130 EXPERIMENT STATION RECORD. 



As regards tlie use of superphosphate- gypsum, it cau not bo stated 

 positively that it will completely prevent loss. It is evident, however, 

 that the loss is reduced to the lowest possible limit by the use of this 

 material. On account of its acid reaction the superpliosphate-gypsuni 

 is specially valuable for neutralizing the alkali of the liquid excre- 

 ment and thus preventing loss of nitrogen. 



Kainit is vahuible for checking ammoniacal fermentation. It does 

 not entirely prevent the evolution of free nitrogen under conditions 

 favorable to this reaction, but it ap])ears to retard it to a considerable 

 extent. 



The method of investigation by which Vogel arrived at the conclusion 

 that when superphosphate-gypsum or other materials containing solu- 

 ble phosphate were used as preservatives for manure the phosphoric 

 acid was largely changed to the reverted form is criticised as unreliable, 

 and results of experinients are adduced to substantiate this statement. 



On the importance of liming soils deficient in lime, Naehric 

 {FiUtliiufs hmdic. Zt(j., 13 {1^94), No. 1:^, pp. o\Si-5'(S/).— Analyses of 23 

 soils in Schleswig are reported, which show a variation in lime con- 

 tent in the surface soil down to a depth of 200 mm. of from G,108 to 

 395,894 kg. of lime per hectare; and experiments during 1893 in liming 

 two of these soils in connection with applications of other commercial 

 fertilizers are also reported. The results show that both sugar beets 

 and beans, even on soils containing considerable percentages of lime, 

 were benefited by applications of this substance. 



The after-manuring of soils containing residues of phosphoric 

 acid from previous fertilizing "with phosphates, A. EMMEiiLi^a 

 {Landir. Wochexbl. Schle.s. Hoist., 14 {H^'Jl), No. 19, pp. 301, 302).— A 

 brief article in reply to an inquiry of a correspondent, in which the 

 author recommends that soils rich in phosphoric acid from previous 

 applications of phosphates should be fertilized for the following crop 

 simply with nitrates in order to get the highest return from the phos- 

 phoric acid present. It is also explained that lime and marl exert a 

 beneficial influence in keeping the soil in a good mechanical condition, 

 thus retarding the conversion of available phosphoric acid into 

 the insoluble phosphates, such as phosphates of iron and alumina. 

 Although these methods will not restore the phosphoric acid to the 

 soluble form in which it was originally applied, they will be very 

 effective in rendering it available to plants. 



Methods to determine the availability of organic nitrogen in 

 fertilizexs {Connecticut State >Sta. Rpt. 1893, pp. 218-237, pi. 1). — The 

 results of tests of the method of pepsin digestion, reported in full in 

 the Annual Report of the station for 1885 (pp. 115-131), are briefly 

 reviewed. The conclusion was then drawn that, although this method 

 had decided value for distinguishing between inert and readily available 

 forms of nitrogen in mixed fertilizers, the extent to which it furnished a 

 measure of the agricultural value of the nitrogen " must be determined 



