100 Irrigation and Drainage 



November 1 and May 1. The tenth census gives the 

 average yield of wheat per acre as 6 to 13 bushels in 

 the south, and from 13 to 20 bushels in the northern 

 part of the valley. The average yield in California 

 in 1879, on 1,832,429 acres, is placed at 16.1 bushels 

 per acre ; while it is stated that certified records of 

 yields as high as 73 bushels per acre are recorded from 

 areas as large as 10 acres. 



If we consider the "dry farming" sections of the 

 state of Washington, where most of the wheat grown 

 has been the spring varieties, sown in April, and some- 

 times as late as May, and harvested in August or early 

 September, we shall have the growing season more 

 nearly the same as that in the corresponding latitudes of 

 the humid parts of the United States. Here, too, 

 the rainfall in amount is very nearly the same as that of 

 the district to the south for the corresponding period of 

 time, but the rains begin a month earlier and continue a 

 month later, so that the amount for the year is from 8.4 

 to 13.5 inches, or about 33 per cent more, while the 

 mean yield per acre was 23.4 bushels in 1879, as 

 against 16.1 bushels in California. There is here 

 in Washington, as in California, a dry period of 

 some 60 days, in which the crop is forced to come to 

 maturity. 



It appears, therefore, from the observations and 

 experiments regarding the number of inches of water 

 which may be used in producing a ton of dry matter, 

 and from practical experience in arid climates, that on 

 deep, fertile soils, well managed, good, paying yields of 

 wheat may be realized where the amount of rain is as 



