1917] Kennedy: New (trasses for California. I - 



inches is precipitated. It is the so-called dry years thai cause a short- 

 age in all farm crops not under irrigation, and interfere seriously 

 with the pasturage on the ranges. The tneaD annual temperature is 

 62.7° F, with a known maximum of 112 F. and a minimum of 16 I- - . 

 Intense sunshine prevails throughout the summer. 



Technically the soil is known as Yolo silt loam. Professor C. P. 

 Shaw describes it as follows: 



A fine, smooth-textured brown soil at the surface, {Trailing at about thn 

 to a light brown subsoil containing slightly more clay loam or .lay. It i- usually 

 free from gravel. The soil when wet has a tendency to run together and l» • 

 puddled, preventing the free downward percolation of water. On drying it 

 tends to form a crust on the surface. If plowed when wet it forms hard clods 

 and lumps. "When handled in the proper condition of moisture, however, 

 comes loose and mellow. It has good moisture-holding capacity, is very pro- 

 ductive, and adapted to a wide range of crops. 



That the soil has exceptionally good moisture-holding capacity, 

 especially at the lower depths, is shown by the following furnished 

 ns by Professor B. A. Madson. The figures represent an average of 

 several plots believed to be similar in all essential details to that on 

 which the Harding grass was grown. 



Moisture Content of Soil, 1916, Davis 



The land on which the experiment with Harding grass was con- 

 ducted had for many years previous been cropped to grain. No 

 manure, artificial fertilizer or irrigation were given the plot, nor 

 could it have been affected by moisture from any adjacent irrigation. 



A strip six by eighteen feet was cut from the plol od May 25, 

 1916, the second year (pi. 7). The estimated green weighl of forage 

 per acre was twenty tons and of cured hay three tons. There still 

 remained on the ground a dense aftermath which would have fur- 

 nished good pasturage. The average yield under field conditions 

 can not be ascertained until the grass has been grown on a larger area. 



The remainder of the twentieth-acre plol was allowed to go to 

 seed. From this we harvested seventeen pounds of seed, 13 per cenl 



