• 한국농공학회:학술대회논문집
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• 한국농공학회 2001년도 학술발표회 발표논문집
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• pp.451-455
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• 2001

This study was performed to examine water and nutrient balance during rice cropping period using difference fertilization paddy plot in ground water irrigation region. The experimental rice paddy consist of three plot, Treatment of Excess fertilization(TEF) and Treatment of Standard Fertilization(TSF) and Treatment of Reduce Fertilization(TRF). As result, input amount to rice paddy was almost rainfall and output was direct runoff through drainage. nutrient input amount was upper paddy in case COD and fertilization in case Total nitrogen and total phosphorus, and output was drainage in all nutrient.

• 식물병연구
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• 제25권3호
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• pp.103-107
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• 2019

Roles of nutrients in controlling plant diseases have been documented for a long time. Among the nutrients having impact on susceptibility/resistance to crop diseases, nitrogen is one of the most important nutrients for plant growth and development. In rice plants, excess nitrogen via fertilization in agricultural systems is known to increase susceptibility to the rice blast disease. Mechanisms underlying such phenomenon, despite its implication in yield and sustainable agriculture, have not been fully elucidated yet. A few research efforts attempted to link nitrogen-induced susceptibility to concomitant changes in rice plant and rice blast fungus in response to excess nitrogen. However, recent studies focusing on phytobiome are offering new insights into effects of nitrogen on interaction between plants and pathogens. In this review, I will first briefly describe importance of nitrogen as a key nutrient for plants and what changes excess nitrogen can bring about in rice and the fungal pathogen. Next, I will highlight some of the recent phytobiome studies relevant to nitrogen utilization and immunity of plants. Finally, I propose the hypothesis that changes in phytobiome upon excessive nitrogen fertilization contribute to nitrogen-induced susceptibility, and discuss empirical evidences that are needed to support the hypothesis.

• 한국토양비료학회지
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• 제47권5호
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• pp.332-339
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• 2014

This research was performed to test the hypothesis that the optimal fertilization rate for red pepper is changed by soil moisture condition. The experiment was conducted in rainfall-intercepted fields in Suwon, South Korea from 2002 to 2003. Soil was irrigated at 30, 50, or 80 kPa of soil moisture tension at 20 cm soil depth in 2002 and 30, 50, 100, or 150 kPa in 2003. For both years, fertilization was performed with four levels: none, 0.5, 1, and 1.5 times of the recommended N, P, and K fertilization rate. The irrigation amount was the greatest at 30 kPa irrigation while the water use efficiency increased with decrease of irrigation amount. The Irrigation amount was 508 mm at 30 kPa irrigation and ranged from 355 mm to 435 mm at 50 kPa irrigation. The maximum yield was found at 30 kPa irrigation and 1.5 times of the recommend fertilization rate in 2002 and 2003. The yield index of red pepper increased linearly with the fertilization rate at 30 kPa which implied that excess irrigation induced nutrient leaching and reduced nutrient availability. The maximum yield in 50 kPa and 80 kPa was found at the recommend fertilization rate while the yield decreased by fertilization at 100 kPa and 150 kPa irrigation. It implies that reduction of fertilization is the feasible practice to mitigate drought stress in fields without stable irrigation resources.

• 한국산림과학회지
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• 제99권2호
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• pp.186-196
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• 2010

Fertilization increases the crop productivity and produces high quality seedlings for plantation. We quantitatively measured both physical performances and nutrient responses of Fraxinus rhynchophylla, Fraxinus mandshurica, Pinus koraiensis, and Abies holophylla seedlings, which are commercially planted species in Korea, to nitrogen, phosphorus, and potassium fertilization. We analyzed the growth performances by using Dickson's quality index (QI) and the nutrient status by using vector diagnosis. Nitrogen or phosphorus treatment increased height and root collar diameter growth of F. rhynchophylla and F. mandshurica, however, did not increase those of P. koraiensis and A. holophylla. The order of QI was N > P > K > control for F. rhynchophylla, P ${\geq}$ N > Control ${\geq}$ P for F. mandshurica, P > Control ${\geq}$ K > N for P. koraiensis and A. holophylla. In F. rhynchophylla, fertilization diluted N concentration in tissues by 5-25% because growth responses were higher than fertilization uptake. P. koraiensis and A. holophylla showed N excess showing "toxic accumulation". F. rhynchophylla and F. mandshurica showed P deficiency with P fertilization, however, P. koraiensis and A. holophylla showed "luxury accumulation". Vector diagnosis indicated that more fertilization was applicable for F. rhynchophylla and F. mandshurica, and high fertilization rates were inefficient for P. koraiensis and A. holophylla. Both QI and vector diagnosis can be applied to verify seedling quality in the light of growth responses and nutrient status in fertilization trials.

• 한국초지조사료학회지
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• 제17권1호
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• pp.35-42
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• 1997

Many farmers apply cattle slurry on grassland, often in excess of crop N requirements, resulting in groundwater contamination. Our research objective was the development of grassland management systems that reduce undesirable sideeffects on other compartment of the ecosystem. Field experiment was conducted during 1991~1993 on sandy loam soil at AllgZiu south western Germany. Different sets of conditions were tested such as : zero fertilization, reduced sluny application$(l20kg N ha^{-1}yr^{-1})$, intensive sluny application(conventional sluny application, $240kg N ha^{-1}yr^{-1}$). The plots of the reduced slurry application had no significant effect on dry matter yields, digestible dry matter and net energy of herbage. Dry matter yield of zero fertilization was significantly lower than that of usual slurry application, however the content of Ca and Mg in herbage tended to increase. We conclude that reduced sluny application can be applied on grassland without adverse effects on dry matter production and quality of herbage.

• 한국초지조사료학회지
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• 제10권2호
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• pp.84-88
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• 1990

This experiment was conducted to evaluate the effect of cutting frequency and nitrogen fertilization on $(NO_3$-N leaching losses under 12 years mixture permanent meadow, The results of this study were summarized as follows: 1. There was no difference in the $(NO_3$-N content of soil water within 1 m soil depth during the whole experimental period. It means that the content of $(NO_3$-N leaching losses was not influenced by botanical composition, cutting frequency and nitrogen fertilization in this experiment. 2. The level of $(NO_3$-N content during the whole experimental period was not in excess of 0.5 ppm level.

• 한국환경농학회지
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• 제31권3호
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• pp.205-211
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• 2012

BACKGROUND: Generally, nitrogen (N) fertilization higher than the recommended dose is applied during vegetable cultivation to increase productivity. But higher N fertilization also increases the concentrations of nitrate ions and nitrous oxide in soil. In this experiment, the impact of N fertilization was studied on nitrous oxide ($N_2O$) emission to standardize the optimum fertilization level for minimizing $N_2O$ emission as well as increasing crop productivity. Herein, we developed $N_2O$ emission inventory for upland soil region during red pepper and Chinese milk vetch cultivation. METHODS AND RESULTS: Nitrogen fertilizers were applied at different rates to study their effect on $N_2O$ emission during red pepper and Chinese milk vetch cultivation. The gas samples were collected by static closed chamber method and $N_2O$ concentration was measured by gas chromatography. The total $N_2O$ flux was steadily increased due to increasing N fertilization level, though the overall pattern of $N_2O$ emission dynamics was same. Application of N fertilization higher than the recommended dose increased the values of both seasonal $N_2O$ flux (94.5% for Chinese cabbage and 30.7% for red pepper) and $N_2O$ emission per unit crop yield (77.9% for Chinese cabbage and 23.2% for red pepper). Nitrous oxide inventory revealed that the $N_2O$ emission due to unit amount of N application from short-duration vegetable field in fall (autumn) season (6.36 kg/ha) was almost 70% higher than that during summer season. CONCLUSION: Application of excess N-fertilizers increased seasonal $N_2O$ flux especially the $N_2O$ flux per unit yield during both Chinese cabbage and red pepper cultivation. This suggested that the higher N fertilization than the recommended dose actually facilitates $N_2O$ emission than boosting plant productivity. The $N_2O$ inventory for upland farming in temperate region like Korea revealed that $N_2O$ flux due to unit amount of N-fertilizer application for Chinese cabbage in fall (autumn) season was comparatively higher than that of summer vegetables like red pepper. Therefore, the judicious N fertilization following recommended dose is required to suppress $N_2O$ emission with high vegetable productivity in upland soils.

• 한국환경농학회지
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• 제36권3호
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• pp.141-146
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• 2017

BACKGROUND: Phosphorus(P) is a vital factor for rice but excess input of phosphorus fertilizer can cause environmental risk and waste of fertilizer resources. We studied to assess the change of available phosphate, P balance, critical concentration of available phosphate under a rice single system. METHODS AND RESULTS: The changes of available phosphate of paddy soil were examined from long-term fertilization experiment which was started in 1954 at the National Academy of Agricultural Science. The treatments were no phosphate fertilization(No fert., and N), phosphate fertilization(NPK, NPKC, and NPKCLS). The available phosphorus concentrations in treatments without phosphate fertilizer (No fert. and N) were decreased continuously. But, after 47 years, available phosphate content in phosphate fertilizer treatment (NPK, NPKC, and NPKCLS) reached at the highest ($245{\sim}331mg\;kg^{-1}$), showing a tendency to decrease afterward. The mean annual P field balance in these treatments (NPK, NPKC, and NPKCLS) had positive values that varied from 16.6 to $17.5kg\;ha^{-1}year^{-1}$, and ratio of residual P were increased. These showed that phosphate fertilizer in soil were converted into the form of residual phosphorus which was not easily extracted by available phosphate extractant. Also, It was estimated that the critical value of available phosphate for rice cultivation was $120mg\;kg^{-1}$ using Cate-Nelson equation. CONCLUSION: We concluded that no more phosphate fertilizer should be applied in rice single system if soil available phosphate is higher than the critical P value.

• Journal of Ecology and Environment
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• 제30권3호
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• pp.225-229
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• 2007

The mating systems of natural populations of Potentilla freyniana in Korea were determined using allozyme analysis. The result suggests that P. freyniana is outcrossing as well as employing vegetative reproduction by stolon (self-fertilization rate, s < 0.5). The values of the inbreeding coefficient of eight populations in Korea varied from 0.244 to 0.331, with an average value of 0.274. For eight natural populations, multi-locus estimates of outcrossing (tm) was 0.603 across 13 polymorphic loci, with individual population values ranging from 0.530 to 0.652. The relatively low outcrossing rates of some populations could be attributed to extensive vegetative reproduction by stolon and the isolation of flowering mature plants. Although P. freyniana usually propagated by asexually-produced ramets, I could not rule out the possibility that sexual reproduction occurred at a low rate because each ramet may produce terminal flowers. Although heterozygote excess was observed in some natural populations, most populations exhibited varying degrees of inbreeding and a heterozygote deficit.

• 한국토양비료학회지
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• 제22권4호
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• pp.315-322
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• 1989

작약(芍藥)을 관행(慣行), 유기(有機), 무기(無機), 유기(有機)-무기(無機) 혼용구(混用區) 및 유기(有機) 무기증비구(無機增肥區)를 설정(設定)하여 생육(生育) 및 수량(收量), 유효성분함양(有效成分含量)을 조사(調査)한 결과(結果) 다음과 같은 결논(結論)을 얻었다. 1. 지상부(地上部)의 생육(生育)에는 각(各) 처리구간(處理區間)에 큰 차리(差異)는 없었으며, 수량(收量)에 있어서는 유기(有機)-무기(無機) 혼용구(混用區)에서 유의성(有意性)이 인정(認定)되었다. 2. 작약근중(芍藥根中) 유효성분(有效成分)인 paeoniflorin, albiflorin, Oxypaeoniflorin 함량(含量)의 년차간(年次間) 변화(變化)는 생육기간(生育期間)이 증가(增加)함에 따라 현저(顯著)히 증가(增加)하는 경향(傾向)을 보였으며 Benzoic acid는 감소(減少)하는 경향(傾向)이었다. 3. 관행구(慣行區)의 수양(收量) 및 약효성분(藥效成分)의 감소경향(減少傾向)이 있으므로 린산비료(燐酸肥料)의 적양시비(適量施肥)에 대(對)한 재검토(再檢討)가 요구(要求)된다. 4. 1차(次) 및 2차(次) 재배시험(栽培試驗)의 1년차(年次)와 2년차(年次)의 수양(收量)과 유효성분(有效成分)을 종합비교(綜合比較)해 볼 때, 무기질비료(無機質肥料)만을 시비(施肥)한 것보다는 유기질비료(有機質肥料)만을 시용(施用)하여 재배(栽培)했을 때 양호(良好)했으며, 유기(有機)-무기질(無機質) 비료(肥料)를 혼용(混用)하면서 무기비료(無機肥料)를 50%, 100% 증비(增肥)했을 때 유기구(有機區)보다 수량(收量)과 유효성분(有效成分)의 증가경향(增加傾向)을 보였다.