220 EXPERIMENT STATION RECORD. 



BOTANY. 



Investigations on the native vegetation of alkali lands, J. B. 

 DAVY (California Sta. Ept. 1895-1897, pp. 53-75, pis. 8, fig. ]).— The 

 object of this investigation was to ascertain if possible whether the 

 characteristic plants of alkali plats would indicate the kind of alkali 

 present aud the degree of its impregnation, so as to enable any one 

 to determine the possibility of reclamation without reference to the 

 station. 



An introductory note by E. W. Hilgard reviews the previous inves- 

 tigations of the station regarding alkali lands which, summed up, 

 shows that the salts found impregnating alkali lands consist in the 

 main of varying proportions of sodium sulphate, sodium carbonate, and 

 common salt. The total content of this mixture varies from a small 

 fraction of 1 per cent to more than 12 per cent of the total weight of 

 the soil taken to a depth of 4 ft. Of the three compounds named, sodium 

 carbonate, or black alkali, is the most injurious to vegetable growth 

 and to the tilling qualities of the soil. In reclaiming alkali lands for 

 cultural purposes the first thing necessary is a transformation of the 

 carbonate into sulphate of soda by the addition of gypsum. In addi- 

 tion to the salts already mentioned other alkalies are found in varying 

 proportions, but as most of these are in the form of soluble plant food 

 they are available for plant growth as soon as the injurious effects of 

 the surplus of other constituents is removed. 



The resistance or tolerance of the several salts by plants varies 

 greatly for the different plants and for the different salts. Thus chen- 

 opodiaceous plants are in general very resistant, while, on the other 

 hand, leguminous plants resent even small quantities of any of the 

 injurious alkalies. The Composite are rather tolerant of alkali, while 

 most cultivated grasses are sensitive to it. 



With a few exceptional cases, the investigations of the station have 

 shown that the bulk of the salts in alkali lands may at all times be found 

 within about 4 ft. of the surface, aud sometimes, as during a very dry 

 season, they may accumulate almost wholly within 6 in. of the surface. 

 Upon the basis of these facts it is thought an estimate of the aggre- 

 gate amount of alkali liable to influence vegetable growth on any land 

 can be made and the methods of reclamation determined. This might 

 be determined by chemical analysis of the soil, but to avoid this expense 

 to the landowners a simpler method was sought, a preliminary sum- 

 mary of which is given in the report. The author collected samples of 

 alkali soils upon which various plants grew at a number of places, and 

 these samples, 58 in number, were analyzed and are reported upon by 

 the agricultural chemist, K. H. Loughridge. 



In studying the natural vegetation of alkali lands the author made 

 several visits to parts of California that are noted for their alkali soils, 

 and in addition to the soil samples taken collected over 1,500 sheets of 



