• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.74-82
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• 2004

This study was conducted to estimate the optimum application rate of fertilizer N based on $NO_3-N$ concentration in soils for tomato (Lycopersicon esculentum Mill.) cultivation in plastic film house. Tomato plants were cultivated with and without fertilizer in twelve soils which have different concentrations of $NO_3-N$ ranging from 46 to $344mg\;kg^{-1}$. Dry weight (DW) of above-ground part of tomato with no fertilizer ranged from 28.9 to $112.5g\;plant^{-1}$, depending on N-supplying capability of soils. The soil $NO_3-N$ was positively correlated with DW ($r=0.83^{**}$) and N uptake ($r=0.78^{**}$) by tomatoes in no fertilizer treatment, and negatively correlated with fertilizer effciencies resulted from the differences of DW and N uptake between fertilized and non-fertilized plot. The relationships between soil $NO_3-N$ concentration and DW, N uptake, and fertilizer efficiency were analyzed to determine the critical levels of soil $NO_3-N$ for tomato cultivation. The limit critical levels of soil $NO_3-N$ were estimated to be more than $280mg\;kg^{-1}$ for no application of fertilizer N and to be less than $50mg\;kg^{-1}$ for recommended application of fertilizer N. These critical levels of soil $NO_3-N$ were nearly the same as those calculated from regression equation between electrical conductivity(EC) and soil nitrate for critical levels of EC in recommendation equation of fertilizer N for tomato under the plastic film house by NationaI Institute of Agricultural Science and Technology. Consequently, the optimal application rate of ferdilizer N for tomato cultivation in the soils containing $NO_3-N$ concentration between $280mg\;kg^{-1}$ and $50mg\;kg^{-1}$ was estimated by the equation Y = -0.4348X＋121.74, where Y is the percent(%) to the recommended application rate of N fertilizer and X is the soil $NO_3-N$ concentration ($mg\;kg^{-1}$).

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.3
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• pp.221-227
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• 1989

This study was conducted to understand the influence of soil compaction on root growth and nutrient uptake characteristics of the soybean roots grown in two soils with different texture. Tap root elongation was measured on young seedling grown in cores compacted to different bulk densities of 1.2, 1.4 and $1.6/cm^3$ with different soil water retention in laboratory. The soil used were Samgag sandy loam and Baegsan loam soils. The wet and dry weight, total length, average radius and total surface area of roots were measured on soybean plants grown in 1/5000 a Wagner pots compacted to different bulk density of 1.2 and $1.4g/cm^3$. The nutrient uptake of soybean shoot was measured and evaluated with the unit surface area of roots at the 7th, 17th and 27th days after germination. The results were as follows: 1. The tap root elongation rate was faster in the loam soil with low bulk density than in the sandy loam soil with high bulk density. The elongation rates were remarkedly decreased when soil water was lower than the retention of 4 bars in loam soil and that of 1 bars in sandy loam soil. 2. Tap root elongation rate sharply decreased as increased soil strength higher than $2kgf/cm^2$ measured by ELE penetrometer showing curvillinear regression. However, it was low regardless of soil strength when soil water retention was 10 bars in sandy loam soil. 3. From the pot experiment, the total length of roots were longer in loam soil than in sandy loam soil and was longer in the soils with lower bulk density. The average radius of fine roots grown in sandy loam soil was larger than that grown in loam soil. The total surface area of roots was greater in the loam soil with low bulk density than in the sandy loam soil with high bulk density as the total length of roots. 4. The amounts of nutrient uptake by soybean shoots were greater in loam soil primarily due to more production of dry matter than in sandy loam soil. The nitrogen influx rates through the unit surface area were 597 to $753nmoles/day-cm^2$ in loam soil and 222 to $365nmoles/day\;cm^2$ in sandy loam soilshowing higher value in higher bulk density. The potasium influx rates were 99 to $175nmoles/day-cm^2$, and those of phosphate were 26 to $46nmoles/day\;cm^2$. Those of Ca and Mg were 175 to 246 and 163 to $205nmoles/day\;cm^2$. The difference in nutrient influx rates between bulk densities of these elements were lower than that of nitrogen.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.2
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• pp.79-86
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• 2016

The purpose of this study is to efficiently improve biological sequencing batch reactor (SBR) system of high-concentrated nitrate nitrogen in reverse osmosis (RO) concentrates by total dissolved solids (TDS) regulation. Since a laboratory-scale SBR system had been operated, we had analyzed specific denitrification rate (SDNR) and specific oxygen uptake rate (SOUR) for microbial activity in according to various injection concentration of TDS. As a result, higher injection concentration of TDS decreased SDNR, and delayed denitrification within denitrification process. Moreover, the higher injection concentration of TDS was, the lower microbial activity was during operation of laboratory-scale SBR system. Therefore, the regulation of TDS injection concentration is necessary to improve efficiency of nitrate nitrogen in the biological SBR system, and treatment of calcium ion ($Ca^{2+}$) is also specifically focused to remove nitrate nitrogen. Moreover, analytical data of SDNR and SOUR can be the effective kinetic design parameters to application of biological treatment of RO concentrate by aerobic granular sludge (AGS).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.84-91
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• 2006

This study was carried out to comparatively evaluate growth characteristics of rice cultivars under rice-mono (conventional) and rice-Chinese milk vetch (Vetch) cropping system. Six rice cultivars such as Geumobyeo, Pungmibyeo, Hwayeongbyeo, Sobibyeo, Junambyeo and Dongjinbyeo were tested in 2005. The results obtained are summarized as follows ; plant height and culm length of all the tested cultivars at heading and harvest time were shorter in rice-vetch cropping system than conventional, however, nitrogen content of rice plants at heading and harvesting time was higher in rice-vetch cropping system. The total amount of nitrogen of rice plants was higher in conventional than rice-vetch cropping system. Nitrogen content of rice plant and uptake of Pungmibyeo was the highest of all the tested cultivars in both cropping systems. Generally, grain yietd ef tested cultivars seemed to be higher in conventional than rice-vetch cropping system. And it was the highest in Junambyeo as compared to those of other cultivars. Head rice ratio and protein content were higher in rice-vetch cropping system.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.18 no.1
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• pp.47-52
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• 2013

Despite the usefulness of nitrogen isotope tracer experiments in nitrogen cycling studies, there are not such many measurement data mainly due to the difficulties in analytical methods. Although Gardner et al. (1996) developed a relatively simple and accurate method that can measure ammonium isotope using HPLC and used it widely in various N dynamics studies, the technique was not adopted to other laboratories. An HPLC-RTS system using updated HPLC pumps that can perform the same measurements as that of Gardner et al. (1996) was built. The result of standard sample showed linear increase of RTS with the $^{15}N$ proportions. Centroid retention times calculated with Matlab$^{(R)}$ program enhanced the linearity of the response. In a sea water incubation experiment spiked with $^{15}NH_4{^+}$, the uptake and regeneration of ammonium could be separately estimated using the temporal change of $^{15}N/^{14}N$.

• Applied Biological Chemistry
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• v.46 no.2
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• pp.134-139
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• 2003

To establish the fertilization condition to increase the productivity of Chasanthemum boreale M. with high quality, the effects of three nutrients (N, P, K) on the yields and the effective components were investigated in the pot scale. NPK was applied by chemical fertilizers with $(N-P_2O_5,-K_2O=250-160-160\;kg/ha)$ as a main treatment, and NP $(N-P_2O_5,-K_2O=250-160-160\;kg/ha)$, NK $(N-K_2O =250-160\;kg/ha)$, and PK $(P_2O_5K_2O=160-160\;kg/ha)$ treatments were settled as comparison. Dry yields of C. boreale M. was increased significantly to 4 fold higher by nitrogen. Nitrogen increased apparently plant growth and inorganic nutrient uptake. In the flower, which is most useful and edible part as a herbal medicine, main amino acids were glutamic acid and aspartic acids, and the total content was increased significantly by three elements of application. In addition, the content of cumambrin A, which is known to have the effect of blood-pressure reduction, was increased source to 6.2 times by nitrogen higher than that in PK treatment. Potassium was more effective in biosynthesis of cumambrin A than phosphorus, but the biological pathway was not clear, still.

• Korean Journal of Medicinal Crop Science
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• v.11 no.5
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• pp.371-376
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• 2003

To develop an efficient cultivation system to increase the productivity and the high quality of Chrysanthemum boreale M., the effects of pig manure (PM) application on the yield and the effective component were investigated in the pot scale (1/2000a scale). PM applied at the equivalent of six rates (with rate of 0, 2000, 4000, 6000, 8000, and 12000 kg $10a^{-1}$). Maximum plant biomass yield was achieved at 9510 kg $10a^{-1}$ and at 9940 kg $10a^{-1}$ for flower biomass. Nitrogen recovery efficiency was more than 42% for all nitrogen treatments and reached 66.6% at 4000 kg $10a^{-1}$. Proline $(7.4{\sim}9.2\;g\;kg^{-1})$ was the most abundant amino acid in the flower of C. boreale M. and the contents of amino acids increased with increasing PM application rate. Contents of cumambrin A. a sesquiterpene compound known to reduce blood-pressure, decreased with increasing PM application. The highly negative correlation was found ($R^2$ = -0.723, P<0.01) between content of cumambrin A and PM application. However, the amount of cumambrin A in flowers increased as PM rate increased, because of increasing flower yield. In conclusion, PM fertilization increases yields and enhances overall quality.

• Journal of Korean Society of Forest Science
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• v.88 no.2
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• pp.266-272
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• 1999

Aboveground biomass and nutrient contents of a 31-year-old pitch pine(Pinus rigida) and a 31-year-old Japanese larch(Larix leptolepis) plantations were measured in the Chungbu Forest Experiment Station, Kyunggi Province. Aboveground biomass was 170.2ton/ha in the pitch pine and 87.2ton/ha in the Japanese larch plantations. Aboveground biomass difference between both plantations was due to the difference of stand density. Aboveground biomass in both plantations was allocated as follows : stemwood>branch>stembark>needle. The concentrations of all nutrients(N, P, K, Ca, Mg) were generally higher in the Japanese larch needle than in the pitch pine because of high nutrient uptake characteristics of larch compared with pine tree species. The nutrient concentration in different tree tissues in both tree species decreased in the order of needle>branch>stembark>stemwood. Nutrient contents of aboveground biomass were : N, 335.9 ; P, 40.4 ; K, 121.4 ; Ca, 188.6 ; Mg, 93.8kg/ha in the pitch pine plantation, while nutrient contents in the Japanese larch plantation were : N, 226 ; P, 11.5 ; K, 72.9 ; Ca, 75.7 ; Mg, 37.1kg/ha. The nitrogen use efficiency calculated as the biomass produced by one unit of nitrogen was higher in the pitch pine than in the Japanese larch plantations. This result suggests that pine with high nitrogen use efficiency could be adapted in lower site productivity area compared with larch tree species.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.598-607
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• 2016

This study was conducted to evaluate the amount of nitrogen (N) top dressing based on the normalized difference vegetation indices (NDVI) by ground based sensors for leaf perilla under the polyethylene house. Experimental design was the randomized complete block design for five N fertilization levels and conventional fertilization with 3 and 4 replications in Gumsan-gun and Milyang-si field, respectively. Dry weight (DW), concentration of N, and amount of N uptake by leaf perilla as well as NDVIs from sensors were measured monthly. Difference of growth characteristics among treatments in Gumsan field was wider than Milyang. SPAD-502 chlorophyll meter reading explained 43.4% of the variability in N content of leaves in Gumsan field at $150^{th}$ day after seedling (DAS) and 45.9% in Milyang at $239^{th}$ DAS. Indexes of red sensor (RNDVI) and amber sensor (ANDVI) at $172^{th}$ day after seedling (DAS) in Gumsan explained 50% and 57% of the variability in N content of leaves. RNDVI and ANDVI at $31^{th}$ DAS in Milyang explained 60% and 65% of the variability in DW of leaves. Based on the relationship between ANDVI and N application rate, ANDVI at $172^{th}$ DAS in Gumsan explained 57% of the variability in N application rate but non significant relationship in Milyang field. Average sufficiency index (SI) calculated from ratio of each measurement index per maximum index of ANDVI at $172^{th}$ DAS in Gumsan explained 73% of the variability in N application rate. Although the relationship between NDVIs and growth characteristics was various upon growing season, SI by NDVIs of ground based remote sensors at top dressing season was thought to be useful index for recommendation of N top dressing rate of leaf perilla.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.215-222
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• 2012

This experiment was conducted to clear up the cause of nutrient physiological disorder and to manage of optimum fertilization for leaf perilla crop under plastic film house condition in Geum-san area in 2009. A nutrient contents of leaf perilla were analyzed during the growing stages of crop from the first harvest to the last harvest stages, and the data were going to use as the nutritional factors for farms' activity in the fields. In survey of leaf perilla growing status at five farmers' fields, it was needed 30 days for growing of 5~10 stems, 60 days for 10~15 stems and 45 days for 15~20 stems of leaf perilla. Contents of nitrogen, phosphorus and potassium in leaf and stem had been kept on some high values in early stages, but it had been decreased in gradually in late stages of growing. Nitrogen and potassium contents were more changeable in leaf than stem, and phosphorus content was kept in more both of leaf and stem than those of nitrogen and potassium. The major macro-nutrient contents of perilla leaf on first of July were 6.34 in N, 0.54 in P, 2.48 in K, 1.98 in Ca and 0.62% in Mg, total uptake amounts of major three elements were $400kg\;ha^{-1}$ in N, $30kg\;ha^{-1}$ in P and $250kg\;ha^{-1}$ in K. Total yield of perilla leaf was $52,000kg\;ha^{-1}$, and total dry matter was $10,510kg\;ha^{-1}$ with $8,680kg\;ha^{-1}$ in leaf dry matter and $1,830kg\;ha^{-1}$ in stem dry matter.