抄録
This paper deals with the effect of lignin upon the decomposition of protein by determining NH_3-N and NO_3-N (and sometimes CO_2) liberated when lignin prapared from various plant materials, was added to protein in culture solution and in soil under both the dry and the paddy field conditions and the following results were obtained : 1) In the case of culture solution, when heated, the decomposition of protein was retarded by lignin within the first four weeks, but when unheated, only within the first two weeks. 2) There was no marked difference in the above depressive effect among lignins from various plant materials except that form Quercus acuta which acted most. 3) In the case of soil, it was determined that the depressive effect was not so remarkable as in the culture solution and that the retardation started when the ratio of lignin and protein was more than six to one. 4) It was also experimented that the effect of lignin was marked on nitrification and only a little on ammonification. The above fact may suggest that the depressive effect of lignin on protein decomposition is important in dry field and not so in paddy field condition.
