• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.680-686
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• 2018

Nitrogen fertilizers, hairy vetch, and slow-release complex fertilizers were applied to the soil during the cultivation of crops. The impact of these factors on $N_2O$ emission was quantitatively assessed and the GHGs reduction effect comprehensively evaluated. Among the three factors, the significant factors affecting $N_2O$ emission were mineral nitrogen>soil moisture>temperature. Yield and fertilizer utilization efficiency were highest in the slow-release complex fertilizer treatment. There was no significant difference in $N_2O$ emissions between the slow-release complex fertilizer treatments and the NPK+hairy vetch treatments. Comprehensive results showed that slow-release complex fertilizers treatment has high yield and fertilizer utilization efficiency but low $N_2O$ emission.

• 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.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.2
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• pp.72-77
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• 1993

This study was conducted to evaluate coated urea complex fertilizer (CUC) application for rice growth and its grain quality on clay loam (Deogpyeong series) and sandy loam (Gangseo series) in southern region of Korea, 1992. The coated urea complex fertilizer used in the experiment was CUC I and II. The CUC I is a complex fertilizer consisting of 18-12-13 for $N-P_2O_5-K_2O$ including 50% of coated urea as nitrogen source, and CUC II is the same complex fertilize as mentioned above but it contains 25% of coated urea. Seventy percent of conventional fertilizer for nitrogen level was applied as basal dose of side-band placement (SBP) and whole plowlayer placement (WPP). Greenish degree of rice leaf color at the late growth stage was high in CUC plots regardless of application method and soil series. Amount of nitrogen uptaken by the rice plant at harvesting stage was mush more in the CUC treatment compared to convential fertilizer, and also much more in CUC I than that of CUC II. In the WPP on clay loam, harvest index of CUC treatment was showed very low level, which was reduced more in CUC II plot. In the CUC treatments, perfect rice grain ratio decreased remarkably, and the notched-belly rice kernel ratios among imperfect rice grain increased drastically. In rice grain, Hon-value(Mg to K.N ratio) decreased, protein and amylose contents increased in CUC application plots in WPP. In addition, gel consitency and alkali spreading value related to eating quality in CUC plots were getting longer and lower, respectively. The yield in CUC plot was similar to conventional fertilizing, but significant decreased in SBP. As a result, the rice grain quality became poor with the coated urea complex fertilizer application, but it could be improved by incorporation with fast-release fertilizer.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.4
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• pp.383-396
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• 1992

In order to find out the reasons for the excessive accumulation of certain fertilizer elements in arable land in Korea, which may be a detrimental factor for her sustainable agriculture in the future, total requirement of fertilizers were estimated from the huge number of soil test data obtained throughout the country using the fertilizer requirement models based on the soil analysis data and the concepts of multi nutrient factor balance or starter fertiliazer. The total fertilizer requirements estimated based on the present soil fertility status were much less than those estimated from the suspected cropping area of various crops cultivated depending on the conventional fertilizer recommendation for each crops or the actual amount of fertilizer elements consumed through National Agricultural Cooporative Federation(NACF). The excessive accumulation of certain fertilizer elements in arable land in Korea must be due to excessively high dose of chemical fertilizers as well as those farm wastes such as animal wasts produced unexpectedly in large amounts or crop residues. And it is suggested that the improved fertilizer recommendation must be developed in consideration both with the soil fertility status and the amounts of nutrient removal by each crop, and that the high analyzed complex fertilizers commonly used by farmers must ugently be developed in a form containing low P and K with Mg and slow release type N for the better balanced management practices of soil fertility by farmers arid for their practices of sustainable agriculture.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.6
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• pp.328-333
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• 2005

Ammonia volatilization is the major form of nitrogen (N) loss from flooded paddy soils and causes low N use efficiency. The effects of controlled release fertilizer (latex coated urea complex fertilizer, LCU) on reducing N loss by ammonia volatilization was measured comparing with urea in rice culture system of direct seeding on dry soil. In the treatment of urea, $NH_4-N$ concentration in surface water after flooding increased rapidly up to $8-10mg\;L^{-1}$ as affected by topdressing, while in the LCU treatment $NH_4-N$ concentration in surface water was less than $1mg\;L^{-1}$ during rice growing season. Relation of $NH_4-N$ concentration in surface water and ammonia volatilization was significant in urea treatment. The amount of ammonia volatilized from rice paddy of LCU treatment was $2.4-3.0kg\;ha^{-1}$ and the rate of ammonia volatilization from N fertilizer applied was only 2.0-2.3% compared with 5.9-7.9% in urea treatment. Therefore, N loss by ammonia volatilization could be reduced by 72-76% with by LCU compared with urea in rice culture system of direct seeding on dry soil.

• Korean Journal of Weed Science
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• v.10 no.2
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• pp.114-121
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• 1990

Inactivation in soil absorption, translocation of 2, 4-D by plants vary depending upon soil environments and herbicide formulations. Experiment was conducted in a glasshouse using rectangular pots($1350cm^2$) to evaluate the growth responses of barnyardgrass (Echinochloa crus-galli) and Indian jointvetch (Aesehyrcomene indica) to two formulations of 2, 4-D. The formulations used were 40% 2, 4-D amin salt (2, 4-D/AS) and 19.7% complex of rice husk lignin and 2, 4-D (2, 4-D/LG) which were applied at 200g ai/ha. Soil environments included fertilizer levels, soil pH, organic matter contents, and soil textures, Each treatment was replicated three times. The herbicidal activity of 2.4-D increased and lasted with increased levels of fertilizer. The activity also increased and lasted with low soil pH and decreased content of organic matter. Generally 2, 4-D/LG showed higher and longer herbicidal activity than 2. 4-D/AS for both test plants under all conditions applied. However, the herbicidal activity was influenced by the formulations more than by soil textures. It was thought that 2, 4-D/AS was released in a short time and inactivated readily while 2, 4-D/LG was slowly released and gave an opportunity of absorption by plants for a long period.