THE MICROBIOLOGICAL DECOMPOSITION OF THE ORGANIC COMPOUNDS INBARNYARD MANURE1

Abstract

N. BENGTSSON AND CHR. BARTHEL

IN the experiments here reported the transforma-tions of the manure nitrogen as well as the

decompositions of the cellulose, pentosans and ligninin the manure were studied. Simultaneously the'"humus" and the organic carbon were determined.The analytical methods used are related in the Annalsof the Agricultural College of Sweden (Vol. 3 :i-i69,1936).

The manure used was obtained from cows whichhad been fed on hay, straw and concentrates; it wasthree months old and contained urine, straw andchaff. The experiments were made in sand at theinitial pH-values 6 and 8. All the samples contained7,560 grams dry sand, 840 grams ground manure and

4.2 grams KH2PO4; they were inoculated with 120ml soil extract. In addition the samples received :

Sample I.—No addition.Sample II.—6.06 grams KNO3.Sample III.—12.12 grams KNO3.Sample IV.—252 ml iN H2SO4.Sample V.—3.97 grams (NH4)2SO4 plus 252 ml

iN H2SO4.Sample VI.—7.94 grams (NH4)2SO4 plus 252 ml

iN H2SO4.Sample VII.—6.06 grams H KNO3 plus 252 ml

iN H2SO4.Sample VIII.—12.12 grams H KNO3 plus 252 ml

iN H2SO4.

'Contribution from the Institute of Microbiology, The Agricultural College of Sweden. Published originally in Trans. ThirdCom. Int. Soc. Soil Sci., A:i33-i36. 1939.

ABSTRACTS 233

The amount of sulfuric acid added to the samplesIV-VIII intended to establish the pH-value 6. Theadditions of potassium nitrate and ammonium sulfatewhich corresponded approximately to one or twoequivalents of the ammonia nitrogen in the manurewere made in order to see especially if the decom-position of the proteins could be accelerated. Thewater content was adjusted to 15% in all the samples.Each sample was divided into 21 parts which were putinto 300 ml glass jars. The jars were stoppered in themanner described in the Annals of the AgriculturalCollege of Sweden (Vol. 7:123, 1939). The jars

were incubated at 20-22 °C. When necessary, waterwas added to replace losses by evaporation.

The results of the investigations which were con-tinued for four years showed the following: All theprocesses of decompositions here studied proceededdecidedly more rapid at the alkaline reaction than atthe acid one. The additions of nitrogen through whichthe ratio C: assimilable N was narrowed from 99 to46 or 30 showed no influence upon the rapidity of theprocesses of decomposition.

A more minute report of these investigations willbe published in the Annals of the Agricultural Collegeof Sweden.—Author abstract.