AGRICULTURE. 15 



they are fairly friable, though when wet they are decidedly sticky. 

 Owing to deficient regional drainage, extensive areas are in native 

 grasses or exist as alkali flats supporting only a growth of salt grass. 



Samples collected in sec. 6, T. 44 N., R. 10 E., showed 3.61 per 

 cent of total alkali salts in the surface foot and 1.91 per cent in that 

 portion of the soil profile included between depths of 12 and 30 inches. 

 In sec. 8, T. 43 N., R. 10 E., about 1 mile southeast of Moffat, the 

 surface foot was found to contain 0.48 per cent of alkali ; the subsoil 

 to the depth of 24 inches carried 0.38 per cent, an amount which is 

 tolerated by the more alkali-resistant crops, but sufficient in con- 

 centration to cause injury to young vegetables and nearly all staple 

 farm crops of the valley. 



The district lying south of Moffat and east of Mosca and Hooper, 

 including the valley trough and eastern slope, is covered mainly by 

 wind-blown sands, broken by barren playas or flats, which during 

 wet weather are occupied by shallow alkali lakes and ponds. The 

 region is sparsely settled and is inadequately supplied with water for 

 irrigation. Artesian wells may be developed, but owing to unfavor- 

 able soil and drainage conditions this region gives but little promise. 

 Where utilized the soils are devoted mainly to grazing. 



The conditions observed in a brief reconnoissance of the northern 

 part of the valley in September, 1910, are in some respects disap- 

 pointing, yet with adequate irrigation and drainage facilities, the 

 soils should prove superior in point of productiveness to the porous 

 sandy and gravelly soils of the central and eastern parts of the 

 valley. 



AGRICULTURE. 



Mexicans entering from New Mexico first settled the valley, lo- 

 cating along the Rio Grande bottoms, where a permanent water 

 supply was available. Stock raising was the principal industry, and 

 irrigation consisted mainly of desultory wild flooding to promote the 

 growth of native grasses. Later there followed a considerable in- 

 flux of American settlers, French Canadians, Scandinavians, and 

 others of foreign birth or extraction. 



The first important irrigation canals were constructed in the 

 sixties to supply lands adjacent to the Rio Grande. Some time later 

 other and more extensive systems taking water from the Rio Grande 

 for the valley floor and slopes were projected, and within a few 

 years a number of canals had been completed. These systems cov- 

 ered most of the district on both sides of "the Rio Grande, and west 

 of the towns of Mosca and Hooper, which became important grain 

 shipping points in the late eighties. From here irrigation extended 

 westward to the coarser gravelly soils of the San Luis series, cover- 

 ing the more elevated slopes of the Rio Grande alluvial fan. 



