Search

Greenhouse-gas emission factors are widely used to estimate emissions arising from a defined unit of a specific activity. Such estimates are used both for international reporting to the United Nations Framework Convention on Climate Change (UNFCCC) and for myriad national and sub-national reporting purposes (for example, European Union Emissions Trading Scheme; EU ETS). As with the other so-called "Kyoto protocol GHGs", the Intergovernmental Panel on Climate Change (IPCC) provides a methodology for national and sub-national estimation of N₂O emissions, based on the sector from which the emissions arise. The objective of this study was to develop a integrated emission factor to estimate the direct N₂O emission from an agricultural field cultivated with the red pepper, soy bean, spring cabbage, autumn cabbage and potato in 2010∼2012. Emission factor of N₂O calculated using accumulated N₂O emission, N fertilization rate, and background N₂O emission over three year experiment was 0.00596±0.001337 kg N₂O-N (N kg) -1 . More extensive studies need to be conducted to develop N₂O emission factors for other upland crops in the various regions of Korea because N₂O emission is influenced by many factors including climate characteristics, soil properties, and agricultural practices.

Environmental effect of water-saving irrigation on the emissions of greenhouse gases (GHGs) has not been well investigated. The objective of this study was to measure the effect of water-saving irrigation on GHGs as well as water use and rice production yield in paddy field condition in Korea. Four experimental runoff plots of 4x35 m in size were prepared at an existing paddy field. GHGs emission was measured during the 2012∼2013 growing seasons while a Japonica rice variety was cultivated. Four different water management methods, 1) Continuous Flooding (CF), 2) Intermittent Drainage (ID), 3) Water Saving (WS), and 4) CF+WS, were used during a rice growing season to compare the effects of water management methods on GHGs emission. CF method is flooding all the time, ID method makes paddy water drained 40 days after transplanting for about two weeks, WS method maintains 2~3 ㎝ water-level, which should be refilled when the water-level decreased to about 0 ㎝, and CF+WS method combines CF method before 30 days after transplanting (DAT) and WS method after 30 DAT. Regardless of water management methods, paddy field water was drained about 30 days before harvest. Amount of GHGs emission from WS plot was reduced by 69.3% compared to that from CF plot and by 59.0% compared to that from ID plot. Amount of GHGs emission from CF+WS plot was reduced by 60.7% compared to that from CF plot and by 47.5% compared to that from ID plot. Weed occurrence in CF+WS plots was reduced to 62.2% in comparison with the WS plot, implying that CF+WS plot showed the best effect to mitigation of the greenhouse gas emission in the atmosphere.

The level of nitrous oxide (), a long-lived greenhouse gas, in atmosphere has increased mainly due to anthropogenic sources, especially application of nitrogen fertilizers. Quantifying emission in the agricultural field is essential to develop National inventories of greenhouse gases (GHGs) emission. The objective of this study was to develop emission factor to estimate direct emission from agricultural field by measuring emissions in the red pepper cultivating field from 2010 to 2012. Emission factor of calculated from accumulated emission, nitrogen fertilization rate, and background emission was N resulted from three year experiment of the research sites. More extensive studies need to be conducted to develop emission factors for other upland crops in the various regions of Korea because emission is influenced by many factors including climate characteristics, soil properties, and agricultural practices.

To estimate greenhouse gas (GHG) emission, the inventory of rice cultivation at the farming without agricultural chemicals was established from farmers in Gunsan, Jeonbuk province in 2011∼2012. The objectives of this study were to calculate carbon footprint and analyse the major factor of GHGs. To do this, we carried out a sensitivity analysis using the analyzed main factors of GHGs and estimated the mitigation potential of GHGs. Also we suggested agricultural methods to reduce GHGs that can be appled by farmers at this region. At the farming system without agricultural chemicals, carbon footprint of rice production unit of kg was 2.15 kg CO₂.-eq. kg -1 . Although the amount of carbon dioxide (CO₂) emission was the largest among GHGs, methane (CH₄) emission had the highest contribution to carbon footprint on rice production system when it was converted to carbon dioxide equivalent (CO₂-eq.) multiplied by the global warming potential (GWP). Main source of CO₂ emission in the rice farming system without agricultural chemicals was combustion of fossil fuels used by agricultural machinery. Most of the CH₄ was emitted during rice cultivation practice and its major emission factor was flooded paddy field in anaerobic condition. Also, most of the N2O was emitted from rice cultivation process. Major sources of the N₂O emission was application of fertilizer such as compound fertilizer. As a result of sensitivity analysis in energy consumption, diesel had the highest sensitivity among the energy inputs. With the reduction of diesel consumption by 10%, it was estimated that CO₂ potential reduction was about 2.0%. With reducing application rate of compound fertilizer by 10%, the potential reduction was calculated that CO₂ and N₂O could be reduced by 0.5% and 0.9%, respectively. At the condition of 10% reduction of silicate and compost, CO₂ and CH₄ could be reduced by 1.5% and 1.6%, respectively. With 8 days more drainage than the ordinary practice, CH₄ emission could be reduced by about 4.5%. Drainage and diesel consumption were the main sources having the largest effect on the GHG reduction at the farming system without agricultural chemicals. Based on the above results, we suggest that no-tillage and midsummer drainage could be a method to decrease GHG emissions from rice production system.

This study was conducted to assess N₂O emissions in agricultural soils of Korea under the 1996 IPCC (Intergovernmental Panel on Climate Change) methodology. N₂O emissions in agricultural soils were calculated the sum of direct emission and indirect emission by the N sources and emissions by field burning of crop residues. N₂O emission was highest in animal manure as 1,547 CO₂-eq Gg. Indirect emissions by atmospheric deposition and leaching and runoff were 1,463 and 1,753 CO₂-eq Gg, respectively. N₂O emission by field burning of crop residues was highest in pepper due to the residue/crop ratio and field burning ratio.

The effects of water-saving irrigation on the emissions of greenhouse gases and the prokaryotic communities in rice paddy soils were investigated through a field experiment. In the Water-Saving (WS) irrigation, the water layer was kept at 2~3 cm while it was kept at 6 cm in the Continuousiy Flooding (CF) irrigation. A plot was treated with Intermittently Drainage (ID) that is drained as fine cracks on the floor were seen after transplanting. GHGs emission amounts from WS plots were reduced by 78.1% compared to that from CF plot and by 70.7% compared to that from ID plot, meaning that WS could help contribute to mitigation of the greenhouse gas accumulation in the atmosphere.

Rice cultivation in the paddy field and the burning of crop residues have been identified as the important sources of methane emission in agricultural sector. This study aimed at assessment of the methane emission from croplands in the year of 2011 with the IPCC guideline methodology. Methane from rice cultivation was emitted 6,813 CO₂-eq Gg in 2011. According to the water management, methane emission amounts by continuously flooded and intermittently flooded were 1,499 and 5,314 CO₂-eq Gg, respectively. Methane emission by crop residues burning was highest in red pepper and followed by rice straw, pulses and barely in 2011. Methane emission by field burning was very little compared with rice cultivation.

Recently, special attention has been given to acid rain and its problem to environment such as acid precipitation and air pollution in East Asia. In the present study, rainwater samples were collected from Apr to Nov in 2012. The samples were chemically characterized for the assessment of emission sources. Suwon and Yeoju regions, typical agricultural areas in South Korea, were chosen for study sites. Ion composition and cation-affected neutralization were determined to evaluate the contribution of cations to the acidity of rainwater. Ion and electrical conductivity between the measured and the estimated showed high correlation. The cations observed in Suwon and Yeoju were Na + > NH 4 + > K + > Ca 2+ > Mg 2+ > H + and Na + > K + > NH 4 + > Ca 2+ > Mg 2+ = H + , respectively. The anions of all sites were SO 4 2- > NO 3 - > Cl - . While the amounts of sulfate, one of the major dissolved components of rainwater, were 77.6 and 75.6 ueq L -1 in Suwon and Yeoju, the ones of NSS-SO 4 2- (Non-Sea Salt sulfate) were 83 and 82% in Suwon and Yeoju, respectively. The comparison of observed pH values (pHobs) with the theoretical pH values (pHthe) showed that the neutralization of rain water considerably went along during the study periods. The highest amounts of rainfall throughout the year in Suwon and Yeoju were 572.3 and 484.6 mm in July, and its corresponding nitrogen loadings in Suwon and Yeoju were 5.28 and 3.50 kg ha-1, respectively. The major ion contents for crop growth with SO 4 2- , Ca 2+ , K + and Mg 2+ were 51.7, 5.2, 11.8 and 1.8 kg ha -1 in Suwon and 34.2, 4.0, 4.2 and 1.1 kg ha -1 in Yeoju.

Water control is mainly one of the key factors that can affect nitrous oxide (N 2 O) emissions from soils. This study was undertaken to determine the effect of intermittent drainage compared to continuous flooding (conventional water regime) on N 2 O emission to global warming potential (GWP) with NPK (standard cultivation practice), NPK+Straw, and PK fertilizations. Nitrous oxide emission rates were collected twice a week using a closed chamber method. With continuous flooding, nitrogen (N) application increased N 2 O emission by 106.6% (0.64 kg ha -1 in NPK) with respect to the PK treatment (0.31 kg ha -1 ), and straw addition to NPK enhanced 148.3% of seasonal N 2 O flux (0.77 kg ha -1 in NPK+Straw). Although seasonal N 2 O emission slightly increased by 16.1-42.9% with intermittent irrigation, its seasonal CH 4 emission drastically reduced at 43.5-52.8% resulting in a lower GWP at 48.9-58.5% with respect to that of continuously flooded treatments (4.51 Mg CO 2 ha -1 , PK; 7.60 Mg CO 2 ha -1 , NPK; 14.55 Mg CO 2 ha -1 , NPK+Straw). Rice yield, at similar fertilization with the continuously-flooded rice field, was not affected by intermittent irrigation. Conclusively, intermittent irrigation can be very effective and a rational soil management strategy to mitigate GWP with considering rice productivity in a temperate paddy rice field like Korea.

This study was performed a comparative life cycle assessment (LCA) among three rice production systems in order to analyze the difference of greenhouse gases (GHGs) emissions and environment impacts. Its life cycle inventory (LCI) database (DB) was established using data obtained from interview with conventional, without agricultural chemical and organic farming at Gunsan and Iksan, Jeonbuk province in 2011. According to the result of LCI analysis, was mostly emitted from fertilizer production process and rice cropping phase. and were almost emitted from rice cultivation phase. The value of carbon footprint to produce 1 kg rice (unhulled) on conventional rice production system was 1.01E+00 kg -eq. and it was the highest value among three rice production systems. The value of carbon footprints on without agricultural chemical and organic rice production systems were 5.37E-01 -eq. and 6.58E-01 -eq. , respectively. Without agricultural chemical rice production system whose input amount was the smallest had the lowest value of carbon footprint. Although the yield of rice from organic farming was the lowest, its value of carbon footprint less than that of conventional farming. Because there is no compound fertilizer inputs in organic farming. Compound fertilizer production and methane emission during rice cultivation were the main factor to GHGs emission in conventional and without agricultural chemical rice production systems. In organic rice production system, the main factors to GHGs emission were using fossil fuel on machine operation and methane emission from rice paddy field.

Terrestrial ecosystem are a strong sink of carbon. Forest ecosystem, one of them, has been expected to play an important role in climate changing process by absorbing atmospheric carbon dioxide. On the other hand, agricultural ecosystem that consists mainly of annual crops is regarded as poor contributor to carbon accumulation, because its production (carbon hydrate) is decomposed into carbon at a short period, which is emitted to the atmosphere. However, it is thought that fruit tree plays a great role in decreasing atmospheric carbon dioxide concentration, same as forest. Net ecosystem exchange of (NEE) was measured to estimate carbon fixation capacity using an eddy covariance (EC) system method in 2 years from 2005 to 2006 at an apple orchard in Uiseong, Gyeongbuk. Average air temperature values were higher in 2006 than in 2005 during the dormant season, and lower by about over the growing season causing visible cold injuries. Accordingly, we investigated long-term exchange of carbon to determine how much difference of carbon fixation capacity was shown between 2006 and 2005 in terms of environmental and plant variables such as NEE, leaf area index (LAI), and Albedo. NEE was in 2005 and in 2006, respectively. Low temperature after July in 2006 decreased LAI values faster than those in 2005. Meanwhile, Albedo values were higher after July in 2006 than in 2005. These results show that the low temperature after July in 2006 apparently affected apple growth.

We established a top-down methodology to estimate carbon footprint as national mean value (reference) with the statistical data on agri-livestock incomes in 2007. We also established LCI (life cycle inventory) DB by a bottom-up methodology with the data obtained from interview with farmers from 4 large-scale farms at Gunsan, Jeollabuk-do province to estimate carbon footprint in 2011. This study was carried out to compare top-down methodology and bottom-up methodology in performing LCA (life cycle assessment) to analyze the difference in GHGs (greenhouse gases) emission and carbon footprint under conventional rice cultivation system. Results of LCI analysis showed that most of was emitted during fertilizer production and rice cultivation, whereas and were mostly emitted during rice cultivation. The carbon footprints on conventional rice production system were 2.39E+00 kg -eq. by top-down methodology, whereas 1.04E+00 kg -eq. by bottom-up methodology. The amount of agro-materials input during the entire rice cultivation for the two methodologies was similar. The amount of agro-materials input for the bottom-up methodology was sometimes greater than that for top-down methodology. While carbon footprint by the bottom-up methodology was smaller than that by the top-down methodology due to higher yield per cropping season by the bottom-up methodology. Under the conventional rice production system, fertilizer production showed the highest contribution to the environmental impacts on most categories except GWP (global warming potential) category. Rice cultivation was the highest contribution to the environmental impacts on GWP category under the conventional rice production system. The main factors of carbon footprints under the conventional rice production system were emission from rice paddy field, the amount of fertilizer input and rice yield. Results of this study will be used for establishing baseline data for estimating carbon footprint from 'low carbon certification pilot project' as well as for developing farming methods of reducing emission from rice paddy fields.

The role of inorganic nitrogen assimilation in the production of amino acids, organic acids and soluble sugars is one of the most important biochemical processes in plants, and, in order to achieve normally, nitrate uptake and assimilation is essential. For this reason, the characterization of nitrate assimilation and metabolite composition from leaves, roots and xylem sap of tomato (Solanum lycopersicum) was investigated under different nitrate levels in media. Tomato plants were grown hydroponically in liquid culture under five different nitrate regimes: deficient (0.25 and 0.75 mM NO 3 -), normal (2.5 mM NO 3 -) and excessive (5.0 and 10.0 mM NO 3 -). All samples, leaves, roots and xylem sap, were collected after 7 and 14 days after treatment. The levels of amino acids, soluble sugars and organic acids were significantly decreased by N-deficiency whereas, interestingly, they remained higher in xylem sap as compared with N-normal and -surplus. The N-excessive condition did not exert any significant changes in metabolites composition, and thus their levels were similar with N-normal. The gene expression and enzyme activity of nitrate reductase (NR), nitrite reductase (NIR) and glutamine synthetase (GS) were greatly influenced by nitrate. The data presented here suggest that metabolites, as a signal messenger, existed in xylem sap seem to play a crucial role to acquire nitrate, and, in addition, an increase in α-ketoglutarate pathway-derived amino acids under N-deficiency may help to better understand plant C/N metabolism.

For better understanding of carbon cycle dynamics of an agro-ecosystem, an accurate assessment of seasonal and daily CO 2 flux is essential to understand the relationship between various environmental factors and crop productivity. We developed the automatic sliding canopy chamber (ASCC) system that measured continuous net ecosystem productivity (NEP) over whole growing season under the natural meteorological rhythm. The ASCC was composed of two main parts which were sliding part for measuring NEP, and automatic opening and closing chamber (AOCC) for measuring soil respiration (SR) on the soil surface. The ASCC was developed by using open flow method for measuring soil CO 2 efflux. The disturbance of natural meteorological condition was minimized by opening the base frames. In the field test with barley (Hordeum vulgare L.), NEP was calculated at 140 mg CO 2 m -2 h -1 on a clear day using continuous data and eliminated the possibility of overestimate about 16% using one hour data during the day time. Unlike other small scale chamber system, installation on cropping-field made it possible to take any modifications which might be caused by natural environmental condition.

Water competition among domestic, industrial and agricultural sectors has been gradually heightened recently in Korea as the lack of water supply is expected in the near future. About 46% of nation's water use is consumed in paddy farming to produce rice. And the conservation of water resource and quality in agricultural sector is a pending issue in the nation's long term water management plan. New paddy rice farming techniques that use significantly less irrigation water are urgently required. System of Rice Intensification (SRI) that is now well known to produce more rice with less water consumption has not been tried in Korea yet. And environmental effect of SRI on greenhouse gases (GHGs) has not been well investigated. The objective of this study was to measure the effect of SRI on GHGs as well as water use and rice yield in a Korean paddy condition. Three experimental runoff plots in size were prepared at an existing paddy field. Runoff, GHGs emission and water quality were measured during the 2011 growing seasons while a Japonica rice variety was cultivated. Rice plants grew better and healthier in SRI plots than in continuously flooded (CF) and intermittently drained (ID) plots. Rice yield from SRI plots increased 112.8 (ID)~116.1 (CF)% compared with CF and ID plots. Irrigation requirement of SRI plots compared to CF plot reduced by 52.6% and ID plot reduced by 62.0%, meaning that about 37.9~47.4% of irrigation water could be saved. GHGs emission from SRI plots reduced by 71.8% compared to that from CF plot and by 18.4% compared to that from ID plot, meaning that SRI could help contribute to ease the greenhouse gas accumulation in the atmosphere. It was believed that SRI is a promising paddy farming technique that could increase rice yield, and reduce irrigation water requirement and GHGs emission not just in Korea but also other rice farming countries all over the world. However, it was recommended that long term studies under different conditions including rice variety, soil texture, water source, climate need to be conducted for reliable data for the development of environmental policies related to GHGs emission control and management.

The importance of environment-friendly agriculture is being magnified as a new growth engine industry in pursuit of low carbon, green growth policies. Since 2010, the Korean government has been promoting the supply of customized fertilizers which were manufactured based on chemical properties of agricultural soils. This aims focused to improve the efficiency of fertilizer used and to protect the agricultural environment. In order to provide technical supports for pushing ahead with the environment-friendly agriculture policies, we have estimated the effects of customized fertilization (CF) on growth and yield of rice and fertilizer reduction compared to conventional fertilization (farm practice fertilization) and single-element fertilization. In rice plant growth and rice yield, no statistically significant difference between the three fertilization treatments was observed. The fertilizer reduction rate with CF compared to conventional fertilization of investigated farms was on average 17%, which covered 6% through 33%. With split ratio, CF 70 reduced the amounts of fertilizer ingredient by 5% compare to CF 50. This paper shows that the customized fertilizer application reduced the amounts of fertilizer used in rice cultivation without decrease of yields.

This study was conducted to estimate the greenhouse gas emissions on local government levels from 1990 to 2010 using 2006 IPCC guideline methodology. To calculate greenhouse gas emissions based on the 16 local governments, emission factor and scaling factor were used with default value and activity data came from the food, agricultural, forestry and fisheries statistical yearbook of MIFAFF (Ministry for Food, Agriculture, Forestry, and Fisheries). The total emissions in crop sector gradually decreased from 1990 to 2010 due to a decline in agricultural land and nitrogen fertilizer usage. The annual average emission of greenhouse gas was the highest in Jeonnam (JN) with 1,698 Gg -eq and following Chungnam (CN), Gyungbuk (GB), Jeonbuk (JB) and Gyunggi (GG). The sum of top-six locals emission had occupied 83.4% of the total emission in cropland sector. The annual average emissions in 1990 by applying 2006 IPCC guideline were approximately 43% less than the national greenhouse gas inventory by 1996 IPCC guideline. Jeonnam (JN) province occupied also the highest results of greenhouse gas emission estimated by gas types (methane, nitrous oxide and carbon dioxide) and emission sources such as rice cultivation, agricultural soil, field burning of crop residue and urea fertilizer.

Polyethylene mulches have been used for weed control in vegetable production in Korea. One of the additional benefits associated with polyethylene mulches is soil warming. The objective of this study was to evaluate the effects of colored mulches on soil temperature change and Chinese cabbage yield. Mulch treatments were green (GV), black (BV), transparent (TV), and non-mulched (NM) soil. The highest soil-warming effect occurred under green mulch, and the lowest effect was found under black mulch. Daily mean values of soil temperature (10 cm depth) under GV were higher than in NM soil. At midday (16:00), mean soil temperature was higher by in GV, in BV, and in TV as compared to NM soil. At night (20:00-06:00), there was no significant difference in soil temperature among the treatments of different colored mulch, but soils in the mulch treatments were higher as compared to NM soil. As compared with NM, the yield of Chinese cabbage under GV, BV, and TV were higher by 6.0, 26.0, and 12.0%, respectively.

Exchangeable cations are often overestimated especially in salt-affected soils due to the presence of high levels of soluble ions in soil solution. Thus, quantitative analysis of the soil exchangeable cation based on ammonium acetate extraction method {(Exch. Cation)total} requires additional process to remove the free ions (pre-washing) in soil with distilled water or alcohol {(Exch. Cation)pw} or subtraction of the soluble ion contents from the total exchangeable cations {(Exch. Cation)ref}. In this research, we compared the three different methods for the determination of exchangeable cations in soils affected by different types of salt accumulation such as the soils from upland, plastic film house, and reclaimed tidal land. In upland soils, non-saline and non-sodic soils, the regular ammonium acetate extraction method did not have any problem to determine the content of exchangeable cations without any additional process such as the pre-washing method or the subtraction method. However, the contents of exchangeable cations in the salt-affected soils might be determined better with the pre-washing method for the plastic film house soils and with the subtraction method for the reclaimed tidal land soils containing high Na.

Copper and Zinc are essential trace elements for all living organisms. When presenting in excess amount in soils, however they can be toxic to plants. In order to examine the transfer of Cu and Zn from soils to plants and to predict their contents in plants using soil factors, we investigated total and mobile contents of Cu and Zn in soils and their uptake by lettuce (Lactuca sativa L.) in plastic film houses. Total Cu and Zn contents in soils were 17.5∼65.9 mg kg -1 (mean: 39.3 mg kg -1 ) and 63.2∼200 mg kg -1 (mean: 137 mg kg -1 ), respectively. Mobile Cu and Zn contents in soils were (0.04)∼0.55 mg kg -1 (mean: 0.18 mg kg -1 ) and (0.05)∼2.62 mg kg -1 (mean: 0.47 mg kg -1 ), respectively. Soil pH ranged from 5.4 to 7.3 and OM from 24.1 to 59.9 g kg -1 . Mean Cu contents in leaves and roots of lettuce were 9.20 and 17.2 mg kg -1 , respectively which showed that Cu was accumulated mainly in root parts of lettuce and not easily transported to leaves. In contrast, Zn was fairly evenly distributed in leaves and roots with mean values of 54.5 and 56.7 mg kg -1 , indicating relative high mobility of Zn in lettuce. Transfer factors of Cu and Zn from soil total contents to roots and leaves of lettuce (TFStR and TFStL) were between 0.1 and 1, while transfer factors from soil mobile contents to roots and leaves (TFSmR and TFS mL) were between 10 and 1000. Transfer factors of Zn were higher than those of Cu, showing Zn was more easily absorbed by plants than Cu. Cu and Zn uptake was stronger influenced by soil pH and mobile contents than total contents and OM and could be significantly described by multiple regression equations including soil pH and soil mobile contents as variables.

Organic fertilizers application has become a popular alternatives to reduce the dependence on chemical fertilizer in Korean farming systems. In this study, we evaluated the nitrogen (N) use efficiency and growth performance of Chinese cabbage grown by black vinyl mulching after application of organic and chemical fertilizers compared with no-mulching. The treatments included chemical fertilizer alone as control (NPK, N- : ), organic fertilizer alone (OF100), 70% organic fertilizer and 30% chemical fertilizer (OF70+N30), and 30% organic fertilizer and 70% chemical fertilizer (OF30+N70), which were all applied in the no-mulching plots and in plots with black vinyl mulching. Daily means soil temperature was higher in the black vinyl mulched treatments throughout the 54 days compared with no-mulched treatments. OF100 with black vinyl mulching gave highest soil inorganic N content. Also, Chines cabbage yield increased 46% by black vinyl mulched compared with no-mulching in OF100 treatment. Without mulching, N use efficiency was, 44, 26, 29, and 27% in NPK, OF100, OF70+N30, and OF30+N70, respectively. However, black vinyl mulching much more effectively increased N use efficiencies by 56, 55, 51, and 39% in the same treatments in the order as mentioned above. Conclusively, combined organic and chemical fertilizers application with black vinyl mulching could be good practical technique to reduce a amount of used nitrogen because of its greater ability to enhance N use efficiency.

The importance of environment-friendly agriculture is being magnified as a new growth engine industry in pursuit of low carbon, green growth policies. In order to provide technical supports for pushing ahead with the environment-friendly agriculture policies, we estimated the effects of customized fertilization on growth and yield of rice and fertilizer reduction compared to conventional fertilization and single-element fertilization. In rice plant growth and rice yield, no statistically significant difference between the three fertilization treatments was observed. In contrast, customized fertilization showed high disaster resistance reducing the damage caused by rice lodging during a typhoon. The average N application in farms showing high rice lodging amounted to while was known as the critical range of rice lodging in Korea. The fertilizer reduction rate of customized fertilization compared to conventional fertilization of investigated farms was on average 22.5%. We estimated the short-term effects of customized fertilization in the first year after application. In future, there is need for continuous examination of rice growth and soil environment change due to successive application of customized fertilizer.

The aim of this study was to know whether leaf nitrate can be a substitute of total leaf N to justify plant N status and how nitrate influences macro elements uptake and physiological parameters of tomato plants under different nitrogen levels. Leaf nitrate content decreased in low N, while showed similar value with the control in high N, ranging from 55 to 70 mg g -1 . Differences in nitrate supply led to nitrate-dependent increases in macro elements, particularly cations, while gradual decrease in P. Physiological parameters, photosynthesis rates and antioxidants, greatly responded in N deficient conditions rather than high N, which didn’t show any significant differences compared the control. Considering nitrogen forms and physiological parameters, total-N in tomato plants represented positive relation with growth (shoot dry weight), nitrate and CO 2 assimilation, whereas negative relation with lipid peroxidation.

Organic farming is rapidly expanding worldwide. Crop growth in organic systems greatly depends on the functions performed by soil microbes, and nutrient supply weed suppression by green manure crops input. Four red-pepper production systems were compared: 1) bare ground (conventional system); 2) hairy vetch monoculture; 3) rye monoculture; and 4) hairy vetch-rye mixture. Soil inorganic N reached the peak at 30 DAI and hairy vetch monoculture was the highest (192 mg kg -1 ) and soil total carbon was fluctuated sporadically during the experiment. Carbohydrate and phenolic compounds in soil kept significantly higher in green manure crops systems from 10 DBI to 30 DAI, however the level was the maximum at 10 DBI (carbohydrate) and 30 DAI (phenolic comounds). Incorporation of green manure crops residue enhanced soil microbial biomass C and N throughout the growing season except that MBN in rye was reduced after incorporation. Green manure crops systems suppressed weed occurrence and, in particular, it was prominent in rye monoculture. Mineral elements composition and production in red-pepper fruits were markedly decreased in green manure crops systems although hairy vetch monoculture has come close to bare ground (NPK-applied). Therefore, it was suggested that higher biomass production should be performed not only to improve soil quality and suppress weeds but to yield suitable red-pepper fruits in green manure crops-based organic farming.

The nitrogen, phosphorus, and potassium contents are the key factors to determine the quality of organic fertilizers and right amount of application for agricultural uses. The major nutrient contents in raw materials used for making organic fertilizers and products were evaluated in this study. Among the raw materials that were investigated, soybean cake gave the highest total N content at , followed by perilla cake (), rape seed oil cake (), cotton seed cake (), and rice bran (). We investigated 43 organic fertilizers and our results showed widely varied concentrations of major nutrients : total N at , total at , and total at . Our study would like to emphasize the importance of nutrient content labeling in packed organic fertilizers to be able to know its efficiency and for determining the right amount for application.

To establish the optimum nitrogen level for rice planting after Italian ryegrass cultivation, one experiment was conducted on a normal paddy soil (Jeonbug series soil taxonomy) with six different nitrogen treatments for two years from 2009 to 2010. The treatments were including no nitrogen fertilization (Free N), 50%-Basal N, 75%-Basal N, 100%-Basal N, 150%-Basal N and 100% of basal fertilization with (100%+N30-Basal N) for decomposing of Italian ryegrass stubble. The highest rice yields were 8,420 obtained by 100%-Basal N. 150%-Basal N and 100%+N30-Basal N produced a rice yield of . Those of 50%-Basal N and Free N were produced 8,020 and , respectively. The correlation between rice yield and nitrogen treatment showed a quadratic relationship in high significant. According to this regression, the highest level of nitrogen treatment was and the highest rice yield was . Nitrogen uptake rates were relatively higher with lower amounts of nitrogen fertilizer treated.