• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.3
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• pp.31-38
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• 2010

Various fundamental and practical theories and technologies are needed for the development of Best Management Practices (BMPs) to manage the problems. The objectives of this paper was to investigate the effect of fertilizer and Non-point suource (NPS) pollution discharges from the field. The effect of fertilizer application was measured with respect to 10 % and 20 % slopes, respectively, using artificial rainfall simulator. The effect of fertilizer application on runoff was not significant because the effect of slope and rainfall intensity were overwhelmed. Runoff from 20 % plots was 21 % larger than that from 10 % plots. While groundwater discharge from 10 % plots was about 70 % larger than that from 20 % plots. It was concluded that runoff and groundwater discharge were largely affected by slope. T-N concentration in groundwater was much higher than that in runoff for both 10 % and 20 % plots. While T-P concentration in groundwater was lower than that in runoff. It explained that T-N moved well through soil pores without adsorption and other chemical reactions but T-P was well adsorbed on the surface of soil particles.

• The Korean Journal of Ecology
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• v.26 no.2
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• pp.71-74
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• 2003

Effects of nitrogen addition on the growth of Indigofera pseudo-tinctoria (Leguminosae) in the waste landfill site was investigated. Nitrogen fertilization in the nitrogen poor soils of waste landfill may influence the growth of nitrogen fixing plants beneficially or detrimentally. When I. pseudo-tinctoria was fertilized with three different levels of nitrogen, the coverage of plants treated with 46 g N/$m^2$ and 460 g N/$m^2$ was significantly less than that of plants treated with 23 g N/$m^2$. The growth rates of plant height treated with 46 g N/$m^2$ and 460 g N/$m^2$ were significantly less than those of plants treated with 23 g N/$m^2$. The growth rates of plant diameter treated with 46 g N/$m^2$ and 460 g N/$m^2$ were significantly less than those of plants treated with 23 g N/$m^2$. Dry weights of whole plants in control sites were higher than those of all the others nitrogen treatment sites. Nodule numbers were higher in control plants than those of plants in all the other nitrogen treatment sites. It is suggested that nitrogen fertilizer addition over 23 g N/$m^2$ affect the growth of some nitrogen fixing plants, such as I. pseudo-tinctoria, negatively.

• Korean Journal of Plant Resources
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• v.14 no.1
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• pp.43-47
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• 2001

For the purpose of sweet potato varietal improvement, yulmi, shinyulmi, gunmi, hongmi and seonmi, whose source and sink are different one another, were cultivated at different amount of fertilizers, and then defoliation at initial stage of tuberous root weight increase on the relation of source and sink was observed as follows. The response of stem, leaf and tuberous root weight by amount of fertilizer and defoliation rate of sweet potato varieties was different. Stem and leaf weight increased along with heavy dressing by the following order; shinyulmi> seonmi> hongmi> gunmi> yulmi. Tuberous root number was the most at $N-P_2O_5-K_2O=60-70-190kg/ha$ amount of fertilizer, showing seonmi the most number. The number of stem, leaf and tuberous root increased along with the lowered rate of defoliation. In case of $N-P_2O_5-K_2O=20-30-90kg/ha$ amount of fertilizer, tuberous root weight increased by increase of stem and leaf weight up to 50% defoliation and the difference of stem, leaf and tuberous root number was low as defoliation rate increases. The total dry weight matter was the most at heavy dressing amount of fertilizer.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.3
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• pp.304-311
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• 1985

This study was carried out to find the spring-season weed growth status on account of different soil physicochemical properties due to continuous application of same fertilizer for 8 years at paddy field. The results examined on weed species, dry weight of weed, and weed growth status were summarized as follows. 1. 1-6 species of weed occurred in the plots treated by continueous application of different fertilizers. Cyperus serotinus could grow only in the phosphate defficient plots, however, in the N+P+K, N+P and N+P+K+compost plots, 4-6 kinds of weed occurred variously. 2. In the plots applied phosphate like as, P, P+K, N+P+K+compost, and N+P+K+plots, large amount of weed occurred apparently. 3. Positive correlation betwaen dry weight of Alopeculus aequalis, polygonum hydropiper and Chenopodium alburn and available phosphate content in soil was showed with high significance. 4. Available phosphate in soil affected weed growth and weed species composition among weed communities. Application of lime fertilizer tended to suppress the occurrence of Alopeculus aequalis. 5. Dry matter of polygonum Longisetum, Chenopodium album and polygonum hydropiper showed higher content of nitrogen, phosphate, calcium, and magnesium. Whereas those of Alopeculus aequalis, Cyperus Serotinus and Stellaria alsine were less.

• Weed & Turfgrass Science
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• v.4 no.4
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• pp.397-404
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• 2015

This study was conducted to find out the optimum nitrogen fertilization for production of good quality and high yield zoysiagrass (Zoysia japonica Steud.), the changes in chemical properties of soil in pot and field experiments treated with different levels of nitrogen fertilizer. In pot experiment, the fresh and dry weights of shoots and stolons and the number of shoots increased as nitrogen levels increased, and showed no significant between 24 and $48kg\;N\;10\;a^{-1}$. In field experiment, the shoot length, fresh and dry weights of shoots, roots and stolons, the number of shoots and total stolons length linearly increased as affected by increased nitrogen application, and were not significantly different between 24 and $32kg\;N\;10\;a^{-1}$. In both experiments, pH and exchangeable cations ($Ca^{2+}$ and $Mg^{2+}$) in soil decreased as the rate of nitrogen application increased. As a results, chemical properties of soil were more deteriorated in the plots of higher nitrogen fertilizer rate. Thus, these results demonstrated that the nitrogen fertilizer rate for maximum growth of zoysiagrass was $24kg\;N\;10\;a^{-1}$ in consideration of growth and soil condition.

• Korean Journal of Medicinal Crop Science
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• v.5 no.2
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• pp.147-153
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• 1997

This experiment was carried out to clarify the effect of different fertilizer on growth and yield of Fritjllaria thunbergii in Chungbuk Rural Development Administration from 1993 to 1995. Emergence date was faster about 1 to 5 days in fertilizer application than that of non-fertilizer, and emergence ratio was lower about 2.4% to 35.7% in fertilizer application than that of non-fertilizer. Plant height was longer about 2.8cm to 10.6cm in fertilizer application than that of non-fertilizer, and leaf length and width had same tendencies. Bulb height was increased about 0.1 to 0.2cm in fertilizer application than 1.9cm in non-fertilizer and bulb width was increased about 0.5 to 0.7cm in fertilizer application than 2.2cm in non-fertilizer. Total yield was increased about 27% in N-P-K fertilizer, 24% in compost, 23% in compound fertilizer for garlic and 21 % in fowl dropping manure than 572kg/10a in non-fertilizer. Yield of marketable goods was high about 79% in compost. 72% in compound fertilizer for garlic and fowl dropping manure, and 69% in organic fertilizer than 229kg/l0a in non-fertilizer. Therfore, in the cultivation of Fritillaria thunbergii the application of organic fertilizer such as compost and fowl dropping manure was considered more profitable than the application of chemical fertilizer in middle region.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.777-782
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• 1999

It has been acknowledged that fertilizer and animal waste have different ratio of \ulcornerN/\ulcornerN which is presented as a symbol of $\delta$\ulcornerN, and that the values of $\delta$\ulcornerN for fertilizer and animal waste are placed less than +8 $\textperthousand$ and higher than +10$\textperthousand$, respectively. By this reason, the demarcation range for the source nitrogen mass ratio is between +8$\textperthousand$ and +10$\textperthousand$. In this study, we would suggest a possible method to trace the major pollution basis using the nitrogen isotope analysis method for management of water quality.

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.5
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• pp.153-162
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• 2001

A study was carried out to investigate the water balance and losses of nutrients at a paddy plot located at the southern Korea. The observed amount of precipitation, irrigation, runoff, evapotranspiration and percolation for the experimental paddy plot during cropping period were 1,030, 566, 701, 551. and 310 mm for 1999 and 1.214, 413, 710, 682, and 234 mm for 2000 year, respectively. The measured input quantities of N and P into the paddy field during cropping period were 122 to 140 kg N $ha^-1$ and 29 to 30 kg $P_2O_5$ kg $ha^-1$ by chemical fertilizer, 20 to 28 kg N $ha^-1$ and 0.35 to 0.36 kg P $ha^-1$ by precipitation, and 26 to 35 kg N $ha^-1$ and 0.57 to 0.72 kg P$ha^-1$ by irrigation water. respectively. The output amounts of N and P from paddy field were measured as follows. They were 48 to 52 kg N $ha^-1$ and 1.1 to 1.6 kg P $ha^-1$by runoff water, and 9 to 12 kg N $ha^-1$ and 0.04 to 0.05 kg $ha^-1$ by percolation water. When the runoff losses of nutrients were compared to applied chemical fertilizer. it was found that 34.3 % to 42.6 % of nitrogen lost via runoff while runoff losses of phosphorus account for 3.8 % to 5.3 % of the total applied amount. When the ratio was calculated between nutrients losses by percolation water and the applied of chemical fertilizer, two year results showed 6.4 % to 9.8 % for the nitrogen and 0.1% to 0.2% phosphorus, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.413-420
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• 2015

Objective of this study was to investigate adsorption characteristics and kinetic models of $NH_4-N$ to biochar produced from rice hull in respective to mitigation of greenhouse gases. $NH_4-N$ concentration was analyzed by UV Spectrophotometer. For the experiment, the soil texture used in this study was sandy loam soil, and application rates of chemical fertilizer and pig compost were $420-200-370kgha^{-1}$ (N-P-K) and $5,500kgha^{-1}$ as recommended amount after soil test for corn cultivation. Biochar treatments were 0.2-5% to soil weight. Its adsorption characteristic was investigated with application of Langmuir isotherm, and pseudo-first order kinetic model and pseudo-second order kinetic model were used as kinetic models. Adsorption amount and removal rates of $NH_4-N$ were $39.3mg^{-1}$ and 28.0% in 0.2% biochar treatment, respectively. The sorption of $NH_4-N$ to biochar was fitted well by Langmiur model because it was observed that dimensionless constant ($R_L$) was 0.48. The maximum adsorption amount ($q_m$) and binding strength constant (b) were calculated as $4.1mgg^{-1}$ and $0.01Lmg^{-1}$ in Langmuir isotherm, respectively. The pseudo-second order kinetic model was more appropriate than pseudo-first order kinetic model for high correlation coefficient ($r^2$) of pseudo-second order kinetic model. Therefore, biochar produced from rice hull could reduce $N_2O$ by adsorbing $NH_4-N$ to biochar cooperated in sandy loam soil.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.1
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• pp.44-49
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• 2015

Urea has been the most useful N-source, due to lower cost per unit of N. But nitrogen use efficiency of urea may be reduced because of losses from agricultural system by volatilization of ammonia to atmosphere. This study was conducted to evaluate the nitrogen efficiency and growth of hot pepper (Capsicum annuum L.) by mixed treatment with nitrogen and zeolite. They were treated with N $161kg\;ha^{-1}$, N $230kg\;ha^{-1}$, nitrogenzeolite mixture (NZM) $161kg\;ha^{-1}$, NZM $230kg\;ha^{-1}$ and N $0kg\;ha^{-1}$, respectively. In the soil chemical properties after experiment, soil pH decreased but available $P_2O_5$, EC and total nitrogen increased in nitrogen-zeolite mixture treatment. $NO_3-N$ content in the soil showed the highest level in NZM $230kg\;ha^{-1}$. NZM $161kg\;ha^{-1}$ treatment increased growth and yield of hot pepper compared to urea alone. Nitrogen utilization efficiency of hot pepper plant was 47.15% at the treatment of NZM $161kg\;ha^{-1}$, while 36.74% at N $230kg\;ha^{-1}$. These results showed that application of mixture of nitrogen and zeolite had positive influence to improve the efficiency of nitrogen utilization and increase of red pepper yield.