• Korean Journal of Soil Science and Fertilizer
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• v.37 no.3
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• pp.156-164
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• 2004

This study was conducted to evaluate the effect of the application of green manure in the form of either green barley and Chinese milkvetch in reducing the amounts of N fertilizers and conventional fertilizers needed for paddy rice. Prior to rice transplanting, the green barley and Chinese milkvetch as a green manure produced respectively $668kg\;10a^{-1}$ and 3,492kg\;$10a^{-1}$ in fresh shoot weight basis. Calculated nitrogen content from harvested green manures was 3.9 and $17.8kg\;10a^{-1}$, respectively. Plant height and tiller number of rice increased when two kinds of green manure incorporated into soil. Above mentioned parameters also increased with increasing amounts of N fertilizers at both ear formation and heading stage of rice. Rice grain number was not affected by green manures treatment but increased when N fertilizers were applied. Although rice panicle and grain number increased with green manure treatments and fertilizer applications, whereas the percentage of ripened grain decreased. Chinese milkvetch with additional N fertilizer applications increased brown rice yield from 1 to 5% compared to rice yields in plots where non-green manure with the conventional amount of fertilizer application was applied. Rice treated with Chinese milkvetch and 30% of the conventional N fertilizer rate yielded the same as rice fertilized conventionally. During the rice growing season, $NH_4-N$ content of paddy soil was higher in green manures treatment than non-green manure one. Average $NH_4-N$ content in paddy soil drastically decreased after heading stage below $5.7mg\;kg^{-1}$ in non-green manure treated plots. While on the other, $NH_4-N$ content in soil slowly decreased in plots those were treated with green manures at harvesting stage, average $NH_4-N$ content was still greater than $5.5mg\;kg^{-1}$. Nitrogen content of rice shoot and brown rice seed was higher in green manure treatment.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.2
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• pp.85-91
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• 2005

Nutrients are built up in paddy soils after greenhouse vegetable cultivations with relatively high rates of chemical fertilizers and composts during winter season, and the continuous nutrient accumulation is problematic in crop cultivation. Rice cultivation after greenhouse vegetables is one option for removing the accumulated nutrients in the soils. The object of this experiment was to examine the effect of reduced fertilization to rice on the removal of accumulated soil nutrients and rice yield in greenhouse vegetables and rice cropping system. Experiments were carried out at Changwon and Uiryeong in Gyeongnam province in 2001. The cropping systems were watermelon-rice and pumpkin-watermelon-watermelon-rice in Changwon and Uiryeong, respectively. The soils were Gangseo series (coarse loamy, mixed, nonacid, mesic family of Aquic Fluventic Eutrochrepts) at Changwon and Hampyeong series (fine loamy, mixed, mesic family of Fluvaquentic Dystrochrepts) at Uiryeong. Treatments of conventional fertilization ($N-P_2O_5-K_2O=11-4.5-5.7$, $kg\;10a^{-1}$), no basal fertilization, no top dressing, and no fertilization were included in the experiments. Plant growth and total nitrogen content in the plant were greater as the amount of fertilizer applied were increased. Whereas $SiO_2/T-N$ rate in rice plant and nitrogen use efficiency were greater as the amount of fertilizer applied were reduced. Rice yields were not significantly different among the treatments of conventional, no top-dressed, and no-basal fertilization in Uiryeong, and the rice yields were significantly also not different between the treatments of conventional and no top-dressed in Changwon. The removal of salts in soils after rice cultivation was the highest at the treatment of no-basal fertilization in both of the sites. Therefore, reduced fertilization for rice cultivation after greenhouse vegetables could remove salts accumulated in paddy soils without any significant reducing of rice yield.

• Korean Journal of Food Science and Technology
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• v.43 no.6
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• pp.683-688
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• 2011

This study was conducted to investigate the effects of different cooking methods on the nutrient composition of genetically modified (GM) provitamin A(PA)-biofortified rice. PA-biofortified rice was subjected to different cooking methods, namely boiling and a soaking, steaming and roasting process. The proximate components (starch, protein, lipid and ash) of raw PA-biofortified rice were similar to those found in the parental non-GM rice, and were not significantly affected by a conventional boiling treatment. When compared with raw rice, boiled PA-biofortified rice showed a similar nutrient composition, despite a slight reduction in a majority of its amino acid contents. However, the PA-biofortified rice that underwent the soaking/steaming/roasting process exhibited a significant reduction in a majority of its amino acids and mineral contents. This procedure also led to a significant reduction in carotenoid contents. The overall results of this study demonstrate that using a conventional boiling method for PA-biofortified rice retains nutrients better than a soaking/steaming/roasting method.

• Korean Journal of Organic Agriculture
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• v.13 no.1
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• pp.85-99
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• 2005

This trial was carried out to determine effects of organic feeds in comparison to conventional diet on feed intake, digestibility, and nitrogen retention in Korean native goats. Twelve Korean native goats were allotted to treatments in four groups of three goats and then they were housed in separate metabolism cages for 21 days. Treatments included conventional diet (A) as a control group and three organic feed groups (B: organic rice straw, C: organic nee leaves, D: organic mixture of rice straw and tree leaves). The A treatment, conventional diet, consisted of common rice straw and commercial concentrates at a proportion of 60 and 40%, respectively. All ingredients of organic feeds treatments were organically produced-agricultural products without any application of chemical fertilizer and pesticide. Four experimental diets were formulated to have the same ratio of forage to concentrate and similar contents for protein and carbohydrate across treatments and they were offered to goats ad libitum. Feed intake, apparent nutrient digestibility and nitrogen retention were investigated. For chemical compositions of experimental diets, all nutrients except crude ash and ether extract were not significantly different across treatments as we expected. Crude ash content was highest in the A treatment (P<0.05), however, it was not significantly different among organic feeds treatments. Ether extract content was higher (P<0.05) in C and D treatments than in A and B. Even if dry matter intakes for organic feeds treatments were not significantly different among them, they were significantly higher (P<0.05) compared with conventional diet. Fecal excreta were not significantly different across treatments, resulting in significantly higher digestible dry matter (g/day) in treatments of organic feeds (P<0.01). Average daily gain (ADG) and feed efficiency (FE) were more increased (P<0.01) in treatments of organic feeds compared with conventional diet. Digestibilities for most of nutrients except NFC had the same trend as ADG and FE, however, NFC digestibilities for C and D treatments were significantly lower (P<0.01) than those of A and B. Nitrogen intakes for organic feeds treatments were significantly higher (P<0.001) than conventional diet, with no difference among organic feeds treatments. Fecal nitrogen loss was higher (P<0.05) for C and D treatments than for A and B. Retained nitrogen contents were significantly higher (P<0.05) for organic feeds treatments than for conventional diet, but nitrogen retention rate did not show any difference across treatments. The results showed that organic feed supplementation more improved feed intake, digestibility and nitrogen retention in comparison with conventional diet, and thus they could be concluded that organic feeds might contribute to animal performance and a safer production of animal product.

• 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.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.4
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• pp.49-57
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• 2011

The objective of this study was to experimentally investigate the feasibility of SRI (system of rice intensification) in Korean rice farming. Eight experimental plots of $5{\times}15$ m in size were prepared on an existing rice field of loam soil. Spacing was $30{\times}15$ cm (conventional treatment: CT), $30{\times}30$ cm, $40{\times}40$ cm and $50{\times}50$ cm, respectively. CT were flooded and SRI plots irrigated intermittently 3 to 5 day interval during cultivation. Organic matter content and pH of the soil were $2.5{\pm}0.03$ % and $6.1{\times}0.2$, respectively, before the cultivation. The highest number of tillers and height of the plant were measured at $50{\times}50$ cm plots. The height and number of tillers and height in $50{\times}50$ cm plots were 10 cm and 1.5 times more than CT. Average irrigation supply to SRI and CT was 243.2 mm and 547.3 mm, respectively. It meant that the reduction of irrigation water in SRI plots over CT was estimated to 55.6 %. Therefore SRI was concluded to have a good enough possibility to be applied in South Korea because it was proven to be more effective in reduction of irrigation water and crop cultivation compare to the CT.

• Korean Journal of Environmental Agriculture
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• v.28 no.1
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• pp.53-58
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• 2009

The propose of this study was to find out optimum conditions for no-tillage rice-winter cover crops cropping system. A field research was conducted to evaluate productivity and quality of rice cultivars (Dongjinbyeo and Junambybyeo) in rice-winter cover cropping systems at Doo-ryangmyeon., Sacheon, Gyeongsangnam-do, Korea from January 2005 to October 2006. The experimental soil was Juggog series (fine silty, mesic family of Fluvaquentic Eutrndepts). The rice cultivars were experimented under some different high residue farming systems, i.e. no-tillage no treatment (NTNT), no-tillage amended with rice straw (NTRS), no-tillage amended with rye (NTR), no-tillage amended with Chinese milkvetch (NTCMV), tillage no treatment (TNT), and conventional cropping system (Control). The miss-planted rate was 8.8% in 2005 and range of 10.8% to 13.3% in 2006 at NTR, and the other treatments were carried out at miss-planted rate ranging from 1.2% to 5.0%. Tiller numbers of Junambyeo, and Dongjinbyeo in both of years were the highest in Control, and decreased nearly in NTCMV, NTR, NTRS, NTNT, and TNT in that order. The lowest grain yield was observed in TNT both cultivars due to the lower tiller numbers per area, and spikelet numbers per panicle. Also, no-tillage treatments were lower grain yield than control. On the other hand, 1,000-grain weight was lowest in control due to higher tiller numbers per area, and spikelet numbers per panicle. Ripened grain ratio was a similar aspect in all treatments. The palatability score of milled rice was lowest in control while protein content of milled rice was highest in control. The NTCMV was considered an effective sustainable farming practice for rice yield and quality.

• Korean Journal of Agricultural Science
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• v.44 no.3
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• pp.416-423
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• 2017

This study aimed to identify milling characteristics depending on the rotating speed of the main shaft of the cutting-type rice milling machine which can minimize the conventional milling process. Brown rice, which was produced in Gunsan-si, Jeollabuk-do, Republic of Korea, in 2016, was used as the experimental material. The milling characteristics of white rice were measured under four different rotating speeds of main shaft: 950 - 1,050 rpm, 1,000 - 1,100 rpm, 1,050 - 1,150 rpm, and 1,100 - 1,160 rpm. For each shaft speed, 300 kg of brown rice was processed, and the milling characteristics were measured according to the whiteness, grain temperature, cracked rice ratio, broken rice ratio, turbidity, and energy consumption. The whiteness of rice grain was found to be consistent at around $40{\pm}0.5$ only when milled at the shaft speed of 950 - 1,050 or 1,000 - 1,100 rpm. The grain temperature during the milling process increased by 11.35 to $11.85^{\circ}C$, showing little differences amongst shaft speeds. The cracked rice ratio increased by 8.2 to 10.4% at all conditions. The broken rice ratio ranged from 0.58 to 0.76%, reflecting a low level. The turbidity after milling was 54.8 ppm when milled at 1,000 - 1,100 rpm. Energy consumption of 12.98 and 12.18 kWh/ton were recorded at the shaft speed of 1,000 - 1,100 and 1,050 - 1,150 rpm, respectively. The result of this study indicates that the optimal rotating speed of main shaft would be 1,000 - 1,100 rpm for a cutting-type rice milling machine.

• Journal of the Korean Society of Food Culture
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• v.9 no.3
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• pp.241-250
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• 1994

In this study, we analyzed 2-day food records of the 1990 Korean National Nutrition Survey data for 2,000 households, and investigated most popular menu patterns by area, income, meal. The basic menu patterns of Korean, excluding side dishes, were Rice+Soup, Rice+Stew, Rice, Others, Rice+Soup+Stew in the order of proportion for all analyzed sectors. And the proportion of menus with the rice as a main dish was about 90% on the whole. The most popular menus of Korean were Rice+Soup+Kimchi(4.52%), Noodle+Kimchi(4.30%). When they ate rice as a main dish, they had soup, kimchi, and 1 or 2 other side dishes. At large cities, Noodle+Kimchi was the most frequent menu(5.20%). On the other hands, small cities and rural areas, Rice+Soup+Kimchi+Cooked vegetable was common. For the households which salaries less than 5 million won, Rice+Stew+Kimchi is the most prevalent, but households which salaries higher than 5 million won, Noodle+Kimchi was most frequent. At breakfast and dinner, the proportion of Rice+Stew+Kimchi+Cooked vegetable was 4.70%. But at lunch, Noodle+Kimchi was the most frequent and other menu combinations based on noodle were also common. Therefore most households showed conventional rice based menu patterns, but these patterns were decreasing for the large cities, and high income households. Especially at lunch, they used various menus which were not based on rice.

• Proceedings of the Korean Society of Sericultural Science Conference
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• 1997.06a
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• pp.23-49
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• 1997

This is a progress report of rice biotechnology including development of gene transformation system, gene cloning and molecular mapping in rice. The scope of the research was focused on the connection between conventional breeding and biotech-researches. Plant transformation via Agrobacterium or particle bombardment was developed to introduce one or several genes to recommended rice cultivars. Two chimeric genes containing a maize ribosome inactivating protein gene (RIP) and a gerbicide resistant gene (bar) were introduced to Nipponbare, a Japonica cultivar, and transmitted to Korean cultivars. The homozygous progenies of herbicide resistant transgenic plant showed good fertility and agronomic characters. To explore the genetic resourses in rice, over 8,000 cDNA clones from immature rice seed have been isolated and sequenced. About 13% of clones were identified as enzymes related to metabolic pathway. Among them, twenty clones have high homology with genes encoding enzymes in the photorespiratory carbon cycle reaction. Up to now about 100 clones were fully sequenced and registered at EMBL and GenBank. For the mapping of quantitative tarits loci (QTL) and eternal recombinant inbred population with 164 F13 lines (MGRI) was developed from a cross between Milyang 23 and Gihobyeo, Korean rice cultivars. After construction of fully saturated RFLP and AFLP map, quantitative traits using MGRI population were analyzed and integrated into the molecular map. Eighty seven loci were determined with 27 QTL characters including yield and yield components on rice chromosomes. Map based cloning was also tried to isolate semi-dwarf (sd-1) gene in rice. A DNA probe, RG 109, the most tightly linked to sd-1 gene was used to screen from bacterial artifical chromosome (BAC) libraries and five over lapping clones presumably containing sd-1 gene were isolated. Rice genetic database including results of biotech reasearch and classical genetics is provided at Korea Rice Genome Server which is accessible with world wide web (www) browser. The server provides rice cDNA sequences and map informations linked with phenotypic images.