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

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.61-61
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• 2022

For high quality bread wheat production in Korea, it is necessary to develop optimal nitrogen (N) fertilizer methods. For optimal N fertilizer, we evaluated the alteration of growth, yield, yield components and end-use qualities according to the treatment of N fertilizer amounts and timings at heading stages. Growth, yield, yield components, and end-use quality weren't altered by various timings of N fertilizer treatment conditions whereas, 1,000 grain weight and lodging degree was increased by increasing amounts of N fertilizer treatment conditions at 7 days after heading (7 DAH). Especially, lodging degree was significantly increased by 6kg/10a of N fertilizer treatment conditions at 7 DAH. The flour protein contents increased by various amounts of N fertilizer treatment conditions. However, SDS-sedimentation and bread loaf volumes were decreased by exceeding 6kg/10a of N fertilizer treatment conditions at 7 DAH. When considering the quality of bread, 6kg/10a N fertilizer treatment is best, but 3kg/10a N fertilizer treatment is more suitable for both quality and lodging at 7 DAH. Therefore, it is preferable to fertilize 3kg/10a of nitrogen at 7 DAH in addition to standard fertilizer when cultivate bread wheat.

• Korean Journal of Environmental Agriculture
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• v.42 no.1
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• pp.44-51
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• 2023

Nitrogen fertilizer is an essential macronutrient that requires repeated input for crop cultivation. Excessive use of nitrogen fertilizers can adversely affect the environment by discharging NH₃, NO, and N₂O into the air and leaching into surrounding water systems through rainfall runoff. Therefore, it is necessary to develop a technology that reduces the amount of nitrogen fertilizer used without compromising crop yields. Fertilizer deep placement could be a technology employed to increase the efficiency of nitrogen fertilizer use. In this study, a deep fertilization device that can be coupled to a tractor and used to inject fertilizer into the soil was developed. The deep fertilization device consisted of a tractor attachment part, fertilizer amount control and supply part, and an underground fertilizer input part. The fertilization depth was designed to be adjustable from the soil surface down to a depth of 40 cm in the soil. This device injected fertilizer at a speed of 2,000 m²/hr to a depth of 25 to 30 cm through an underground fertilizer injection pipe while being attached to and towed by a 62-horsepower agricultural tractor. Furthermore, it had no difficulty in employing various fertilizers currently utilized in agricultural fields, and it operated well. It could also perform fertilization and plowing work, thereby further simplifying agricultural labor. In this study, a newly developed device was used to investigate the effects of deep fertilizer placement (FDP) compared to those with urea surface broadcasting, in terms of rice and soybean grain yields. FDP increased the number of rice grains, resulting in an average improvement of 9% in rice yields across three regions. It also increased the number of soybean pods, resulting in an average increase of 23% in soybean yields across the three regions. The results of this study suggest that the newly developed deep fertilization device can efficiently and rapidly inject fertilizer into the soil at depths of 25 to 30 cm. This fertilizer deep placement strategy will be an effective fertilizer application method used to increase rice and soybean yields, in addition to reducing nitrogen fertilizer use, under conventional rice and soybean cultivation conditions.

• Journal of The Korean Society of Grassland and Forage Science
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• v.35 no.2
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• pp.87-92
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• 2015

This experiment was conducted to evaluate the effect of seeding methods and application levels of nitrogen fertilizer on the yield and forage quality of whole crop rice (WCR). The WCR variety "Namil" was directly seeded on April 25 and transplanted on May 25. Five levels of nitrogen fertilizer were applied (90, 110, 140, 170 and 200 kg/ha). There were no significant differences (p<0.05) of the emergence date, heading date and disease resistance based on the nitrogen fertilizer rates; however, the WCR became dark at higher nitrogen fertilizer rates. The plant height increased at higher nitrogen fertilizer rates and the tiller number showed the same trend. In contrast to a direct seeding method, transplanting increased the tiller number. The dry matter (DM) content did not show a certain tendency based on nitrogen fertilizer rates, while the fresh and dry matter yields increased with incremental changes of the nitrogen fertilizer rates (p<0.01), and the transplant method increased the yield size. In yield analysis, the plot direct-seeded with 140 kg N/ha and the transplanting with 170kg N/ha showed the highest yields. The crude protein (CP) content increased with higher nitrogen fertilizer rate, but there was no significant differences between transplant and direct-seeding methods. The content of ADF (acid detergent fiber) and NDF (neutral detergent fiber) increased with higher nitrogen fertilizer rate, but total digestible nutrient (TDN) content decreased with increased nitrogen levels. Although high nitrogen applications increased the fresh and DM yields, the 140 kg/ha nitrogen fertilizer level is recommended as the proper nitrogen fertilizer level, considering both yield and the environments.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.6
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• pp.345-350
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• 2006

Recently we have interest on rice products developed by environment-friendly management. The technology of paper mulching was practised without herbicide in machine transplanting cultivation of paddy. A field experiment was conducted on Gangseo series (coarse loamy, mixed, nonacid, mesic family of Aquic Fluventic Eutrochrepts) at the National Institute of Crop Science (NICS), RDA, Suwon, Gyeonggi province, Republic of Korea in 2004. This experiment was carried out to evaluate rice growth, weed control and nitrogen efficiency by the different controlled-release fertilizer levels in paper mulching transplanting. Treatments consisted of conventional fertilization, controlled-release fertilizer (100%, 80%, 60%) compared with nitrogen amount ($110kg\;ha^{-1}$) of conventional fertilization and no nitrogen plot. Mulching paper consisted of recycled paper which was coated with biodegradable plastics. There were no differences between conventional rice transplanting and paper mulching on missing hills. Weed occurrence and control were diverse and low as fertilizer amount increased. Plant height and tiller number per hill increased as fertilizer amount decreased. There were no difference between controlled-release fertilizer 80% and conventional fertilization plot on rice growth traits. Leaf color and $NH_4{^+}-N$ in soil had similar trends. There was no difference in yield between controlled-release fertilizer 80% and conventional fertilization plot. Agronomic nitrogen-use efficiency was high as fertilizer amount decreased. Therefore, these results suggested controlled-release fertilizer 80% should be optimum amount under paper mulching transplanting of rice considering weed control, rice growth and nitrogen efficiency.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.37-40
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• 2005

In order to find out better cultivation practices in mid-mountainous area to produce high quality rice, an experiment involving seven nitrogen fertilizer rates and three varieties was carried out, during past two years$(2003\~2004)$. There was an interaction effect on palatability of milled rice between nitrogen fertilizer rate and variety. The palatability of Junambyeo grown by the treatment of nitrogen fertilizer yale wasn't different across the rates significantly, but Hwayongbyeo's palatability grown by 0 kg/ha nitrogen treatment was better than 50, 70,170 kg/ha, and Sangmibyeo's palatability grown by 70 kg/ha nitrogen treatment was better than 90, 110, 140, 170 kg/ha. Amylose content of milled rice was showed without a significant difference between nitrogen fertilizer rate, but in between variety, the amylose content of Sangmibyeo was lower than Hwayongbyeo's, also Hwayongbyeo's amylose content was lower than Junambyeo's. Protein content of milled rice was showed an interaction effect between nitrogen fertilizer rate and variety. The protein content of Hwayongbyeo and Junambyeo grown by the treatment of nitrogen fertilizer rate wasn't different across the fertilizer yale significantly, but Sangmibyeo's protein content grown by 0 kg/ha nitrogen treatment was lower than the rest of treatments, and it's protein content grown by 50, 70, 90 and 110 kg/ha nitrogen treatment was lower than 140 and 170 kg/ha. Bead rice yield of milled rice grown by lower nitrogen fertilizer rate, was lower than that grown by higher nitrogen fertilizer rate. In a conclusion gathering all above the results to produce high quality rice in Mid-mountainous area, the applicative nitrogen fertilizer rate was 70 kg per ha for Sangmibyeo, 110 kg/ha for Hwayongbyeo and 140 kg/ha for Junambyeo, in considering with head rice yield, palatability, amylose${\cdot}$protein content and productivity.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.1
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• pp.84-88
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• 1997

To establish N fertilizer recommendation method based on nitrate content of the soil for the Chinese cabbage grown in the plastic film house. Chinese cabbage was grown in the pots containing the plastic film house soils with various levels of $NO_3{^-}-N$ and different levels of fertilizer N. The nitrate nitrogen showed the positive correlation with nitrogen uptake amount by plant and the negative correlation with fertilizer nitrogen use efficiency of plant. The content of nitrate nitrogen in soil for maximum yield of Chinese cabbage was 310 mg/kg. An equation for the recommendation of fertilizer N for Chinese cabbage based on $NO_3{^-}-N$ in the soil was suggested.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.2
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• pp.135-140
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• 1997

This study was conducted to investigate the effect of levels of nitrogen fertilizer on the nitrate accumulation in Italian ryegrass. Italian ryegrass was grown at the experimental field, College of Agriculture, Chonnam National University, Kwangju from September, 29, 1987 to June, 24, 1988. The experiment was arranged as a randomized complete block design with three treatment(2.5, 7.5 and 15kg-NIlOa). The results obtained are summarized as follow; Nitrate nitrogen content of the stem, leaves and whole was increased as increasing nitrogen fertilizer(P< 0.05). Total nitrogen content in the leaves was much higher than that of stem, and not significance among the levels of nitrogen fertilizer. Total water soluble carbohydrate content in stem was higher than that in the leaves and decreased after cutting as increasing nitrogen fertilizer(P < 0.05)

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

• Korean Journal of Soil Science and Fertilizer
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• v.9 no.2
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• pp.83-92
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• 1976

The relationships between various nitrogen efficiencies among 57 rice cultivars grouped into three developmental categories were investigated by simple correlation with (12kg/10a) and without nitrogen fertilizer under the field condition. The relationship showed similar in a group or among all varieties of three groups. Yield among varieties showed highly significant correlation with Fe (fertilization efficiency: yield increment/nitrogen applied), E (nitrogen efficiency for yield), Ef(efficiency of nitrogen derived from fertilizer) and Eu (fertilizer use efficiency: nitrogen derived from fertilizer divided by total nitrogen applied). The E was correlated significantly and positively with harvest index (HI), percent translocation (T) of nitrogen to ear and negatively with nitrogen uptake amount (N), nitrogen concentration in grain (GN%) and in straw (SN%). The E depends almost on Ef and only inTongil group partly on Es (efficiency of nitrogen derived from soil). The Ef contributes to Fe more than Eu does (Fe = $Ef{\cdot}Eu$). It appears that Ef and Eu increased from the old group to the recommended local varieties, but only EF and Es increased markedly when rice was developed from recommended local group to Tongil line ($indica{\times}japonica$ hybrid selction). The fact that E and Fe depend more on Ef among rice varieties is very good contrast to the result that E and Fe depend more on Es and Eu respectively among soils in the previous investigatigation. The Ef appears as the most important parameter for rice varietal selection under fertilizer application system.