CHLORIDEAE 99 



appointed continually until they get to understand that the 

 abundance of vegetation in a region is a pretty close measure 

 of the precipitation (other things being equal). Desert or 

 arid land plants stand just about as thickly as they can and 

 live. The natural adjustment of the plants of a region to 

 their environment is a very delicate and well balanced one 

 and the only substitutions that can be made will be those of 

 plants that will endure conditions about the same as or more 

 unfavorable than those surrounding the native plants of the 

 region. The governing factor in New Mexico is more often 

 water than anything else. Under such circumstances the 

 farmer must ( 1 ) either develop more water for irrigation — 

 but in order to make this pay he must do intensive farming 

 of high priced crops: (2) so handle the water which falls on 

 his place as to get the greatest possible advantage from it — 

 i. e. keep the land in the best condition to absorb and retain 

 all the moisture that falls; or (3) cultivate some crop which 

 normally requires less water than the locality supplies, — no 

 such crop has yet been found or developed that will give as 

 desirable results as Blue Grama for a pasture grass in this 

 region. The natural conclusion then is that Blue Grama 

 should be encouraged ; but the farmer must not expect a 

 pasture of Blue Grama to produce acre for acre anything 

 like as much feed as Kentucky Blue Grass pastures where 

 the precipitation is 30 to 40 inches instead of from 10 to 15 

 inches annually. ..^ 



Much of the land now covered with Blue Grama grass 

 and its natural associates will no doubt ultimately be dry 

 farmed, but some pasture lands will have to be maintained 

 on the farms and it is very probable that the best grasses now 

 known for these lands are tlie native ones. There is lUtle 

 doubt in the author's mind that the productivity of such 

 pastures can be materially increased by the proper treatment, 

 and that such treatment will be given tlicm. The carrying 

 capacity, however, will always be small as compared with 

 pastures in the humid region with which we are all prone to 

 make comparisons and standardize our judgments. 



