110 EXPERIMENT STATION RECORD. 



per cent. In 63 determinations in which the samples for the lime 

 method only were ignited w4th sulphuric acid the results showed an 

 extreme variation of 0.29 per cent and less than 0.20 per cent in -IB 

 comparisons. In 45 determinations without ignition the extreme varia- 

 tion was 0.55 per cent, nothing being claimed for the milk-of-lime 

 method under such conditions. 



SOILS. 



The report on this subject was made by the referee, F. P. Veitch. 

 The work during the year consisted in the determination of available 

 phosphoric icid and available potash in soils and the analysis of alkali 

 soils and crusts. The 8 samples of soil used in the phosphoric acid 

 and potash work were obtained from 6 States and were representative 

 of different kinds of soil. Each had a full crop and fertilizer history 

 for a number of years. Determinations of available phosphoric acid 

 and potash made b}^ the referee and C. C. Moore with the N-200 hydro- 

 chloric acid method showed sufficient harmony with crop history to 

 warrant further trial of the method. The necessity of determining 

 available plant food to the full feeding depth of plants was recognized 

 by the referee, but he was unable to take up this line of work during 

 the year. A letter from Milton Whitney, Chief of the Bureau of 

 Soils, dealing with the value and methods of mechanical analysis and 

 the work of the Bureau in the classification of soils based upon physical 

 examination, was read by the referee, who had been instructed b}^ the 

 association to consider the subject of mechanical analysis. Professor 

 Whitney pointed out the advantages of adopting the grades alread}^ in 

 use by the Bureau, namely, fine gravel, coarse sand, medium sand, 

 fine sand, very fine sand, silt, and clay, calling attention to the fact 

 that over 3,000 analyses had been published by the Bureau and that 

 the soil survey work had been extended to 30 States. The points which 

 received attention b}^ the referee in the study of methods for the analy- 

 sis of alkali soils were the effect of dilution upon the amount of salt 

 dissolved and titration methods for the determination of carbonates, 

 bicarbonates, and chlorids. ""The results may be summed up as fol- 

 lows: The concentration of the solution materially affects the speed of 

 solution of sulphates, particularly calcium sulphate, and it is quite 

 evident that equilibrium has not always been reached in 24 hours. The 

 chlorin determination is the most satisfactory and appears to be the 

 least affected by the concentration of the solution, while equilibrium 

 is usuall}^ reached within the 24 hours. The determination of carbon- 

 ates and of bicarbonates when present in large quantities has not been 

 very satisfactory to the referee." 



Studies in nitrification were reported in a paper read by G. S. Fraps. 

 Two kinds of tests were made, one in which nitrification was carried 

 out in soil as it came from the field and the other in sterile soil inoc- 



