734 EXPERIMENT STATION RECORD. 



24 hours, the manure for each series being kept separate. The liquid 

 excrement was weighed and examined dail}'. The precautions observed 

 in the sampling of the feed and litter; the construction of the stalls, 

 manure heaps, and liquid manure pits; the weighing and sampling of 

 the solid and liquid manure; the determination of the milk production 

 and increase in live weight; and the analytical methods used are 

 described. The balance for the first and second periods gave a loss of 

 8.3 per cent of nitrogen, a gain of 2.7 per cent of phosphoric acid, and 

 no change in the amount of potash. The balance for the heaps of 

 mixed solid and liquid manure (after an average of 107 days) showed 

 a loss of 19.1 per cent of nitrogen, and an increase of 3.6 per cent of 

 phosphoric acid and 0.8 per cent of potash. The results obtained 

 indicate the reliability of the methods used, but investigations with a 

 view to their improvement are to be continued. 



Denitrification and the action of barnyard manure, T. Pfeiffer 

 and O. Lemmerjiaxn {Landic. Vers. Stat., 5 If. {1900), Xo. 5-G,2)I>' 386- 

 Ifi'2). — From the results of an extended series of experiments in pots 

 and on plats in continuation of those previousl}' reported (E. S. K., 11, 

 p. 134) the following conclusions are drawn: The utilization of the 

 nitrogen supply of the soil is unfavorably influenced both by an increase 

 of organic matter and of denitrifying organisms. B}^ the addition of 

 barnj^ard manure denitrification is promoted, both by the organic 

 matter and by the bacteria, which are thus supplied to the soil. The 

 injurious effects noted in pots during the first season disappear during 

 the second. An increase of organic matter b}" the addition of a solu- 

 tion of calcium citrate, as well as the use of a pure culture of denitri- 

 fying organisms, resulted in the evolution of free nitrogen. The loss 

 of nitrogen in the free state as a result of the application of barn^^ard 

 manure in pot experiments is considered of only secondary importance 

 in comparison with other factors influencing the utilization of nitrogen 

 by the crop. The utilization of applications of nitrate of soda on light, 

 sandy soils is serioush^ interfered \\ath b}' applications of cattle or horse 

 manure at rates of 800 metric centners per hectare (17.81 tons per acre). 

 Since the same manure gives ver}" different results in pots and on plats, 

 the authors caution against the direct application of the results of pot 

 experiments with manure in actual practice. The variable action of 

 the nitrogen of manure can not be explained b}' ordinary analyses, in 

 which the contents of ammoniacal, amid, and digestible proteid nitrogen 

 are detemiined. It is claimed that the variable action of different kinds 

 of manure is explained by variations in the extent of denitrification. 

 In the authors' experiments no relation was found to exist between the 

 content of nitrogen-free organic substances, particidarly pentosans, 

 and the action of the nitrogen. There is wide difference in the ease 

 and rapiditr with which the nitrogen compounds of different kinds of 

 manure undergo decomposition, and in the authors' opinion this is one 



