• Korean Journal of Organic Agriculture
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• v.5 no.1
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• pp.79-85
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• 1996

This experiment was carried out to investigate the effect of slow-release fertilizers on yield of radigh. Fertilizers were treated with CDU, MEISTER, Jobi Gohyungbok-hapbiryo, Kyungki Wonyebokbi 1ho, Kyungkibokbi Nojeok, Kyungki Jeonjakgo-hyungbokbi, Tradidtional manuring, and No maunring. Yields of radish were increased with slow-release fertilizers, CDU and MEISTER were effective to radish shoot, also. But analysis of chemical components of plants and soil were no difference. It was very effect to increase yields of radish, to reduce in number of supplementary manuring and laboring.

• Korean Journal of Environmental Biology
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• v.32 no.4
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• pp.327-334
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• 2014

Emission reduction of $CH_4$ (methane gas) from rice paddy soil is a very important measure for climate change mitigation in agricultural sector. In this study, we investigated the changes in crop yield and $CH_4$ emissions in response to application of biochar and fertilizers. The experimental site is located in Hwasung, Kyunggido and experimental design is the split-plot method with three replicates. Treatments included rice straw (RS) and biochar (BC) amendments nested with the conventional NPK fertilizer (NPK) and slow release fertilizer (SRF). Control was also prepared with the soil with the conventional NPK fertilization with no amendment. Measurement of $CH_4$ emission was conducted during the growing season of 2014 using a dynamic chamber method. The results showed that application of rice straw increased daily $CH_4$ emission rate by 15%, while application of biochar reduced daily $CH_4$ emission rate by 38%. When we combined biochar application with slow release fertilizer, $CH_4$ emission was reduced by 45%. Further, the crop yield was also increased in all treatments compared with the control except for the treatment of rice straw application with slow release fertilizer. Overall results imply that biochar amendment to agricultural soil can be an effective strategy to decrease annual $CH_4$ emission with no reduction in crop yield.

• Korean Journal of Organic Agriculture
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• v.5 no.2
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• pp.85-91
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• 1997

This experiment was carried out to investigate the effect of slow-release fertilizers on yield of lettuce. Fertilizers were treated with CDU, MEISTER, Jobi Gohyungbokhapbiryo, Kyungki Wonyebokbi 1ho, Kyungkibokbi Nojeok, Kyungki Jeonjakgohyungbokbi, Traditional manuring, and No manuring. Yields of Spinach was increased with slow-release fertilizers, also. But analysis of chemical components of plants and soil were no difference. It was very effect to increase yields of lettuce, to reduce in number of supplementary manuring and laboring.

• Food Science and Preservation
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• v.5 no.2
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• pp.127-132
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• 1998

In order to fad out an efficient way of topdressing nitrogen fertilizer in mulch-cropping system of onion(Allium cepa L.), solid, slow-release, and liquid forms of nitrogen fertilizers were allied to cv. 'Changnyungdaego' various number of times at different time, with 5 topdress applications of solid fertilizer serving as a control. Whole basal application of conventional solid fertilizer and 2 slow-release fertilizers were labor-saving and showed improved storage quality of bulbs, but resulted in poor plant growth and considerably low yield due to fertilizer shortage from early April. This suggests that topdress application is necessary. Liquid form of nitrogen fertilizer was more effective for plant growth and yield and saving labor than the solid form. Early applications was effective for increasing yield and storage quality of onion bulbs harvested. Thus two applications of liquid form of nitrogen fertilizer in February and March at rome month interval are recommended in mulch crowing system of onion.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.1
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• pp.8-14
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• 2013

The newly developed fertilizer is the slow-releasing fertilizer which can be used as a basal fertilizer without no additional fertilization at tillering stage. It has 30-4-6% of $N-P_2O_5-K_2O$ and was coated with mixture of LDPE (Low density polyethylene), EVA (Ethylene vinyl acetate), BDP (Bio degraded polymer), TALC and nonionic surfactant for the controlled release up to 50 days after application. Coating materials were designed to be decomposed naturally. This fertilizer can be applied directly to the seedling tray mechanically just before transplanting, resulting in significant labor saving effect. The developed slow-release fertilizer, which can replace both basal fertilization and top dressing at tillering stage by single application directly to seedling tray, showed the highest release at 14~21 days after transplanting. Considering the plant growth at different growth stages and yield, the optimal application rate of developed slow-release fertilizer was 300 g per rice nursery tray and the yield of rice at this application rate was 5.25 MT/ha. Rice quality in terms of head rice grain ratio, amylose content, whiteness, and taste value decreased as fertilization rate increased from 200 g to 500 g per nursery tray. Fertilization rate based on quantity of fertilizer ingredients (N, P, K) was reduced by 49.3% compared to the standard application rate and there was 49.2% reduction in labor input for fertilization.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.2
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• pp.108-113
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• 1997

A field experiment was conducted to evaluate effect of phosphate coated slow release fertilizer on the directly seeded rice. Odae byeo was seeded by drill under dry condition. The soil was a sandy clay loam soil located in the Experimental Farm of the Kangweon National University, Chuncheon, Kangweon-Do. The yield of rice from the urea applicated directly seeded field was 84.9% of the yield from the transplanted field, and showed no difference between split application treatments. The yield from the phosphate coated slow release fertilizer was the highest showing 110.7% of the yield from the urea application. The yield from the polymer coated slow release fertilizer was 90.4%. The yield from the organic fertilizer 400kg/10a treatment was 81.8% and was 94.8% from the organic fertilizer 600kg/10a treatment. In 1996 experiment, the yield from the phosphate coated slow release fertilizer was higher than the yield from the transplanted field. The $NO_3-N$ and $NH_4-N$ concentrations in soil solution at the depth of 15cm revealed that nitrogen leaching was the highest from the urea N40-0-30-30 treatment, and the lowest from the phosphate coated slow release fertilizer. The phosphorus concentration showed similar pattern. Therefore, use of phosphate coated slow release fertilizer increased rice yield and decreased loss of nitrogen and phosphorus loss.

• Korean Journal of Organic Agriculture
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• v.4 no.2
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• pp.86-96
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• 1995

This experiment was carried out to investigate the effect of slow-release fertilizers on yield of chinese cabbage and spinach. Fertilizers were treated with CDU, MEISTER, Jobi Gohyungbokhapbiryo, Kyungki Wonyebokbi 1ho, kyungkibokbi Nojeok, Kyungki Jeonjakgohyungbokbi, Traditional manuring, and No manuring. Yields of chinese cabbage were increased with slow-release fertilizers, and CDU was more effective to the head than to the out-leaf, especially. Spinach was increased with slow-release fertilizers, also. However, analysis of chemical components of plants and soil were no difference. It was very effective to increase yields of chinese cabbage and spinach, to reduce in number of supplementary manuring and laboring.

• 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 Environmental Agriculture
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• v.26 no.3
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• pp.228-232
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• 2007

Slow-release fertilizers (SRF) have been used to reduce nutrient loss through increasing fertilizer efficiency and to save labor. Several SRFs were developed for rice plant in Korea, but there is few for horticultural crop plants. Two slow-release complex fertilizers, 100T and 150T, which made for controlling nitrogen release time up to 100 and 150 days, respectively, were selected for the incubation test cto evaluate nitrogen (N) release rate in soil. The N of urea selected as the control was completely released within a week after application. Sixty three and 53% of total N were released from 110T and 150T of slow release fertilizers within 8th weeks after application, respectively. For pepper cultivation CF110 and CF150, new slow-release complex fertilizer, were made of mixing 40% of conventional fertilizer and 60% of 110T and 150T, respectively, based on the amount of recommended fertilizer for pepper cultivation $(N-P_2O_5-K_2O=190-112-149\;kg\;ha^{-1})$, and were totally applied before pepper transplanting in the field as the basal fertilizer. Inorganic N $(NH_4^+-N+NO_3^--N)$ concentration in soil was higher in the CF110 treatment than in the control (NPK) at all period of pepper cultivation. In the CF150 treatment concentration of inorganic N in soil was low compared to control up to 8th weeks after transplanting. However, there was no difference in plant height and nutrient content of pepper leave between CF110 treatment and the control. In comparison, plant height was significantly lower in CF150 than the control and CF110 treatments. Around 4% of fresh pepper yield was increased in CF110 compared to the control, but it was decreased to about 2% by CF150 treatment. Conclusively, CF110 form could be recommended as a slow release fertilizer for pepper cultivation.

• Resources Recycling
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• v.16 no.4
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• pp.10-16
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• 2007

As a basic study for reusing converter slag as slow-release potassium fertilizer by a sintering process, powdery converter slag and reagent grade $SiO_2\;and\;K_2CO_3$ were mixed with ball mill above 24 hours and sintered at $900^{\circ}C{\sim}1000^{\circ}C\;for\;10{\sim}60$ min. Basicity of the mixed powder was controlled to 0.7, 1.0 and 1.4 and content of $K_2O$ was fixed with 22 mass%. After sintering, property of the potassium fertilizer was investigated with X-ray diffraction pattern and ICP analysis. Also effects of basicity, sintering temperature and time on the making slow-release potassium fertilizer was investigated. Water solubility of KBO in sample were decreased with sintering time, temperature and decreased with basicity. Citric acid solubility of $K_2O$ were increased with basicity and decreased with sintering temperature.