THE IRRIGATION AGE. 



the excessive evaporation losses from soil surfaces. The 

 results of our experiments thus far seem to show that 

 about one-half of the water which is spread over fields 

 in irrigation passes off into the air without benefiting 

 the plants. 



The greater part of this loss occurs during the time 

 when water is applied and for a day or two afterwards. 

 On orchard soils in warm weather the evaporation from 

 the soil may reach 70 tons per acre in 24 hours. Now 

 it has been shown that the cultivation of the surface 

 to a depth of six inches prevents more than one-half 

 of the subsequent loss. 



The use of well pulverized soil mulches is another 

 means of checking evaporation. The tests conducted 

 in southern California show that a 10-inch layer of 

 dry granular soil gives complete protection, that an 

 8-inch layer will save five-sixths of the moisture be- 

 neath, and a 4-inch layer two-thirds of the moisture. 



COLORADO. 



Irrigation as a State Developer. 



BY JOHN EDWABD BUCK. 



PUEBLO, Colo., July 28. Colorado is a State of 

 unlimited resources, both mineral and agricultural. In 

 acres the area of the State is 66,560,000, one-third of 

 which is arable. More than 2,000,000 acres are already 

 under cultivation, and 4,000,000 acres can be reclaimed 

 by means of irrigation. Here as elsewhere throughout 

 the semi-arid region through which we have traversed 

 over the Northern Pacific, Southern Pacific and San 

 Pedro Baflroads, irrigation is a great State developer, 

 and has already worked miracles in enhancing the 

 quality and increasing the yield of cereals, fruits and 

 vegetables. 





Garden Spot, near Blackfoot, Idaho. On American Falls Canal. 



Wherever it is practical and for deep-rooted plants. 

 deep irrigation should be practiced, since it retards 

 evaporation. On a citrus orchard near Kiverside, in 

 August of 1905, for every 137 gallons which were 

 evaporated from surface irrigation, only 98 gallons 

 were evaporated from furrows nine inches deep. 



Some crops cannot be cultivated during the period 

 of growth, but even in the case of these much can be 

 done to check evaporation from the surface. One 

 means is to irrigate less often and apply larger quan- 

 tities. In following this practice the bulk of the water 

 will be placed beyond the reach of the agencies which 

 vaporize moisture. Another means which is frequently 

 employed is to apply the water after sunset. Tho 

 main factor in evaporation is temperature. Warm 

 water at 89 degrees Pahr. loses by evaporation about 

 seven times more than cold water at 54 degrees. Th<> 

 difference between day and night temperatures in tho 

 West is usually 25 degrees; hence the advantage of 

 supplying water after sunset. 



In many respects Colorado is unique. The State 

 may be said to be the summit of the North American 

 continent, for from its craggy apex rivers flow in every 

 direction. The headwaters of no less than five great 

 river systems are to be found in the melting snows of 

 Colorado's mountains. 



Colorado is almost midway between the oceans. 

 The clouds which rise from evaporation in the Pacific, 

 the Atlantic, the Great Lakes or the Gulf of Mexico 

 are largely dissipated before they get to Colorado. 

 Only the highest peaks and bare ridges catch the clouds 

 to extract their moisture to make them white mantles 

 of snow. Being high in elevation, Colorado enjoys a 

 cool climate. Being far from the sea, Colorado enjoys 

 a cloudless climate. This means a great deal of sun- 

 shine, without burning heat. There are other arid re- 

 gions, south of Colorado, but being lower down they 

 are too hot to make the finest quality in fruit or vege- 

 table. There are other high regions, further north, but 

 thev are so far north that the climate is too cool. The 



