1915.] PUBLIC DOCUMENT — No. 31. 47 a 



Soils for complete analysis 4 



Soils for partial analysis, ........ 21 



Tobacco soils suffering from over-fertilization, suspected of caus- 

 ing malnutrition of the crop, ....... 14 



Greenhouse soils suffering from over-fertilization, suspected of 



causing malnutrition of the crojD, 13 



The usual time has been given to co-operative work with the 

 Association of Official Agricultural Chemists, Mr. Walker hav- 

 ing served the association in the capacity of associate referee 

 on phosphoric acid and Mr. Haskins as associate referee on 

 nitrogen. In this connection studies have been made on new 

 methods for the determination of the three fertilizer constituents 

 (nitrogen, phosphoric acid and potash) in fertilizers. 



(d) Field Experiments with Basic Slag Phosphate. 

 The work begun in 1913 to study the availability of the phos- 

 phoric acid in basic slag phosphate, as outlined by the Associa- 

 tion of Official Agricultural Chemists, has been continued. 

 The data resulting from this experiment would indicate that 

 the field is not sufficiently depleted in phosphorus to warrant 

 making the final field experiment, and it is probable that the 

 growing of crops on the land another year will be necessary. 



(e) Field Experiments ivith New Mineral Fertilizer and 



Stone Meal. 

 This experiment, begun in 1912, has been continued. The 

 conclusions drawn from this year's experiment will be found in 

 Bulletin ISTo. 2, control series, published in connection with the 

 results of the fertilizer inspection. 



(/) Other Vegetation Experiments. 

 The experiment begun in the greenhouse in the winter of 

 1914 for the purpose of comparing the nitrogen availability of 

 some suspected brands of fertilizer found in the 1913 fertilizer 

 inspection was completed. Conclusions will be found in Fer- 

 tilizer Bulletin ]^o. 2, Control Series. Similar work has been 

 started with fertilizers collected in 1914. 



