126 EXPERIMENT STATION RECORD. [Vol.37 



deficient in basic constituents. Too much empnasis has been laid upon soil 

 acidity, and the more important theme, soil basicity, has been neglected. 



" Calcium and magnesium are retained in the soil mainly as silicates, pos- 

 sibly partly in combination with organic matter. 



" Field tests show that the yields of clover on plats treated with acid 

 phosphate have been less than on plafc? where bone meal and basic slag were 

 used as carriers of phosphorus. The evidence obtained by laboratory studie.s, 

 however, does not indicate that acid phosphate has any important influence 

 toward the depletion of the soil's supply of bases ; effects due to the acid 

 nature of this fertilizer are insignificant when compared with those attribut- 

 able to the use of ammonium sulphate. 



" Dried and green crop residues mixed with soil did not increase its lime 

 requirement as determined in the laboratory. Field ob.servations and tests 

 made do not indicate that organic matter furnished by green crops causes 

 acidity in soil. A mulch of fermenting material (apple pomace) caused the 

 lime requirement of the soil beneath to be increased. Sawdust similarly used 

 had little effect. 



" Pot experiments indicate that the base of various silicates, including blast- 

 furnace .slag, may be of benefit to crop growth. 



" Lime requirement determinations on samples taken at various depths of 

 a limed soil indicate that the effect of lime applied is perceptible to a depth 

 of 24 in. or more. 



" Unusual weather conditions to which the soil may have been exposed in 

 the field have had no great effect upon the lime requirement as determined in 

 the laboratory." 



Effect of some manganese salts on ammonification and nitrification, P. E. 

 Brown and G. A. Min(;es {loira Sta. Research Bui. So (1916), pp. 5-22).--Ex- 

 periraents on the effects of manganese sulphate, manganese chlorid, manganese 

 nitrate, and manganous oxid In varying amounts on the ammonification of dried 

 blood and the nitrification of ammonium sulphate in a clay-loam soil are 

 reported. 



It was found that " manganese chlorid, in applications greater than 2,000 

 lbs. per acre, depresised both ammonification and nitrification, the depression 

 increasing as the size of the application was increased until a point was 

 reached at which both processes ceased. With smaller amounts of the chlorid 

 the effects on the two processes were not identical, Itiit tended in the same 

 direction. Thus the applications of 100 and 200 lbs. per acre gave increases 

 which were slight in the case of ammonification, but quite distinct In the case 

 of nitrification. With amounts greater than 200 lbs. per acre and less than 

 2,000 lbs., however, ammonification was depressed while no appreciable depres- 

 sion was apparent on nitrification. 



"Manganese sulphate, when applied to the soil at the rate of 100 lbs. per 

 acre, increased appreciably both ammonification and nitrification. In amounts 

 greater than 100 lbs. per acre and less than 2.000 lbs., ammonification was in- 

 creased, but to a less extent than with the 100-lb. application, but with nitri- 

 fication no gains nor depressions were found with the.se amounts. In applica- 

 tions equal to or greater than 2,000 lbs. per acre nitrification and ammonification 

 were depressed by manganese sulphate, the depression increasing with the size 

 of the application. 



" Manganse nitrate added to the soil at the rate of 500 lbs. per acre, or in 

 greater amounts, depressed both ammonification and nitrification, the depres- 

 sion increasing as the size of the application was increased. Manganous oxid, 

 when applied to the soil at the rate of 2,000 lbs. per acre or in larger quantities. 



