72 THE MONTHLY BULLETIN. 



River is an illustration. In such cases we must watch that the water 

 table does not rise fatally near the surface, and that injury from the 

 rise of alkali is not risked. Silt soils along rivers in California are 

 usually so well drained that danger is greatly lessened. 



Four methods are used in our arid regions to bring water to the 

 plants: Strip, or border, check, flooding and ditches. See Farmers' 

 Bulletin, U. S. Dept. Agr., No. 373. 



Border irrigation is used when much water is at command ; it is 

 inexpensive to operate. The cost of preparation is an objection. Here 

 long narrow strips are surrounded by levees to retain the water. A 

 head ditch at the upper end with acljustable gates lets in the water. 

 The ground must be well graded. If the grade is considerable, the 

 separate pieces nmy be contoured. This method is much iLsed in parts 

 of California. 



The check system has small square or rectangular areas, also enclosed 

 each with a levee. If necessary, these may run in contour lines. Water 

 is introduced into each by a gate. In applying water, the highest check 

 is watered first. In both of these methods the irregularities are incon- 

 venient. This method has the same advantages as the border, but to a 

 less degree. These small checks are desirable in very sandy areas and 

 in very stiff clay. The objections are also the same, rather exaggerated. 



The flooding method is most common. It permits quite a grade and 

 even depressions. By means of laterals from the head ditch water is 

 carried to the highest points, and there laterals follow contour lines. 

 Canvas dams, or manure, may be placed in the laterals to hold back the 

 water to irrigate each succeeding level in turn. 



In certain places furrows are used much as they are in orchards, 

 especially in the case of irrigating cover crops. Here slow percolation 

 gives the needed water supply. 



Usually three irrigations a season are sufficient though many irrigate 

 after each cutting. Of course the character of the soil is the factor 

 which controls in this case. Clay holds moisture much longer than does 

 sand. As in orchard work, the plants should never feel the need of 

 water. Such vigor as shown in the alfalfa fleld calls for a great water 

 supply. 



ALFALFA IN THE ORCHARD. 



Orchardists often grow alfalfa among the trees. If as is said : 

 "Alfalfa boards itself and pays for the privilege," then this practice 

 is not to be brushed lightly aside. Mr. Hampton of Corona has grown 

 alfalfa in his citrus orchard, he thinks with advantage. I have seen 

 an olive orchard in Tehama County which had been greatly benefited 

 apparently by the presence of alfalfa. I am told that the best orchards 

 in Yakima, Washington, are growing great crops of alfalfa as well as 

 of finest apples. In case alfalfa is grown among the trees great quan- 

 tities of water must be at command, else it is not to be thought of. Of 

 course it would be better for the orchard to leave the alfalfa wholly for 

 manure, but it might pay better to cut it and feed to stock, using the 

 manure formed to fertilize the orchard. The large amount of water 

 demanded by alfalfa, may be harmful, possiblj^ fatal, to some varieties 

 of fruit trees. 



