• Korean Journal of Soil Science and Fertilizer
• /
• v.42 no.3
• /
• pp.152-159
• /
• 2009

This study was carried out to investigate optimum application rate with mixed organic fertilizer for chemical fertilizer alternative where the paddy rice (Chucheong) was cultivated in clay loam of paddy field. The mixed organic fertilizer were applied at 0, 50, 100 and 150% levels of recommended nitrogen by soil testing plot compared with plot of chemical fertilizer (nitrogen, phosphate and potash), respectively. The ammonium nitrogen content in paddy soil and surface water of mixed organic fertilizer 100% plot were higher than chemical fertilizer plot. The absorbed amount of nitrogen and nitrogen use efficiency by rice plant in mixed organic fertilizer 100% plot were higher than chemical fertilizer plot. The number of tillers on rice at 30 days and 60 days after transplanting mixed organic fertilizer 100% plot were many more than chemical fertilizer plot. The milled rice yield of mixed organic fertilizer 100% plot was increased by 4% than chemical fertilizer plot. The optimum application rate of mixed organic fertilizer was as follows ; $OAR_{MOF}(Mg\;ha^{-1})=[(NAR_{ST}{\div}NC_{MOF}/1,000{\times}0.93)/1,000]$ ($OAR_{MOF}$ : Optimum application rate of mixed organic fertilizer, NARST : Nitrogen application rate($kg\;ha^{-1}$) by soil testing, $NC_{MOF}$ : Nitrogen content($g\;kg^{-1}$) of mixed organic fertilizer, and $0.93:124.3kg\;ha^{-1}/133.0kg\;ha^{-1}$, respectively).

• Korean Journal of Soil Science and Fertilizer
• /
• v.7 no.2
• /
• pp.113-118
• /
• 1974

A study was carried out to investigate the effect of application time of fertilizer nitrogen on its rate of uptake and its distribution in rice plant. The rate of applied fertilizer was 100kg/ha, as a single application at transplanting time and four equal split applications of 25kg/ha was applied at transplanting time, 3 weeks after transplanting, 1 week before the primodial initiation stage of growth and at the flag leaf stage of growth, respectively. The ammonium sulfate was labelled with N-15, as 1% atom excess for single application and 4.4% atom excess for split applications. The results are sumarized as follows: 1. The effect of split application of nitrogen on yield was observed. The yield of brown rice of the single application at transplanting time was 3.1 ton/ha and the split application was 3.4 ton/ha. However, without nitrogen the yield was reduced to 1.9 ton/ha. 2. The number of grains per panicle and 1000 grains weight were increased as split application of nitrogen, but for the number of panicles per hill and maturing rate, the single application of nitrogen revealed favorable results. 3. The rate of uptake of applied fertilizer nitrogen showed a tendency that the efficiency of fertilizer nitrogen increased by top dressing. The rate of uptake of applied nitrogen as basal application, first top dressing, second top dressing and third top dressing was 28%, 33% 51% and 63%, respectively. 4. After shooting stage of the growth, nitrogen in straws transfered to grains. The nitrogen applied at flag leaf stage was absorbed by root and easily accumulated in grains rather than straw.

• Korean Journal of Soil Science and Fertilizer
• /
• v.50 no.6
• /
• pp.574-587
• /
• 2017

Excessive application of nitrogen (N) fertilizer to support switchgrass growth for bioenergy production may cause adverse environmental effects. The objective of this study was to determine optimum N application rate to increase biomass yield of switchgrass and to reduce adverse environmental effects related to N. Switchgrass was planted in May 2008 and biomass yield, N uses of switchgrass, nitrate ($NO_3$) leaching, and nitrous oxide ($N_2O$) emission were evaluated from 2010 through 2011. Total N removal significantly increased with N rate despite the fact that yield did not increased with above $56kg\;N\;ha^{-1}$ of N rate. Apparent nitrogen recoveries were 4.81 and 5.48% at 56 and $112kg\;N\;ha^{-1}$ of N rate, respectively. Nitrogen use efficiency decreased into half with increasing N rate from 56 to $112kg\;N\;ha^{-1}$. Nitrate leaching and $N_2O$ emission were related to N use of switchgrass. There was no significant difference of cumulative $NO_3$ leaching between 0 and $56kg\;N\;ha^{-1}$ but, it significantly increased at $112kg\;N\;ha^{-1}$. There was no significant difference of cumulative $N_2O$ emission among N rates in crest, but it significantly increased at $112kg\;N\;ha^{-1}$ in toe. Excessive N application rate (above $56kg\;N\;ha^{-1}$) beyond plant requirement could accelerate $NO_3$ leaching and $N_2O$ emission in switchgrass field. Overall, $56kg\;N\;ha^{-1}$ might be optimum N application rate in reducing economic waste on N fertilizer and adverse environmental impacts.

• Food Science and Preservation
• /
• v.5 no.2
• /
• pp.123-126
• /
• 1998

This study was carried out investigate to optimum levels of nitrogen and phosphate fertilizer to get a higher yield and a quality of an onion(Allium Cepa L.) from 1993 to 1994. Three fertilizer levels were applied with 120, 240 and 360kg/ha of nitrogen and 100, 200 and 300kg/ha of P2O5 during the onion growing season. After harvesting the onion, it was storaged at given deposit. The growth and yield of the onion were better at the fertilizer levels of both 240 and 360kg/ha of nitrogen and of both 200 and 300kg/ha of P2O5 than at the level of 120kg/ha in nitrogen and 100kg/ha of P2O5. The content of total nitrogen and P2O5 in plant was decreased with reduced application levels of nitrogen and phosphate fertilizer. The rotting rate was higher at the levels of both 360kg/ha in nitrogen and 300kg/ha in P2O5 than the other treatment during the storage period. The sprouting rate tended to be high at 240kg/ha of nitrogen and 100kg/ha of P2O5.

• Journal of the Korean Society of Tobacco Science
• /
• v.4 no.1
• /
• pp.29-35
• /
• 1982

Potassium deficiency symptoms were studied with flue-cured tobacco which was applied with different levels of compound fertilizer (10-15-20) ; 75kg, 100hg, and 125kg/10a. Ratio of N/$K_2O$ in leaves was increased from bottom to top stalk position due to the increase of nitrogen content in leaves. Nitrogen content in leaves was increased from stalk to tip as wall as from midrib to laminae, but vice versa in potassium content. Consequently, resulting in potassium deficiency symptoms in tip of leaves. Rate of reabsorption by rainfall during the latter part of growth was highest at top stalk position in case of nitrogen, but lowest in potassium. This observation was more evident with higher application rate of fertilizer. Nitrogen content of about 4 % in leaves of top stalk position applied with 125kg/10a was maintained up to 85days after trans planting. No increase in potassium in upper leaves was observed over the level of 100kg/10a fertilizer application. As the result, N/$K_2O$ ratio in leaves of top stalk position applied with 125kg/10a was kept at more than 1.0 up to 85days after transplanting, but it was less than 0.9 at 65days after tracts planting with less than 100kg/10a fertilizer application.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.45 no.2
• /
• pp.128-133
• /
• 2000

This study was carried out to investigate the effect of forms and levels of nitrogen fertilizer on plant growth and essential oil production of Agastache rugosa. Calcium nitrate had more influenced on length and width of leaves and lateral branch length than did urea. When nitrogen fertilizer level was increased from 12 kgN/I0a to 24kgN/I0a, plant growth was stimulated and dry matter of leaf and inflorescence were increased. Top dry matter of plant with calcium nitrate treatment (38.4 g) was heavier than that of urea treatment (32.8 g). Interactions among accession and nitrogen form and nitrogen rate were not significantly different for top dry matter. The forms and rate of nitrogen fertilizer did not affect estragole content. The estragole contents was higher in leaf (91.8%) than that of inflorescence (81.3%). While the essential oil content was not affected by different nitrogen forms, nitrogen level affected the essential oil contents positively by increasing dry matter. Essential oil yield was not affected by accession or nitrogen form, but by nitrogen rate. With increasing N application from 12kgN/I0a to 24 kgN/I0a, essential oil yield was increased by 95.8 %.

• Plant Resources
• /
• v.7 no.3
• /
• pp.181-186
• /
• 2004

To find out the optimum fertilizer level for high yielding variety, Paldanghomil, experiment was conducted with 15 compositions of fertilizer levels at the experiment field of forage rye in Sunchon National University from Sep. 1998 to Aug. 1999. The effects of nitrogen fertilizer on plant growth were large significant but increasing rate of application in potassium and phosphate fertilizers above 10kg/10a had negligible effects on plant growth. Raising nitrogen application rate of fertilizers turned out to be 18-10-10kg/l0a of N-P$_2$O$_{5}$-K$_2$O. Content of crude protein was the highest and that of crude fiber such as NDF, ADF, cellulose and lignin were lowest at this rate. Furthermore, IVDMD was high and dry matter yield were the highest at the optimum rate.e.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.6
• /
• pp.1009-1016
• /
• 2012

The purpose of this study was to determine the effects of organic fertilizers on soil properties and growth and quality of melon. Organic fertilizer was applied in soil at the rate of 0, 0.5, 1, 2N according to Rural Development Administration guideline in Korea. The fertilizer had no effects on plant growth-rate parameters, including plant height, leaf number, and leaf size. There were minor effects on the fruit quality parameters such as fruit weight, fruit length, fruit width, placenta and seed weights, sugar content, and starch content. Ascorbic acid level was decreased as fertilizer level was increased. The level of nitrate in groundwater increased with increased levels of N.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.51 no.1
• /
• pp.32-40
• /
• 2006

The nitrogen (N) absorption and partition of the rice plants are important indicators that can be used to improve the N use efficiency (NUE) of the plants. Improving the plant NUE can help to avoid nutrient waste that may cause environmental pollution. To investigate the N absorption and partition of the rice plants, Hwaseongbyeo (Japonica) and Dasanbyeo (indica/japonica) were applied with N fertilizers at the rates of 60, 120, and 180 kg N per ha in paddy field. Also micro plots of $0.81m^2$ were established inside each plot for application of $^{15}N-labeled$ fertilizer. The differences in N utilization of the rice plants were associated with the total N absorption and partitioning after the heading stage. In the grain filling period, the increase of nitrogen content in the total and leaf blades of Dasanbyeo was higher than that of Hwaseongbyeo. Soil N was the main contributor for the increase of total N of Dasanbyeo during the grain filling period. The N fertilizer uptake rate of Hwaseongbyeo rapidly increased with the increment of N fertilization rate. In Dasanbyeo, N fertilizer uptakes were similar under all rates and times of N application. From heading stage to harvest, Dasanbyeo continued accumulating nitrogen, whereas Hwaseongbyeo had small changes. In conclusion, the difference in nitrogen absorption and partition after heading of the two cultivars was caused by the ability of Dasanbyeo to accumulate and remobilize soil nitrogen to the grains during the grain filling period.

• Korean Journal of Environmental Agriculture
• /
• v.29 no.1
• /
• pp.33-38
• /
• 2010

To improve the existing nitrogen recommendation method based on chemical properties of soils and to establish new recommendation rates of nitrogen fertilizer due to different types of soils, the application rates of nitrogen fertilizer were examined in different soils of 12 experimental rice paddy fields. The application rates of nitrogen fertilizer estimated by soil-testing were higher than the rates of nitrogen standard recommendation that has been used. The application rates for minimum rice productivity ranged from a low of 168 kg/10a in sandy soil to a high of 315 kg/10a in saline soil. Amounts of nitrogen absorption in rice were proportional to the application amounts of nitrogen fertilizer in soils. Nitrogen use efficiency was the highest, 36.7%, in immatured paddy field and it was inversely proportional to the application amounts of nitrogen. the rice tasty value was the highest in the soils without nitrogen application, and also it was the lowest in the saline soils with or without nitrogen application. As comparing with the nitrogen application rates obtained by the existing nitrogen recommendation method, optimal nitrogen application rates estimated by the standardization of nitrogen application efficiency rate, environmental index, and rice quality were 1.0 fold in the well adapted soil and sandy soil fields, 0.92 fold in the immatured soil field, and 0.83 fold in the saline soil field.