SOILS FERTILIZERS. 623 



pot culture and field work. The application of lime to field soils was reflected 

 in decreased lime requirements and increased crop production even after a pro- 

 longed period (upwards of 17 years). The values of calcium oxid and car- 

 bonate were found to be identical, provided the lime requirements (for neu- 

 tralization purposes) were not fully satisfied. After the neutral point was 

 reached calcium oxid exercised its specific effect. An application of carbonate 

 to a soil accelerated the process of ammonification and nitrification to a lesser 

 degree. " The results of an acidity, or lime requirement, test and not those of 

 determinations of free carbonate should be taken into consideration when the 

 needs of any particular soil are concerned. In the case of soils on the same geo- 

 logical formation a definite relation between soil reaction and natural flora 

 has been traced. The occurrence of certain plants on acid soils appears to be 

 determined by their capacity of resistance to acidity." 



A list of references to literature bearing on the subject is appended. 



Probable combination of the chlorin ions in alkali salts, R. F. Hare (iVeto 

 Mexico Sta. Bid. 95 {1915), pp. 3-6). — Experiments showing the effect of heat 

 on chlorids in the residue from some New Mexico irrigation waters and show- 

 ing the loss of chlorids on heating 0..5 per cent solutions of magnesium chlorid, 

 calcium chlorid, and sodium chlorid singly and in different mixtures are 

 reported. The results are taken to indicate " that heating the . residue of 

 chlorids from a water or soil solution at a low red heat for ten minutes might 

 furnish a method for determining the chlorin in mixed alkali salts that exist 

 In combination with magnesium." 



The effect of arsenite of soda on the soil, W. T. McGeorge (Haicaii Sta. 

 Press Bui. 50 {1915), pp. 16, figs. 3). — Investigations on the effect of sodium 

 ar.senite on the growth of millet, cowpeas, and buckwheat and on the physical, 

 chemical, and biological activities in heavy red clay, brown clay, and highly 

 organic silt soils are reported. 



It was found that the effect of sodium arsenite on plant growth depends upon 

 the resisting power of the plant and upon the chemical and physical nature of 

 the soil. In small quantities plant growth was stimulated in most instances, 

 but when added at the rate of 0.1 to 0.2.5 per cent plant growth was made prac- 

 tically impossible. Sodium arsenite materially altered the mechanical condi- 

 tion of the soil, its action being primarily that of a deflocculating agent, thus 

 checking the movement of the water. 



The influence of sodium arsenite on ammonification and nitrification varied 

 considerably in the different soil types, and no general rule applicable within 

 reasonable limits was established. 



Sodium arsenite was strongly fixed by the soil, even resisting the M'ashing of 

 heavy rains, and accumulated in the top layer. An analysis of a sample of soil 

 from a tract of land sprayed three times a year for five years at the rate of 5 

 lbs. of sodium arsenite per acre per application showed all the arsenic to be 

 present in the top 4 in. of soil. 



The influence of zinc vessels in culture experiments, K. Ghedkoiz {Selsk. 

 Khos. i Liesov., 3^5 {191-i), July, pp. 625-627; abs. in Tntcrnat. Inst. Agr. 

 [Rome], Mo. Bui. Agr. Intel, and Plant Diseases, 6 {1915), No. 1, pp. 57, 58). — 

 Pot experiments during three years showed that the sulphate and chlorid of 

 zinc had almost the same effect on the growth of mustard. The effect on barley 

 differed from that observed in the case of mustard, as with 0.02 per cent of zinc 

 the growth of mustard ceased, while barley gave a relatively good yield. Zinc 

 in very small quantities, however, stimulated the growth of mustard, but had a 

 depressing effect on barley. 

 9635°— No. 7—15 3 



