CONVENTION OF OFFICIAL AGRICULTURAL CHEMISTS. 409 



the NH3 solution were not concordant. The amounts of nitrogen dis- 

 solved by KOH and NaOH were identical, ])ut in the case of 3 samples 

 in which the percentat»'e of humus was high the amounts of nitrogen 

 dissolved bv KOH and NaOH were comparatively low. The referee 

 recommended more extended investigation along this line by a com- 

 mittee, with the referee on soils as chairman. 



The Rothamsted method of sampling soils was described, and several 

 objections pointed out. The method is deemed less applicable to the 

 larger part of the arable lands of Calif ornia than the use of a post-hole 

 auger, as adopted ]\v Hilgard. The latter method requires less work 

 and less time for taking the sample, the exact point of change from 

 surface to subsoil can be ascertained, and much less bulk has to be 

 handled. In view of the necessity of a rational S3\stem of sampling 

 soils, and of a method for determining the available plant food, the 

 referee suggested that a committee be appointed for the consideration 

 of these subjects. 



W. A. Withers presented a paper on the rate of nitrification of vari- 

 ous nitrogenous materials. W. Frear requested the consideration of 

 the su])ject of determining the proportion of soluble hunuis in alkali 

 soils, and made a statement of some of the results obtained at the 

 Pennsylvania Station. 



F. K. Cameron })rought to the attention of the association a paper 

 by A. Seidell on the Chemical examination of alkali soils, published 

 as a bulletin of the Division of Soils (see p. 428). He moved that 

 the article as printed, or modified as might be deemed necessary, be 

 referred to the committee on recommendations, with the view that 

 it l)e accepted as the official method for the chemical examination of 

 alkali soils. 



C. G. Hopkins stated that in the work on soils in Illinois there has 

 been trouble in the separation of alkalis. After precipitating the 

 barium hydroxid and the calcium and barium by means of ammonium 

 car})onate, the final filtrate was found to be by no means free from 

 barium. To overcome this error the ofificial method was modified hj 

 precipitating the last traces of ])ariuui with ammonimn sulphate. A 

 sufficient quantity of this latter is added so that in the ignition of the 

 residue the alkalis are converted to sulphate and rendered less liable 

 to volatilization. 



The association adopted provisionally the method followed at the 

 Illinois Station for soil sampling, and authorized the appointment of a 

 committee to stud}^ methods of soil sampling. The determination of 

 potash in soils was referred to the referee for the ensuing year, and 

 also methods for determining soluble constituents in alkali soils. It 

 was recommended that the referee take up the subject of the mechan- 

 ical analysis of soils and report at the next meeting, and also consider 

 the determination of available plant food in soils. 

 13639— No. 5 2 



