CHAPTER XXV. 191 



one ton of oranges or lemons; now, allowing 20,000 pounds of fruit 

 per acre, let us see how far one inch of water would take us. Oranges 

 contain in round numbers 18 per cent, of solid matter and 82 per 

 cent, of water, therefore, 20,000 pounds of fruit would contain 3,600 

 pounds of dry matter; if we multiply this factor by 200, the number 

 of pounds of water it takes to raise one pound of dry fruit, and with 

 this result, namely, 720,000, divide the total number of pounds in an 

 annual inch of water, we would get 54.5, which would represent the 

 number of acres of oranges producing 20,000 pounds of fruit per acre, 

 that one inch perpetual flow would supply, making no allowance for 

 water put into the ground by winter rains. 



SURFACE IRRIGATION. 



There are four systems of surface irrigation in general use in South- 

 ern California. The first method is a basin method where they cover 

 the whole of the ground; a double furrow runs down between every 

 other row of trees, the furrow large enough to carry from fifteen to 

 fifty inches of water. Let us trace this stream, starting from the 

 head ditch. The attendant breaks down the furrow enough to let all 

 the stream flow into the first basin, requiring from one to three min- 

 utes to fill it according to the size of stream and basin, every other 

 tree Is irrigated until the last tree is reached, when the attendant works 

 back, irrigating the trees he omitted on his downward course; thus 

 when the last tree is irrigated in both rows, the attendant is back at 

 the head ditch, where he can quickly turn the stream between other 

 rows without loss of time. The cost of making these basins is vari- 

 ously estimated from $1.50 to $2.50 per acre. 



The second method is also a basin method, the basins covering 

 the whole of the ground but without furrows. The water is run into 

 the first basin until it is filled; when a portion of the lower side Is 

 broken down and the water allowed to flow into the next basin; and 

 so on down through the whole row. When the last basin is filled and 

 while the water is still running, the attendant goes back to the head 

 ditch and turns the water into the next row of basins. 



The third method is where the basins are made only over a por- 

 tion of the ground, thus omitting to irrigate a part of the land. 



The fourth method is called the "Modern Method." It consists in 

 having a head ditch at the highest side of the orchard and running 

 the water down through small furrows to the lowe end. The num- 

 ber of furrows used varies from one to eight. It is an easy, conven- 

 ient and cheap method. 



