FERTILIZERS. 321 



tui'iiip.s, carrots, and potatoes are tal)ulato(l aiul discussed. The con- 

 clusion drawn from this data is that if farmers would preserve "all the 

 liquids Avith the solids in water-tig'ht troughs behind the animals, using- 

 cut straw for bedding- and as an absorbent; then distribute this o\er the 

 land in a fresh condition before any of the liquids so rich in fertilizing 

 constituents are decomposed, the saving effected would be enormous, 

 and the value of barnyard manure in bringing increased crops would 

 probal)ly be nearly double what it now is." 



The reduction of nitrates in the presence of barnyard manure, 

 J. P. Street (^W//' Jei'Kry Sfa.s. Rpf. lHOO,_[>p. 80-96). — Previous inves- 

 tigations on the subject are briefly noted, and an account is given of a 

 study of the changes in the nitrogen of a mixture of fresh solid cow 

 manure (about 30 gm.) with nitrate of soda (1.25 gm.), with sulphate 

 of ammonia (1 gm.), and with dried blood (1..5 gm.), with or without 

 the addition of gypsum, acid phosphate, kainit, and sulphur (each 0.2 

 gm.), and carbon bisulphid (20 cc). The volume was in each case made 

 up to 300 cc. with water and the mixtures kept in open flasks in the 

 laboratory at about 20^ C. from February 28 to March 29, with occa- 

 sional shaking. Two series of experiments were made — one being 

 examined for nitrates by the Schulze-Tiemann method at intervals of 

 7, 11, and 21 days, the other remaining undisturbed until the end of the 

 period. In case of the mixture of manure and nitrate denitrification 

 was complete in 21 days; with other substances added to this mixture, 

 the periods of denitritication were as follows: With gypsum 27 days, 

 acid phosphate 27 days, kainit 16 days, and sulphur 23 da3's. The mix- 

 ture sterilized with carbon bisulphid lost only 9.6 per cent of its nitrates 

 in 21 days. 



In case of sulphate of ammonia the changes in the nitrogen were 

 slight, the greatest loss in 21 days being 1.1 per cent where acid phos- 

 phate was used. There was a slight gain in case of kainit and gypsum. 



The examination of the second series of tests showed approximately 

 the same results as the first as regards the nitrate. 



" The loss where kainit was used was complete, as it was before, while the nitrate 

 alone and nitrate with acid phosphate suffered a loss of over 97 per cent. The losses 

 where sulphur and plaster was used were somewhat less, being 93.7 per cent and 85.4 

 per cent, respectively. The plaster seemed in this test to have a slight retarding 

 effect on denitrification. The loss where carbon bisulphid was used, while more than 

 in the first series, was only about one-fourth of that sustained by the other tests." 



In the sulphate of ammonia tests, the changes in nitrates and total 

 nitrogen were comparatively insignificant. There was a considerable 

 gain in soluble organic nitrogen in every case, being most pronounced 

 where carbon bisulphid and sulphur were used. This was also true of 

 the nitrate series. There was also a marked gain in insoluble organic 

 nitrogen in the sulphate of ammonia tests, being largest where the sul- 

 phate was used alone and least where carbon bisulphid was used. 



