SOILS — FERTILIZERS. 31 



of the soil may have an importaut beariug on the action of other rather insolu- 

 ble fertilizers, and fertilizers containing acid salts. 



The influence of stall manure upon the bacterial flora of the soil, J. C. 

 Temble (Georgia Sta. Bui. 95, pp. 3-5). — Experiments are reported in detail in 

 this bulletin which tend to show that the addition of cow manure to the soil 

 greatly increases the number of bacteria, and that this increase continues over 

 a considerable period. It was found that there was a larger increase in the 

 number of bacteria in soil to which sterilized manure was added than in soil 

 to which unsterilized manure had been applied. The addition of the manure 

 also increased the ammonifying efficiency of most of the soils experimented with 

 and this was true whether the manure was sterilized or unsterilized. 



The nitrifying efficiency was as a rule increased by the addition of manure. 

 This increase was greatest when sterilized manure was added to the soils, 

 which were then inoculated by the addition of a small amount of unsterilized 

 manure, indicating that the increase in nitrification was due to the introduction 

 of nitrifying organisms the activity of which was promoted by nutrient sub- 

 stances supplied by the manure. 



A bibliography is appended. 



Report of the agriculturist, W. P. Brooks (Massachusetts Sta. Rpt. 1910, 

 pt. 1, pp. 3-'i-50). — This is a report of progress in various experiments with fer- 

 tilizers which have been going on for a number of years (E. S. R., 24, p. 233). 



In a comparison of manure, sodium nitrate, dried blood, and ammonium sul- 

 phate as sources of nitrogen for a succession of crops in experiments which have 

 been in progress since 1S90, the relative efficiency of the different materials, 

 based upon increase in crop as compared with no-nitrogen plats and taking 

 sodium nitrate as 100, has been barnyard manure 78.85, dried blood 72.82, and 

 ammonium sulphate 53.17. 



In comparative tests of muriate and sulphate of potash the muriate was more 

 effective in increasing yield in case of asparagus and oat hay, and the sulphate 

 was more effective in case of rhubarb, blackberries, and potatoes. The percent- 

 age of starch was also considerably higher in the potatoes fertilized with sul- 

 phate. 



In comparative tests of ammonium sulphate, sodium nitrate, and dried blood 

 in combinations with muriate and sulphate of potash it was found that combi- 

 nations containing ammonium sulphate were distinctly unfavorable to aspara- 

 gus and onions but gave the highest yields in case of strawberries. 



In a series of experiments comparing different forms of potash it was found 

 that the average increase of yield of hay resulting from the use of potash ex- 

 ceeded that of the plats receiving no potash by only 600 lbs., indicating that the 

 grasses (timothy and redtop), which made up the bulk of the first crop, "are 

 not dependent in very high degree upon an application of potash." The potash 

 salts were, however, distinctly favorable to the later growth of clover in the 

 rowen. On the plats receiving ground feldspar, however, the clover rapidly dis- 

 appeared, indicating that the potash of this material is not as available as that 

 of potash salts. 



In a continuation of the comparative tests of fine ground rock phosphates, phos- 

 phatic slag, acid phosphate, and bone meal, -it was observed that the only phos- 

 phate which gave any considerable increase in merchantable potatoes was an 

 Arkansas rock phosphate, but the results are not considered entirely conclusive 

 as to the superiority of this phosphate. In fact, the results obtained in this 

 series of experiments Indicate that the potato Is relatively independent of a 

 supply of immediately available phosphoric acid. The application of available 

 phosphoric acid, however, decidedly hastens the growth of the vine. The pota- 



