볏짚시용(施用)이 논토양(土壤)의 미생물상(微生物相)에 미치는 영향(影響) -III. 질소고정(窒素固定)에 관여(關與)하는 미생물상(微生物相)과 질소고정능(窒素固定能)

Effects of Rice Straw on the Microflora in Submerged Soil -III. Microflora in Relation to Nitrogen Fixation and Acetylene Reducing Activity

논토양(土壤)에 볏짚을 시용(施用)하고 투수조건하(透水條件下)에서 수도재배중(水稻栽培中), 토양중(土壤中) 질소고정(窒素固定)에 관여(關與)하는 미생물(微生物)의 소장(消長)과 질소고정능(窒素固定能)을 조사분석(調査分析)한 결과(結果)는 다음과 같다. Azotobacter는 경시적(經時的)으로 약간 증가(增加)하고 볏짚시용(施用)으로 균수(菌數)가 낮아지는 경향(傾向)이었다. Clostridia 는 경시적(經時的)으로 크게 증감(增減)되지 않았다. Blue green algae는 출수기(出穗期)까지 증가(增加)하다 감소(減少)했으며 볏짚시용(施用)으로 균수(菌數)가 증가(增加)하는 경향(傾向)이다. 질소무황세균(窒素無黃細菌)은 재배기간중(栽培其間中) 거의 검출(檢出)되지 않았고 Yeast는 경시적(經時的)으로 약간 증가(增加)하는 경향(傾向)이었다. 질소고정미생물(窒素固定微生物)의 균수(菌數)가 증가(增加)되면 acetylene환원력(還元力)도 증대(增大)되었으며 수도재배기간중(水稻栽培其間中) 질소고정력(窒素固定力)은 0.2~0.4kg/10a이었다. 수도무재배구(水稻無栽培區)에서 질소(窒素)의 고정력(固定力)은 볏짚시용(施用)으로 약간 증가(增加)되었으나 투수(透水)의 효과(效果)는 뚜렷하지 않다.

The results of these experiments which were carried out to investigate the effects of rice straw for nitrogen metabolism and acetylene reducing activity, during rice plants were cultured under the percolated condition, are as follows. Azotobacter had tendency to increase with the passage of time, but decreased when rice straw was added. Population change of Clostridia was little as rice grew. Blue green algae increased until heading stage but decreased after the stage. And the application of rice straw increased the number of microorganisms. Thiorhodaceae were never detected, but yeast tended to increase slightly with passing time. Acetylene reducing activity was increased with increasing the number of nitrogen fixing microorganisms, and nitrogen fixing activity was between 0.2kg N/10 a and 0.4kg N/10 a during the growing season of rice plants. Though acetylene reducing activity was promoted by the use of rice plants on non-plant area, but the activity was not clearly affected by percolation.