IRRIGATION AND DRAINAGE 107 



Not all crops will pay for irrigation. Some crops are 

 much more profitable than others because of market conditions 

 and other influences. In regions where drouths are not too 

 severe; there are many crops which it will not pay to irrigate. 

 Any gardener raising a few special crops must determine for 

 himself whether these crops can be irrigated with profit. 

 For home and school gardens, the element of profit is usually 

 not one of vital consideration. If some plan of irrigation is 

 installed, all parts of the garden, whether at home or at school, 

 will be given the benefit of it. 



The water supply is obtained fxom such sources as 

 dammed streams, ■wells, elevated springs, waste water from 

 dwellings and barnyards, rain-water basins or tanks. Very 

 small streams are sometimes easily dammed in narrow cuts 

 so as to impound a sufficient supply of water to carry on 

 considerable irrigation. Wells that are not too deep often 

 supply plenty of water for irrigating gardens and large fields. 

 The overflow from troughs where stock are watered may be 

 used directly upon the garden. 



Water is raised or forced to the point desired for irri- 

 gation purposes in a number of different ways. In some cases 

 gravity carries the water from elevated springs to the garden. 

 Such cases are rare. Windmills are perhaps more commonly 

 used than any other method. The water is pumped to an ele- 

 vated tank and from here it is conducted as desired. Water 

 pumps may be operated by water-wheels, gasoline engines, 

 steam engines, and even by hand or horse power. Hydraulic 

 rams are frequently used where a slight fall is found in a 

 stream, sufficient to operate the ram. A constant stream of 

 water is thus sent to a reservoir or tank higher than the garden 

 and from there it is used for irrigation. Of these different 

 methods the cheapest are perhaps the windmill and hydraulic 

 ram. 



Conveying the Water. — The simplest method of convey- 

 ing the water from any supply provided is by hand. This is 



