TWO METHODS OF FARM IRRIGATION. 243, 



the result. This is due either to watcrlug-g-ing- the low places, or 

 burying- them under a layer of mud. Then agam it means a shock- 

 ing; waste of water ; because in trying- to wet all his land he has 

 used far too much water — water that should have been used on. 

 another piece of ground. If he wants to get a hig-h duty, that is,. 

 if he wants to irrigate as much land as po^ssible with the water at 

 his command, he must arrange to use all the surplus water and not 

 waste it. I remember once watching a farmer irrigate his field - 

 and was struck by the large quantity of water that poured oft the 

 lower end into a donga. This was an absolute waste of water, 

 and took place at a time when all the farmers along the furrow 

 \Vere complaining of a shortage. If men irrigate like that they 

 can never get the full value from the water. 



The lesson to learn from this is that the plot should have been- 

 graded to a unijorm surface. It is often difficult to induce: 

 t)eginners to realize the importance of doing this thoroughly ; but 

 it pays handsomely in the long run. For annual crops like oats, 

 wheat, etc., it means a yearly loss of money; while for a per- 

 manent crop, such as lucerne, it means not only a loss, but the 

 constant annoyance of knowing that you would be making more 

 money if it had been properly done in the first instance. When 

 lucerne is once well established, very few men would care to- 

 |)lough it, grade the plots, and plant again. Bear in mind the- 

 important fact that badly graded plots mean a waste of water,, 

 extra cost to irrigate, and almost always a reduced yield of crop. 

 Be cautious how you economize in preparing your lands, for it 

 may cost you far more every year afterwards. 



Having- levelled your ground, divided it into plots, and built 

 banks round them, the next points to consider are the sluices for 

 letting" the water in and out, the quantity of w ater to use, and the ■ 

 rate of delivery. If the water comes in too slowly, it takes so 

 long to spread that the top part gets more water than it needs and J 

 the lower part not enough. A large quantity is lost by evapora- 

 tion : there is a waste of water and a waste of time. If you turn 

 on too much water, the rush washes out great holes in the ground. 

 and often washes out the seeds and young plants. The amount of 

 water to be turned into one of your plots or basins can only be 

 learned by experience. It depends on the soil, slope, etc. As for 

 the basins, it is generally better to have them of a moderate size. 

 I ha\e heard of a basin in Mexico i,ooo acres in extent, and of 

 others about 20 feet square. In California they range from about 

 200 acres to less than half an acre. With very extensive basins 

 such a large flow of water is required that it becomes difficult to 

 manage ; while in small basins there should not be much waste of 

 water. Some successful irrigators use basins about half an acre 

 in extent ; but much depends upon the shape of the land to be ■ 

 irrigated. 



It pax's an irrigator to devote some time and attention to the 

 openings for diverting water into the basin or plots. Most of the 

 irrigators that I know simply dig out a place in the bank and 

 shovel the stuff into the furrow to form a dam. Then they dig 

 out the dam and throw the stuff back to fill up the opening. Every 

 time this is done there is a certain amount of earth washed awav,. 



