124 BOARD OF AGRICULTURE. [Pub. Doc. 



the whole matter is no longer regarded from an experimental 

 standpoint. Irrigation is largely a matter of insurance, and 

 makes crop production more certain. When properly handled 

 it insures the germination of seeds, successful transplant- 

 ing and maximum yields, provided other conditions arc 

 favorable. 



Irrigation is very widely employed by greenhouse vege- 

 table growers. Probably 75 per cent of the growers of lettuce 

 under glass now employ the Skinner system of watering. It 

 is a great labor-saving device, and when properly managed 

 secures uniform distribution of water. 



Irrigation and the use of stable manures in vegetable grow- 

 ing have a very close connection. Although definite experi- 

 ments have not been made to determine the relation between 

 irrigation and the amount of manure to produce a maximum 

 yield, there is a consensus of opinion that irrigation makes it 

 possible to produce maximum crops with less manure than is 

 possible without irrigation; i.e., it is highly probable that 

 irrigation and the annual application of 25 tons of manure 

 will produce as large average annual yields as 40 tons with- 

 out irrigation. Yields are probably more frequently reduced 

 by lack of moisture than lack of fertility. This whole prob- 

 lem is of interest to vegetable growers because the supply of 

 city livery stable manure will likely become less and less 

 with the increased use of automobiles ; i.e., in the future our 

 great city markets will be supplied by vegetables grown far- 

 ther and farther away from the city, where operations need 

 not be so intensive and where an abundant supply of water 

 is available. 



The Humus Problem. 

 There is universal agreement among market gardeners that 

 the all-important factor in the annual production of large 

 crops is the maintenance of humus in the soil. Producers 

 near large cities have been able to keep up the supply of 

 vegetable matter by the proper use of stable manures. In 

 more remote districts growers have learned how to use cover 

 crops and manures so successfully that they can maintain 

 fertility and secure large crops without the use of stable ma- 

 nures. There are striking examples of such success in vari- 



