CONVENTION OF OFFICIAL AGRICULTURAL CHEMISTS. 43] 



ammonium bydroxid from a limed and unlimed soil receiving various 

 phosphates. The results with Hat turnips indicated thai this crop ina\ 

 serve a useful purpose in testing the relative assimilabilitj of different 

 phosphates. Ammonium hydroxid of \. fa, and ,,',,, normal strength 

 and nitric acid of ,,',„ and J- normal strength failed to extract from 

 the soil amounts of phosphorus corresponding to crop results. It was 

 considered doubtful if any solvent will extract from all soils amounts 

 of phosphorus bearing relations to those removed by a given crop. 



F. I*. Witch presented in abstract a paper on The Effect of Fertili 

 zers on the Reaction of Soils. The reaction and acidity of some of 

 the limed and unlimed plats, which had received different fertilizer 

 treatment in the rotation experiments of the ( >hio Experiment Station, 

 were determined by the lime-water method and by the sodium-chlorid 

 method and it was found that those unlimed plats which had received 

 large applications of sodium nitrate, either alone or in conjunction 

 with phosphates and potash salts, were less acid than those plats 

 receiving no nitrate. Acid phosphate alone slightly reduced acidity, 

 but with other materials produced no change. Potassium chlorid did 

 not change the acidity of the soil. The results obtained on this soil 

 are not considered to be of general application to soils of different 

 constitution. 



The same author also presented a paper on Plant Growth as Influ- 

 enced by Soil Acidity. The results of experiments with red clover, 

 cowpeas, alfalfa, tomato, lettuce, wild marsh grasses, corn, and timo- 

 thy were considered as indicating the desirability of rendering the soil 

 faintly alkaline with calcium carbonate rather than stopping with 

 smaller applications, and it was suggested thai possibly with \ci-y 

 sensitive plants, such as alfalfa, it may he necessary to incorporate 

 the lime to a greater depth than can he done by the ordinary harrow 

 or cultivator. 



[NORGANIC PLANT CONSTITUENTS. 



Samples of corn meal, ground oat-, cotton-seed meal, and white 

 mustard were sent out by the referee, K. W. Thatcher, for collabora 

 tive work on the determination of sulphur by the nitric-acid, sodium 

 peroxid, Barlow-Tollens, and chromyl -chlorid method-. The results 

 were considered as proving conclusively that the nitric-acid method 

 does not yield all the sulphur present in plant tissues. The peroxid 

 method was considered the most accurate and feasible method. The 

 combustion method of Barlow-Tollens proved satisfactory t«> the two 

 chemists who used it. The chromyl-chlorid method gave unsatis 

 factory results. It was recommended that the provisional nitric-acid 

 method he dropped and the peroxid method lie adopted provisionally . 

 which was done. The referee for next year was requested to investi 

 gate the Barlow-Tollens method as a means of distinguishing between 

 organic sulphur and sulphur of the ash. 





