생리학적(生理學的) 질소고정(窒素固定)에 관(關)한 연구(硏究) -제(第) II 보(報). 답토양(畓土壤)의 물리적특성(物理的特性)-답류형(畓類型), 토성(土性), 배수정도(排水程度), 농업기후대(農業氣候帶)-이 광합성(光合成) 및 타양성질소고정력(他養性窒素固定力)에 미치는 영향(影響)

Studies on Physiological Nitrogen Fixation -II. Effects of soil physical properties-soil texture, soil type, drainage and agricultural locality-on the changes of photo synthetic and aerobic heterotrophic nitrogen fixing activity

담수상태(湛水狀態)의 논토양(土壤)에서 광합성미생물(光合成微生物) 및 타양성미생물(他養性微生物)에 의한 질소고정력(窒素固定力)을 알기 위하여 우리나라 전국(全國) 수도(水稻) 삼요소시비량시험지(三要素施肥量試驗地) 16개소(個所)의 무질소구(無窒素區) 표토(表土)를 채취(採取)하여 초자실(硝子室)에서 항온(恒溫)하면서 토양통(土壤統), 농업기후대(農業氣候帶), 논토양유형(土壤類型), 토성(土性) 및 배수정도(排水程度)에 따른 질소고정량(窒素固定量) 차이조사(差異調査)를 한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 담수항온기간중(湛水恒溫期間中) 광합성질소고정미생물(光合成窒素固定微生物)에 의한 Acetylene 환원력(還元力)은 항온(恒溫) 7일째, 그리고 타양성질소고정미생물(他養性窒素固定微生物)에 의한 Acetylene 환원력(還元力)은 항온(恒溫) 35일째 가장 높았다. 2. 타양성미생물(他養性微生物)에 의한 질소고정력(窒素固定力)이 가장 높은 토양통(土壤統)은 장계(長溪), 옥천(沃泉) 및 화동통(華東統)이었으며 질소고정력(窒素固定力)이 낮은 토양(土壤)은 부용(芙蓉) 및 대정통(大靜統)이었다. 광합성미생물(光合成微生物)에 의한 질소고정력(窒素固定力)이 가장 높은 토양(土壤)은 대정(大靜) 및 지산통(芝山統)이였으며 낮은 토양(土壤)은 장계(長溪), 함창통(咸昌統)이였다. 3. 항온(恒溫) 105 일간(日間) Acetylene 환원법(還元法)에 의한 생물질소고정량(生物窒素固定量)은 광합성미생물(光合成微生物)에 의하여 3.0mg, 그리고 타양성미생물(他養性微生物)에 의하여 4.9mg/100g이었다. 4. 농업기후대별(農業氣候帶別) 생물질소고정량(生物窒素固定量)은 광합성미생물(光合性微生物)의 경우 기온(氣溫)이 온난(溫暖)한 남부해안지역(南部海岸地域)에서 높고 타양성미생물(他養性微生物)은 산간지(山間地)와 충청내륙지역(忠淸內陸地域)에서 높았다. 5. 답토양유형별(沓土壤類型別) 질소고정량(窒素固定量)은 광합성미생물(光合成微生物)의 경우 보통답(普通沓) 토양(土壤)에서 높고 타양성미생물(他養性微生物)의 경우는 조립질(粗粒質)의 사질답(砂質畓) 토양(土壤)에서 높았다. 6. 토양(土壤)의 특성별(特性別) 질소고정력(窒素固定力)을 볼 때 광합성미생물(光合成微生物)은 배수(排水) 약간불량(若干不良)한 식질(埴質) 혹(或)은 식양질토양(埴壤質土壤)에서 높고 타양성미생물(他養性微生物)은 배수양호(排水良好)한 사질토양(砂質土壤)에서 높았다.

A green house experiment was conducted to find out the acetylene reducing and $N_2$-fixing activity from photosynthetic and aerobic heterotrophic nitrogen fixing microorganisms in submerged paddy soil under different agricultural locality, soil series, soil texture, soil type, and drainage condition in which samples taken from without nitrogen treatment plot of NPK trials on 16 sites of the farmer's field. The results obtained were summarized as follows: 1. The highest acetylene reducing activity was observed at 7 days after incubation in the light condition (photo synthetic microbes+heterotrophic bacteria) while it was observed at 35 days incubation in the dark condition (heterotrophic bacteria). 2. Among the soil series, photosynthetic nitrogen fixing activity was pronounced more in Jangae, Ogcheon and Hwadong series while lower was obtained in Buyong and Daejeong series. Aerobic heterotrophic nitrogen fixing activity was high in Buyong and Daejong series. 3. Estimated amount of $N_2$-fixation from acetylene reducing activity was equivalented to 3.0 mg in light condition and 4.9 mg/100g/105 days in dark condition. 4. Among the agricultural locality, photosynthetic nitrogen fixing activity was high in rather warm southern part while heterotrophic nitrogen fixing activity was predominated more in mountainous area and Chungcheong continental. 5. Photosynthetic nitrogen fixing activity was predominated in high productive soil while aerobic heterotrophic nitrogen fixing activity was pronounced more in crose coarse sandy soil. 6. The soils properties of high photosynthetic nitrogen fixing activity were constituted of poorly or imperfectly drained clay or clay loam soil while heterotrophic nitrogen fixing activity was pronounced more in well to moderately well drained sandy or sandy loam soil.