136 Journal of Agricultural Research voi. xiir, no. 2 



OUTUNE OF EXPERIMENTS AND DESCRIPTION OF WEATHER 



CONDITIONS 



In the preceding discussion literature has been cited only for the pur- 

 pose of an introduction to the presentation of the data obtained in the 

 following experiments. No attempt has been made to make the review 

 of the literature complete or even extensive. It is believed that the lim- 

 ited data obtained in the field tests hereafter described will be of value 

 not only in establishing the climatic limitations of the sorghums but also 

 in indicating the principles which underlie the results of numerous "Date 

 of planting" experiments with this crop. 



It has been noticed that the sorghums behave very peculiarly in local- 

 ities which have continuously low temperatures. In 191 5 an attempt was 

 made to obtain data on this effect of low temperatures by growing cer- 

 tain selected varieties of sorghum under widely varying cUmatic con- 

 ditions. Plantings were made at Puyallup, Wash.; Chico, Berkeley, 

 Bard, and Pasadena, Cal. ; and Chillicothe, Tex. It was thought that 

 these points represented the extremes of humidity and heat, as well as 

 the more intermediate conditions. At Puyallup the temperatures and 

 the percentage of sunshine are low through the summer, and the nights 

 are cool. At Berkeley there is high humidity with moderate tempera- 

 tures, while at Chico and Bard the temperatures are high, the humidity 

 low, and the sunshine abundant. At Pasadena and Chillicothe somewhat 

 intermediate cUmatic conditions prevail. 



Very complete notes were made regarding the growth of these sorghums 

 at Berkeley, but the plots were not irrigated; and as there was practically 

 no rain from May until September, the lack of soil moisture may have 

 exerted as much influence on their growth as did the weather factors. It 

 has seemed best, therefore, to substitute for the Berkeley results of 191 5 

 those obtained at Chula Vista in 191 6. Summer conditions at Chico and 

 Bard, Cal., are so similar and the results so nearly alike that only the 

 results at Bard are given. In Uke manner Chillicothe was chosen to 

 represent intermediate climatic conditions. 



Table I gives in considerable detail the chief features of the weather at 

 ChilHcothe, Bard, and Puyallup in 1915 and Chula Vista in 1916, showing 

 the maximum, minimum, mean, and normal temperatures, the mean 

 relative humidity, the inches of rainfall, and the percentage of actual to 

 possible sunshine for each month. 



For ChilHcothe only the rainfall and mean monthly temperature rec- 

 ords were obtained directly at that point. The relative humidity and 

 percentage of sunshine are those recorded by the United States Weather 

 Bureau at Abilene, Tex., and the remainder of the data was taken from 

 the Weather Bureau records for Quanah, Tex., 13 miles west of Chilli- 

 cothe. It is probable that the relative humidity at Abilene, 130 miles 

 south of Chillicothe, is a trifle too low and the percentage of sunshine may 



