inches during these three months. 

 Temperature as high as 106° is common in summer, with almost con- 

 tinuous high winds, low humidity, and consequently high evapora- 

 tion. 



On the plains and foothills the soil ^^ shows an almost entire absence 

 of humus, and there is no change in texture with depth, except such 

 as may be purely geological. The lime content is very high, and a 

 highly limy layer or " caliche " is characteristic. The development of 

 this caliche layer is greatest under sandy or gravelly soils and least 

 under the heavier clay soils. 



On the plains light-textured soils, principally redish sand loams, 

 loamy sand, and loose incoherent wind-blown soils predominate. 

 On the rolling plain near the foothills of the mountains, areas of 

 coarse gravelly soils are found, and in the center there are flats of 



1 The Jornada Range Reserve was created by Executive Order May 3, 1912, at the 

 request of the Department of Agriculture, witli tiie idea of securing a complete range 

 unit for conducting experiments and demonstrations in range management under con- 

 ditions existing in southern New Mexico and similar country in adjoining States. The 

 boundaries were slightly modified by Executive Order Apr. 24, 1916, and at present include 

 about 202,000 acres. Since May 1, 1915, the investigations have been made by the 

 Forest Service of the Department of Agriculture. 



" Jardine, James T., and Hurtt, L. C, Increased Catlle Production on Southwestern 

 Ranges, U. S. Dept. Agr. Bull. 588, 1917. 



2" Classification of soils on the reserve made by U. S. Bureau of Soils. 



