EFFECT OF CLIMATIC FACTORS ON THE HYDRO- 

 CYANIC-ACID CONTENT OF SORGHUM 



By J. J. WiLLAMAN and R. M. West, Assistant Chemists, Agricultural Experiment 

 Station of the University of Minnesota 



[In collaboration with F. S. Harris, Agronomist, Utah Agricultural ExperiTnent Station; L. E. Call, Agron- 

 omist, Kansas Agricultural Experiment Station; and Beyer Aune, Superintendent, Belle Fourche Experi- 

 ment Farm., Newell, S. Dak.] 



INTRODUCTION 



The present experiments are a continuation of those carried out in 

 1914 (10)^ on sorghum (Sorghum vulgare). In the latter a correlation 

 was sought between the soil conditions, especially the supply of nitrogen, • 

 and the amount of the cyanogenetic glucosid (dhurrin) in the sorghum. 

 It was found that on fertile soils nitrogenous fertilizer has no appreciable 

 effect, but on poor soil added nitrogen may increase the amount of 

 hydrocyanic acid, though only to a small extent. Since the evidence 

 indicated that climate and variety may be more important factors than 

 soil nitrogen in determining the amount of the glucosid in this plant, 

 experiments were carried out during 19 15 to study the effect of climatic 

 conditions. It was thought that conditions of high or low temperature, 

 much or little available water, slow or rapid growth, might affect the 

 metabolism of sorghum sufficiently, not only to show the causes of the 

 varying amount of dhurrin, but also to throw some light on the physio- 

 logical function of this glucosid. 



EXPERIMENTAL WORK 



Seeds of two varieties of sorghum were obtained. One was Early 

 Amber, grown in Minnesota, and is designated in these experiments 

 Variety N. The other was Southern Cane, a variety similar to the 

 first, but grown in Missouri. It is designated Variety S. In order to 

 secure as widely varying climatic conditions as possible, one-twentieth- 

 acre plots of each variety were grown at four different State experiment 

 stations. A brief description of each plot follows: 



1. University Farm, St. Paul, Minn. Very fertile, black loam, fair drainage. 

 Planted on June 3; sprouted on June 12; cultivated twice. Season very cold and 

 wet; sorghum three or four weeks behind the normal in development; did not reach 

 maturity, but was killed by frost in the soft dough stage. 



2. Agricultiural Experiment Station, Logan, Utah. Irrigation farming. Plots on 

 McNiel farm, North Logan; the two varieties alternated with beans; soil a clay loam, 

 rich in maniu"e. Planted May 15; appeared aboveground on June i; irrigated on 

 July 9 and August 11; cultivated on June 10, June 17, July i, July 13, and August 17. 

 Rainfall up to June 10 was abnormally high, which kept the soil cold and retarded 

 growth of crops. During the rest of the season optimum moistiu-e content of soils 



'Reference is made by niunber to "Literature cited," p. 272. 



Journal of Agricultural Research, Vol. VI, No. 7 



Dept. of Agriculture, Washington, D. C. May is, 1916 



dr Minn.— 9 



(261) 



