SOILS FERTILIZERS. 131 



Leavy soils was found to permit better aeration and drainage and to result in 

 a more complete utilization of the nitrogen of the soil organic matter. 



A comparative study of the effects of equal amounts of nitrogen as dried 

 blood and ammonium sulphate, W. H. McIntiee {Pennsylvania Sta. Rpt. 1912, 

 pp. 75-S2). — Experiments with dried blood and ammonium sulphate, when ap- 

 plied to a silty clay loam soil in amounts equivalent to 24 and 72 lbs. of nitrogen 

 per acre to determine their effect on the nitrifying properties, organic matter con- 

 tent, and the amounts of potassium, calcium, phosphoric acid, and total solids of 

 the soil soluble in distilled water, and to determine any correlation between soil 

 temperature and soil composition as affected by the two treatments, are reported. 



The most nitrate was recovered from the soils treated with ammonium sul- 

 phate. The largest occurrence of nitrogen as nitrates was found upon the plat 

 with the least content of total nitrogen, while the smallest recovery of nitrates 

 was obtained from the plat having the greatest total nitrogen content. More 

 nitrogen was conserved in the soil when applied as dried blood. The heavier 

 application of ammonium sulphate resulted in the largest recovery of potash, 

 the lesser treatment and the two amounts of dried blood being practically iden- 

 tical. Large amounts of lime were recovered where the sulphate of ammonia 

 was applied. No determinable difference in phosphorus recovery was noted. 

 The ammonium sulphate treatments increased the amounts of total solids re- 

 covered in case of both volatile and nonvolatile constituents. No difference was 

 observed in the seasonal moisture content of the soils receiving the smaller 

 amounts of the two forms of nitrogen, but heavier treatments of the sulphate 

 decreased the seasonal moisture content. Both amounts of sulphate of ammonia 

 resulted in less organic matter contents than the corresponding amounts of 

 nitrogen as dried blood. The lighter application of each form of nitrogen seemed 

 conducive to greater conservation of organic matter than the heavier treatments. 

 The light applications of each form were coincident with higher temperatures. 

 The lowest temperature was recorded in the soil receiving the heavy ammonium 

 sulphate treatment, while the light application of this substance gave the highest 

 temperature. 



The results of long-continued use of ammonium sulphate upon a residual 

 limestone soil of the Hag'erstown series, J. W. White (Pennsylvania Sta. Rpt. 

 1913, pp. 55-104, pis, 21). — Field and laboratory experiments conducted since 

 1882 on the effect of the use of ammonium sulphate upon a resitlual limestone 

 i^oil are reported in detail, the results indicating that the long-continued use of 

 ammonium sulphate has had a pronounced influence upon the reaction of the 

 soil by virtue of its tendency to produce acidity and has exerted an injurious 

 effect as indicated by the decreased yield of hay and, to a less degree, of corn, 

 oats, and wheat. 



The soil under consideration showed wide variation in the degree of acidity 

 produced upon areas treated similarly for thirty years, which is attributed to 

 unequal distribution of active lime. The limestone bedrock markedly influenced 

 the composition of the soil where it approached within 2 ft. of the surface. The 

 percentage of lime and magnesia present as carbonates was found to be greater 

 on areas of low acidity. The alkali-soluble humus on areas of high acidity was 

 found to be largely in an uncombined state. The acidity of the soil of one plat 

 receiving 72 lbs. per acre of nitrogen as ammonium sulphate was such as to 

 inhibit the growth of clover except where the underlying limestone approached to 

 within 2 ft. of the surface. " In relation to the quantity of nitrogen applied, the 

 plat receiving 24 lbs. per acre of nitrogen has produced the highest acidity." 

 Nitrification was not entirely checked on the areas showing high acidity. " The 

 low efficiency of sulphate of ammonia as compax-ed with nitrate of soda and 

 dried blood is due primarily to the controlling influence of the accumulated 



