• Korean Journal of Organic Agriculture
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• v.14 no.2
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• pp.191-204
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• 2006

This study was conducted to identify the effect of planting date and cultivation method on soybean growth and yield in paddy field. The plant height of soybeans in single cropping(SC) was higher than those in cultivating after barley culture (CB). Considering planting date and cultivation method, plant height tend to be higher in SC with level row cultivation(LR) and in CB with high ridge cultivation(HR). In this SC method, nodule formation in LR was better than in HR, but number of nodules of cv. Hwangkeumkong was highest, regardless of planting date and cultivation method. In the progress of growth stage, leaf areas of all cultivars were distinctively increased in CB than in SC. However, dry weight of top plants and roots in SC was comparably higher than that in CB due to growing periods of the soybeans. In cultivation methods, general type of dry weight of top plants was higher in LR than in HR, however, root dry weight was via verses. Growth responses varied depending on cultivars, cultivation methods, and planting date and these factors affected to shoot root (T/R) ratio. The T/R ratios in LR and SC were higher than those in HR and CB. In R8 stage, number of pods and ripened seed varied depending on cultivars. cv. Hwaeomputkong, which showed early maturing trait, was lowest. However, both yield factors tended to be higher in HR and CB than in LR and SC. The ratios of ripened seeds percentage of cv. Hwangkeumkong and cv. Eunhakong were higher in CB than in SC. However, yields of cv. Daewonkon and cv. Taekwangkong were higher in CB than in SC.

• Journal of Plant Biology
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• v.35 no.4
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• pp.317-322
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• 1992

The nitrogen fixation activity and environmental factors of Lespedeza bicli!oy Turcz, forming annual root nodules by symbiotic Rhizobium sp. were analyzed in the field conditions during the growing period. Seasunal changes of $N_2-fixation$ activity showed the maximum value of $120\;\mu\textrm{M}\;C_2_H4{\cdot}noduie\;g\;fw^{-1}{\cdot}hr^{-1}$ during the active growing period (June) and varied significantly depending on the growth phase and environmental factors. The maximum activities were attained at the conditions of pH 7, $30^{\circ}C$ of temperature, 18 Kpa of oxygen partial pressure and inhibited by water stress and nitrogen sources. The habitat soil was weak acidic and poor in nitrogen, phosphorus and organic matter contents. The leaf area ratios and chlorophyll contents were ranged from 442 to $48;\textrm{cm}^2{\cdot}g\;dw^{-1}$ and from 33 to $38\;\mu\textrm{g}\;chI{\cdot}\textrm{cm}^2$. Nitrogen contents in each organ showed the maximum of 46, 19 and $11\;mg{\cdot}g\;dw^{-1}, respectively for leaf, rool and stem in the early period. The highest phosphorus contents were 4.2, 1.2 and $0.6\;mg{\cdot}g\;dw^{-1}$, respectively for leaf. root and stem in early growing period. The allocation ratios of nitrogen quantity showed 60% for leaves and 73% for roots during the active and late growth period, and 22% [or stems in average. The allocalion ralios o[ phosphorus quantity showed 58% for leaves during the most productive period, 70% for roots in the pre-growth stage and 26% for stems in average.verage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.3
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• pp.295-305
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• 1994

Greenhouse and laboratory studies were conducted to investigate the allelopathic potential of alfalfa and vetch residues on soybean and corn using various extract concentrations (0, 5, 10, 15 and 20%, w/v) and residue rates (0, 0.25, 0.5, 0.75 and 1%, w/w). Aqueous extracts of alfalfa (Medicago sativa L.) and vetch (Vicia spp.) exhibited an allelopathic effect on soybean and corn seed germination, seedling length and weight. The degree of inhibition significantly increased as the aqueous extract concentration increased. Alfalfa and vetch 20% extracts reduced soybean seed germination, seedling length and weight by 35%, 57%, 32% and 15%, 42%, 25% respectively, when compared to control. Corn germination, seedling length and weight was inhibited by 20%, 23%, 38% by alfalfa and 19%, 18%, 35% by 20% vetch extracts. Alfalfa and vetch extracts inhibited secondary root formation and branching as the extract concentration increased. Alfalfa and vetch 20% extracts inhibited by 41% and 32% secondary root numbers, respectively as compared to control. It was found that the aqueous extract of alfalfa resulted in greater reduction in germination, seedling length and weight of soybean than that of vetch. Alfalfa and vetch 1% residue rate inhibited soybean plant height by 30% and 10%, leaf area by 31% and 23%, and dry weight by 18% and 1%, nodule number by 27% and 20% also. Alfalfa and vetch residue significantly enhanced plant height, leaf area and dry weight of corn. The maximum stimulation occurred with 0.25% and 1% of alfalfa and vetch residue rates, respectively. Plant height, leaf area, and dry weight increased by 23%, 59%, 58% and 17%, 52%, 94% with alfalfa and vetch residues of 0.25% and 1%, respectively. This study demonstrates that there is an allelopathic potential resulting from alfalfa and vetch residues on soybean growth and yield. It also suggests that these residues may affect crop growth and development due to the inhibitory or stimulatory effects of allelochemicals existing in the residue.

• Journal of The Korean Society of Grassland and Forage Science
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• v.7 no.1
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• pp.25-30
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• 1987

There are differences in opinion as to whether nitrogen fertilizer should be used when establishing alfalfa (Medicago sativa L.). Various reports show that under a hot environment, rhizobia (Rhizobium meliloti) are not as effective in fixing atmospheric nitrogen as they are under moderate temperatures. It is also believed that the addition of nitrogen fertilizer inhibits nodulation of alfalfa seedlings. A replicated experiment was conducted under controlled environmental conditions at the University of Nevada-Reno, Reno, Nevada, USA, to determine the effects of nitrogen application on seedling growth and nodulation of alfalfa grown in a hot environment. Sterile sand was used as the growing media to which a complete nutrient solution minus nitrogen was applied volumetrically to each pot daily. In addition, half of the pots received NH4-$NO_3$, at the rate of 11.2 kg per ha at seeding and at two and four weeks after planting giving a total nitrogen application rate of 33.6 kg per ha during the seven-week experimental period. Rhizobia inoculant (R-12) consisted of a mixture of strains 171-15a, 1682c and 80 PI 265 of (Rhizobium meliloti). Inoculant was applied to the seeds prior to planting and to the sand media at two and four weeks after seeding. Twenty seeds were planted in pots 14.0 cm in diameter and 11.5 cm deep. Plants were thinned to ten plants per pot after emergence and were grown in a controlled environment chamber with a 16-hour light period. Soil temperature at 6 cm depth ranged from 17.4^{\circ}C.$ to 31.1^{\circ}C.$ and had a daily mean of 26.5^{\circ}C.$. Plants were harvested at weekly intervals for seven weeks. Root, shoot and total length, dry weight, volume and number of nodules per plant were determined. Root, shoot, and total length were greater in seedlings grown in soil where nigrogen was applied than that grown in soil to which no nitrogen was applied. The average size of the seedlings as determined by volume and weight was more than two times greater where plants were fertilized with nitrogen. Nodule number per seedling was also greater when nitrogen was applied compared to those which received no nitrogen. The differences were greater as the plants became older. The rhizobia did not fix enough nitrogen for adequate growth of seedlings. This is probably due to high temperature growing conditions that caused the rhizobia to become relatively ineffective as compared to cooler growing conditions. Data suggests it would be desirable to apply nitrogen at seeding when alfalfa is established under hot conditions that occur in mid- or late summer.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.3
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• pp.197-203
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• 1993

Greenhouse experiments were conducted to avaluate strain competition, nodulation, patterns of nodule occupancy and population changes of Bradyrhizobium sp. strain HCR-46 $str^{r}cep^{r}$ and CB756 $str^{r}rif^{r}$ in the rhizosphere of peanut(Arachis hypogaea L.) under different root temperatures. Inoculated with two strains using seed coating with peat slurry under different root temperatures, population of each strain in the rhizosphere increased with plant growth and multiplication rate of inoculum in the unit weight of root were showed the highest from 10 to 15days after sowing. The multiplication rate of inoculum in the rhizosphere was $28^{\circ}C$>$34^{\circ}C$>$22^{\circ}C$. The density of HCR-46 $str^{r}cep^{r}$ was more increased than that of CB756 $str^{r}rif^{r}$ under $22^{\circ}C$ and $28^{\circ}C$. While the density of two strains showed no difference under $34^{\circ}C$. Inoculated with HCR-46 $str^{r}cep^{r}$ and CB756 $str^{r}rif^{r}$, respectively at 22, 28 and $34^{\circ}C$, nodulation of each strain was dominated in its inoculation portion. Inoculated with the mixture of HCR-46 $str^{r}cep^{r}$ and CB756 $str^{r}rif^{r}$, occupancy rate of HCR-46 $str^{r}cep^{r}$ was dominated over that of CB756 $str^{r}rif^{r}$ at $22^{\circ}C$ and $28^{\circ}C$, but that was similar between them at $34^{\circ}C$. Dry mass, nodulation, nitrogen content per plant and nitrogenase activity showed higher at $28^{\circ}C$ than at $32^{\circ}C$ and $22^{\circ}C$, while those were higher in HCR-46 $str^{r}cep^{r}$ and mixing HCR-46 $str^{r}cep^{r}$ with CB756 $str^{r}rif^{r}$ than in CB756 $str^{r}rif^{r}$.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.1
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• pp.69-76
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• 1991

A pot experiment was conducted to find out the effects of lime and phosphate application on the changes of number of soil microorganisms, indigenous Rhizobium japonicum, nodule formation, and ureide-and amide-N in leaf and stem exudate of soybean plant under uncultivated hillside red earth in very low pH value, organic matter, available phosphate, and cation exchange capacity. The results obtained were summarized as follows : 1. The plant height, stem length, root dry weight and nodule weight were significantly increased with the application of lime and phosphate application than that of control plot. 2. The concentration of amide-N in soybean plant at the 45 days after sowing was obtained as high in order of control>lime> lime+phosphate while the concentration was obtained in order of Iime+phosphate>lime> control at flowering stage 3. However, concentration of ureide-N in the soybean leaf at the 45 days after sowing was obtained as high in order of control>lime>lime+hosphate while reversed concentration was obtained in stem. 4. The number of soil microorgan isms were increased with increase of pH value, available phosphate and soil exchangeable cation. 5. Significantly negative high correlation were obtained with the concentration of Al, Fe in soil and the concentration of amide-and ureide-N in soybean plant at flowering stage while positive correlation was obtained with plant growth and the concentration of ureide-N.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.1
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• pp.67-77
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• 1987

To obtain basic information concerning the soybean cultivar differences of physiological and ecological responses to soil pH to select and breed stably higher yielding cultivars, and to improve cultural management of soil differing in pH, the responses of soybean plants in growth, grain yield, nodule formation and its activity, and major chemical compositions of soybean plants were investigated using six cultivars and two levels of soil pH 5 and 7 of the pot and field experimental soil in Suwon, 1985. Acidic soil condition suppressed overall vegetative growth of soybean plants and thereby decreased stem length, number of nodes, leaf area, dry weight of the plants, root activity, nodulation and nodule activity, the content of allantoin nitrogen, total nitrogen, phosphorous, calcium, and magnesium of the plants. Due to the such responses of soybean plants to the acid soil, grain yield also decreased along with less grains per plant. However, the little difference in growth and yield of the cultivar Janbaeglcong in response to soil pH is considered to be a good source of breeding materials tolerant to acidic soil condition. In this regard Bongeui and Oialkong also were relatively stable in the growth and grain yield under the different soil acidity conditions.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.1
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• pp.84-91
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• 1983

These experiment were conducted to investigate the seasonal changes of nodule formation and $N_2$-fixing activitues of soybean root nodules which grown in pot on five cultivars in different soils. The results obtained were as follows; 1. It was found that the development of nodules starts from 20 days after planting and continues to increase up to 50-60 days after planting. 2. $N_2$-fixing activities were different with cultivars of soybean. The trend was high in order H-25 > Suweon 63 > Hill > Yugwoo 3# > Gwanggyo 3. Rhizobium japonicum isolated from different soybean cultivars showed different acetylene reducing activities in vitro ; high in order A62-1 > Suweon 63 > Hill > Gwanggyo > Yugwoo 3#.

• Korean Journal of Soil Science and Fertilizer
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• v.23 no.4
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• pp.281-286
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• 1990

Field experiments were conducted to avail the accumulated phosphorus by silica 200kg/10a and compost 2,000kg/10a instead of phosphate fertilization in 1988 to 1989. Cultivated varieties were Dongjinbyeo in paddy soils of Av. $P_2O_5$ 233ppm, and Baegunkong in upland soils of Av. $P_2O_5$ 530ppm. The results were as follows. 1. Available phosphorus in the soil was increased about 60ppm in silica and compost application compared with control. Its increment rate by silica and compost application was higher in paddy soils than in upland soils. 2. Absorbed phosphorus by plant was increased in silica and compost application compared with control, whose difference was higher in soybean plant than in rice plant. 3. Amount of absorbed phosphorus in plant was negative in relation to soil DTPA-Fe, but was positive in relation to soil reduction and root nodule of soybean. 4. Persistence rate of phosphorus was about 80 percent in compost application and 100 percent in phosphate fertilization compared with control, and it was apt to decrease by silica. 5. The yield of rice was no difference between with and without phosphate fertilization, but the yield of soybean was increased 5 percent in none application compared with phosphate fertilization.

• Applied Biological Chemistry
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• v.38 no.4
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• pp.313-319
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• 1995

The involvement of the cell-wall degrading enzymes in Rhizobium has long been an unsolved question about the infection process in the formation of root nodule. To assess the contribution of the cellulase to the nodulation of rhzobia, here we report the production of cellulase from R. meliloti TAL1372 which degrade carboxymethylcellulose (CMC) model substrate with CMC-plate method. We constructed a genomic library by cloning Sau3A-digested genomic DNA from R. meliloti TAL1372 into the BamHI site of the cosmid vector pLAFR3. Out of more than one thousand transductants of E. coli, one clone (pRC8-71) had CM-cellulase activity and contained pLAFR3 cosmid with 30 kb insert of R. meliloti DNA The product of CM-cellulase gene was analyzed by native PAGE. About 45 kD protein was considered to be a product of the gene. Tn5 mutagenesis reveals that the structural gene located in a ca. 3 kb KpnI fragment. The cellulase-minus mutants of R. meliloti TAL1372 were obtained by Tn5 mutagenesis of pRC8-71 and marker exchange techniques. Analyses of the nodulation ability of these Tn5 mutants showed that the CM-cellulase gene of R. meliloti TAL1372 may be involved in early nodulation development on alfalfa (Medicago satiua).