126 EXPERIMENT STATION EECOED. 



In preliminary experiments with Miieat and sugar beets on a loam soil, using 

 the chloric!, carbonate, and sulphate of sodimn and magnesium sulphate, it was 

 found that the toxicity of sodium chlorid was relatively high when comparetl 

 with that of the other salts, and that there was germination and growth with con- 

 siderably more sodium carbonate than sodium chlorid. Magnesium sulphate 

 was only slightly toxic, v.liile sodium sulphate in the same amount was more 

 toxic, but permitted the production of fair crops. It was also found that the 

 number of seeds germinating, the average height of plants, and the dry matter 

 produced decreased with the increased concentration of the alkali. The plants 

 appeared able to endure alkali better with a fair supply of moisture in the soil 

 than where the soil was dry. Salts were more toxic when added in solution 

 than when mixed with the dry soil. In a sand soil sodium carbonate was more 

 toxic than sodium chlorid. 



In the main experiments it Avas foimd that only about half as much alkali 

 was requiretl to prohibit the growth of crops in sand as in loam. Crops varied 

 greatly in their relative resi.stanco to alkali salts, but for the ordinary mixtures 

 of salts it is considered probable that barley is the most resistant in the seedling 

 stage, followed in order by oats, wheat, alfalfa, sugar beets, corn, and Canada 

 field peas. 



The action of the various salts in soils was somewhat different from that 

 observed in solution cultures. Plants were able to endure nuich stronger chlo- 

 rids and nitrates in solution cultures than in the soil, while the carbonates 

 retarded growth more in solution than in the loam, but not as much as in the 

 sand. The number of plants alive at the end of three weeks decreased as the 

 concentration of the .solution increased. There was a corresponding decrease in 

 number of leaves per plant, height of plants, length of roots, weight of tops, and 

 weight of roots as the concentration of salts increased. In the cultures in which 

 no salts were added, the height of plants, the length of roots, and the dry matter 

 produced were not so great as in cultures containing salts in low concentrations. 

 These results are taken to indicate the inadvisability of applying too widely to 

 the soil the results obtained with solution cultures of alkali. 



The period of germination of seeds was considerably lengthened by the pres- 

 ence of soluble salts in the soil. The anion, not the cation, was found to deter- 

 mine the toxicity of alkali salts in the soil. Of the anions used the chlorid was 

 decidedly the most toxic, while sodium was the most toxic base. The injurious 

 action of alkali salts was not in all cases proportionate to their osmotic pressures. 

 The order of toxicity of soluble salts in the soil was found to be as follows : So- 

 dium chlorid, calcium chlorid, potassium chlorid, sodium nitrate, magnesium 

 chlorid, potassium nitrate, magnesium nitrate, sodium carbonate, potassium car- 

 bonate, sodium sulphate, potassium sulphate, and magnesium sulphate. The 

 antagonistic effect of combined salts Avas not so great in soils as in solution cul- 

 tures. 



It is thought probable that lands containing more than about the following 

 I)ercentages of soluble salt are not suited, without reclamation, to produce ordi- 

 nary crops : In loam, chlorids 0.3 i>er cent, nitrates 0.4 per cent, carbonates 0.5 

 per cent, and sulphates above 1 per cent ; and in coarse sand, chlorids 0.2 per 

 cent, nitrates 0.3 per cent, carbonates 0.3 per cent, and sulphates 0.6 per cent. 



A bibliography of cited literature is appended. 



The effect of organic compounds in pot experiments. G. S. FRvrs (Texas 

 f'^ta. Bui. J7Jf (1015), pp. 13). — I'ot culture experiments on several unpro<luctivc 

 soils to determine the extent of the harmful effect on corn and sorglnim of addi- 

 tions of dihydroxystearic acid at rates of from 500 to 1.200 parts per million, 

 of vanillin, quinone, and cumarin at I'ates of from 100 to 2.000 parts per mil- 

 lion, and the effect of phosphatic and nitrogenous fertilizers, carbon black, and 



