• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.53 no.1
• /
• pp.50-57
• /
• 2008

Winter season cultivation of rye as green manure for soybean have been a favorite with farmer because it could remove a risk of injury by continuous cropping and increase N uptake and yield of soybean. Effects of rye green manure on soybean N uptake, $N_2$ fixation and yield were investigated with $^{15}N$ as pot experiment in greenhouse in 2004 and field in 2005, respectively. The N derived from N fertilizer ($^{15}N$) in rye green manure increased with increasing of N fertilizer rate compared to N derived from soil. N uptake and DM yield of soybean at the pot with paddy soil was higher than those at the pot with upland soil mainly due to the increase of N uptake from paddy soil. Total $^{15}N$ recovery in soil was higher at rye green manure than no green manure because $^{15}N$ applied to rye plant was remained highly as soil organic N compared to chemical N fertilizer. $^{15}N$ recovery in soybean plant increased in proportion to amounts of N fertilizer applied to rye. The N fractions from $N_2$ fixation of soybean plant at the pot experiment in 2004 ranged from 92% to 95%, on the other hand those in field experiment in 2005 ranged from 82% to 84%. Estimation of amount of $N_2$ fixation was not different between Difference method and $^{15}N$ method in 2004 and 2005.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.31 no.4
• /
• pp.423-430
• /
• 2011

This study was carried out to examine the nutritive values and quality of agricultural bag (AG-BAG) silage manufactured with corn grown in reclaimed paddy field of Sukmoon at Dangjin Province in Korea. The cultivars of silage corn used in this experiment 1 were both Kwangpyungok and P32B33. The fertilizer were applied with the amounts of customary applications (200 kg N/ha, 150 kg $P_2O_5$/ha and 150 kg $K_2O$/ha). The content of moisture in corn AG-BAG silage ranged from 68 to 79%. The pH in corn AG-BAG silage stages ranged from 3.49 to 3.65 and was not influenced by the harvest time. The contents of crude protein (CP) in corn AG-BAG silage decreased with delayed harvest time. However, the contents of ADF (acid detergent fiber) and NDF (neutral detergent fiber) increased. The content of lactic acid increased with delayed harvest time, but the content of acetic acid decreased. Therefore, we suggest that the system of AG-BAG silage can improve the quality of corn silage and be one of the economical and effective methods to manufacture corn silage.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.46 no.6
• /
• pp.473-477
• /
• 2001

Chinese milkvetch (Astragalus sinicus L.) has been traditionally used as a green manure supplying mineral N and organic matters to soil. In rice-Chinese milkvetch interrelay cropping system, three rice cultivating methods (no-till direct seeding, no-till transplanting, and tillage transplanting) were evaluated for stand reestablishment without reseeding Chinese milkvetch with two cropping times (May 25 and June 4) for two years. Chinese milkvetch incorporated was decomposed rapidly in the first week. Decomposition was fast in topsoil than in subsoil. Natural milkvetch reestablishment (NMR), following harvest of no-till-direct-sown rice was good enough to cover the paddy field in both cropping times, but rice yield of this method was lower than that of transplanted rice on paddy field without milkvetch cultivation. Even though good NMR was secured in no-till rice transplanting, the shoot of milkvetch should be removed before machine-transplanting of rice seedlings. NMR was better in rice cropping at the mid-ripening stage of milkvetch (June 4) than at the late-bloom stage (May 25). Rice yield was higher in tillage transplanting at the mid-ripening stage of milkvetch (June 4) than in the other rice cropping method.

• Korean Journal of Soil Science and Fertilizer
• /
• v.34 no.2
• /
• pp.110-116
• /
• 2001

This experiment was carried out to investigate the effects of amount of nitrogen application with the barley straw application on the changes in soil physical and chemical properties. nutrient uptake and percentage recovery of chemical fertilizer N in the rice plant from 1997 to 1998. The soil physical properties, such as bulk density, hardness, porosity and gaseous phase were improved by barley straw application. There was also improvement or increment in the soil chemical properties, such as pH, organic matter, T-C. T-N, available $SiO_2$, exchangeable K and cation exchange capacity, but decrease in available $P_2O_5$. The $Fe^{+{+}}$ content in soil after barley straw application was high from tillering stage to panicle forming stage, but becoming lowered toward the heading stage, while $Mn^{+{+}}$ content was increased. N uptake with barley straw application was increased in the N $126kg\;ha^{-1}$ plot, but decreased in the N $141kg\;ha^{-1}$ plot. The uptake of fertilized N was continued longer in barley straw application than none-application plot. Percentage recovery of chemical fertilizer N in rice straw was around 1% at tillering stage, but was highly increasing till maximum tillering stage, while the recovery was generally low in barley straw application. Meanwhile, fertilizer P uptake in barley straw application was high, but potassium uptake was low at all different levels of N application.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.24 no.4
• /
• pp.59-68
• /
• 2016

The application of the Life Cycle Assessment (LCA) methodology to assess the environmental impact of rapeseed cultivation in winter fallow after harvesting rice was investigated and compared with barley cultivation in crop rotation system. Data for input materials were collected and analyzed by 1 ton rapeseed and barley as functional unit. For the Life Cycle Impact Assessment (LCIA) the Eco-indicator 95 method has been chosen because this is well documented and regularly applied impact method. From the comparison of impact categories such as greenhouse effect, ozone depletion, acidification, heavy metals, carcinogens, summer smog, and energy resources for 1 ton of final product, emission potential from rapeseed was higher than that from barley. The range from 65 to 96% of these potential came from chemical fertilizer. On the other hand, eutrophication potential from barley was higher than that from rapeseed, mainly came from utilizing the chemical fertilizer. During the cultivation of barley and rape, environmental burden by heavy metals was evaluated by 0.5 Pt, larger than points from other impact categories. The sum of points from all impact categories in barley and rapeseed was calculated to be 0.78 Pt and 0.82 Pt, respectively. From the sensitivity analysis for barley and rapeseed, scenario 1 (crop responses to fertilization level) showed the environmental burden was continuously increased with the amount of fertilization in barley cultivation, while it was not increased only at the optimum crop responses to fertilization in rapeseed (R3). With these results, rapeseed cultivation in winter fallow paddy contributed to the amounts of environmental burden much more than barley cultivation. It is, however, highly determined that environmental weighted point resulted from evaluating both cultivation was not significantly different.

• Economic and Environmental Geology
• /
• v.38 no.3 s.172
• /
• pp.207-219
• /
• 2005

The physical and chemical characteristics of soils in a small watershed were investigated and the effect of geology and land use on soil quality were examined by using multivariate statistical methods, principal components analysis and discriminant analysis. The soil developed from andesite had finer texture and higher contents of water extractable inorganic components, clay, and mafic minerals than the soil developed from granite. It is considered that the accumulation of salts in the farmland soils indicated by electrical conductivity, contents of cations and anions and pH was caused by fertilizer input during cultivation. The low contents of organic matter in the farmland soils was due to the enhanced oxidation of organic matter by tillage and by the harvest of crops. The contents of inorganic components are increased as following order: upland > orchard > paddy field > forest. The high contents of water soluble $SO_4\;^{2-}$ of paddy soils is due to the oxidation of sulfides mineral formed during the flooding period during the air-dry and extraction. The results of principal components analysis show the difference of soil quality was controlled by geology and land use. PCI indicate the input of fertilizer, mineral weathering and ion exchange reaction by application of nitrogenous fertilizers. The results of two discriminant analyses using water extractable inorganic components and their ratios by land use were also clearly classified by discriminant function 1 and 2. In discriminant analysis by components, discriminant function 1 indicated the effect of fertilizer application and increased as following order: upland > orchard > paddy field > forest soil. The investigated and predicted data for land use from discriminant analysis showed similar results. The discriminant analysis can be used as a useful method certifying the change of land use.

• Korean Journal of Environmental Agriculture
• /
• v.37 no.1
• /
• pp.15-20
• /
• 2018

BACKGROUND: The global mean surface temperature change for the period of 2016~2035 relative to 1986~2005 is similar for the four representative concentration pathway (RCP)'s and will likely be in the range of $0.3^{\circ}C$ to $0.7^{\circ}C$. Climate change inducing higher temperature could affect not only crop growth and yield, but also dynamics of carbon in paddy field. METHODS AND RESULTS: This study was conducted to evaluate the effect of elevated temperature on the carbon dynamics in paddy soil and rice growth. In order to control the elevated temperatures, the experiments were set up as the small scale rectangular open top chambers (OTCs) of $1m(width){\times}1m(depth){\times}1m(height)$ (Type 1), $1 m(W){\times}1m(D){\times}1.2m(H)$ (Type 2), and $1m(W){\times}1m(D){\times}1.4m(H)$ (Type 3). The average temperatures of Type 1, Type 2, and Type 3 from July 15 to October 30 were higher than the ambient temperatures at $0.4^{\circ}C$, $0.5^{\circ}C$, and $0.9^{\circ}C$, respectively. For the experiment, Wagner's pots (1/2,000 area) were placed inside chambers. The pots were filled with loamy soil, and chemical fertilizer and organic compost were applied as recommended after soil test. The pots were flooded with agricultural water and rice (Shindongjin-byeo) was planted. It was observed that TOC (total organic carbon) of the water increased by the elevated temperatures and the trend continued until the late growth stage of the rice. Soil TOC contents were reduced by the elevated temperatures. C/N ratios of the rice plant decreased by the elevated temperature treatments. Thus, it was assumed that the elevated temperatures induced to decompose soil organic matter. Elevated temperatures significantly increased the culm length (P<0.01) and culm weight (P<0.05) of rice, but the number and weight of rice panicle did not showed significant differences. CONCLUSION: Based on the results, it was suggested that the elevated temperatures had an effect on changes of soil and water carbons under the possible future climate change environment.

• Journal of Korean Society on Water Environment
• /
• v.25 no.4
• /
• pp.589-596
• /
• 2009

The spectroscopic characteristics and chemical oxygen demand (COD) oxidation efficiencies were investigated for dissolved organic matters (DOM) from diverse sources, which may indirectly affect the concentrations and the quality of DOM found in watersheds. The DOM investigated for this study showed a wide range of the percent distributions of refractory organic matter (R-OM) from 8 to 100%. Relatively high R-OM distributions were observed for the DOM with the source of head water, sediments, paddy soils, field soils, and treated sewage whereas the DOM from livestock waste, reed, weeds, algae, and attached algae exhibited lower R-OM percent distributions. The percent distribution of R-OM had positive correlations with specific UV absorbance (SUVA) and humidification indices (HIX) of DOM. The investigated DOM was classified into four different source groups (i.e., biota, vegetables, soils, sediments) by comparing the synchronous fluorescence spectra. The DOM group from biota source was characterized by a prominent presence of protein-like fluorescence (PLF) whereas fulvic-like fluorescence (FLF) was additionally observed for vegetable-source DOM. FLF became significant for the DOM from both soils and sediments although no PLF was found for soil-derived DOM. A range of COD oxidation efficiency was observed for the various DOM, ranging from 36 to 94% and from 65 to 125% for $COD_{Mn}$ and $COD_{Cr}$, respectively. The results indicate that $COD_{Cr}$ reflects the higher OM concentration than $COD_{Mn}$. However, 95% confidence intervals of the COD oxidation efficiencies were similar for the two types of COD, suggesting that $COD_{Cr}$ may not be the superior OM index to $COD_{Mn}$ in terms of the variability of the oxidation efficiency. No significant correlations were obtained between COD oxidation efficiencies and the spectroscopic characteristics of DOM for this study.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.64 no.3
• /
• pp.176-184
• /
• 2019

The rice variety Chucheongbyeo is mostly cultivated for organic farming in the central region of Korea. This variety is more delicate than the recently developed varieties in rice yield, quality, and pest resistance, and is therefore, not suitable for organic farming. This study was conducted to select suitable varieties for organic rice farming in the central plain area of Korea. We tested 15 different varieties in the organic paddy field of Cheongju city from 2011 to 2013. As the experimental field had good fertility because it had been organically managed for many years, culm length and number of panicles developed better than the varietal characteristics. Daebo, Chinnong and Hyeonpum had slightly lower ripened grain ratio than Chucheongbyeo. The milled rice yield of Samkwang, Sukwang, Haiami, Cheonghaejinmi and Daebo increased by 9-18% compared to that of Chucheongbyeo. The protein content was under 7% for Cheongnam, Sukwang, Daebo, Samkwang, Hyeonpum, Chinnong, Chilbo, Hopyung, Hwangkeumnuri, Suryeojinmi and Jinsumi and under 6% for Sukwang and Samkwang. The whiteness was over 40 in Sukwang, Daebo, Samkwang and Jinsumi. The palatability grade and head rice ratio were good in Daebo, Sukwang, Samkwang and Jinsumi. Therefore, this study recommended Samkwang, Daebo, and Jinsumi as the optimal varieties for organic rice farming in the central plain area of Korea. These varieties could replace Chucheongbyeo, which is inferior to the recently developed varieties in terms of disease and pest resistance and yielding performance.

• Korean Journal of Environmental Agriculture
• /
• v.32 no.4
• /
• pp.323-331
• /
• 2013

BACKGROUND: Liquid pig manure(LPM) is a useful resource if it is sufficiently fermented and utilized in the agriculture; it provides nutrients to soils, circulates organic materials and replaces chemical fertilizers(CF) with reasonable costs. Currently, there are not many trials in paddy field to continuously cultivate the crops in winter and summer season using LPM. METHODS AND RESULTS: When cultivating winter forage crops (Whole-crop-barley(WCB), Rye, Triticale, Italian ryegrass(IRG)) and summer feed corns in the rice field, CF was treated with $N-P_2O_5-K_2O$(winter forage crops: 120-100-100kg/ha, summer feed corn: 200-150-150 kg/ha), and subsequently, growth, yields, feed values and chemical properties of soil were investigated. LPM-applied areas in both winter and summer forage crops showed higher plant lengths and tillers than those of CF-applied areas, but the yield in CF-applied areas was higher than that of LPM-applied areas under continuous application of 2 years. Crude protein, neutral detergent fiber(NDF), acid detergent fiber(ADF) and total digestion nutrient(TDN) in feed values showed almost similar results between LPM and CF-applied areas. EC, organic matter, available phosphate and exchangeable cations of soils after the experiment increased in LPM applied areas, and especially, the contents of available phosphate and exchangeable sodium were high. CONCLUSION(S): Considering the above results, it was concluded that if LPM are properly utilized for continuous winter and summer cultivation of feed crops at paddy field, the cultivation costs could be decreased and be helpful to the stable production of domestic feeds.