• Journal of Radiation Protection and Research
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• v.47 no.4
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• pp.195-203
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• 2022

Background: The aim of the present study was to determine radioactive concentrations in fertilizers known to contain essential nutrients. Results of this study could be used as basic data to monitor the impact of chemical fertilizers on the environment and public health. Nitrogen fertilizers, calcium fertilizers, sulfur fertilizers, phosphate acid fertilizers, and potassium chloride fertilizers were used in this study. Materials and Methods: Five chemical fertilizers were pulverized, placed in polyethylene containers, and weighed. The time to measure each specimen was set to be 3,600 seconds for a scintillator-based gamma-ray spectroscopy system. Concentration of gamma radionuclide was analyzed based on obtained spectra. At the end of the measurement, the spectrum file was stored and used to calculate radioactive concentrations using a gamma-ray spectrometer software. Results and Discussion: In the nitrogen fertilizer, 3.49 ± 5.71 Bq/kg of ¹³⁷Cs, 34.43 ± 7.61 Bq/kg of ¹³⁴Cs, and 569.16 ± 91.15 of ⁴⁰K were detected whereas ¹³¹I was not detected. In the calcium fertilizer, 5.74 ± 4.40 Bq/kg of ¹³⁷Cs (the highest concentration among all fertilizers), 22.37 ± 5.39 Bq/kg of ¹³⁴Cs, and 433.67 ± 64.24 Bq/kg of ⁴⁰K were detected whereas ¹³¹I was not detected. In the sulfur fertilizer, 347.31 ± 55.73 Bq/kg of ⁴⁰K, 19.42 ± 4.53 Bq/kg of ¹³⁴Cs, 2.21 ± 3.49 of ¹³⁷Cs, and 0.04 ± 0.22 Bq/Kg of ¹³¹I were detected. In the phosphoric acid fertilizer, 70,007.34 ± 844.18 Bq/kg of ⁴⁰K (the highest concentration among all fertilizers) and 46.07 ± 70.40 Bq/kg of ¹³⁴Cs were detected whereas neither ¹³⁷Cs nor ¹³¹I was detected. In the potassium chloride fertilizer, 12,827.92 ± 1542.19 Bq/kg of ⁴⁰K was and 94.76 ± 128.79 Bq/kg of ¹³⁴Cs were detected whereas neither ¹³⁷Cs nor ¹³¹I was detected. The present study examined inorganic fertilizers produced by a single manufacturer. There might be different results according to the country and area from which fertilizers are imported. Further studies about inorganic fertilizers in more detail are needed to create measures to reduce ⁴⁰K. Conclusion: Measures are needed to reduce radiation exposure to ⁴⁰K contained in fertilizers including phosphoric acid and potassium chloride fertilizers.

• Korean Journal of Agricultural Science
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• v.50 no.3
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• pp.437-446
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• 2023

As the interest in sustainable and environmentally friendly agriculture continues to grow, there is a corresponding increase in organic fertilizers utilization. However, studies on ammonia (NH₃) emissions, which are primarily generated in the agricultural sector, by organic fertilizers are lacking. Additionally, the reliance on imported ingredients in the production of organic fertilizers hinders the widespread adoption of organic fertilizers. This study aims to evaluate NH₃ volatilization by incorporating rice husk biochar into organic fertilizers. The study also aims to assess whether domestically produced rice husk biochar can serve as a viable substitute for imported ingredients. Here, the dynamic chamber method was used under controlled conditions. Results show that inorganic fertilizers readily undergo hydrolysis, thereby rapidly generating significant amounts of NH₃, particularly in the initial stages. In contrast, organic fertilizers decompose gradually, leading to relatively long-term NH₃ emissions. The incorporation of rice husk biochar into organic fertilizers demonstrated diminished daily NH₃ emissions compared to those from commercial organic fertilizers, resulting in decreased total NH₃ volatilization. These findings show that the combination of rice husk biochar can reduce NH₃ volatilization and serve as an alternative to imported ingredients for organic fertilizers. The results of this study can be utilized as fundamental information for the assessment of biochar as a potential ingredient for organic fertilizers.

• 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 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.

• Korean Journal of Organic Agriculture
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• v.20 no.3
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• pp.345-356
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• 2012

We conducted a survey of actual using conditions of farm-made liquid fertilizers by investigating their formulation types, materials, making processes, using methods and various beneficial effects on 29 farms certified by National Agricultural Products Quality Management Service to produce environment-friendly agricultural products in 2009. Most of the materials used to make liquid fertilizers are those that can be easily obtained around the farms. Molasses or black sugar are added as an energy source of microorganism. And leaf mold, bacterial cultures supplied by agricultural extension centers of local governments, and cultures of native microorganisms were used as microbial sources for fermenting effective microorganisms. Types of the farm-made liquid fertilizers were fermented liquid fertilizers, fermented plant juices, amino acid liquid fertilizers, calcium-liquid fertilizers, and phosphoric acid liquid fertilizers. Effects of liquid fertilizers used by the farms were found to promote plant growth by supplying nutrition, to accelerate blooming and flower bud formation, to enhance the quality of agricultural products such as increase of sugar contents and improvement of storing conditions, to induce resistance against diseases and insect pests, and to cause endurance to high temperature stress. Chemical properties of the liquid fertilizers collected were analyzed. As a result, pH and EC range showed differences according to kinds of the liquid fertilizers. Amount of macro-nutrients, such as nitrogen and phosphoric acid, in most of the collected liquid fertilizers, was found to be low. Even though the liquid fertilizers were made from same materials, their contents was found to be different depending on the making process.

• Korean Journal of Organic Agriculture
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• v.27 no.2
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• pp.205-224
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• 2019

This study was carried out in order to evaluate the growth promotion effects on tomato crops and to assess the mineral nutrient concentrations of farm-made liquid fertilizers used in organic cultivation in South Korea. We hope that this study will help to develop of a standardized manufacturing technique for these organic liquid fertilizers. We collected 62 farm-made liquid fertilizers made from various raw materials including fish, seaweed, food scraps, plant and crop by-products, and other materials. Two groups of tomato seedlings were treated at different times, one at 20 days and the other at 40 days after sowing. We used both foliar and soil applications. These seedlings were treated using liquid fertilizers at various dilution rates (x1000, x500 and x100). When foliar application was used, seedlings after 20 days had a 20-30% increase in shoot fresh weight with 47-48 fertilizers and seedlings after 40 days had a 20-30% increase in shoot fresh weight with 17-32 fertilizers. When soil application was used, seedlings after 20 days had the same increase in shoot fresh weight with 30-31 fertilizers and seedlings after 40 days also saw the same increase with 6-7 fertilizers. Therefore, our studies showed that application of liquid fertilizers to seedlings 20 days after sowing was most effective and that foliar treatment was more effective than soil treatments. We also observed that the higher the concentrations of fertilizer, particularly when applied twice rather than just once, the higher the rates of growth, which promoted shoot fresh weight more than plant height. Our results imply that mineral nutrients in liquid fertilizers seem to be the probable cause for the growth promotion observed in this study. However, more study is required to determine exactly which mineral nutrients are most effective.

• Journal of Plant Biology
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• v.9 no.1_2
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• pp.25-30
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• 1966

The writer presented in the report 7th of this series(Chong, 1959. '62 a.b. '64, '65) the result of fertlizer application on Sasamorpha purpurascens var. borealis with regards to soil conditions, climate, planting position etc. and this report is on the effectiveness of fertilizers by kinds of the new (1-year old) and old(3-to 4 years old) Phyllostachys retticulata. The ineffectiveness of fertilizers for old bamboos aged more than 8-years old has been reported previously. The study site was chosen in a bamboo groven situated at Hyunnae Ri, Okkye Myun, Myungju Gun, Kangwon Do. Each plot was so designed that only one individual remained at the center of a circular area with a dimeter of meters by eliminating the clums and severing the rhizomes, of other individuals around it. And, for the fertilizer test, 10 individuals(the new and old: 5 to 5) were observed per kind of fertilizer used; thus marking the total number of 160 plots in all. The second part of this study was conducted for the potted individuals which numbered 48, successfully established ones out of 55 the transplanted to pots. The 48 were divided into 8 treatments: whole fertilization (NPK＋compost＋human manure); NPK; N; K; Human manure; compost; and the control. Amoung of fertilizers applied was 200 grams for the natural plots and 100 grams for pot; it continued for 3 years and applied twice a year (spring and summer) following the theory of Dr. Koichi-ro Ueda(1954, '60 a.b.). Measurements were taken in August each year. The resutls were confirming the fact that the bamboos require a great deal of fertilizers. The results show the following points: 1) Fertilizers were more effective in the 3 to 4 year old bamboos. 2) The order of effectiveness of fertilizers by kind was the whole fertilization, NPK, and N treatments for Phyllostachys reticulata. 3) Organic matter in addition to commercial fertilizers showed better result than the soil application of the latter due to better soil aeration.

• Korean Journal of Agricultural Science
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• v.49 no.4
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• pp.657-666
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• 2022

Nitrogen (N) is a vital element in growing crops and is essential for improving the yield and quality of crops. Thus, N fertilizer is the most widely used fertilizer and the primary N input source in soil-crop systems. Inorganic fertilizers such as urea are known to improve crop productivity and increase soil fertility. However, application with excessive amounts can interfere with crop growth and accelerate soil acidification. For these reasons, the use of organic fertilizers, which mainly contain organic nitrogen, has gradually increased worldwide. Therefore, this study evaluated the effects of N fertilizer on the growth of Chinese cabbage including its functional compounds glucosinolates (GSLs). For the cultivation of Chinse cabbage, inorganic fertilizer was used for urea, and organic fertilizers were divided into conventional and biochar-based fertilizers. The growth parameters of Chinese cabbage treated by organic fertilizers was better than those of the inorganic fertilizers. Additionally, it was found that their co-application was more efficient. However, their GSL contents were lower with the application of the organic fertilizers. The characteristics of the experimental soil also changed according to the type, amounts and co-application of fertilizers. Therefore, this study presents the basis for an eco-friendly method that can increase the functionality and productivity of Chinese cabbage compared to conventional cultivations.

• 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 Organic Agriculture
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• v.9 no.1
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• pp.29-36
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• 2001

This study was conducted to investigate the effects of microbial fertilizers on the yield of altari radish, chemical components of plant and soil, and the microbial floras. Six microbial fertilizers, MPK＋Husk＋Palma, Husk＋Palma, MPK＋Compost, Compost, Bio livestock cattle system (BLCS) cattle dropping, and Tomi, were used in this experiment. The yield of altari radish was increased in treatments of all microbial fertilizers. The concentration of all chemical components in plant were not significantly different. Whereas the amount of $P_2$$O_{5}$ in soil was increased in Compost treatment, the other components were not significantly different compared with control. The total bacteria and bacilli in soil were increased in Tomi, Husk＋Palma, and MPK＋Husk＋Palma treatments, and actinomycete and fungi were increased in Tomi treatment.