• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.3
• /
• pp.332-338
• /
• 2012

Soil compaction is one of the major problems facing modern agriculture. Overuse of machinery, intensive cropping, short crop rotations, intensive grazing and inappropriate soil management leads to compaction. This study was carried out evaluate of the effects soil texture and different compaction levels within the soil profile on the soybean root growth and productivity. The soybean plants were grown in $21cm{\o}{\times}30cm$ cylinder pots using three different soil textures (clay, fine loamy and coarse loamy) compacted at different compaction levels (1.25, 1.50, 1.75, and 2.00 MPa). Results revealed that soybean development is more sensitive on penetration resistance, irrespective of soil type. Soybean yield and root weight density significantly decreases with increasing levels of soil compaction in both clayey and fine loamy soils, but not in coarse loamy soil. The highest root weight density was recorded in coarse loamy soils, followed by fine loamy and clay soils, in descending order. The root growth by soil compaction levels started to decline from 1.16, 1.28 and 1.60 MPa for clay, fine loamy and coarse loamy soils. Soybean production in the field experiment decreased about 30% at compacted sub-soils compared to undisturbed soils.

• Weed & Turfgrass Science
• /
• v.2 no.1
• /
• pp.8-14
• /
• 2013

Collection of weeds were done in 3 remodeled paddy fields located in different districts with different soil moisture conditions such as Samolpo district (14.6%), Gimhae (9.8%) and Chilhyun (5.6%). Remodeled paddy fields composed of 62 plant species belonging to 23 families. Among 23 families, Compositae was the largest family with 11 species belonged to (17.7%) followed by Poaceae with 9 species (14.5%), Leguminosae with 8 species (12.9%), Cyperaceae with 7 species (11.3%), and Polygonaceae with 5 species (8.1%). Summed dominance ratio of each species based on number, coverage, frequency, and plant height in Samolpo district was Echinochloa oryzoides (100%) > Cyperus difformis (9.0%) > Bidens frondosa (5.3%) > Panicum dichotomiflorum (4.8%) > Eclipta prostrata (4.4%). In Gimhae; Digitaria ciliaris (100%) > Panicum dichotomiflorum (49.4%) > Echinochloa oryzoides (48.8%) > Persicaria hydropiper (27.1%) > Chenopodium ficifolium (10.2%), and in Chilhyun were Panicum dichotomiflorum (90.8%) > Digitaria ciliaris (66.7%) > Cyperus iria (8.6%) > Bidens frondosa (7.6%). Total dry weight of weeds recorded was 535.4 g $m^{-2}$, 316.1 g $m^{-2}$ and 346.2 g $m^{-2}$ in Samolpo, Gimhae and Chilhyun districts, respectively. Simpson's index was calculated to 0.09~0.28, which showed that weed occurrence in remodeled paddy fields with different soil moistures varied.

• 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.

• Korean Journal of Agricultural Science
• /
• v.41 no.4
• /
• pp.327-334
• /
• 2014

Light intensity is one of the most important requirements for plant growth, affecting growth, development, survival, and crop productivity. Sunlight is the main energy source on Earth which is energy used by photosynthesis to convert light energy to chemical energy. In this study, the light use efficiency and photosynthetic characteristics of high-quality rice cultivars were evaluated after shading on ripening stage. For the study, we treated of three levels of shade (0, 50 and 70%) on rice at ripening stage and two levels of nitrogen (9 and 18 kg/10a) used three high yielding rice cultivars, such as Boramchan, Hopum, and Honong. The shade was given for the respective plots from heading up to harvesting. We were performed to determine growth survey, SPAD and chlorophyll fluorescence every 10 days interval after shading on ripening stage. At harvest stage, grain yield and yield components were determined. Results of analysis of the results representing the maximum photosynthetic efficiency of PSII, Fv/Fm, and SPAD were decreased by depending on the time at full sunlight. But shade treatments were not changed and a significant difference among cultivars did not appear. Compared with the full sunlight, shade treatments significantly delayed ripening rate and decreased rice quality of cultivated rice. Therefore, rice yield, can be reduced in proportion to the shading density is apparent, the rate of decrease was not observed difference between varieties, when protected from light 70%, and decreased to less than 50%. The adverse effects of low light intensity on the yield and yield components were not able to significantly minimize by the nitrogen level.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.40 no.11
• /
• pp.1617-1622
• /
• 2011

We conducted this study to investigate the quality characteristics of saccharified rice gruel prepared with different cereal koji mold (rice, buckwheat, sorghum, adlay, or Italian millet koji). The moisture, crude protein, crude lipid, and crude ash content of rice, buckwheat, sorghum, adlay, and Italian millet showed a range of 11.12~12.85, 5.81~16.24, 0.56~4.36, and 0.28~1.93%, respectively. The proximate composition of saccharified rice gruel prepared with different cereal koji was significantly (p<0.05) higher than unsaccharified rice gruel. The pH, L, a, and b values of saccharified rice gruel ranged between 6.09~6.39, 60.38~78.25, -0.87~5.70, and 7.74~13.37, respectively. The viscosity of saccharified rice gruel prepared with different cereal koji was significantly (p<0.05) lower than the unsaccharified rice gruel. After saccharification, the soluble solids, glucose, and maltose content of saccharified rice gruel prepared with different cereal koji were significantly increased in the range of 11.47~13.03$^{\circ}Brix$, 0.60~1.44%, and 0.47~0.88%, respectively. A sensory evaluation indicated that saccharified rice gruel was significantly (p<0.05) better than unsaccharified rice gruel. In conclusion, cereal koji could be used as a gruel processing method to increase the sensory properties and nutritional values of gruels.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.57 no.4
• /
• pp.331-336
• /
• 2012

This study was carried out to evaluate the wheat cultivation system to reduce costs and mechanize wheat production. A field study was conducted for 2 years (2009 to 2010) at the National institute of crop science, Iksan, Korea. We used working system I and working system II for the experiment. Working system I is used a multiple machine attached with a spreader tractor (seeding, fertilization, seed coverage, and weed control functionality) and working system II is used a multiple machine with a tractor which works for simultaneous job when seeding step (seeding, fertilization, and seed coverage). Sowing to harvesting operation time is 118 hours/ha for mechanize with conventional planting. Working system I is a multiple machine and a combine machine with a tractor, which worked 26 hours/ha lower than conventional planting. Working system II is 18 hours/ha lower than conventional planting. The reduced work efforts of working system I and II were 78% and 85% respectively. The growth and yield of wheat according to working system I and II is lower than conventional planting. Therefore, a multiple machine needs to study for appropriate seeding rate. Mechanization cost in consideration of the mechanical break-even point when the working system I is 3.7 ha and working system II is 4.2 ha. The farm income is enhanced by working system I (778,110 won/ha) and working system II (849,930 won/ha). The results showed that application of a multiple machine lowered costs of wheat production.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.57 no.4
• /
• pp.441-448
• /
• 2012

This study was carried out to evaluate the productivity of rice cultivation in extremely late season in Korea and to confirm the effects of pot-raising seedling culture in this case by assessing the growth and yield performance of rice cultivars that are well adapted to late culture. Suitable cultivars for extremely late culture should not have premature heading habit when transplanted around late July and also secure appropriate growth duration before heading. Geumobyeo 1 and Manjongbyeo showed small decrease in the emerged leaves in transplanting in late July or early August and heading occurred at the same time relatively without premature heading. At transplanting from late July to early August in extremely late rice cultivation, ripening was relatively good until transplanting on August 5. At transplanting on July 30, accumulated temperature from heading to the first frost was $853^{\circ}C$ and ripening was good enough. However, heading was delayed by low temperature at transplanting on August 10 and ripening was very poor due to low accumulated temperature of below $800^{\circ}C$, causing drastic decrease of rice yield. The rice yield increased in transplanting with pot seedling, especially the effects of pot seedling was higher in Geumobyeo 1, but panicle number was not enough to secure rice yield owing to short growth duration. In order to cultivate rice in extremely late season, we should select adaptive rice cultivars that have suitable growth duration and excellent ripening in low temperature. Here, pot-seedling did a great role to secure early growth and bigger growth amounts.

• Korean Journal of Food Science and Technology
• /
• v.30 no.2
• /
• pp.385-390
• /
• 1998

The effect of agglomeration treatment was examined to prevent the parched cereal powder from clumping when it is blended with water. Parched cereal powder was composed of 66.9% carbohydrate, 7% water, 12.1% crude protein, 12.1% crude fat and 1.9% ash, respectively. Particle size of parched cereal powder was generally enlarged by agglomeration treatment. This phenomenon was confirmed by particle size analyzer and microscopic observation. The color of agglomerated sample was shown to be slightly darker than the untreated sample. The water absorption indices of agglomerated samples which were steamed for 2min and re-dried were significantly increased as compared with the untreated sample. The water solubility indices of agglomerated samples showed generally lower values than those of untreated samples. In views of quality and processing time, the optimum condition of agglomeration treatment for manufacturing well-dispersable parched cereal powder in water was 15min re-drying after 2min steaming. It is concluded that the agglomeration treatment improves the dispersibility of parched cereal powder and thus facilitates the intake of it after mixing with water.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.5
• /
• pp.704-710
• /
• 2012

The lower portion of sloping paddy fields normally contains excessive moisture and the higher water table caused by the inflow of ground water from the upper part of the field resulting in non-uniform water content distribution. Four drainage methods namely Open Ditch, Vinyl Barrier, Pipe Drainage and Tube Bundle for multiple land use were installed within 1-m position from the lower edge of the upper embankment of sloping alluvial paddy fields. This study was conducted to evaluate soil physical characteristics by drainage improvement in poorly drained sloping paddy field. The results showed that subsurface drainage by Pipe Drainage improves the productivity of poorly drained soils by lowering the water table and improving root zone soil layer condition. In an Pipe drainage plot, soil moisture drained faster as compared to the other drainage methods. Infiltration rate showed high tendency to Piper Drainage method about $20.87mm\;hr^{-1}$ than in Open Ditch method $0.15mm\;hr^{-1}$. And Similarly soil water and degree of hardness and shear strength phase of soil profile showed a tendency to decrease. From the above results, we found that when an subsurface drainage was established with at 1m position from the lower edge paddy levee of the upper field in sloping poorly drained paddy fields Pipe Drainage was the most effective drainage system for multiple land use.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.5
• /
• pp.744-748
• /
• 2012

This study was carried out to investigate the incorporation effect of green manure crops (GMC) such as the hairy vetch on improvement of soil environment in reclaimed land during sorghum${\times}$sudangrass hybrid (SSH) cultivation over the past three years from 2009 to 2011. Plots consisted of conventional fertilization (CF) and incorporation of GMC were divided by rates of additional nitrogen fertilizer ($100kg\;ha^{-1}$) and decreased percentage of 30 50 70 100 fertilization in addition to non nitrogen fertilization (NNF). Soil physico-chemical properties, growth and yield potential were examined. The results were as follows. The testing soil was showed strong alkaline saline soil with low organic matter contents and less available phosphate while exchangeable sodium and magnesium were higher. Soil salinity was increased during cultivation of summer crop. However, SSH was not affected by salt content. The fresh weight of GMC at incorporation time was $18,345kg\;ha^{-1}$. Content of total nitrogen at incorporation time was 3.09% and the C/N ratio was 12.8. Fresh and dry matter yield of SSH were higher in the order of 30%, CF, N50%, N70%d, N100%, and NNF. Fresh and dry matter yield of SSH increased in the order of CF ($55,050kg\;ha^{-1}$, $16,250kg\;ha^{-1}$), N contents from 30% to 9%. Soil physical properties, such as bulk density were decrease with incoporation of GMC, while porosity was increased. Soil chemical properties, such as pH was decreased while content of exchangeable calcium, available phosphate, and organic matter were increased. Also contents of exchangeable sodium and potassium were decreased with incorporation of GMC than those before experiment. Thus, we assumed that incorporation of hairy vetch was more effective that can lead to reduce chemical nitrogen fertilizer and to improve soil environment in cultivating SSH on Saemangeum reclaimed land.