A Study on Nitrogen Forms in Forest Soils

삼림토양(森林土壤)의 질소(窒素)의 존재형태(存在形態)에 관(關)한 연구(硏究)

The composition of the nitrogen forms of the organic layer and mineral soil horizons of 8 differing soil type was measured to find a clue to elucidate the problem on the fertility and nitrogen availabilities of forest soils. The ratio of inorganic $N(NH_4-N+NO_3-N)$ to total N was very low in every 0 layer and its maximum was only about 2%. And the inorganic N concentration of every mineral soil horizon was low, and the maximum of its rate to N was 3.7% in surface horizon and about 4.1% in lower horizon. Organic N form of O layer were characterized by the decrease of aminoacid-N, and the increased of hexosamine-N and amide-N according to the advance of decomposing process. The ranges of hydrolyzable-N of every flesh litter, F and H layer of the selected soils were about 80-90% and they- were hardly affected by the differences of tree species and decomposing process. The organic N form of every litter was similar and it was follows : aminoacid-N was not abundant and it ranges were about 40-50%, more than half of hydrolyzable-N. The hexosamine-N was eery poor and it ranged to only 2-7%. The amide-N teas low and about 10-23%. No distinguished difference was seen between the organic N forms of the O layer and surface horizon of dry and wet soils in brown forest soils.

삼림토양(森林土壤)의 비옥도(肥沃度)를 질소성분(窒素成分)의 면에서 해명하기 위한 하나의 수단으로서 서로 다른 8개(個) 토양형(土壤型)에 대하여 질소(窒素)의 형태(形態)를 검토하였다. 유기물층(有機物層) 및 광질토양층(鑛質土壤層)의 무기능질소(無機態窒素)($NH_4-N+NO_3-N$)는 전질소(全窒素)에 대한 비율이 O층(層), 표층토(表層土) 및 하층토(下層土)에서 각각 약 2%, 3.7% 및 4.1% 이었다. O층(層)에 있어서의 유기능(有機能) 질소(窒素)의 형태(形態)는 분해(分解)가 진행됨에 따라 전반적으로 aminoacid-N의 감소와 amide-N 및 hexosamine-N의 증가(增加)경향이 있었다. 공시(供試)한 O층(層)의 각층위에 있어서 가수분해성질소(可水分解性窒素)는 약 80-90%로 수종간(樹種間) 또는 층위별간(層位別間)의 큰 차이는 없었다. L층(層)에 있어서는 aminoacid-N가 가장 많아 약 40-50%에 달했으며, 가수분해성질소(可水分解性窒素)의 반(半)이상을 점하였다. Amide-N은 적었으며 약 10-23% 이었다. 이들 유기능질소(有機態窒素)의 각(各) 획분조성(劃分助成)에 있어서 수종(樹種)에 따른 영향은 크게 나타나지 않았다. 환경인자(環境因子)의 영향(影響)을 가장 크게 반영하는 O층(層) 및 표층토(表層土)에 있어서 건성형(乾性型) 토양(土壤)과 습성형(濕性型) 토양(土壤)간의 명료한 차이는 없었다.