CEREAL EXPERIMENTS AT CHICO, CALIF. 9 
Wind. 
Wind velocities at Chico are exceptionally low. No wind data are 
available for Chico, but those recorded at the Biggs Rice Field 
Station, Biggs, Calif., during: the eight-year period from 1914 to 1921 
show that the maximum wind velocity seldom exceeds 12 miles per 
hour, while the average hourly velocity ranges from 2.4 miles in 
October to 4.2 miles in March. The Biggs Rice Field Station is 
located about 20 miles south of Chico, in more open country, but the 
conditions at the two points are very similar. 
Evaporation. 
Evaporation data from a free water surface were recorded at the 
Biggs Rice Field Station, Biggs, Calif., for the seven months from April 
to October, inclusive, in the eight-year period from 1914 to 1921, in- 
clusive. The amount of evaporation at this station closely approxi- 
mates what would be likely to occur at Chico, although the presence 
of irrigation water in the rice fields throughout the summer at Biggs 
probably results in reduced evaporation. The data show the highest 
rate of evaporation to be in June and July, when the average daily 
evaporation was 0.29 inch. The average total evaporation during 
the seven months was 45.36 inches. 
One of the most important factors conducive to this large evapora- 
tion is the great number of clear sunny days. Table 6 shows the 
annual and average number of clear, partly clear, and cloudy days 
at Chico in the 12-year period from 1910 to 1921, inclusive. The 
heavy draft on soil moisture by growing crops and evaporation during 
the long dry season leaves the soil dry and hard and well depleted 
of soil moisture. 
Table 6. — Annual and average number of clear, partly clear, and cloudy days at Chico, 
Calif., in the 12-year period from 1910 to 1921, inclusive. 
Number of days. 
Number of days 
Prevailing 
wind. 
Year. 
Prevailing 
wind. 
Year. 
Clear. 
Partly 
cloudy. 
Cloudy. 
Clear. 
S^louay. 
1910 
252 
•77 
86 
South. 
1917 
245 
63 
57 
Southeast. 
1911 
259 
26 
80 
Do. 
1918 
224 
83 
58 
Do. 
1912 
218 
32 
116 
Do. 
1919 
257 
53 
55 
Do. 
1913 
235 
21 
109 
Do. 
1920 
239 
76 
51 
1914 
240 
24 
101 
Do. 
1921 
234 
58 
73 
234 
217 
29 
65 
102 
Do. 
Southeast. 
1916 
Average. 
237.8 
46.4 
81 
EXPERIMENTAL METHODS. 
PREPARATION OF THE LAND. 
The customary method of soil preparation for a crop of grain is to 
summer-fallow or to plow as early as possible after the first fall rains. 
The proper time to plow is early in spring, usually the latter part of 
March or April, when weeds and other vegetation may be turned 
under and the soil is in proper condition for plowing. Tillage to 
keep down weeds usually is not required during the dry summer 
a Jones, Jenkin W. Rice Experiments at the Biggs Rice Field Station in California. I". S. 
Agr. Bui. 1155, 60 p., 15. fig. 1923. 
48604—23 2 
Dept. 
