• Korean Journal of Soil Science and Fertilizer
• /
• v.25 no.1
• /
• pp.38-43
• /
• 1992

A field experiment was conducted to find out the effect level of nitrogen fertilization on the yield and quality of hop (Hallertau variety) emphasis given to ${\alpha}$-acid content. Nitrogen was applied by the rates of 0, 12, 18, 24, 30 and 36kg per 10a. Results were summarized as follows. 1. Stages of cone-hair developing and coneripening were delayed with increment of nitrogen applied. Number of nodes and length of vine increased with nitrogen applid by up to 24kg N/10a. 2. Yield was the highest in the 24kg N/10a plot and cone weight had high significant correlations with yield without regard to the years of growth. No.of flower per side blanch and weight of 100 cones had a significant correlation with yield in the four-year old and five-year old Hop plants. 3. Nutrient content in Hop plants was in the order of CaO, total nitrogen, $K_2O$, MgO and $P_2O_5$. Content of total nitrogen, CaO and MgO was high in leaves while that of $P_2O_5$ and $K_2O$ was high in cone. Nitrogen, phosphorus and magnesium increased with increment of nitrogen fetilized while potassium and calcium decreased. 4. As for the distribution of nutrients in cone developing stage $SiO_2$ content was higher in lower part than in the upper part while $P_2O_5$ contetn was higher in upper part than in lower part of the plant. And content of nitrogen and potassium was higher in middle height than in upper and lower part. 5. The optimum levels of nitrogen application were 19.3kg for 2 years, 24.3kg for 3-year, 27.9kg for 4 years and 31.8kg/10a for 5-year old Hop, respectively. 6. Nitrogen uptake in cone showed a positive correlation with the content of ${\alpha}$-acid and ${\beta}$-acid in cone.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.18 no.5
• /
• pp.37-48
• /
• 2015

Soil nutrient management is important to maintain the constant productivity of seedling production in the nursery for successful forest restoration. This study investigated the effects of organic manure and chemical fertilizer application levels on the growth, soil properties, and nutrient concentrations of yellow poplar seedlings. One-year-old yellow poplar seedlings were treated with the combination of 3 level organic manures(0, 5 Mg/ha, 10 Mg/ha; mixture of poultry manure, cattle manure, swine manure, and sawdust) and 3 level nitrogen-phosphorus-potassium(NPK) chemical fertilizers(0, 1x(urea, $30g/m^2$; fused superphosphate, $70g/m^2$; potassium chloride, $15g/m^2$), 2x). Organic manure significantly increased the soil pH and the concentrations of nitrogen, available phosphorous, exchangeable potassium, calcium, and magnesium. In contrast, the NPK chemical fertilizer decreased the soil pH and exchangeable calcium concentration, did not affect the soil concentrations of nitrogen and magnesium, and increased the concentrations of available phosphorous and exchangeable potassium. Both organic manure and NPK chemical fertilizer treatments increased the seedling height, root collar diameter, and dry weight by 39% and 25%, respectively. The treatment with manure 5 Mg/ha and NPK 2x chemical fertilizer mostly increased seedling dry weight by 2.6 times more than that of the control. Compared to the effects of the fertilization treatments on the soil properties, the effects on nutrient concentrations in the leaves were relatively small. These findings indicate that organic manure that was derived from livestock byproducts and sawdust can be utilized with chemical fertilizer to improve seedling production as well as conserving soil quality.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.50 no.4
• /
• pp.247-255
• /
• 2005

ice yield and plant growth response to nitrogen (N) fertilizer may vary within a field, probably due to spatially variable soil conditions. An experiment designed for studying the response of rice yield to different rates of N in combination with variable soil conditions was carried out at a field where spatial variation in soil properties, plant growth, and yield across the field was documented from our previous studies for two years. The field with area of 6,600 m2 was divided into six strips running east-west so that variable soil conditions could be included in each strip. Each strip was subjected to different N application level (six levels from 0 to 165kg/ha), and schematically divided into 12 grids $(10m \times10m\;for\;each\;grid)$ for sampling and measurement of plant growth and rice grain yield. Most of plant growth parameters and rice yield showed high variations even at the same N fertilizer level due to the spatially variable soil condition. However, the maximum plant growth and yield response to N fertilizer rate that was analyzed using boundary line analysis followed the Mitcherlich equation (negative exponential function), approaching a maximum value with increasing N fertilizer rate. Assuming the obtainable maximum rice yield is constrained by a limiting soil property, the following model to predict rice grain yield was obtained: $Y=10765{1-0.4704^*EXP(-0.0117^*FN)}^*MIN(I-{clay},\;I_{om},\;I_{cec},\;I_{TN},\; I_{Si})$ where FN is N fertilizer rate (kg/ha), I is index for subscripted soil properties, and MIN is an operator for selecting the minimum value. The observed and predicted yield was well fitted to 1:1 line (Y=X) with determination coefficient of 0.564. As this result was obtained in a very limited condition and did not explain the yield variability so high, this result may not be applied to practical N management. However, this approach has potential for quantifying the grain yield response to N fertilizer rate under variable soil conditions and formulating the site-specific N prescription for the management of spatial yield variability in a field if sufficient data set is acquired for boundary line analysis.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.29 no.2
• /
• pp.157-174
• /
• 1984

Four different levels of nitrogen were applied to 3 naked barley cultivars (Hordeum vulgare L.) Yonezawa, Baekdong and Yeongsanbori. Changes in chlorophyll content, green leaf area and light penetration were monitored after heading. Yield and its components were examined upon these changes. Increased level of N-application delayed the days to heading and ripening by 2-3 and 6-7 days, respectively, in Yonezawa. Yonezawa with a short culm was more resistant to lodging than two tall ones (Baekdong, Yeongsanbori) under heavy nitrogen applications. Yield was affected mostly by the number of spikes per unit area and 1, 000 grain weight at all levels of N-applications. The increase in dry weight of Baekdong was more than in that of Yonezawa. A sharp increase in dry weight was observed after 3 weeks of heading. Maximum yield was obtained at $N_2$ in Yonezawa (234kg/10a) and Baekdong (302kg/10a) and at $N_1$ in Yeongsanbori (332kg/10a). It appears essential to attain the sufficient leaf area and the increase in chlorophyll content for maximum yield. However, too much leaf area at the highest N level up to the ripening stage was not beneficial for dry matter production.

• Journal of Ginseng Research
• /
• v.44 no.4
• /
• pp.627-636
• /
• 2020

Background: Cultivation of medicinal crops, which synthesize hundreds of substances for curative functions, was focused on the synthesis of secondary metabolites rather than biomass accumulation. Nutrition is an important restrict factor for plant growth and secondary metabolites, but little attention has been given to the plasticity of nutrient uptake and secondary metabolites synthesis response to soil nitrogen (N) change. Methods: Two year-field experiments of Sanqi (Panax notoginseng), which can synthesize a high level of saponin in cells, were conducted to study the effects of N application on the temporal dynamics of biomass, nutrient absorption, root architecture and the relationships between these parameters and saponin synthesis. Results: Increasing N fertilizer rates could improve the dry matter yields and nutrient absorption ability through increasing the maximum daily growth (or nutrient uptake) rate. Under suitable N level (225 kg/ha N), Sanqi restricted the root length and surface and enhanced the root diameter and N uptake rate per root length (NURI) to promote nutrient absorption, but the opposite status of Sanqi root architecture and NURI was found when soil N was deficient. Furthermore, increasing N rates could promote the accumulation of saponin in roots through improving the NURI, which showed a significant positive relationship with the content of saponin in the taproots. Conclusion: Appropriate N fertilizer rates could optimize both root architecture and nutrient uptake efficiency, then promote both the accumulation of dry matter and the synthesis of saponins.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.62 no.4
• /
• pp.293-303
• /
• 2017

To elucidate the physiological responses of rice plants to the essential mineral silicon (Si), we assessed the effects of treatments with Si, nitrogen ($NH_4NO_3$; ammonium nitrate), and calcium ($CaCl_2$; calcium chloride), independently or in combination on mineral uptake rates and levels of the hormones abscisic acid (ABA), gibberellin ($GA_1$) and jasmonic acid (JA). We found that nitrogen and calcium uptake was inhibited by Si application. However, solo application of nitrogen or calcium did not affect Si uptake. Compared to the untreated plants, the application of Si, $NH_4NO_3$ or $CaCl_2$ increased the endogenous hormone levels in treated plants. In particular, the concentrations of $GA_1$ and JA increased significantly after the application of Si or $NH_4NO_3$. The level of $GA_1$ observed after a treatment (solo or combine) with Si, and $NH_4NO_3$ was higher than that of the control. By contrast, independent application of $CaCl_2$ or a combined treatment with Si and $CaCl_2$ did not alter $GA_1$ levels. The highest level of $GA_1$ was present in plants given a combination treatment of Si and $NH_4NO_3$. This effect was observed at all time points (6 h, 12 h and 24 h). Endogenous JA contents were higher in all treatments than the control. In particular, a combination treatment with Si and $NH_4NO_3$ significantly increased the JA levels in plants compared to other treatments at all time points. A small increase in JA levels was observed after 6 h in plants given the $CaCl_2$ treatment. However, JA levels did not differ between plants given a $CaCl_2$ treatment and controls after 12 h or 24 h of exposure. We conclude that treatment with $CaCl_2$ alone does not affect endogenous JA levels in the short term. Endogenous ABA contents did not show any differences among the various treatments.

• Korean Journal of Veterinary Research
• /
• v.28 no.2
• /
• pp.307-310
• /
• 1988

This experiment was carried out to provide the data of blood chemistry in use of application to clinical diagnosis in racehorses. Blood was collected from 30 racehorses(♀ 17, ♂ 13). Calcium, inorganic phosphorus, blood glucose, blood urea nitrogen, cholesterol, bilirubin, fibrinogen and ketone body in serum were analyzed as follows. 1. The values of calcium and inorganic phosphorus were maintained a certain level without much variation regardless of sex and species, Ca/P ratio was in the range of 3.13~3.35. 2. The value of blood glucose was 60 mg/100ml, Age and sex of racehorses make no difference in the value. 3. The value of blood urea nitrogen and total cholesterol showed a tendency to increase according to the age. Total cholesterol value was somewhat higher in male than in female. 4. The value of total bilirubin showed a tendency to increase according to the age. There was no difference between sexes in the value. 5. The value of fibrinogen showed no apparent difference with age and sex. 6. Ketone body was negative in all of the cases. 7. There was no variation in the species of the racehorses.

• Journal of Environmental Health Sciences
• /
• v.31 no.4 s.85
• /
• pp.260-265
• /
• 2005

Indoor air quality might be affected by source strength of indoor pollutants, ventilation rate, decay rate, outdoor level, and so on. Although technologies measuring these factors exist directly, direct measurements of all factors are not always practical in most field studies. The purpose of this study was to develop an alternative method to estimate the source strength and deposition constant by application of multiple measurements. For the total duration of 60 days, indoor and outdoor $NO_2$ concentrations every 3 days were measured in 30 houses in Seoul, Asan and Daegu. Using a compartment model by mass balance and linear regression analysis, penetration factor (ventilation divided by sum of air exchange rate and deposition constant) and source strength factor (emission rate divided by sum of air exchange rate and deposition constant) were calculated. Subsequently, the source strength and deposition constant were estimated. Natural ventilation was $1.80{\pm}0.42\;ACH,\;1.11{\pm}0.50\;ACH,\;0.92{\pm}0.26\;ACH$ in Seoul, Asan and Daegu, respectively. Calculated deposition constant(K) and source strength of $NO_2,$ in this study were $0.98{\pm}0.28\;hr^{1}\;and\;16.28{\pm}7.47\;ppb/h,$ respectively.

• Korean journal of applied entomology
• /
• v.9 no.1
• /
• pp.7-13
• /
• 1970

1. Kum Nam Poong which is highly susceptible to bacterial leaf blight was used as the host plant throughout this experiment. Xanthomonas oryzae 6526 was inoculated on the top of upper leaves by single needle inoculation method. After 14 days, the enlarged spots were examined in the experimental pots. Each of 3 levels of nitrogen, phosphate and potassium pots were arranged at random with three replications. 2. The amounts of nitrogen fertilizer applied and the lesion development of bacterial leaf blight were positively correlated regardless of application of phosphate and potassium fertilizers. 3. The effect of phosphate fertilizer on the lesion development was not significantly different from standard level. The lesion development was stimulated when the amount of phosphate fertilizer was increased as twice as standard level. 4. The inhibitory effect of potassium fertilizer on leaf blight was maximum by applying standard level. The stimulative effect of potassium fertilizer on the lesion development, however, was noticed. when potassium fertilizer applied was increased as twice as the standard level. 5. The heading date and spike number of rice plant were significantly correlated with the lesion development, and such phenomena were depended on the amount of nitrogen fertilizer applied regardless of the other fertilizers applied in this experiment.

• Korean journal of applied entomology
• /
• v.12 no.1
• /
• pp.33-39
• /
• 1973

The yield of rice is increased to amounts of fertilizer applied in paddy field but excessive application of fertilizer stimulates outbreaks of disease and insect pest. If, therefore, diseases and pests stimulated by excessive application of fertilizer would be effectively controlled, increaseed yield of rice would be possible. This experiment was conducted to determine the fertilizer application rate that would produce maximum yields when diseases and pests are controlled. 1. The fertilizer application rates and the incidence of leaf and apanicle blast were positively correlated at the $1\%$ level. 2, Without disease and pest control the maximum yield of hulled rice was 347-378kg/10a, which occurred at nitorgen application levels of 8.0-8.5 kg/10a. with effective control of diseases and pests the maximum yield of hulled was 453-462 kg/10a, which occurred at nitrogen application levels of 18.5-19.0 kg/10a. Yield increase at appropriate nitrogen levels by disease and pest control resulted in more than 100 kg/10a. 3. There was no significant yield difference between the NPK experimental plots with fixed PK levels and with varying PK levels. 4. The maximum effect of disease and pest .control as expressed biy yield index of hulled rice was $65\%$, the minimum effect was $30\%$, the average effects were $42-45\%$.