• Korean Journal of Organic Agriculture
• /
• v.26 no.4
• /
• pp.719-729
• /
• 2018

Green manure crops can be efficient replacements of high nutrient materials such as livestock compost, organic fertilizers, etc. in organic farming. Grass-legume mixtures or mixed cropping of legumes with non-legumes can aid in abating the shortcomings of each plant type under monoculture (i.e. legumes have low biomass yields while grasses are poor at fixing nitrogen). This study was conducted to investigate the effects of barley (B) and hairy vetch (H) mixtures on green manure yield in nutrient accumulated organic upland soils of Korea. In one cropping season, single crops of barley and hairy vetch (Barley: 160 kg/ha, Hairy vetch: 90 kg/ha) as well as mixtures of both crops at different seeding rates (B66:H33, B33: H66) were grown and the obtained results are as shown below. The biomass yield and nutrient productivities were higher in barley-hairy vetch mixture. The biomass yield and total phosphorus content were higher for the mixed crops by 78~132% and 200% respectively than those of the hairy vetch monoculture. Total nitrogen content of the mixed crops was also higher than those of the barley monoculture by 43~44%. The biomass yield (5.60 Mg/ha) and nutrient contents (87.7 kg N/ha, 23 kg $P_2O_5/ha$) were highest in the case of B66:H33 seeding rate. Accordingly, this study concludes that the barley-hairy vetch mixtures cropped at B66:H33 seeding rate is efficient in increasing green manure productivity due to complementary effects observed and the highest biomass yield and nutrient contents.

• Journal of Plant Biotechnology
• /
• v.4 no.3
• /
• pp.109-115
• /
• 2002

Submerged cultures of Ganoderma lucidum, a valuable mushroom in traditional Chinese medicine, were used for production of bioactive Banoderic acids and Ganoderma polysaccharides. The significant effects of oxygen supply were demonstrated in both shake flasks and bioreactors. By changing the medium loading volume in a shake flask, a different value of initial volumetric oxygen transfer coefficient ($K_L$a) was obtained, and a higher $K_L$a value led to a higher biomass density and a higher productivity of both intracellular polysaccharide and ganoderic acid. In a stirred bioreactor, at an initial $K_L$a of 78.2 $h^{-1}$, a maximal cell concentration of 15.6 g/L by dry weight was obtained, as well as a maximal intracellular polysarcharide (IPS) production of 2.2 g/L and its maximal productivity of 220 mg/(L.d). An increase of initial $K_L$a led to a higher production and productivity of GA, and the GA production and productivity at an initial $K_L$a of 96.0 $h^{-1}$ was 1.8-fold those at an initial $K_L$a of 16.4 $h^{-1}$. The fundamental information obtained in this study may be useful for efficient large-scale production of these valuable bioactive products by the submerged cultures.

• Proceedings of the KSRS Conference
• /
• 1999.11a
• /
• pp.107-114
• /
• 1999

The large-scale distribution of crops Is usually determined by climate. We present the results of a climate-crop prediction based on spatial bio-physical process model approach, implemented in a GIS (Geographic Information System) environment using several regional and global agriculture-environmental databases. The model utilizes daily climate data like temperature, rainfall, solar radiation being generated stocastically by in-built model weather generator to determine the daily biomass and finally the crop yield. Crops are characterized by their specific growing period requirements, photosynthesis, respiration properties and harvesting index properties. Temperature and radiation during the growing period controls the development of each crop. The model simulates geographic/spatial distribution of climate by which a crop-growing belt can also be determined. The model takes both irrigated and non-irrigated area crop productivity into account and the potential increase in productivity by the technical means like mechanization is not considered. All the management input given at the base year 1995 was kept same for the next twenty-year changes until 2015. The simulated distributions of crops under current climatic conditions coincide largely with the current agricultural or specific crop growing regions. Simulation with assumed weather generated derived climate change scenario illustrate changes in the agricultural potential. There are large regional differences in the response across the country. The north-south and east-west regions responded differently with projected climate changes with increased and decreased productivity depending upon the crops and scenarios separately. When water was limiting or facilitating as non-irrigated and irrigated area crop-production effects of temperature rise and higher $CO_2$ levels were different depending on the crops and accordingly their production. Rise in temperature led to yield reduction in case of maize and rice whereas a gain was observed for wheat crop, doubled $CO_2$ concentration enhanced yield for all crops and their several combinations behaved differently with increase or decrease in yields. Finally, with this spatial modeling approach we succeeded in quantifying the crop productivity which may bring regional disparities under the different climatic scenarios where one region may become better off and the other may go worse off.

• ALGAE
• /
• v.25 no.2
• /
• pp.89-97
• /
• 2010

To test the feasibility of using chlorophyll ${\alpha}$ fluorescence to assess the establishment success of seagrass transplants, photosynthetic characteristics of eelgrass Zostera marina transplants were measured using a Diving-pulsed amplitude modulation fluorometer in Jindong Bay on the southern coast of Korea. Maximum quantum yield ($F_v/F_m$), photosynthetic efficiency ($\alpha$), saturating irradiance ($E_k$) and maximum electron transport rate ($ETR_{max}$) of transplants and reference plants in a nearby transplant site were measured using the fluorometer for 5 months. Additionally, shoot morphology, individual shoot weight and productivity of transplants and reference plants were also monitored. Shoot height, leaf weight and productivity of transplants were significantly reduced during the first two or three months after transplantation compared to those of reference plants, and then increased to the levels of reference plants Characteristics of chlorophyll a fluorescence, including $F_v/F_m$, $\alpha$, $E_k$ and $ETR_{max}$ of transplants were also significantly reduced in the initial period, but recovered slightly sooner than shoot morphology or leaf productivity. These results indicated that after transplantation, Z. marina transplant photosynthesis recovered faster than shoot morphology, biomass or productivity. Thus, chlorophyll a fluorescence can be used as an indicator for early assessment of the status of eelgrass transplants without destructive sampling.

• Korean Journal of Food Science and Technology
• /
• v.27 no.1
• /
• pp.129-133
• /
• 1995

Continuous fermentations were performed in order to investigate the effect of culture condition on the yeast RNA accumulation and autolysis efficiency. The content of intracellular RNA increased with increasing dilution rate, showing its maximum value of 14.8% at D=0.35 $h^{-1}$. Also, both RNA productivity and specific RNA productivity tended to increase with the increase of dilution rate. The maximum biomass was obtained at $30^{\circ}C$ in the fixed dilution rate of 0.2 $h^{-1}$, whereas the maximum RNA content appeared at the lowest temperature experimented. Growth rate affected significantly on the yeast autolysis efficiency such that the extraction ratio(TN/TN) increased with increasing growth rate, whereas the hydrolysis ratio(AN/TN) was reversed. On the other hand, its efficiency was little affected by cultivation temperature.

• Journal of Life Science
• /
• v.14 no.3
• /
• pp.472-477
• /
• 2004

To improve biomass and astaxanthin production by wild-type Xanthophyllomyces dendrorhous simultaneously in shake flask culture, physical factors, nutritional factors and carotenogenesis stimulating factors affecting astaxanthin production were studied on base of HPLC quantitative analysis. The results suggested that carotenogenesis precursor composition acetic acid, mevalonic acid, tomato extract, and carrot extract could increase the productivity of astaxanthin markedly based on the optimized temperature, initial pH value, carbon and nitrogen sources conditions.

• ALGAE
• /
• v.35 no.3
• /
• pp.237-252
• /
• 2020

Temperate rocky reefs dominated by the giant kelp, Macrocystis pyrifera, support diverse assemblages of benthic macroalgae that provide a suite of ecosystem services, including high rates of primary production in aquatic ecosystems. These forests and the benthic macroalgae that inhabit them are facing both short-term losses and long-term declines throughout much of their range in the eastern Pacific Ocean. Here, we quantified patterns of benthic macroalgal biomass and irradiance on rocky reefs that had intact kelp forests and nearby reefs where the benthic macroalgae had been lost due to deforestation at three sites along the California, USA and Baja California, MEX coasts during the springs and summers of 2017 and 2018. We then modeled how the loss of macroalgae from these reefs impacted net benthic productivity using species-specific, mass-dependent rates of photosynthesis and respiration that we measured in the laboratory. Our results show that the macroalgal assemblages at these sites were dominated by a few species of stipitate kelps and fleshy red algae whose relative abundances were spatially and temporally variable, and which exhibited variable rates of photosynthesis and respiration. Together, our model estimates that the dominant macroalgae on these reefs contribute 15 to 4,300 mg C m^-2 d^-1 to net benthic primary production, and that this is driven primarily by a few dominant taxa that have large biomasses and high rates of photosynthesis and / or respiration. Consequently, we propose that the loss of these macroalgae results in the loss of an important contribution to primary production and overall ecosystem function.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.54 no.4
• /
• pp.422-426
• /
• 2009

Sweetpotato is one of the important starch crops, current more considered as an industrial crop rather than food because it has higher starch content (over 80% of biomass), it is used for bio resources for industrial area. In this study, we generated S598A (a mutant gene of oat phytochrome A) sweetpotato plant using Agrobacterium-transformation method. Morphological characteristics of S598A plant were compared with the wild type sweetpotato, S598A had darker green leaves, increased chlorophyll content higher than to two-fold, delayed leaf senescence, shorter plant height (60% shorter than that of the wild type), more number of leaves and petioles about 1.8-fold, shorter petiole length (30% shorter), 1.2-fold more branches and 1.6-fold thicker stem diameters. From this study, S598A plants with such phenotypic characteristics might be able to use the solar energy efficiently, to have increased tolerance to biotic and abiotic stresses and finally to increase productivity (not only starch yield but also root biomass yield). S598A sweetpotato lines are under field trials.

• Korean Journal of Soil Science and Fertilizer
• /
• v.48 no.2
• /
• pp.146-152
• /
• 2015

Heavy metal pollution has been a critical problem in agricultural field near at the abandoned metal mines and chemical amendments are applied for remediation purpose. However, biological activity can be changed depending on chemical amendments affecting crop productivity. Main purpose of this research was to evaluate biological parameters after applying chemical amendments in heavy metal polluted agricultural field. Result showed that soil respiration (SR) and microbial biomass carbon (MBC) were changed after chemical amendments were applied. Among three different amendments, lime stone (LS), steel slag (SS), and acid mine drainage sludge(AMDS), AMDS had an effect to increase SR in paddy soil. Comparing to control ($93.98-170.33mg\;kg^{-1}day^{-1}$), average of 30% increased SR was observed. In terms of MBC, SS had an increased effect in paddy soil. However, no significant difference of SR and MBC was observed in upland soil after chemical amendment application. Overall, SR can be used as an indicator of heavy metal remediation in paddy soil.

• Microbiology and Biotechnology Letters
• /
• v.22 no.2
• /
• pp.197-202
• /
• 1994

Microalga, Spirulina platensis has been cultivated in a pilot scale photo-bioreactor to treat wastewater and to produce high protein feedstocks from swine waste containing medium. 0.31(1/day) of specific growth rate and 0.170 of bioenergeric yield were obtanined from batch cultivation in 30% waster containing medium, compared to 0.71(1/day) and 0.545 from clean culture. An optimal dilution concentration was decided as 20% of working volume, based upon the cell growth and biomass productivity. The removal rate of nitrates in the wastewater was decreased as the adding concentration of wastewater was increased while the decrease of total phosphates was reversed, showing 0.33(1/day) and 0.30(1/day) of rate constants for nitrate removal in 10% addition and for phosphate removal in 30% addition, respectively. The chemical composition and amino acid profile of the biomass were superior to those of commerically available health food product, Spirulina sp.