Timely Hints for Farmers. 113 



•shade the surface of the soil so as to check evaporation there, the 

 evaporation from their leaves is much more rapid than it would 

 be from the surface of the unshaded soil, if it were properly cul- 

 tivated. Thus, the destruction of weeds by cultivation not only 

 curtails the loss of plant food and of water, but the process produ- 

 ces all the desirable conditions of the soil mentioned above. 



A. J. McClatchie, 

 Department of Agriculture and Horticulture. 



GRAZING VERSUS IRRIGATION. 



No. 18, June 15. 



At the present time there is much controversy in Arizona as 

 to the disastrous effect of grazing, more particularly sheep graz- 

 ing, in lessening and rendering less constant the flow of water 

 from the mountain regions to the irrigated valleys. 



It is a well known fact that the agricultural interests of Ari- 

 zona depend entirely upon the amount of water available for irri- 

 gation and further, that all this available water flows from the 

 wooded mountain regions to the valleys below where it is taken 

 from the streams through canals and ditches to the various farms. 



The development of irrigation in Arizona has raised the value 

 of thousands of acres of land from practically nothing to a maxi- 

 mum value of one hundred dollars or more per acre. It has made 

 possible the building of villages and cities in regions which with- 

 out irrigation would be uninviting and uninhabitable. 



Through irrigation, agriculture in Arizona has prospered 

 until today it is the greatest and most enduring industry in the 

 Territory and gives employment directly and indirectly to more 

 people than all other industries combined. When we consider the 

 great value of available water to Arizona agriculture we can read- 

 ily see the necessity of giving the closest attention to its conserv- 

 ation and of guarding against every condition that can be over- 

 come by man that lessens or renders more irregular its flow. 



It is universally recognized the world over that soil covers, 

 including forest, chaparral and all other vegetable growth as well 

 as the litter and humus from this growth, are the great conserv- 

 ators of moisture. All growth tends to bind the scanty soil to the 



