• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.4
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• pp.264-268
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• 1998

The experiment was conducted to clarify irrigation requirement and percolation rate in rice paddy. The four rice cultural system of no-tin, till, transplanting, and direct seeding condition were treated in the lysimeter filled with sandy loam soil. The amounts of irrigation and soil percolation were measured daily, and irrigation requirement was estimated. The daily percolation was 19.5 l/$\textrm{m}^2$ in no-till direct seeding on flooded paddy surface, 17.4 l/$\textrm{m}^2$ in both of till-direct seeding on flooded surface and no-till transplanting, and 15.2 l/$\textrm{m}^2$ in transplanting plot. This is equivalent to 19.5, 17.4, and 15.2 mm per day, respectively. Highest irrigation requirement was 3,770 l/$\textrm{m}^2$ in no-till direct seeding plots. Others were 3,249, 2,577, and 2,321 l/$\textrm{m}^2$ in till-direct seeding, no-till transplanting and transplanting plot, respectively. The estimated irrigation requirement of no-till transplanting, till-direct seeding and no-till direct seeding was increased by 11, 37, and 59% compared to till-transplanting plot. Percolation rate of no-till transplanting, till direct seeding and no-till direct seeding was increased by 12%, 40%, and 66%, respectively compared to the till-transplanting plot. The percolation rate in paddy soil was increased greatly after reproductive stage of rice.

• Journal of The Korean Society of Grassland and Forage Science
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• v.28 no.4
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• pp.307-314
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• 2008

No comprehensive tillage system of corn (Zea mays L.) has been conducted in Korea. Therefore, this experiment was carried to determine soil characteristics, weed and forage production in tillage system of corn. Plot was allotted to one of four treatments in a randomized block design using tillage system. The four treatments were (T1) conventional tillage, plow and rotary till, (T2) rotary till, (T3) disk till, and (T4) no-till system. In soil characteristics before planting and after harvest of corn, pH and organic matter at planting date was higher than at harvest date, however, there were no difference among tillage system. Days from planting to silking of no-till was the longest among tillage system. Lodging resistance of disk and no-till were higher than conventional and rotary till due to its thicken stem diameter. Main weed in corn field are barnyard grass (Echinochloa crusgall), velvetleaf(Abutilon avicennae), crabgrass (Digitatia saguinalis), and redroot pigweed (Amaranthus retroflexus). Weed population was lower in no-till than others tillage system. Dry matter (DM) content and ear percentage of conventional and rotary till were higher than others in corn field. However, DM and total digestible nutrients (TDN) yields of disk and no-till were higher than those of conventional and rotary till. Therefore, disk and no-till are more suitable in corn silage system because of high lodging resistance and forage yield, and low weed population.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.3
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• pp.196-199
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• 2003

This experiment was conducted to evaluate the differences in physicochemical properties of soil, grain yield and milling recovery ratio and grain appearance of rice grown in long-term no-till and ordinary till systems. The paddy in no-till rice system was unploughed but straw-mulched for 15 years from 1988 to 2002 at the Experimental Paddy of Gyeongnam Agricultural Research and Extension Services, while the paddy in ordinary till system was ploughed and puddled every crop year, A 5cm organic layer was formed in 11-year no-till rice system, in which exchangeable cation and phosphate were accumulated. In no-till paddy organic matter, bulk density and solid phase of surface soil significantly increased, while pH, exchangeable cation, phosphate, liquid and gaseous phase decreased. Tillage made the very top soil soft, but made deep soil below 5cm significantly hard. In the 1st year of no-till, topsoil showed hard, but in the process of the time in no-till system, the top- and sub-soil showed softer, Yield and yield components of rice showed no differences between till- and no-till rice systems. Milling recovery ratio and grain appearance were not significantly different between no-till and till-rice systems.

• Korean Journal of Organic Agriculture
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• v.7 no.2
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• pp.153-161
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• 1999

No-till direct-sown rice-wheat relaying cropping system has major advantages such as labor and cost saving by eliminating tillage and preparation of seed bed and transplanting. In this system, rice sowing was done simultaneously wheat harvesting. A paddy field experiment was conducted to evaluate effects of no-till years on soil microbial changes and soil physico-chemical characteristics with rice growth and development. Chemical fertilizers and agricultrual chemicals was not applied in no-till system. As the year in no-till direct-sown system the air permeability was increased and after water submerging soluble nitrogen was released Aerobic microbial-n was highest in May and then decreased after water irrigation. The population of aerobic soil microorganisms were steeply decreased after water submerging Soil microorganisms was decreased with the increased the soil depth. A month was needed for the seedling establishment in a no-tillage rice-wheat cropping system. Increased cropping years improved leaf greenness and leaf area index(LAI). But stomatal conductance(Gc) was higher in conventional cultivation system than no-till system. Stomatal conductance at panicle initiation stage was increased higher in conventional condition of leaves but the difference between conventional and no-till system was increased at heading stage. In no-till 4 years condition rice grain yield was spikelet numbers per panicle.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.3
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• pp.143-152
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• 2013

No-till farming system has been extensively studied all over the world as the effective method for maintaining the soil fertility. The general advantages of this system have been well known for reducing the labor, fuel, machinery, and irrigation cost as well as for increasing the soil quality through soil aggregation, water infiltration, microbial population and etc. Recently, it becomes more popular with the increase of interest on sustainable agriculture, especially because of its higher carbon sequestration potential compared to conventional tillage. Crop residue management should be essentially included to look forward to achieving the positive effect on reduction of greenhouse gas. Nonetheless, there are also negative opinions on effect of no-till farming system. For example, some researchers reported that soil physical properties were not improved by no-till under certain soil and climatic conditions. This means no-till farming systems were strongly affected by the soil characters and climatic conditions. Therefore, the researches to meet the specific-regional characters are greatly needed in order for no-till farming system to successfully settle in Korea. The objective of the review article is to present the future direction and perspective on no-till farming system in Korea. For this purpose, we summarized the results of domestic and foreign researches about no-till farming system until now. Specifically, the chapter on foreign research consisted of four parts: positive and negative effects, the effect in paddy soil, and latest research direction (2012-2013) of no-till farming systems. Whereas, review for domestic researches was divided into two main parts: paddy and upland soils. In the final chapter, the priorities for the optimum conservation tillage in Korea were discussed and proposed through the previous researches.

• Journal of Aquaculture
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• v.15 no.1
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• pp.49-60
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• 2002

Research on practices for improving water quality in channel catfish Ictalurus punctatus ponds was conducted at the Auburn University Fisheries Research Station, Auburn, Alabama, in 1998 and 1999. The objective of this two-year study was to determine better management practices to enhance water quality and improve production efficiency. In the first year, oxidation of bottom soil by drying, tilling, and applying sodium nitrate was performed (dry-till and dry-till with sodium nitrate treatments). The second year, based on the results obtained during the first year, precipitation of phosphorus (P) from water by applying gypsum was compared to the dry-till treatment (dry-till and dry-till with gypsum treatments). Control ponds were not subjected to bottom drying, tilling, sodium nitrate, or gypsum treatment. Channel catfish fingerings were stocked at 15,000/ha. In the first year, water in ponds from dry-till and dry-till with sodium nitrate treatments had lower concentrations (P < 0.01) of soluble reactive P, nitrate ($NO_{3} ^{-}) and nitrite ($NO_{2} ^{-}) nitrogen (N), total ammonia ($NH_3$) nitrogen, total suspended solids and turbidity, and higher values of pH, Secchi disk visibility, total alkalinity, total hardness, and calcium ($Ca^{2+}) hardness than water in control ponds. Ponds of the dry-till treatment also had lower concentrations (P < 0.01) of total P and total N than control ponds. Total fish production and survival rate did not differ among the treatments (P > 0.05). The findings suggested that drying and tiling pond bosoms between crops could achieve water quality improvement. Applying sodium nitrate to dry, tilled pond bosoms did not provide water quality improvement. In the second year, the treatment with the best results from the first year, dry-till, was compared with a dry-till with gypsum treatment. Enough gypsum was applied to give a total hardness of about 200 mg/L, and gypsum was reapplied as needed to maintain the hardness. Compared to the control, dry-till and dry-till with gypsum treatments had lower concentrations (P < 0.01) of total and soluble reactive P, total N, and total $NH_3$-N, and higher concentrations (P < 0.01) of dissolved oxygen. Ponds of the duty-till with gypsum treatment also had lower concentrations (P < 0.01) of chlorophyll $\alpha$, chemical oxygen demand, and total alkalinity than the control. Total fish production and survival rate did not differ (P > 0.05) among the treatments. These findings suggest that drying and tilling pond bosoms between crops and treating low hardness waters with gypsum could achieve water Quality improvement.

• Current Research on Agriculture and Life Sciences
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• v.18
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• pp.33-42
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• 2000

A field case study was performed to investigate the effect of shallow ponding in paddy field on irrigation water requirement of direct seeded rice. In addition, an economic analysis was made to see the effect of no-till direct seeded rice on cost reduction. A field study was performed at a 2.1ha paddy field in Kimjae city, Chonbuk province from 1991 to 1999. Various direct seeding methods such as dryland seeding, wetland seeding, and no-till wetland seeding were introduced. Then, cost reductions due to the direct seeding and no-till were calculated. In addition, to investigate the effect of shallow ponding on irrigation water requirement, field measurements such as irrigation water volume, drainage water volume, rainfall depth, and ponding depth, were made at a 40a plot within the same area in 1988 and 1990. The results of the shallow ponding study showed that the irrigation water depth, rainfall, and the drainage depth were 379mm, 458mm, and 448mm in 1988 growing season, and 274mm, 819mm, and 736mm in 1990, respectively. The shallow ponding irrigation method saved irrigation water by about 20% with higher yield compared with the traditional method. The economic analysis showed that won \640,000 per ha can be saved by direct seeding due to no nursery cost, and \1,220,000 per ha due to no-till and no nursery cost. The yields ranged 540 to 640 kg per 10a during the study period with an average of 590kg per 10a. If these cropping techniques with no-till direct seeding and shallow ponding depth for rice cropping prove to be advantageous with further study, they can be adopted for the most of the paddy fields in Korea.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.1
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• pp.98-105
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• 1997

Sudax fodder (Sorghum sudanense ${\times}$ Sorhum vulgare) was ensiled in laboratory silos with or without 20, 30, or 40 percent broiler litter and 6 percent molasses with or without Candida yeast. The samples were analyzed for pH, lactic acid and nitrogen fractions at the start of the experiment and at 5 days interval, thereafter till 40 days. A sharp decline in pH and increase in lactic acid content was observed on fifth day of ensiling. Thereafter, the rate of pH decline decreased till 20 days and that of lactic acid increase till 25 days and the remained constant. Increasing levels of broiler litter had adverse effect on pH drop and lactic acid increase of silages. Total-N content of the silages had little variation throughout the ensiling period. A sharp decline in protein-N and increase in ammonia-N content was observed on day 5 of ensiling. Thereafter, the content of protein-N increased till 20 days and that of ammonia-N decreased till 15 days, but these changes were very small compared to that occurred during the first 5 days of ensiling. The level of broiler litter had inverse relationship with protein degradation and direct relationship with ammonia production. The yeast inoculum failed to produce any significant effect.

• Geomechanics and Engineering
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• v.2 no.2
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• pp.107-123
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• 2010

Ground settlements and pore pressure changes were monitored around a shallow tunnel constructed in clay till during the excavation and primary lining installation. The settlements above the tunnel continued to develop for up to 100 days after the primary lining installation. Triaxial compression tests were carried out to estimate the short-term and long-term deformation characteristics of the till. Numerical simulation was conducted to history match the field measurements, and thus, to quantify the settlements induced by ground stress relief, consolidation and creep. It was found that the surface settlements due to ground stress relief, consolidation and creep are 17, 12 and 71% of total settlement (about 44 mm), respectively. In addition, early installation of rigid concrete lining could be an effective means to reduce the settlement due to creep.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.144-150
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• 2000

A field case study was performed to investigate optimum cropping technique of direct seeded rice. In addition, an economic analysis was made to see the effect of this method. Field study was performed at a 2.1㏊ paddy field in Kimjae city, Chonbuk province from 1991 to 1999. Various direct seeding method such as dryland seeding, wetland seeding, and no-till wetland seeding were introduced. Optimum cropping techniques such as when and how to manage the rotary till, water supply, herbicide application, and ponding depth were developed for different cropping methods. Based on this study ￦640,000 per ㏊ can be saved by direct seeding due to no nursery cost, and ￦l,220,000 per ㏊ can be saved by no-till and no nursery cost. With further study these cropping techniques including the no-till direct deeding proves to be advantageous these can be adopted for the most of the paddy fields in Korea.