• Asian-Australasian Journal of Animal Sciences
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• v.17 no.7
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• pp.1026-1032
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• 2004

In this study, we assess the recent changes in the amount of excretion by the livestock industry, and discuss the effects of increasing the ratio of cultivated land on the reduction of surplus nitrogen from a cost-performance perspective. Nitrogen has contributed to acidification of ecosystems and nitrate concentrations in groundwater, especially in Europe. Therefore, we assessed the level of nitrogen waste from the domestic Japanese livestock industry, including cattle, swine and poultry during the period 1987-2001. This assessment assumed that 40% of the nitrogen from the domestic livestock industry was emitted as gas into the air and that 60% of the nitrogen was contained in manure used on domestic cultivated land. Nitrogen excreted from livestock, excluding gas emission, decreased by 11% from 0.504 million tons to 0.447 million tons during 1993-2001. Thus, the peak period of nitrogen excretion from livestock is already past in Japan. However, the area of cultivated land under management also decreased during 1990-2000. In addition, the area of paddy and upland fields left unplanted for a year increased during 1990-2000. Therefore, if all manure from the domestic livestock industry had been utilized on the fields as organic fertilizer, but not on arable land left uncultivated for the past year, the nitrogen per net area of cultivated land would have increased by 5%, from 125 to 131 N kg/ha, during 1990-2000. To reduce the nitrogen ratio on cultivated land through the planting of feed grain to utilize the nitrogen, a comparison of the cost performance of feed grains indicated that barley would be more suitable than wheat, rice or soybean. Had barley been planted in 100% of the land left fallow for the past year in 2000, 4% (20,000 tons) of the nitrogen from livestock waste would have been used in the harvest, and the nitrogen per land unit would have not increased but decreased from 125 to 121 N kg/ha during the same decade. Furthermore, when converted into Total Digestible Nutrients, 7% of imported feed corn could have been replaced with the harvested barley in 2000. Planting barley on this fallow land had three benefits; reducing the risk of manure overload on the land, slowing down the decrease in cultivated land, and raising the feed self-sufficiency ratio. Thus, it would be beneficial to plant feed grain such as barley in land left fallow for the past year through utilization of manure.

• Journal of Environmental Science International
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• v.28 no.12
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• pp.1061-1069
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• 2019

Common reed (Phragmites australis) is widespread in reclaimed land and wetland habitats. Every year, the common reed produces extensive colonies by means of underground rhizomes and ground-surface stolons. From an agricultural point of view, the common reed's large biomass is a good material for supplying organic matter. However, it has not yet been studied in terms of seedling production, transplanting conditions, and decomposition characteristics in reclaimed land. Seeds were harvested from the native common reed in Saemangeum, South Korea, the previous year and stored on an open field. The seeds were sowed in the greenhouse at the beginning of April. Common reed decomposition was studied from June to September, with the use of coarse mesh (5 mm) stem litterbags, on three samping dates and with five replicate packs per sample. These packs were dug in five soil condition (low-salinity topsoil, subsoil, high-salinity topsoil, subsoil, paddy topsoil) to 0.2 m and 0.4 m depth. The highest germination rate of common reed seeds was observed in non-salt solution, but the exhibited germination rate was 70% at 9.38 dS m^-1. The plant height of young reed decreased steadily with increasing salinity, but leaf number did not decrease by 9.38 dS m^-1. The survival rate of the two-year-old reed was 83.3%, which was 35% higher than that of the one-year reed. The transplant success rate was 0% in the no vinyl mulching in the soil, but the first year and second year seedlings survived rates were 63% and 83.3%, respectively, in vinyl mulching. Common reed decomposition rates were faster low salinity than high salinity. All nutrient contents were found to fluctuate significantly with time by soil conditions. We also need to study the growth rate of reed transplanting seedlings by soil moisture contents and the comparison of degradation in common reed tissues.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.1
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• pp.25-32
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• 2016

A long-term field experiment under different fertilization treatments had been conducted to explore the effects of rice yield and soil chemical properties from 1978 to 2008 in Suwon, Korea. The paddy was applied eight fertilization treatments which were F0 (no fertilizer), PK (phosphorous and potassium), NK (nitrogen and potassium), NP (nitrogen and phosphorous), NPK (nitrogen, phosphorus and potassium), NPKC (NPK with compost), NPKS (NPK with straw) and NPKL (NPK with lime). Results of 31 years experiment showed that yield index (the ratio of yield in each treatment to NPK) was the lowest in F0 (0.52) and the highest in NPKC (1.18). Yield index was gradually increased in NPKC but decreased in F0 and NK. The yield index of PK, NP, NPKS and NPKL were not changed long-term treatment. Soil acidity of NPKL showed the highest with pH 7.9, and that of other treatments ranged from pH 6.3 to 6.8. Available phosphorous content of soil was increased in all plots by long-term fertilization, was the highest in PK and NPKC. Soil organic matter was higher in NPKC (1.8%) and NPKS (1.8%) than other treatments (1.3~1.4%) in the early experiment, but that was remarkably increased in only NPKC (2.5%) according to annual long-term application. Thus we suggest that annual compost application with optimum NPK could make stable and sustainable rice production.

• Korean Journal of Environmental Agriculture
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• v.5 no.1
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• pp.11-23
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• 1986

Soils and rice plants in wastewater irrigated area of the Mangyeong River receiving waster from the Jeonju Industrial Complex and municipal sewage were sampled at two depths to assess the nature and content of Cd, Cu, Pb and Zn, particularly with respect to distance from wastewater source. For metal levels of soils in these area, no difference in the heavy metal contents between the surface and the subsurface soils was found. Total contents of Cu, Pb and Zn in soils were negatively correlated with distance from the source. A positive correlation was found between contents of total and 0.1N-HCl extractable or $1N-CH_3COONH_4$ extractable heavy metals in surface soils of these area. Total contents of heavy metals in soils were positively correlated with clay, soil organic matter and cation exchange capacity. Heavy metal contents of brown rice sampled at the Jeon-ju Industrial Complex area ranged from 0.15 to 0.91 ppm for Cd, from 1.13 to 5.68 ppm for Cu, from 0.22 to 7.16 ppm for Pb and from 11.74 to 38.66 ppm for Zn. Negative correlation was found between the contents of Cd, Cu, Pb, and Zn in the brown rice and the distance from the source. The contents of Cd, Cu and Zn in rice straw were positively correlated with those in the brown rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.562-568
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• 1995

Changes in rice yield and soil chemistry of dry seeded rice in double cropping of rice and barley were investigated at National Yeongnam Agricultural Experiment Station during 5 years (1990-1994). Barley straw added or removed dry seeding had safe rice seedling stand for good rice production. However, the coefficient of variation of seedling stand by year was higher than dry seeding in rice single crop. Rice seedling height was slightly reduced by barley straw incorporation. However, it recovered soon as rice growing progressed. Heading time delayed 4 days in flat seeding method but not in high-ridged seeding method which imply that. this is more safe seeding technology than flat seeding method. Comparing to rice single crop, barley straw added dry seeding increased rice yield by 2∼19%(Average of 5 years: 8%) from second year due to higher panicle and spikelet number. Contents of organic matter was 2.71% in 1990. In 1994, it decreased 2.61% for rice single crop, while increased 3.02% and 3.41% for barley straw removed or added field, respectively. Rice grain quality was not significantly different among cropping patterns.

• Korean Journal of Environmental Agriculture
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• v.34 no.4
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• pp.355-358
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• 2015

BACKGROUND: Changes in Korea's agricultural soil properties were analyzed at a four-year interval from 1999 to 2002 on a national scale and used as basis for the determination of the appropriate agricultural policy on maintaining food safety and soil quality. The scope of this study ideally requires sampling thousands of paddy, greenhouse, upland and orchard land across the country, however, due to limitations in economic and manpower resources, it was deemed necessary to reduce sampling site to greenhouse soil. In this study, we try to investigate the applicability of cultivated crops as criteria for selecting representing fields in greenhouse soils.METHODS AND RESULTS: Soil samples were collected from red pepper, oriental melon, watermelon and strawberry cultivated soil. Principal components analysis (PCA) was performed on soil chemical properties of the selected fields: pH, electron conductivity (EC), available phosphate (Av-P₂O₅), organic matter (OM), and exchangeable cation (Ex.-K, Ca, and Mg). Soil chemical properties of oriental melon cultivated soil was separated from red pepper, watermelon, and strawberry cultivated soil on PC1 and red pepper cultivated soil was separated from watermelon cultivated soil on PC2. Position on PC1 was strongly correlated with pH, Ex.-Ca and Ex.-Mg and position on PC2 was strongly correlated with OM and Av-P₂O₅.CONCLUSION: The soil chemical properties of greenhouse soil was assorted amongst the different crops. Therefore, the cultivated crops as a criteria for the selection of representative field in greenhouse soil would be used in the future.

• Korean Journal of Agricultural Science
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• v.38 no.4
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• pp.631-639
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• 2011

This research was conducted to investigate potential use of New Zealand spinach (Tetragonia tetragonoides) as a new vegetable crop which will be cultivating in salt-affected soils including reclaimed land. Traditionally New Zealand spinach has been studied to explore functional compound or salt removing potential. To cultivate the crop species in the salt-affected soil widely, it is essential to obtain salt and soil texture responses under the controlled environment. Fifty nine New Zealand spinach ecotypes native to Korean peninsula first collected over seashore areas, and primitive habitat soil environment was evaluated by analyzing soil chemical properties from 32 locations. Different textures of sandy, silt loam, and sandy loam soils were prepared from nearby sources of sea shore, upland and paddy soils, respectively. Target salinity levels of 16.0 dS/m, 27.5 dS/m, 39.9 dS/m, and 52.4 dS/m in electrical conductivity (ECw) were achieved by diluting of 25, 50, 75, 100% (v/v) sea water to tap water (control, 0.6 dS/m), respectively. Various measurements responding to soil texture and irrigation salinity included plant height, root length, fresh weight (FW), dry weight (DW), leaf parameters (leaf number, leaf length, leaf width), lateral branching, and inorganic ion content. was found to adapt to diverse habitats ranging various soil chemical properties including soil pH, organic matter, exchangeable bases, EC, and cation exchange capacity (CEC) in Korea. Responding to soil texture, New Zealand spinach grew better in silt loam and sandy loam soil than in sandy soil. Higher yield (FW and DW) seemed to be associated with branch number (r=0.99 and 0.99, respectively), followed by plant height (r=0.94 and 0.97, respectively) and leaf number (r=0.89 and 0.84, respectively). Plant height, FW, and DW of the New Zealand spinach accessions were decreased with increasing irrigation salinity, while root length was not significantly different compared to control. Based on previous report, more narrow spectrum of salinity range (up to 16 dS/m) needs to be further studied in order to obtain more accurate salinity responses of the plant. As expected, leaf Na content was increased significantly with increasing salinity, while K and Ca contents decreased. Growth responses to soil texture and irrigation salinity implied the potential use of New Zealand spinach as a leafy vegetable in salt-affected soil constructed with silt loam or sandy loam soils.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.2
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• pp.114-120
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• 2000

The aim of this study was to investigate the effects of slow-released nitrogen fertilizer(SRNF) on the growth and yield of rice. SRNF produced from wasted paper was applied to a clay loam paddy field comparing to urea fertilized field and only P-and K-fertilized field. Some agronomic components like as growth development and yield component were observed and physico-chemical properties of the soils were analyzed. Plant height and tiller numbers per hill showed higher in rice plant treated with SRNF than in one treated with urea at the early grow stage whereas they appeared to be all much the same at the end of growth stage. While the chlorophyll content in SRNF-treated rice shoot was higher than in urea-treated one, the photosynthetic activity in urea-treated rice shoot was slightly higher than in SRNF-treated rice. In harvested grain, the nitrogen content was higher than in SRNF treated rice than in urea treated rice, but in straws the content was less. At the harvesting stage, nitrogen uptake in grains was about 4% higher in SRNF-treated rice than in urea treated rice whereas in straws rather 20% lower. The N efficiency in SRNF treated rice was lower than in urea treated rice. In the soils treated with SRNF, pH, organic matter and phosphorus were higher than in the soils treated with urea. Total N content in SRNF treated soil was lower after experiment than in urea treated soil.

• Journal of Climate Change Research
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• v.6 no.3
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• pp.233-241
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• 2015

In 2014, the United Nations Framework Convention on Climate Change (UNFCCC) agreed to submit the Intended Nationality Determined Contributions (INDCs) at the conference of parties held in Lima, Peru. Then, the South Korean government submitted the INDCs including GHGs reduction target and reduction potential on July, 2015. The goal of this study is to predict GHGs emission and to analyze reduction potential in agricultural sector of Korea. Activity data to estimate GHGs emission was forecast by Korea Agricultural Simulation Model (KASMO) of Korea Rural Economic Institute and estimate methodology was taken by the IPCC and guideline for MRV (Measurement, Reporting and Verification) of national greenhouse gases statistics of Korea. The predicted GHGs emission of agricultural sectors from 2021 to 2030 tended to decrease due to decline in crop production and its gap was less after 2025. Increasing livestock numbers such as sheep, horses, swine, and ducks did not show signigicant impact the total GHGs emission. On a analysis of the reduction potential, GHGs emission was expected to reduce $253Gg\;CO_{2-eq}$. by 2030 with increase of mid-season water drainage area up to 95% of total rice cultivation area. The GHGs reduction potential with intermittent drainage technology applied to 10% of the tatal paddy field area, mid-drainage and no organic matter would be $92Gg\;CO_{2-eq}$. by 2030.

• Journal of the Korean Society of International Agriculture
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• v.30 no.4
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• pp.285-291
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• 2018

The System of Rice Intensification (SRI) has been spread very quickly in southern Cambodia. To understand the motivation of farmers in adapting SRI, and its benefits, we conducted an on-farm study at Popel commune, Tramkak district, Takeo province in southern Cambodia, during the 2012 and 2013 wet season. We noticed a significant difference between SRI and conventional farmers' practices (FP) in rainfed lowland rice ecosystem. Despite of low nitrogen input, without chemical fertilizers, high grain yield was achieved in SRI 1 (6.0 t ha) and SRI2-Bottom ($7.2t\;ha^{-1}$) in 2013. SRI 1 and SRI 2 of panicle and number of panicle were high than SR 3, FP 2, and FP 3 due to early transplant. Relationships between total number of spikelet and plant nitrogen were ($r^2=0.95$) highly positive at harvest. SRI fields were, most of them achieving highly superior yield and number of panicle compared to their FP fields. The results indicated that SRI practices of planting younger seedling, with organic material and topography of paddy, lead to increased grain yield.