SOILS FERTILIZERS. 819 



the uitrification of organic uitrogeu was at first more rapid than that of 

 ammonium sulphate. In general, the most rapid nitrification was observed in 

 all soils between the third and the sixth week after the addition of ammonium 

 sulphate. Only in the case of the clay soil with the highest moisture content 

 was the most rapid iiitriflcatiou observed during the first three weeks. Appre- 

 ciable denitrification was observed without the addition of organic matter only 

 with the highest water content. Ammonium sulphate in loam soil showed a 

 loss of 19.8 per cent of the applied nitrogen at the end of the experiment. With 

 horn meal furnishing an abundant supply of carbonaceous food there was a 

 greater loss (32.2 per cent in loam and 32.7 per cent in clay soils) in the 

 heavier soils but a very small loss in sandy soils (9 per cent). 



The addition of organic matter, as for example in the form of sugar, reduced 

 the amount of soluble nitrogen compounds in the soil. In all soils the addition 

 of sugar increased this fixation of ammonium .sulphate nitrogen but did not 

 affect the nitrate nitrogen. The .-imount of nitrogen fixed was increased by the 

 addition of sugar from 18.18 to 20.18 per cent in sandy soils, from 22.32 to 43.2 

 per cent in loam soils, and from 29.08 to 38.38 per cent in clay soils. 



The danger of bacterial destruction of nitrate in the field, H. Fischer 

 {FilhliiKfs Landw. Ztf/.. 63 (1914), No. 7, pp. 24Jf-252). — Reviewing various 

 investigations on this subject, the author concludes that under normal condi- 

 tions, particularly of drainage and aeration, the danger of denitrification in 

 the field is not great. 



Hurtful actors on cultivated plants, T. Jamieson (Ayi-. Rcxeaixli, Assoc. 

 [Scot.] Rpt. 1913, pp. 1.5-37). — Summai'izing the results of experiments on the 

 subj^iet, the author concludes that the increased productiveness following the 

 heating of the soil or treatment with substances inimical to life is " due simply 

 to the riddance, in varied degree, of the varied forms of animal life in soil 

 that prey on plants," and not to any Influence ujwn the bacterial activity of 

 the soil. 



Barren spots, A. Hutin {Biil. Asso<-. Vhitn. ISncr. et DistiU., 31 (1914). No. 

 12. pp. 968-D7f^). — A study of the causes of barren spots in sugar cane fields is 

 reported. 



Faulty soil aeration due to various causes is indicated as at least partly 

 responsible for barrenness in certain cases. A study of the organic matter of 

 certain of the barren soils- which were apparently greatly benefited by liming 

 showed the presence of a very large amount of soluble organic matter of a 

 mucilaginous nature (pectates and parapectates). It is suggested that the 

 unproductive character of the soil in such cases may be due to faulty aeration 

 resulting from the presence of excessive amounts of the organic matter, and 

 that liming coagulates this matter and thereby improves the aeration and 

 drainage of rhe soil. 



The fertility of the soil, M. F. Miller (Missouri Sta. Circ. 69 {1914), pp. 

 19, figs. 3). — This is a popular discussion of the problem and means of main- 

 taining soil fertility, particularly under Missouri conditions. Emphasis is laid 

 upon the fact that under present methods of management Missouri soils are 

 not, on the whole, maintaining their fertility. It Is pointed out that the ex- 

 tensive agriculture which prevails does not lend itself well to the profitable 

 use of large quantities of commercial fertilizers. They can not be depended 

 upon alone to maintain soil fertility and should therefore be used only in 

 connection with good systems of crop rotation, manuring, and legume growing. 



Fertilizer experiments {Yerslag. en Meded. Dir. Landh. Dept. Land!)., Nijv. 

 en Handel, No. 3 (1914), pp. 1-39). — The results of a number of fertilizer 

 experiments completed during the years 1910 to 1912 at different Dutch expei'i- 

 ment stations are briefly reported. 



