• 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 ($mg\;kg^{-1}$).

• Journal of The Korean Society of Grassland and Forage Science
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• v.6 no.3
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• pp.151-156
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• 1986

There are differences in recommendations in the USA as to whether nitrogen fertilizer should be applied when establishing alfalfa (Medicago sativa L). The reason for not applying nitrogen is because some researchers found the addition of nitrogen reduced nodulation of alfalfa plants. A replicated experiment was conducted under controlled environmental conditions at the University of Nevada-Reno, Reno, Nevada, USA, to determine the effects of nitrogen application on seedling growth and nodulation of alfalfa when grown in a cool environment. A sterile sand was used in the growing media to which a complete nutrient solution minus nitrogen was applied volumetrically to each pot daily. Half of the pots received $NH_4NO_3$, at the rate of 11.2 kg/ha, at seeding and two and four weeks after planting, giving a total nitrogen application rate of 33.6 kg/ha. Rhizobia inoculant (R-12) consisted of a mixture of strains 171-15a. 1682c and 80 PI 265 of Rhizobium meliloti. Inoculant was applied to the seeds prior to planting and to the sand media at two and four weeks after seeding. Twenty seeds were planted in pots 14.0 cm in diameter and 11.5 cm deep. Seedlings were thinned after emergence to ten plants per pot. They were grown in a controlled environment chamber with a 16-hour light period. Soil temperatures at 6 cm depth ranged from $5.7^{\circ}C\;to\;21.5^{\circ}C$ and had a daily mean of $16.2^{\circ}C$ Plants were harvested at weekly intervals for seven weeks at which time root, shoot and total length, dry weight, volume and number of nodules per plant were determined. Root, shoot and total length were not affected by nitrogen fertilizer. However, application of nitrogen increased the size of the seedlings as determined by dry weight and volume when compared to plants which were not fertilized. This indicates that rhizobia did not fix enough atmospheric nitrogen to promote good growth. Nitrogen application resulted in significantly more nodules per plant. The effect of nitrogen fertilizer became more apparent as the plant became older. Results of this experiment show there are benefits from applying nitrogen at a low rate when establishing alfalfa under a cool environment.

• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.1049-1056
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• 2020

Ultrafine dust causes asthma and respiratory and cardiovascular diseases when inhaled. Ammonia (NH3) plays a big role in ultrafine dust formation in the atmosphere by reacting with nitrogen oxides (NOx) and sulfur oxides (SOx) emitted from various sources. The agricultural sector is the single largest contributor of NH3, with the vast majority of emissions ensuing from fertilizers and livestock sector. Interest in using biochar to attenuate these NH3 emissions has grown. This experiment was conducted to study the effects of using rice hull biochar pyrolyzed at three different temperatures of 250℃ (BP 4.6, biochar pH 4.6), 350℃ (BP 6.8), and 450℃ (BP 10.3) on the emission of ammonia from soil fertilized with urea. The emissions of NH3 initially increased as the experiment progressed but decreased after peaking at the 84th hour. The amount of emitted NH3 was lower in soil with biochar amendments than in that without biochar. Emissions amongst biochar-amended soils were lowest for the BP 6.8 treatment, followed in an ascending order by BP 10.3 and BP 4.6. Since BP 6.8 biochar with neutral pH resulted in the lowest amount of NH3 emitted, it can be concluded that biochar's pH has an effect on the emissions of NH3. The results of this study, therefore, indicate that biochar can abate NH3 emissions and that a neutral pH biochar is more effective at reducing gaseous emissions than either alkaline or acidic biochar.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.3
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• pp.293-304
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• 1997

A field experiment was conducted at the forage experimental plots, Seoul National University, Suweon h m 1995 to 1996 to determine the effect of legume residues as a N source and N fertilizer on corn (Zea mays L.) silage yield, N uptake, and availability of inorganic N in the soil. Corn was grown following (i) red clover (Trifolium pratense L.), (ii) crimson clover (Trifolium incarnatum L.), (iii) alfalfa (Medicago sativa L.) and (iv) winter fallow. The plots were split into two rates of fertilizer N (0 and 90kg Nlha) in a split-plot experimental plan. Compared with fallow treatment, legumes depleted soil water in the surface 15cm at corn planting by 17 to 26%. As a result, corn emergence was markedly delayed with legume residues by 8 to 11 days. Corn silage DM yield was significantly reduced in the presence of legume residues by 2.0 to 3.4 and 1.5 to 2.5 tonlha compared with winter fallow treatment at 0 and 90kg fertilizer Nlha, respectively, but no significant difference in the corn DM yield was found between legume residue treatments. There was an overall tendency for increased corn yields with 90kg fertilizer Nlha compared to Okg fertilizer Nlha, although not all yield increases were significantly greater. The corn yield response to applied N suggests that a source of N from legume residues was not sufficient for a succeeding corn crop. There was significantly more N (P

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.2
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• pp.140-147
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• 1985

This experiment was conducted in the field to investigate the effects of mulched condition on nutrient's mineralization and its mobility as affected by environmental changes (soil moisture and soil temperature) in the plow layer. 1. Nitrogen mineralization was faster owing to the prevention of evaporation and the increase of soil temperature in the poly ethylene mulched plot. As a result, nitrate form of nitrogen was much earlier available for plant in mulched plot than in non mulched plot. 2. Available $P_2O_5$ content in the plow layer was kept highest in the fertilized zone (10-20 cm depth) regardless of difference between mulched and non mulched condition, and was nearly constant without showing difference between planting and non planting of tobacco due to the lower availability of phosphorus by tobacco. 3. Potassium applied in the plow layer was remained a large quantity until the latter growth stage resulting in the lower recovery of potassium by tobacco. 4. Mineralized nutrients such as $NH_4-N$, $NO_3-N$, and K in the plow layer of mulched plot were transported from the fertilized layer (10-20 cm depth) and accumulated to the surface layer (0-10 cm depth) as the growing time goes by, but those in non mulched plot were distributed to the deeper layer. 5. Mobility of available nutrients in the plow layer was If order as $NO_3-N$ $$\geq_-$$ $NH_4-N$ > K > available $P_2O_5$. 6. Leaching degree of mineralized nutrients in the mulched plot was much lower than in the non mulched plot.

• Journal of Korean Society of Forest Science
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• v.110 no.1
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• pp.35-42
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• 2021

In this study, the relationships between bamboo expansion and the nutrient characteristics of bamboo biomass, the forest floor, and mineral soil (at 30-cm depth) were determined in unfertilized expansion sites and fertilized plantations of Phyllostachys nigra var. henonis in Jinju, Gyeongsangnam-do. Nitrogen and phosphorus concentrations in bamboo components (culm, branches, and foliage) were significantly higher in the plantation site than those in the expansion site (P < 0.05). However, the nutrient concentration of the forest floor did not differ significantly between the plantation and expansion sites. Mean organic carbon concentration at 0-30-cm soil depth was significantly higher in the plantation site (30.80 g kg-1) than that in the expansion site (15.64 g kg-1). In addition, total nitrogen, phosphorus, and exchangeable K+ at 0-30-cm soil depth were significantly higher in the plantation site than those in the expansion site. These results indicate that bamboo can spread to areas with low-nutrient concentrations in adjacent forests.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.4
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• pp.290-296
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• 2016

Green manure has been used as alternative to chemical fertilizer. To evaluate the effect of green manure on the chemical properties of top-soil and sorghum yield, hairy vetch (Vicia villosa Roth, HV), manure barley (MB), and a mixture of hairy vetch and manure barley (HV+MB) were incorporated into the soil at a rate of $100kg-N\;N\;ha-1$ before the sorghum was transplanted. Total biomass of sorghum grown in the HV, MB, and HV+MB treatments was 13.1, 31.6, and $25.2t\;ha^{-1}$, respectively, and the nitrogen production of the treatments was 81, 74, and $145kg\;ha^{-1}$, respectively. The SPAD value of the uppermost leaf of sorghum plants grown in the soils with HV, MB, or HV+MB were very similar until heading stage; however, at maturity, the SPAD value of sorghum cultivated in the soils with HV was lower than that of sorghum in the soils with MB or HV+MB. This could be because the nitrogen release from HV was too rapid to supply nitrogen to sorghum during the later stage of grain filling. Compared with chemical fertilizers, the incorporation of green manure increased the pH, exchangeable cations ($K^+$, $Mg{^{+}^{+}}$, and $Ca{^{+}^{+}}$), and total nitrogen in soil postharvest, indicating an improvement in soil chemical properties. Total carbon content increased in soil with green manure incorporated, but decreased in the chemical fertilized soil, suggesting that sorghum cultivation using green manure may sequester carbon in soils. The yield of sorghum cultivated with green manure was not different from the yield of sorghum cultivated with chemical fertilizers. These results suggest that the mixture of hairy vetch and manure barley can be a useful chemical fertilizer alternative in sorghum cultivation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.4
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• pp.273-278
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• 2002

An efficient low-input system (LIS) for fertiliser use in rice cultivation is necessary to reduce fossil energy use and pollution. Japanese people like Japonica rice, especially cv. Koshihikari. However, it has very low lodging resistance in Japanese weather condition. Our objective was to develop a LIS with the minimum sacrifice of grain yield in rice. Koshihikari was grown using conventional fertilization as a control (CON) with 4 g N $m^{-2}$., 8g $P_2$ $O_{5}$ $m^{-2}$ and 8 g $K_2$O $m^{-2}$ as a basal fertilizer dressing. It was compared with a low fertilizer treatment (LF) with only 4 g $P_2$ $O_{5}$ $m^{-2}$ as a basal dressing in the first year and no basal phosphorus fertilizer in the second year. Chopped rice straw was incorporated into the soil before the cropping season in both years. Fertilizer of 4 g N $m^{-2}$ was top-dressed at 15 days before heading in CON plots and 30 days before heading in LF plots in both years. Lodging was significantly less in LF than in CON plots, however, no rice straw effect was found in low fertilized condition. Grain yields in LF plots were reduced by 15-16% below those of CON plots. Lower yields in LF plots were associated with a reduced number of spikelets per unit area. However, big spikelet size was acquired in LF by 10 days earlier N top dressing than CON plots. A close relationship was found between spikelet numbers and N content of the plant at heading, and between grain yield or shoot dry weight and N content of the plant at maturity. Regardless of the fertilizer application methods, N use efficiency for the number of spikelets, final total dry matter and grain yield was essentially identical among fertilizer treatments. The reduced growth and yield in the LF plots resulted from low absorption of nitrogen. Conclusively, LIS can drastically reduce chemical fertilizer use and facilitate harvest operations by reducing lodging with some yield reduction..

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.4
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• pp.254-259
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• 1991

The present study was carried out to investigate the effect of nitrogen(urea) application on the seasonal change in pH content of Bray No.1-P, organic matter, and exchangeable cations along the grassland soil profile and further to provide the fundamental information for optimizing the rate of fertilizer application to grassland. Soil samples were taken 20cm intervals upto 100cm soil depth in spring(May 26), summer(July 27), and autumn (October 18) of 1990. The obtained results are summerized as follow 1. In spring and summer, soil pH at 0-20cm soil depth of 28kg N/10a treatment was lowered by 0.7 and 1.0 in comparison with those the same soil depth of 0 kg N/10a treatment and the tendency in pH decrease during all season at the soil depth below 20cm was in the order of summer>spring>autumn. 2. Although Bray No.1-P content at the soil depth 0-20cm of 28kg N/10a treatment was lowered by 20ppm compared to 0 kg N/10a treatment in summer, there was no great difference in its content between 0kg N/10a and 28kg N/10a treatment at all soil depth in spring and summer. In autumn, its content at soil depth below 20cm of 28kg N/10a treatment was higher than that of in summer. 3. Organic matter content at 0-20cm soil depth of 0 and 28kg N/10a treatment in autumn was slightly lowered and on the whole there was very little change in it by soil depth and nitrogen application. 4. The calcium content of 0 and 28kg N/10a treatment was also slightly lowered by increase in soil depth and Mg and K contents were below 0.4 and 0.2 me/100g during all seasons, respectively. 5. Positive correlations were shown among the $NH_4-N$ content and pH, organic matter, Ca and Mg of 0 kg N/10a treatment, however, there was negative correlation ($r=-0.534^{*}$) between $NO_3-N$ content and pH of 28kg N/10a treatment in summer.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.2
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• pp.102-108
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• 1991

A field experiment with microplots(D.20cm, L. 85cm) was conducted to obtain quantitative information on the downward movement of nutrients applied to the soils by different amount of irrigation water. The microplots were installed by embedding PVC column(D. 20cm, L. 90cm) filled with sieved soils in the field. Urea, fused and superphosphate, and KCl were broadcasted over the soil in the microplots and surface layer was covered with lime-amended soils. Microplots were removed 1 week after water application and analysed for Cl, $NH_4$ and $NO_3-N$, Bray 1-P and exchangeable cations of Ca, Mg, and K in each segment. Effect of irrigation rate on the movement of these ions were evaluated with the mean downward movement(MDM) determined with nutrient concentration of each segment and the distance to the segment from the site fertilized. For the nutrient studied, MDM was linearly related to the amount of water applied. When one pore volume of water needed for 0.1 bar soil moisture tension was applied, MDM(cm), computed as the piston front of applied water advanced 10cm, was found to be in the order; Cl, 7.52>Inorganic N, 6.03> K, 3.50> Mg, 2.69>Ca, 1.19>P, 0.29. After the downward movement of applied nutrients soil pH seemed to decrease with irrigation in the surface layer(0-15cm) and increase in the subsurface layer. It was also found that ammonium-nitrogen evolved from urea hydrolysis was more effective in raising the subsoil pH rather than the exchangeable Ca and Mg.