In order to study the effect of barley, Italian ryegrass (IRG), and legume mixture on nitrogen fixation and transfer to grasses on spring paddy field, an experiment was carried out from Oct. 2006 to June 2007 in Naju, Korea. A split plot design with three replications was used for the experiment. One reference plot was assigned for each treatment to determine nitrogen fixation. Main plots consisted of Chinese milk vetch, crimson clover, forage pea, and hairy vetch with barley, respectively. Subplot treatment were barley or IRG with four seeding ratio of legumes (50:50, 60:40, 70:30, and 80:20). To estimate N fixation by legumes, 15N isotope dilution technique was used. 15N fertilizer [(15NH4)2SO4 solution at 99.8 atom N] was uniformly applied to 600 cm2 in the middle of each plot on April 15, 2007. Plots were harvest by hand on June 8, 2007. Dried sample were ground to a fine power and analyzed for total N isotope N. 15N was determined using elemental analyzer-isotope ratio mass spectrometry. The calculation of N transfer was determined with the isotope dilution method. The content of N was higher in legumes than that in barley or Italian ryegrass. Nitrogen level in forage pea was significantly higher than that of other legumes. There were significantly differences in N content between legumes in IRG mixture. Atom % 15N excess was significantly different in legumes with barley. The 60:40 sub plot had higher (p<0.05) atom % 15N than other seeding ratio treatments. The enrichment ranged from 0 to 0.58. Compared to barley, the enrichment of IRG with its accompanied legumes was higher, ranging from 0.38 to 1.0. The N derived from the atmosphere (Ndfa) ranged from 0% to 49.5% with barley-legume mixture. It ranged from 0 to 60.5% in IRG-legume plots. N transfer from legumes to neighboring grasses was 12.3 to 90.9 kg/ha for barley-legume mixture and 31.7 to 107.8 kg/ha for IRG plots. IRG plots showed higher N transfer for IRG-legume mixture in general based on difference method. Based on 15N dilution method, the N transfer was 0 to 36.1 kg/ha for barley-legume mixture and 0 to 50.6 kg/ha for IRG plots. There was a tendency toward higher N transfer on the difference method than that of the 15N dilution method.

Field research was undertaken to determine how barley + legume mixtures influence nitrogen fixation and N transfer to barley. Barley + legume (main plot) and 4 different sowing rate was the experiment design. Isotope dilution was used to estimate N₂ fixation and subsequent transfer to barley. Botanical composition of legume was from 1.6% to 13.9% when harvest. Legume N derived from atmosphere ranged from minus value to 58percentage in whole plant N. N transfer amount to barley varied from 12.11㎏ to 7㎏ by different method.

분뇨이용에 대한 관심이 높아지면서 질소고정을 통해 동반하는 작물에 질소를 고정하고 이동하는 두과와 화본과의 혼파가 주목을 받고 있다. 본 연구는 각기 다른 혼파조합이 춘계논토양에서 두과작물의 질소고정과 이의 이동을 규명하고자 실시하였다. 시험처리는 난괴법 3처리, 3반복이었으면 세 개의 다른 혼파처리는 호밀+벳치, 이탈리안라이그래스+크림손클로버 그리고 연맥+완두였다. 충남 서천의 논토양을 포트에 채워 시험을 하였다. 호밀과 헤어리벳치구는 수원의 진흥청

The purpose of this research was to investigate the effect of P fertilization and cutting fkquency without N fertilizer on nutritive value and nitrogen fixation activity of alfalfa. A field experiment was conducted on the experimental farm of Kongju Natio

본 시험은 석회(0, 250, 1,000kg/10a)와 인산(0, 17 및 34kg/10a)t용이 alfalfa의 생장 및 질소고정에 미치는 영향을 구명하기 위하여 전남대학교 농과대학내 온실에서 pot로 수행되었는데 그 결과를 요약하면 다음과 같다. 실험기간동안 alfalfa의 지상부와 지하부의 건물중, 근류중량 및 acetylene환원력은 pH6.2인 토양에서 석회시용 효과가 인정되지 않았지만, 인산시용 효과는 인정되었다(p<0.05). 파종 후 7주

본 시험은 석회(0, 250, 500, 1,000kg/10a)와 인산(0, 17, 34kg/10a) 시용이 alfalfa(Medicago sativa L.)의 생장 및 질소고정에 미치는 영향을 구명하기 위해 전남대학교 농과대학내 온실에서 pot로 수행되었다. 파종후 9과에 alfalfa의 지상부와 지하부의 건물중 및 아세틸렌 환원력에 있어서 석회 및 인산시용효과가 나타났으며(p<0.05). 파종후 14과(개화초기)에는 alfalfa의 지상부와 지하부의

방목초지에서 자생하는 라디노 클로버 포복경을 l/5,000a 와그너 포트에 이식하여 온실에서 겨울동안 1일 12시간 조명시키면서 재배하였다. 50일 동안 재배 후 제 1차 수화하였고 20일 후 2차, 그리고 다시 20일 후에 3차 수확을 하였다. 처리로는 질소시비를 2.5kg/10a, 5.0kg/10a, 7.5kg/10a를 이식 및 각 예취후에 시비하였다. 조사항목으로는 생장점, 지상부 수량, 지하부 수량 그리고 엽면적을 측정하였고 그밖에 질소고정량 및

질소원(窒素源)을 달리한 비료시용(肥料施用)이 대두(大豆)의 생육(生育), 수량(收量), 영양성분(營養成分) 및 단백질(蛋白質) 소화율(消化率) 등(等)에 미치는 비효(肥效)는 다음과 같다. 대두(大豆)의 생육상황(生育狀況)은 시비조건간(施肥條件間)에 대체로 유사(類似)하였으나 유안구(硫安區)와 무질소구(無窒素區)에 있어서 절수(節數)가 적었다. 근류수(根瘤數)와 무게는 유안구(硫安區)와 무질소구(無窒素區)가 낮았고 그 밖의 처리구(處理區)에 있어서는 차이가 보이지 않았다. 근류수(根瘤數) 당(當) 질소고정력(窒素固定力)은 생육초기(生育初期)와 개화기(開花期)에는 거의 비슷하였으나 pod 신장기(伸長期)에서는 개발복비구(開發複肥區)가 타처리구(他處理區)보다 비교적 높았다. 대두(大豆)의 100립중(粒重) 및 10a 당(當) 수량(收量)은 개발복비구(開發複肥區)가 타처리구(他處理區)보다 높았고 무질소구(無窒素區)는 질소원(窒素源) 비료(肥料)의 시용구(施用區)보다 대체로 낮았다. 또한 대두(大豆)의 조단백질(粗蛋白質) 함량은 질소원(窒素源) 비료(肥料)의 시용구(施用區)가 무질소구(無窒素區)에 비해 높았고 조지방(粗脂肪) 함량은 오히려 낮았다. 조회분(粗灰分) 함량은 시용구간(施用區間)에 대체로 비슷하였으나 조섬유(粗纖維) 함량은 기존복비구(旣存複肥區)가 타처리구(他處理區)에 비해 높았다. Ca, P, Na, K, Mg, Zn, Mn 및 Cu 함량은 시비조건간(施肥條件間)에 대체로 비슷하였으나 Fe 함량은 무질소구(無窒素區)가 질소원(窒素源) 비료(肥料)의 시용구(施用區)에 비(比)해 월등히 낮았으며, 단백질(蛋白質) 소화율(消化率)은 무질소구(無窒素區)에서 가장 높았다.

刈取가 알팔파根瘤의 着生 및 發達과 室素固定活性에 미치는 影響을 檢討하기 위하여 圃場實驗에서는 刈取區와 非刈取區로 구분하여 時期別로 Acetylene還元法에 의하여 根瘤의 室素固定活性을 測定하였다. 養液栽培實驗에서는 地上部의 50%와 90%刈取, 花芽의 除法, 根瘤의 50%와 100% 除法등을 組合處理後 알팔파 再生과 根瘤의 着生과 發達에 미치는 影響을 檢討하였다. 1. 圃場實驗에서 根瘤의 무게는 1回刈取後 30%, 2 回刈取後 25%의 減少가 있었고

광교(光敎)를 비롯한 12개품종(個品種)의 대두근류(大豆根瘤)로부터 탐색분리(探索分離)한 질소고정균(窒素固定菌)의 생리적(生理的) 특성(特性) 및 숙주작물(宿主作物)과의 접종친화성(接種親和性)을 조사(調査)한 결과(結果)는 다음과 같다. 1. YMA배지(培地)에서 자란 질소고정균(窒素固定菌)의 색상(色相)은 백색상(白色相), 반투명색상(半透明色相), 투명색상(透明色相)이 각각(各各) 60%, 30%, 10%였으며 Litmus milk 반응(反應)은 alkali, acid serum, alkali serum, acid가 각각(各各) 51%, 29%, 9%, 11%로 나타났다. 2. 우량질소고정균(優良窒素固定菌)의 YM배지(培地)에서의 생육속도(生育速度) 및 pH의 변화(變化)는 S 022, S 096이 생육속도(生育速度)가 느리고, alkali를 생성(生成)하였으며 S 080, S 090, S 118은생육속도(生育速度)가 빠르고 산(酸)을 생성(生成)하였다. 3. YM배지(培地)의 초기(初期) pH가 6.0~7.0의 범위(範圍)에서 Rhizobia의 생육(生育)이 가장 좋았다. 4. 질소원(窒素源)으로서 glutamine, asparagine, allantion 등(等)은 Rhizobia의 생육(生育)을 촉진(促進)시켰다. 5. 분리(分離)한 균주(菌株) 전부(全部)가 대두(大豆)에 근류(根瘤)를 형성(形成)시켰으며, 우량질소고정균주(優良窒素固定菌株)는 그중 색상(色相)이 백색(白色)이고 colony가 소형(小型)이며 질산환원력(窒酸還元力)이 있고 아질산환원력(亞窒酸還元力)이 없으나 비교적(比較的) 높은 질소고정력(窒素固定力)을 나타냈다. 6. 동일균주(同一菌株)라도 숙주작물(宿主作物)의 친화성(親和性)에 따라서 질소고정능력(窒素固定能力)에 차이(差異)가 있었으며, 질소고정능력(窒素固定能力)이 없는 무효근류(無效根瘤)를 형성(形成)하는 균주(菌株)도 있었다.

Rhizobium의 Nitrogenase 생성요인(生成要因)과 감염기작(感染機作)을 구명(究明)하고 배양세포(培養細胞)와 Rhizobia의 혼합배양(混合培養)에서 질양고정계(窒養固定係)를 확립(確立)하기 위(爲)하여 황금(黃金), 남천(南川), D68-0099등(等) 세 품종(品種)을 조직배양(組織培養)한 결과(結果)는 다음과 같다. Callus 형성능(形成能)은 배(胚)와 유근(幼根)에서는 양호(良好)하나 배축(胚軸)에서는 전혀 없었으며 2mg/ 2,4-D, 4mg/ NAA에서 가장 양호(良好)하고 2,4-D/Kinetin 조합농도(組合濃度)에서는 0.2mg(2,4-D)/과 0.05mg(Kinetin)/에서 가장 이상적(理想的)이었다. 배양세포(培養細胞)의 성장(成長)에는 2,4-D 2mg/와 2,4-D (0.2mg/)/Kinetin(0.05mg/)일 때가 가장 양호(良好)하며 R. japonicum 019, 011을 접종(接種)하였을때 배양세포(培養細胞)의 성장(成長)은 상당히 둔화되었다. 단일(單一) 아미노산은 배양세포(培養細胞)의 성장(成長)을 저해(沮害) 하였는데 황금(黃金)의 경우 Methionine, Leucine에서 저해(沮害)가 가장 컷으며 다른 아미노산의 첨가(添加)로 저해작용(沮害作用)이 상당히 회복되었다. 부정근(不定根)의 생성(生成)은 2,4-D 2.0mg/에서나 0.2mg/ 2, 4-D/0.05mg/ Kinetin에서 양호(良好)하였다. 배양세포(培養細胞)-Rhizobium의 친화(親和)에 의(依)한 질소고정력(窒素固定力)은 25개(個) 사용(使用) 균주중(菌株中)에서 황금(黃金)에서는 10개(個) 균주(菌株), 남천(南川)에서는 7개(個) 균주(菌株)에서 나타났으며 D68-0099에서는 전혀 나타나지 않았으며 황금(黃金)의 경우(境遇) 85-HG-1 019, 007, 남천(南川)에서는 007, 119등(等)이 높은 활성(活性)을 나타내었다.

To find out the growth conditions for the maximum activity of nitrogenase which catalyzes nitrogen fixation in Rhodobacter sphaeroides, the promoter activities of nifA and nifH were analyzed and the results indicated that expression of both nifA and nifH was increased in response to deprivation of both O2 concentration and nitrogen source. The nifA mutant was constructed by deleting the gene to investigate the effect of NifA, the transcriptional regulator, on the nifH and nifA expression in R. sphaeroides. Analysis of expression of nif genes using the nifA::lacZ and nifH::lacZ fusions in the nifA mutant revealed that NifA acts as a positive activator for nifH and an autoregulator in its own expression. The promoter activities of nifA and nifH in the prrA mutant grown under anaerobic and NH4 +-free conditions were derepressed, comparing with those of the wild-type grown under the same conditions, indicating that the prrA product acts as a positive regulator in expression of nifA and nifH.

Nitrogen fíxatíon by legumes can be valuable sources for organíc farmíng. Thís study was to ínvestígate the effect of dífferent legume mixtures on nitrogen fíxatíon and transfer to grasses on sp끼ng paddy fíeld. Three different mixtures were used (rye+haíry vetch, Italían ryegrass+crímson clover, oat+pea) in a randomized complete block design with three replications and sowed ín pots wíth different sowing rate (5:5 rye:haíry vetch,7:3=ltalian:crimson, 6:4=oat:pea) on early March. t 5NH4hS04 solutíon at. 99.8 atom%15N was applied to the each pot at the rate of 2kg N ha.1 on 16h Ap끼1. Forage were harvested at ground level ín heading stage and separated ínto legume and grass. Total N content and 15N value were determíned using a continuous f10w stable ísotope ratio mass spectrometry. DM yield of rye+vetch, Italian+crimson and 。at+pea were 6,607, 3,213 and 4,312kg/ha, respectively. Proportion of N from fixatíon was 0.73(rye+vetch), 0.42(1talian+crimson) and 0.93(oat+pea). The percentages of N transfer from legume to grass were from 61% to 24% in dífferent method by treatments and -35% to 21% in ísotope dilutíon method.

This experiment was conducted to clarify the functions of supernodulating characters on seed yield determination through the comparison of agricultural traits of supernodulating soybean mutants, Kanto100, SS2-2, and their parent cultivars, Enrei and Shinpaldalkong2. The supernodulating soybean mutants Kanto100, SS2-2 were previously characterized by their superior capabilities of nitrogen (N) fixation and photosynthesis, and thereby it is expected to offer high yields. However, it is likely to be susceptible to waterlogging during the vegetative growth stage, which frequently occurs in major soybean producing areas. The presentstudy was intended to show the effects of waterlogging on nodulation, N fixation, photosynthesis and growth of Kanto100 and SS2-2.The supernodulating cultivar Kanto100 and its normally-nodulating parental cultivar Enrei, grown in pots,were subjected to waterlogging treatment that was imposed at the successive three vegetative growth stages for two years,2005 and 2006. The waterlogging treatment significantly reduced the number and weight of nodules of both cultivars, and the magnitude of the reduction was more pronounced in Kanto100 and SS2-2. The acetylene reduction activity (ARA) of nodules and apparent photosynthetic rate (AP) of leaves were generally depressed immediately after waterlogging treatment, but both functions exhibited remarkable recovery at the pod-filling stage irrespective of cultivar. No marked cultivar difference was found in the magnitudeof the reduction of ARA per plant and AP measured immediately after waterlogging and at the pod-filling stage irrespective of year, but growth impairment was more pronounced in Kanto100 and SS2-2 in one of the two years. These results indicate that Kanto100 and SS2-2 exhibits a marked decrease in dry matter production by waterlogging, but yield decrease is compensated to level similar to that of Enrei and Shinpaldalkong2 because of its enhanced nodule growth during the recovery stage. The supernodulating cultivar Kanto100 and SS2-2 is more susceptible to waterlogging under certain growing conditions than their normally-nodulating parent cultivar.

This experiment was conducted to investigate the soil nitrogen credit of biological nitrogen fixation (BNF) and the nitrogen balance of soybean in soybean-barley cropping systems. Soybean cultivar, Shinpaldalkong2 and barley cultivar, Olbori, were used in soybean mono-cropping (SM), barley monocropping (BM), and barley­soybean double cropping system. The barley-soybean double cropping system was treated with two different levels of nitrogen fertilizers, 0 nitrogen fertilizer (BS-F0), and standard nitrogen fertilizer (BS-F1). Nitrogen and organic matter concentrations in soil of BS-F1 plot on October, 2001 were increased 4.8~%~;and~;5.9~% , respectively, compared with those on October, 2000. The ranges of BNF rate in soybean were 69.1~~ 88.2~% in two years, and the rate was the highest in BS-F0 plot and the lowest in SM plot. The ranges of nitrogen harvest index (NHI) in all treatments were 83.9~~86.7~% . The yield was 270 kg/10a in BS­F1 plot and 215 kg/10a in BS-F0 plot. However, the nitrogen balances were +0.6 kg/10a of gain of soil nitrogen in BS-F0 plot and -0.4 kg/10a of loss of soil nitrogen in BS-F1 plot. In comparisons of SM and BS-F1 plots, although the seed yields were similar in two plots, the loss of soil nitrogen was higher in SM than BS-F1 plot. Overall, our results suggest that barley-soybean double cropping system was more effective in respect to seed productivity and soil nitrogen conservation than soybean monocropping system, and the N credit to following crops by soybean cultivation was identified in soybean double cropping system.