• Korean Journal of Soil Science and Fertilizer
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• v.31 no.4
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• pp.324-329
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• 1998

To investigate the changes of $NH_4-N$ in soil, nitrogen uptake by rice plant, nitrogen use efficiency and rice yield by the application of Latex Coated Urea(LCU) on direct seeding rice, rice was planted on paddy field, Jeonbuk series at the Honam area, from 1996 to 1997. Nitrogen in LCU applied as basal dressing in whole layer was dissolved almost untill non-productive stage. Thus, nitrogen deficiency symptom appeared and N in shoot was 1.75% showing 28.1 of SPAD value at heading stage. However percentage recovery of fertilizer N was higher in LCU than with urea application. Top dressing of urea at panicle initiation stage in addition to basal dressing of LCU, increased rice yield by 9%. Conventional split application of urea on the surface decreased the percentage recovery of fertilizer N to 56.9% of whole layer application plot.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.1
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• pp.50-54
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• 1991

This study was conducted to evaluate the effect of five newly developed slow-release compound fertilizer varying urea/formaldehyde mole ratios on chinese cabbage against the checked plot of straight fertilizer. The chinese cabbage was obtained the highest yield in the product V which was 1.0 mole ratio of urea/formaldehyde adding with 6.7% urea resin, however, it was lowest in the product VII which the lowest mole ratio of urea/formaldehyde and the highest amount of the resin added. The appropriate product with one basal application for chinese cabbage should be one with 76.1 % of T-N dissolution in water after 24hrs and 71.7 % of T-N dissolution in soil 100 days after treatment. The total nitrogen content of the harvest plant in the product plot was lower compared to the checked plot of N P K and the available soil phosphrous after harvest was higher than that of the checked.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.4
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• pp.237-240
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• 2000

This experiment was conducted to evaluate the effect of split application of nitrogen(N) on development of vascular bundle(VB) and yield components of rice. Two cultivars were used in this study; IR58, an indica type and Shinunbongbyeim a japonica type. The number and total cross sectional area of the VB in the peduncle and leaf blade were more and bigger in N split application than 100 percent basal fertilizer. Nitrogen split application at necknode differentiation stage increased the number and size of the VB. Nitrogen split application resulted in increased panicle number with application of N before transplanting and at tillering stage; increased spikelets number with N application at necknode differentiation stage; and increased spikelet fertility and 1000 grain weight with N application at necknode differentiation and heading stages. Grain yield increased 7-10% in N split as compared to all basal application. The total cross sectional area of VB in peduncle closely correlated with the number of spikelets per panicle. Nitrogen management can have an impact on spikelet differentiation through more and bigger VB and increase grain yield potential.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.619-622
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• 2003

The concentrations of nutrients in precipitation increased slightly from May to June and did not change afterwards. Regarding irrigation water, the nutrient concentrations were high in the early stage of rice growth but decreased during the period of mid-June to mid-July. The concentration of Tot-N in runoff water increased significantly during the period of fertilizer application (basal, tillering, and panicle fertilization) and then decreased. The concentrations of Tot-N in runoff water ranged from 0.4 to 39.8mg/L (average of 5.9mg/L). The concentration of Tot-P in runoff water ranged from 0.0004 to 0.2084mg/L (average of 0.055mg/L). The Tot-P concentrations were high only at the early stage of rice growth after fertilizer application and did not change afterwards.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.6
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• pp.499-505
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• 1992

This experiment was carried out to find out the optimum application method of slow-release fertilizer under different soil textures, clay loam(Deogpyeong series), sandy loam (Gangseo series) in the southern region(Milyang, Kyeongnam) of Korea. The fertilizers used were Chosun slow-release fertilizer(silicate latex coated fertilizer: N-P$_2$O$_{5}$-K$_2$O=18-12-13) and Meister 15 (thermoplastic resin coated fertilizer : N-P$_2$O$_{5}$-K$_2$O=14-14-14). The two whole basal application methods such as side band placement at transplanting time of rice plant(cv.Donghaebyeo) and incorporation with soil as basal were tested. The released amount of ammonium nitrogen from the soils for 4 days submerged was 95ppm in sandy loam and 60ppm in clay loam. The greenish degree of rice leaf was higher at the whole plow layer placement method than the others. The nitrogen efficiencies of the fertilizers were Meister 15 > convention > Chosun in order and between the application methods were similiar. The growth status was better at the whole plow layer placement application method of Meister 15 regardless of soils and seedling ages. The ripening ratio was increased at slow-release fertilizer application, and between application methods, whole plow layer placement was lower because of lodging damage. The yield in clay loam soil showed a significant difference between the ferilizers, but there were slight differences between the application methods and fertilizers in sandy loam soil. As a result, the slow-release fertilizer, Meister 15, applied at the whole layer showed a good rice growth and seemed a plausible fertilizing method.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.5
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• pp.306-313
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• 2002

The investigation was conducted to find out amounts and ratios of N, P and K fertilizers applied on summer Chinese cabbage in 58 farmers' fields of highland area. The application levels of N, $P_2O_5$, $K_2O$, livestock manure and lime fertilizers were 444, 188, 390, 9,920 and $2,160kg\;ha^{-1}$, respectively, for summer Chinese cabbage. The ratios of basal dressing were 48% in N, 46.6% in $K_2O$. The frequencies of top dressing both N and K were 1.7 times. The kinds of compound fertilizers were in the order of 11-10-10+3+0.3 > 11-6-6+4+13+17 > 12-9-11+3+0.3 in basal application and 18-0-18+0.3 > 13-0-13+1+0.3 > 18-0-15+0.3 in top dressing. From the surveyed results, we could estimate that total 4,347 tons of N, $P_2O_5$, and $K_2O$ fertilizers were over used for summer Chinese cabbage by farmers in highland.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.1
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• pp.104-111
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• 2007

As protein content of milled rice, generally used as a benchmark for rice eating quality, is greatly affected by N fertilization and nutrition status of rice plant, understanding its response to nitrogen rate and plant nitrogen status at different growth stage is important for recommending N fertilizer management for high quality rice production. The responses of milled-rice protein content were compared and quantified under various combinations of basal+tillering and panicle N application levels in 2001 and 2002. Protein content of milled rice was ranged from 6 to 9%, increasing significantly with increasing basal+tillering and panicle N rates. However, milled rice protein content was raised much greater by panicle N than by basal+tillering N fertilization. Even though basal+tillering N increased up to 20 kg/ha, protein content of milled rice was observed less than 7% in case that panicle N was applied below 1.8 kg/10a. Regression analysis revealed that nitrogen accumulated until harvest was partitioned with almost constant rates of 58.3% and 46.5% to panicle and milled rice, respectively. The partitioning rates was slightly but not significantly different between experimental years. Protein content of milled rice showed linear and quadratic responses to the shoot N accumulation until panicle initiation stage (PIS) ant shoot nitrogen accumulation from PIS to harvest, respectively. The increment of milled-rice protein content per unit N increase was much greater in shoot N accumulation from PIS to harvest than in that until PIS. Regardless of shoot N accumulation until PIS upto 8 kg/10a, protein content of milled rice was lower than 7% and ranged from 6.5 to 7.5% in case that shoot N accumulation from PIS to harvest was below 3.0 kg/10a and below 6.0 kg/10a respectively. It would be concluded that even under the same N accumulation until harvest milled rice protein content could be different according to the N fertilizer management and weather condition especially during ripening, providing rooms for controlling protein content by N fertilizer management without damage to grain yield.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.1
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• pp.7-10
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• 1987

This study was conducted to evaluate the effect of a newly developed paste fertilizer on rice growth. It was applied to two vars. of Taeback and Cheonma byeos as a basal treatment. It needs a unique applicator attached to transplant machine for rice plant and was injected about 3cm depth of paddy soils. The polished rice yields were obtained competitively with a 20 percent reduction of N applied with top dressing. Plant development treated paste fertilizer was good compared to control at the early growing stage, however, not different at the late growing stage. Nitrogen uptake in plant was high at the early growing stage in paste fertilizer treatment but there were no significant difference at the late growing stage.

• Korean Journal of Environmental Agriculture
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• v.37 no.4
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• pp.235-242
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• 2018

BACKGROUND: About 81% of nitrous oxide ($N_2O$) emissions from agricultural land to the atmosphere is due to nitrogen (N) fertilizer application. Mitigation of $N_2O$ emissions can be more effective in controlling biochemical processes such as nitrification and denitrification in the soil rather than decreasing fertilizer application. The use of urease inhibitors is an effective way to improve N fertilizer efficiency and reduce $N_2O$ emissions. Several compounds act as urease inhibitors, but N-(n-butyl) thiophosphoric triamide (NBPT) has been used worldwide. METHODS AND RESULTS: Hot pepper and chinese cabbage were cultivated in five treatments: standard fertilizer of nitrogen-phosphorus-potassium(N-P-K, $N-P_2O_5-K_2O$: 22.5-11.2-14.9 kg/ha for hot pepper and $N-P_2O_5-K_2O$: 32.0-7.8-19.8 kg/ha for chinese cabbage), no fertilizer, and NBPT-treated fertilizer of 0.5, 1.0, and 2.0 times of nitrogen basal application rate of the standard fertilizer, respectively in Gyeonggi-do Hwaseong-si for 2 years(2015-2016). According to application of NBPT-treated fertilizer in hot pepper and chinese cabbage, $N_2O$ emission decreased by 19-20% compared to that of the standard fertilizer plot. CONCLUSION: NBPT-treated fertilizer proved that $N_2O$ emissions decreased statistically significant in the same growth conditions as the standard fertilization in the hot pepper and chinese cabbage cultivated fields. It means that NBPT-treated fertilizer can be applied for N fertilizer efficiency and $N_2O$ emissions reduction.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.6
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• pp.460-464
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• 2007

This study was carried out to elucidate the proper split application method of nitrogen fertilizer for early dry seeding culture of rice in Honam plain area from 1997 to 1998 in Korea. Dongjinbyeo was selected as rice variety for this experiment. The rate of $160kg\;ha^{-1}$ of nitrogen was split as 40-30-30% of total nitrogen at three different application time combination ; T1) basal-5th leaf-panicle formation(PF) stage, T2) 3rd leaf-5th leaf-PF, and T3) 3rd leaf-7th leaf-PF. The content of $NH_4-N$ in soil at 5th leaf stage was higher in top dressing plots(T2, T3) compared with basal application(T1), at 7th leaf stage it was most in top dressed at 3rd leaf and 5th leaf stage, but there was no difference at heading stage. Amount of nitrogen uptake and nitrogen use efficiency was higher in the order of T3, T2 and T1(basal application). Spikelet number per unit area was more in the order of T3, T2 and T1, but rate of ripened grain and 1,000 grain weight were not significantly different among three nitrogen split application methods. Milled rice yields were higher in top dressed plots compared with basal nitrogen application plots. From the results of this experiment, reasonable nitrogen split application method for early dry seeding culture of rice could be 40-30-30% of total nitrogen at 3rd leaf, 7th leaf and panicle formation stage.