720 



EXPEKIMENT STATIOlSr EECORD. 



The alkaline reacfion produced in soils by acids in relation to plant nutri- 

 tion. — I, Solubility of iron compounds in the soil, G. Masoni (Staz. Sper. 

 Ayr. Ital., 7/7 (.191^), No. 9-10, pp. 674-701; abs. in Chem. ZcntU., 1915, 1, No. 10, 

 p. 498; Chem. Abs., 9 {1915), No. 13, p. 1816). — Experiments based in part 

 on results noted in a previous study (E. S. R., 30, p. 122) are reported. The 

 dissolving power of hydrochloric, nitric, sulphuric, phosphoric, formic, acetic, 

 oxalic, succinic, malic, tartaric, and citric acids and of potassium sulphate, 

 monopotassium phosphate, monopotassium oxalate, monosodium tartrate, and 

 monopotassium citrate, when used in twentieth-normal, fiftieth-normal, and 

 in normal solutions were observed on the iron compounds in a calcareous soil, 

 with and without additions of ferric and ferrous salts and with and without 

 the presence of carbon dioxid. The processes involved both direct mixing and 

 percolation. 



The dilute solutions of all the acids, excepting citric, tartaric, and malic acids, 

 failed to throw iron into solution from the soil alone, and even when ferrous 

 and ferric salts had been added. Dilute citric acid dissolved considerable iron 

 under all conditions and tartaric and malic acids relatively less, as did also 

 the solutions of their corresponding salts. The reaction was, however, always 

 for ferrous iron. The presence of relatively large quantities of carbon dioxid 

 did not modify the results. Similar experiments made with pure calcium car- 

 bonate yielded similar results. 



The normal solutions of the acids and acid salts in practically every case 

 dissolved iron in a more or less marked degree. 



The results of these experiments are considered to throw more or le.?s light 

 on the cause of chlorosis in plants growing in limestone soils, in that the weak 

 acids from plant roots act in the same manner as the weak acids noted above. 

 This results in the iron compounds being precipitated in insoluble form. 



Soil moisture investigations (Washington Sta. Bui. 127 (1915), pp. 15-20, 

 figs. 3). — The results of three seasons' investigations on the water requirements 

 of seven of the more important crops are given in the following table. " Mois- 

 ture determinations were made to a depth of 10 ft. at time of planting and at 

 harvest on both cropped and check plats. . . . The difference between the 

 cropped and check plats is what was taken by the crops." 



Yield and iratcr requirements of crops. 



In an attempt to ascertain whether there is any variation in the distribu- 

 tion of nitrates at relatively small distances in soil, a cubic yard of soil so 

 laid oft that a sample was taken every 4 in. parallel to the faces of the cube, 

 making in all 1,000 samples. Analyses of these for nitrate content showed that 

 " the samples containing more than 10 parts of nitrates per million of dry soil 



