SOIL FACTORS AFFECTING THE TOXICITY OF ALKALI 



By F. S. Harris, Director and Agronomist, and D. W. Pittman Assistant Agronomist, 

 Utah Agricultural Experiment Station 



INTRODUCTION 



In alkali studies carried out at the Utah Experiment Station during a 

 number of years, variations in toxicity under different conditions have 

 been very evident. This has already been reported by one of us/ in 

 results wherein the various alkali salts and particularly the carbonates 

 were injurious in lower concentrations in sand than in loam. Other soil 

 factors were also found to influence the action of soluble salts on plants. 

 In order to gain more information regarding these factors, the investiga- 

 tions herein reported were undertaken, since it was realized that no ade- 

 quate idea of the alkali problem could be had without an understanding 

 of the factors involved. 



Millions of acres of land in the arid part of America contain certain 

 soluble salts in sufficient concentration to interfere with the best growth 

 of crops. The value of much of this land is uncertain, since the salt 

 content is near the concentration that renders it worthless. It is im- 

 portant, therefore, to know as nearly as possible just what the critical 

 concentrations are. Hilgard and other early investigators contributed 

 much to our knowledge of alkali lands, but their investigations did not 

 make clear all the factors involved. This work is an attempt to deter- 

 mine with more exactness the quantities of the various salts that pro- 

 hibit crop growth under different soil conditions. 



The earlier paper^ reviews the important literature on the subject; 

 consequently no literature is reported in the present paper. 



METHODS OF EXPERIMENTATION 



The first method used was the direct empirical experiment of growing 

 crops in prepared alkali soils in glass tumblers. Over 12,000 tumblers 

 were planted in this experiment. The general method of procedure was 

 exactly the same as was used previously^ in studying the effect of differ- 

 ent salts and combinations of salts. The tumblers were made to a uni- 

 form weight by placing washed gravel in the bottom. Two hundred 

 gms. of soil, to which the salts had been added in solution as required in 

 the experiment, were placed in each tumbler, and 10 kernels of New 

 Zealand wheat planted in each. Daily notes were taken on the number 

 of plants up in each tumbler and on any other observable data. The 



1 Harris, F. S. effect of alk/\h salts in soils on the germination and growth op crops. In 

 Jour. Agr. Research, v. s, no. i, p. 1-53, 48 fig. 1915. Literature cited, p. 52-53. 

 ' Harris, F. S. op cit. 



Journal of Agricultural Research, Vol. XV, No. 5 



Washington, D. C. (287) Nov. 4, 1918 



qc Key No. Utah-9 



