논토양(土壤)의 탈질작용(脫窒作用)에 관(關)한 연구(硏究) -제(第)4보(報) 토양유기물함량(土壤有機物含量), 온도(溫度), pH, 질소비종(窒素肥種) 및 시비량(施肥量)이 탈질작용(脫窒作用)에 미치는 영향(影響)

Studies on the Denitrification in the Submerged Paddy Soil -IV. Influences of soil organic matter contents, soil temperature, pH values, kinds and levels of N-fertilizer on the evolution of N₂O gas

담수상태(湛水狀態)의 논토양중(土壤中) 유기물함량(有機物含量), 온도(溫度), pH 질소비종(窒素肥種) 및 시비량등(施肥量等)을 달리했을때 탈질작용(脫窒作用)과 탈질량(脫窒量)을 알고저 질내(窒內)에서 항온시험(恒溫試驗)한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 담수상태(湛水狀態)의 논토양(土壤)에서 탈질량(脫窒量)에 관계(關係)가 큰 요인(要因)은 토양유기물함량(土壤有機物含量) > 항온온도(恒溫溫度) > pH가(價) > 질소비종(窒素肥種) > 질소시비량(窒素施肥量)의 순(順)으로 컸다. 2. $N_2O$ gas의 생성량(生成量)은 토양유기물함량(土壤有機物含量) 3.0%인 토양(土壤)에서 항온온도(恒溫溫度) $20^{\circ}C$, pH 6.0일때 $KNO_3$ 20mg/100 토양(土壤) 시용구(施用區)에서 가장 많았다. 3. $N_2O$ gas 1 mole 생성(生成)하는데 소모(消耗)되는 탄소(炭素)는 전체평균(全體平均)이 0.5 mole 이였으며 탄소량(炭素量)이 제일(第一) 많이 요구(要求)되는 경우는 토양유기물함량(土壤有機物含量) 1.0%인 토양(土壤)에서 류안(硫安) 10mg/100g 토양(土壤) 시용시(施用時)(1.06 mole)였으며 제일(第一)적은 탄소요구(炭素要求)의 경우는 유기물함량(有機物含量) 3.0%인 토양(土壤)에서 $KNO_3$ 20mg/100g 토양(土壤) 시용시(施用時)(0.13 mole)였다. 4. Michealis-Menten의 효소반응식(酵素反應式)에서 유도(誘導)된 $N_2O$ gas의 V/2가(價)는 유기물(有機物) 1.0% 토양(土壤)에서 $(NH_2)_2CO$ 시용시(施用時) 550, $KNO_3$ 시용시(施用時)는 $1100N_2O{\mu}g/100g$ 토양(土壤)이였고 3.0%인 토양(土壤)에서 $(NH_4)_2SO_4$ 시용시(施用時)는 $490N_2O{\mu}g/100g$ 토양(土壤)이였으며 $KNO_3$ 시용시(施用時)는 시비량(施肥量)이 증가(增加)할수록 V/2가(價)는 계속 증가(增加)되었다.

A series of laboratory experiments were carried out to find the effects of soil organic matter contents, soil temperature, pH values, kinds and amount of nitrogen fertilizers on the denitrification-$N_2O$ gas evolution-. The results obtained were summarized as follows: 1. Denitrification rate, amount of $N_2O$ gas evolution, was influenced the order of organic matter contents>soil temperature>pH values>kinds of N-fertilizer>levels of N-fertilizer. 2. The highest dentrification rate was observed in organic matter content of 3.0%, pH values at 6.0 with application of $KNO_3$ at levels of 20 mgN/100g soil. 3. For the evolution of I mole $N_2O$ gas, averaged carbon consumption was obtained as 0.5 mole in all these experiment condition. However, the highest carbon consumption rate was obtained in organic matter contents for 1.0% with application of $(NH_4)_2SO_4$ at levels of 10 mgN/100g soil (1.06 mole) while lowest carbon consumption rate was obtained in organic matter contents for 3.0% with application of $KNO_3$ at levels of 20 mgN/100g soil (0.13 mole). 4. According to Michaelis-Menten's equation, the V/2 values for evolution of $N_2O$ gas was estimated by progress curve. The results obtained was as 550 ug for $(NH_2)_2CO$ and 1100 ug $N_2O/100g$ soil by application of $KNO_3$ in organic matter contents of 1.0% soil. On the other hand, when the application $(NH_4)_2SO_4$ the V/2 values of $N_2O$ gas was obtained as the amount of 490 ug/100g soil while V/2 values of $N_2O$ gas by application of $KNO_3$ was on the linear line in soil organic matter contents of 3.0%.