1017] SOILS FERTILIZERS. 25 



ericton, N. B., and Kentville, N. S., and in 1914 at Agassiz, B. C, are reported, 

 from which the following conclusions are drawn : 



"A judicious and rational use of fertilizers may in a very large number of 

 instances, be depended upon to yield a profit. Injudiciously applied a mone- 

 tary loss may result. With certain crops, especially potatoes and roots, 

 the yield may be largely increased by fertilizers, frequently doubled. The 

 proft obtained, over and above the cost of fertilizer, should always be calculated, 

 and not merely the increa.«;e in yield noted. ... In general, it is advisable to 

 use a complete fertilizer. . . . 



" Fertilizers give increases in crop yields on many types of soil ; even those 

 soils which are considered fairly rich frequently yield increases, though these 

 increases may not in all cases show a profit after deducting the cost of the 

 fertilizer. Large dressings of fertilizer do not necessarily mean large increases 

 in yield or large net profits. In experiments with potatoes, the profitable 

 application has seldom exceeded 400 lbs. per acre. . . . 



" The manipulation of fertilizer formulas to meet the specific requirements 

 of certain crops, as frequently practiced and advertised by fertilizer manufac- 

 turers is of little significance." 



Protein decomposition in soils, E. C. Lathrop (Soil Sci., 1 (1916), No. 6, pp. 

 509-632). — Experiments to determine the changes taking place in dried blood 

 in a fine sandy loam soil are reported. 



" The anunonification of the dried l)lood in the soil during the first SG days 

 was very rapid, after which time the amount of anunonia produced and the 

 late of ammonification decreased markedly until the end of the experiment. At 

 the end of the experiment the rate of transformation of hydrolyzable nitrogen 

 into ammonia nitrogen in the soil was but about 10 per cent of the rate observed 

 after the decomposition had been proceeding for 18 days. During the 240 days 

 of the experiment 79 per cent or more of the nitrogen of the dried blood proteins 

 was converted into ammonia nitrogen. 



" The ammonia produced during the decomposition of the dried blood was 

 derived from (1) the hydrolytic cleavage of the proteins of the dried blood, as 

 evidenced by the rapid vanishing of the amid compounds from the soil during 

 the first five days of the experiment; and (2) from the decomposition by the 

 micro-organisms of the products resulting from the hydrolytic cleavage of the 

 proteins. . . . With the exception of the amid compounds, lysin .seems to have 

 disnppo;ire<l most rapidly and completely from the soil. The monoamino acids 

 contributed about 89 per cent of their nitrogen to the formation of ammonia, 

 and arginin and histidin each contributed about 83 per cent. 



An analy.'sis of the figures obtained by the Van Slyke method i)oints to the 

 generation of new pi'otein materials in the soil. This is indicated by (1) the 

 unequal loss of monoamino acids and hydrolyzable nitrogen from the soil dur- 

 ing the early stages, (2) by an increase in amid nitrogen during the early 

 stages, (3) by an increase in histodin nitrogen during the early stages, (4) by 

 an increase in arginin nitrogen during the later stages, and (5) by an increase 

 in lysin nitrogen during the later stages. This new form of protein seems to 

 be more resistant to the action of the micro-organisms than were the proteins 

 of the dried blood, since the amid compounds of the dried blood vanished 

 very largely from the soil in five days, but the amid compounds produced in the 

 soil decreased only to the extent of 57 per cent during the remaming 222 days 

 of the experiment, and also since the lysin of the dried blood almost entirely 

 disappeared from the soils during the first 86 days of the experiment, but during 

 the last 154 days of the experiment a continual increase in this form of nitrogen 

 was observed. 



