• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.178-178
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• 2020

본 연구에서는 벼 생육시기별로 염수 관개가 벼 작물에 미치는 생육 영향정도(민감도)를 평가하기 위하여 벼 재배실험(포트실험)을 수행하였다. 벼 재배실험은 일반 논토양(삼광벼)과 간척 논토양(신동진벼)을 대상으로 하였고, 벼 생육시기는 이앙기~활착기, 활착기~유수형성기, 유수형성기~수잉기, 수잉기~출수기, 등숙기의 5단계로 구분하였다. 벼 재배는 3반복 실험을 위해 총 126개의 포트(Φ215×Φ170×210mm(H))를 조성하여 5월 20일에 1주 3본으로 이앙을 하였다. 물 관개방식은 생육시기별로 염도를 1,000, 1,500, 2,000, 2,500 ppm으로 조절한 각각의 염수를 관개하고, 그 이외의 기간에는 담수(지하수)를 관개하였다. 벼 생육시기별로 염수 관개에 의한 벼 생육에 대한 민감도를 평가하고자 벼의 초장, 분얼수, 수확량을 조사하였다. 간척 논토양에서 초장, 분얼수는 생육초기인 이앙기의 염수에 의해 가장 민감하게 영향을 받는 것으로 나타났고, 수확량은 이앙기, 분얼기, 유수형성기 순으로 민감하게 영향을 받는 것으로 나타났다. 일반 논토양에서는 초장, 분얼수는 생육시기에 따른 염수관개에 의한 영향이 크지 않았으며, 수확량은 염분농도에 관계없이 이앙기, 분얼기, 유수형성기 순으로 염수에 의해 민감하게 영향을 받는 것으로 나타났다. 이러한 결과는 다수의 선행연구(Hassen Ebrahimi 등, 2011)의 벼 생육기인 분얼기, 유수형성기의 염수 관개가 수확량에 가장 많은 영향을 받는 결과와 일치하였다. 일반 논토양과 간척 논토양 모두 이앙기, 분얼기, 유수형성기 순으로 염수 관개에 민감한 영향을 나타내고 있으며, 특히 염분 배경농도가 높은 간척토양은 저농도의 염수에서도 민감한 반응을 보이고 있는 것으로 나타나, 벼 생육초기의 관개용수 염도관리는 매우 중요하다고 판단된다.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.720-725
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• 2013

When highly shrinkable materials such as coir dust are major component of root media, the degrees of compaction during container filling of root media severely influences the physical properties of root media. It results in the changes in total porosity (TP), container capacity (CC) and air-filled porosity (AFP). This research was conducted to secure the fundamental information in changes of soil physical properties as influenced by the compaction of root media during container filling. To achieve this, three root media were formulated by blending coir dust (CD) with expanded rice hull (CD + ERH, 8:2, v/v), carbonized rice hull (CD + CRH, 6:4) and ground and raw pine bark (CD + GRPB, 8:2). Based on the optimum bulk density, the amount of root media filled into 6.0, 7.5, 8.5, 10.5 and 12.5 cm were adjusted to 90, 100, 110, 120 and 130% based on the weight of root media. Then the changes in TP, CC, and AFP were measured. Elevation of the packing amount of root media in all sizes of pot resulted in the decrease of TP. But the decrease was more severe in CD + ERH and CD + CRH than those in CD + GRPB. The CC also decreased gradually as the packing amounts were elevated in three root media, but the decreases were severe as the container sizes became larger. The AFP decreased drastically by the elevation of the packing amount of root media in all sizes of pot. The AFP was the highest in CD + CRH medium when pot sizes were smaller than 7 cm, but that was the highest in CD + ERH when the pot sizes were larger than 8.5 cm among the 3 root media tested. In this research, the elevation of packing amount of three root media influenced more severely the AFP rather than CC. This result indicates that the packing amount should be controlled to maintain appropriate level of AFP because AFP rather than CC influence severely crop growth. The results obtained through this study can be used to predict the changes in physical properties of root media as influenced by packing amount in various sizes of pots.

• Journal of Bio-Environment Control
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• v.18 no.4
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• pp.316-325
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• 2009

Adequate conditions of water content and aeration of container media are major environmental factors in the production of pot plant. This experiment was carried out to find optimum physical property of media for the production of small potted Ardisia in capillary mat irrigation system. The plant materials used in this experiment were Ardisia pusilla and Ardisia japonica. Seven substrates were formulated by blending perlite or fresh rice hulls at 20%, 40%, 60% (v/v) with sphagnum peat. Total pore space (TPS) increased by blending sphagnum peat with fresh rice hulls, but decreased by blending sphagnum peat with perlite. As fresh rice hull (FRH) and perlite content increased, air filled pore space (AFP) of substrate increased but container capacity (CC) decreased. Substrate blended with fresh rice hull was higher AFP than blended with perlite and the rate of increase was higher for FRH-containing substrate. As AFP increased, the $CO_2$ concentration in the pot decreased and the $CO_2$ concentration of substrate blended with FRH was higher than blended with perlite. The fresh and dry weight of Ardisia pusilla and A. japonica was the highest in the substrate contained 60% FRH, but the ratio of shoot dry weight to root dry weight was the lowest. The optimum total pore space, air-filled pore space, water holding capacity of substrate for the growth of Ardisia pusilla and A. japonica in the capillary mat irrigation system were 82.8%, 25.6%, and 57.2% respectively.

• Korean Journal of Ecology and Environment
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• v.37 no.2 s.107
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• pp.248-254
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• 2004

This study was conducted to investigate the effects of salinity in irrigation water on the growth, yield components, yield and grain quality of rice plant by the pot experiments. Irrigation waters were supplied with control and amended with NaCl at 1,000, 2,000, 3,000, 5,000, and 7,000 ${\mu}s\;cm^{-1}$ electrical conductivity. A randomized block design was used with four replicates for each treatment and control. As increasing salt concentration, plant height, tiller number, SPAD value, dry weight, content of N, P, and K, ripened grain ratio (%), 1,000 grain weight, and protein content (%) tended to decrease, especially, significant at 3,000 ${\mu}s\;cm^{-1}$ of salt level. Grain yield decreased significantly at all treatments. The percentage of head rice slightly tended to increase as the salt concentration due to the decrease of green kernel. The percentage of green kernel was significantly lower at 3,000 ${\mu}s\;cm^{-1}$ of salt level than the control.

• Horticultural Science & Technology
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• v.33 no.1
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• pp.47-54
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• 2015

This research was conducted to investigate the changes in moisture retention capacities of expanded rice-hull (ERH)-based root media and their influences on the growth of mother and daughter plants in vegetative propagation of 'Seolhyang' strawberry. The proportion of water at the container capacity of ERH medium was in the range of 20 to 23%. This range was lower than the 60 to 66% of strawberry-specialized medium, the 30 to 34% of soil mother material (SMM) and the 30 to 35% of loamy sand. The moisture content of ERH was reduced to 10 to 12% at 8 hours after irrigation, and there were large variations among replications of ERH medium. Among four kinds of root media formulated to contain ERH, the medium of ERH + coir dust (CD) (55 + 45%, v/v) had 26.5 and 32.5% water contents at 20 and 40 days after irrigation to daughter plants, respectively. The m edia o f ERH + sandy loam (S L) and E RH + S MM showed similar trends i n moisture r etention. The pH and EC i n the all root media tested were in the range of 6.7 to 7.1 and 0.03 to $0.08dS{\cdot}m^{-1}$, respectively. The pHs and ECs measured at 20 and 40 days after irrigation were not significantly different in each root medium. Among the root media formulated to contain ERH, the growth of daughter plants was the highest in the treatment of ERH + SL (55 + 45%, v/v). As the blending rate of coir dust was elevated in the ERH + CD media, moisture retention capacity increased gradually, but the growth of daughter plants became worse even though the medium showed higher moisture retention capacity than other root media tested. The growth of roots and aboveground tissues of daughter plants deteriorated in the root media formulated by blending ERH + perlite (PE) at various ratios. The results of this research suggest the optimum formulations of root media and management of moisture content in raising of strawberry daughter plants when ERH is a component of root media.

• Journal of Bio-Environment Control
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• v.14 no.3
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• pp.182-189
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• 2005

This research was conducted to determine physical properties of four root media, peatmoss + vermiculite (1:1, v/v; PV), peatmoss + composted rice hall (1:1, PR), peatmoss + composted saw-dust (1:1 : PS) and peatmoss + composted pine bark (1:1 PB), as influenced by incorporation rate of Stock-sorb C (STSB). Each root medium containing STSB was packed in 22 cm diameter plastic pot and the physical properties were determined at 5 weeks after packing. As incorporation rate of STSB were elevated, total porosity increased in PV, PS and PB media with statistical differences at $5{\%}$ level. Those also resulted in increase of container capacity in PS and PB media, but statistical differences were not observed in PV and PR media. Elevated incorporation rate of STSB in PV, PS and PB media resulted in increase of air space with statistical differences. Trends in air space of the three root media showed a linear as well as quadratic responses to STSB contents of media. As incorporation rate of STSB increased, more water was retained in four root media at the soil moisture tension of 4.90 kPa, 9.81 kPa, 29.4 kPa and 1.5 MPa. The amount of water retained in PS medium was the highest at the moisture tension at 29.4 kPa and 1.5 MPa followed by PB, PR and PV medium. These results indicated that elevation of incorporation rate of STSB to various root media increased moisture retention capacity, but did not increase the available water holding capacity.

• Horticultural Science & Technology
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• v.28 no.6
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• pp.964-972
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• 2010

Objective of this research was to determine the influence of physico.chemical properties of root substrates on growth of daughter plants that were developed through plastic bag cultivation of mother plants in 'Seolhyang' strawberry propagation. Six different formulations of root substrates for daughter plant cultivation were peatmoss + vermiculite (5:5, A), peatmoss + perlite (7:3, B), coir dust + perlite (7:3, C), coir dust + peatmoss + perlite (3.5:3.5:3.0, D), rice-hull + coir dust + perlite (2:7:1, E), and rice hull + coir dust (3:7, F). The 10 cm plastic pots filled with formulated substrates were located near the plastic bag where mother plants were growing. Then the runners and daughter plants originated from mother plants were fixed on each root substrate filled into 10 cm plastic pot and daughter plants were grown in the plastic pots. The container capacity and air space showed big differences among substrates tested. The substrates E and F had the less container capacity and the higher air space than other substrates tested. This indicates that the two substrates would have difficulties in water managements during the raising of daughter plants. The substrates of A, B, and D which contained peatmoss in formulation had higher nitrogen concentrations than those containing coir dust or rice hull. The substrates of E and F which contained rice hull had lower nitrogen, phosphorus and potassium concentrations than those that contained coir. The crown diameters of daughter plants grown in substrate A were around 13 mm which is thicker than those grown in other substrates. The fresh weights of daughter plants grown in A substrate were the heaviest followed by C, F, D, E, and B. The dry weight of daughter plants showed similar tendency to those of fresh weight. The daughter plants which had heavy fresh and dry weights and thick crown diameter are considered good seedlings. Based on this justification, the substrates of A, C and F are acceptable for daughter plant growth of 'Seolhyang' strawberry.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.1
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• pp.8-15
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• 1992

An experiment was conducted to find out effect of soil water condition on shoot and root growth and P, K uptake by soybean plants. Soybean plants were grown under different soil water table levels, 20cm, 40cm and 60cm below the soil surface using minirhizotron with 20cm in diameter, and well irrigated and water stressed conditions using 1/2000a Waganer pots. Three soybean plants, Paldal culfivar, were grown and sampled at the early growing period, 37 days after planting, and at the harvesing period, 115 days after planting. Shoot and root growth were restricted by water stresed condition and by excessive soil water condition with the 20cm water table. Little difference in shoot and root growth were found between well irrigated condition and 40cm or 60cm water table conditions. The P and K contents in shoot under water stressed condition were higher than well irrigated condition at the early growing period but reversed at later harvesting period. The dry weight and length of roots were more severely restricted by water stress than those of shoots. Root morphological difference was found by anatomical observation. Normal cortex was developed under the well irrigated condition, while abnormal cortex with aerenchyma formed by lysis under excessive water conditions of 20 or 40cm water talbes. Aerenchyma was formed at outer skirt of pericycle. Role of formation of aerenchyma of soybean roots might be an adaptation to excessive soil water condition and possibly related to survival of soybean roots growing under near flooding condition on dikes of paddy lands.

• Magazine of the Korean Society of Agricultural Engineers
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• v.11 no.4
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• pp.1775-1782
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• 1969

The results of the study on the consumptine use of irrigated water in paddy fields during the growing season of rice plants are summarized as follows. 1. Transpiration and evaporation from water surface. 1) Amount of transpiration of rice plant increases gradually after transplantation and suddenly increases in the head swelling period and reaches the peak between the end of the head swelling poriod and early period of heading and flowering. (the sixth period for early maturing variety, the seventh period for medium or late maturing varieties), then it decreases gradually after that, for early, medium and late maturing varieties. 2) In the transpiration of rice plants there is hardly any difference among varieties up to the fifth period, but the early maturing variety is the most vigorous in the sixth period, and the late maturing variety is more vigorous than others continuously after the seventh period. 3) The amount of transpiration of the sixth period for early maturing variety of the seventh period for medium and late maturing variety in which transpiration is the most vigorous, is 15% or 16% of the total amount of transpiration through all periods. 4) Transpiration of rice plants must be determined by using transpiration intensity as the standard coefficient of computation of amount of transpiration, because it originates in the physiological action.(Table 7) 5) Transpiration ratio of rice plants is approximately 450 to 480 6) Equations which are able to compute amount of transpiration of each variety up th the heading-flowering peried, in which the amount of transpiration of rice plants is the maximum in this study are as follows: Early maturing variety ; Y=0.658+1.088X Medium maturing variety ; Y=0.780+1.050X Late maturing variety ; Y=0.646+1.091X Y=amount of transpiration ; X=number of period. 7) As we know from figure 1 and 2, correlation between the amount evaporation from water surface in paddy fields and amount of transpiration shows high negative. 8) It is possible to calculate the amount of evaporation from the water surface in the paddy field for varieties used in this study on the base of ratio of it to amount of evaporation by atmometer(Table 11) and Table 10. Also the amount of evaporation from the water surface in the paddy field is to be computed by the following equations until the period in which it is the minimum quantity the sixth period for early maturing variety and the seventh period for medium or late maturing varieties. Early maturing variety ; Y=4.67-0.58X Medium maturing variety ; Y=4.70-0.59X Late maturing variety ; Y=4.71-0.59X Y=amount of evaporation from water surface in the paddy field X=number of period. 9) Changes in the amount of evapo-transpiration of each growing period have the same tendency as transpiration, and the maximum quantity of early maturing variety is in the sixth period and medium or late maturing varieties are in the seventh period. 10) The amount of evapo-transpiration can be calculated on the base of the evapo-transpiration intensity (Table 14) and Tablet 12, for varieties used in this study. Also, it is possible to compute it according to the following equations with in the period of maximum quantity. Early maturing variety ; Y=5.36+0.503X Medium maturing variety ; Y=5.41+0.456X Late maturing variety ; Y=5.80+0.494X Y=amount of evapo-transpiration. X=number of period. 11) Ratios of the total amount of evapo-transpiration to the total amount of evaporation by atmometer through all growing periods, are 1.23 for early maturing variety, 1.25 for medium maturing variety, 1.27 for late maturing variety, respectively. 12) Only air temperature shows high correlation in relation between amount of evapo-transpiration and climatic conditions from the viewpoint of Korean climatic conditions through all growing periods of rice plants. 2. Amount of percolation 1) The amount of percolation for computation of planning water requirment ought to depend on water holding dates. 3. Available rainfall 1) The available rainfall and its coefficient of each period during the growing season of paddy fields are shown in Table 8. 2) The ratio (available coefficient) of available rainfall to the amount of rainfall during the growing season of paddy fields seems to be from 65% to 75% as the standard in Korea. 3) Available rainfall during the growing season of paddy fields in the common year is estimated to be about 550 millimeters. 4. Effects to be influenced upon percolation by transpiration of rice plants. 1) The stronger absorbtive action is, the more the amount of percolation decreases, because absorbtive action of rice plant roots influence upon percolation(Table 21, Table 22) 2) In case of planting of rice plants, there are several entirely different changes in the amount of percolation in the forenoon, at night and in the afternoon during the growing season, that is, is the morning and at night, the amount of percolation increases gradually after transplantation to the peak in the end of July or the early part of August (wast or soil temperature is the highest), and it decreases gradually after that, neverthless, in the afternoon, it decreases gradually after transplantation to be at the minimum in the middle of August, and it increases gradually after that. 3) In spite of the increasing amount of transpiration, the amount of daytime percolation decreases gadually after transplantation and appears to suddenly decrease about head swelling dates or heading-flowering period, but it begins to increase suddenly at the end of August again. 4) Changs of amount of percolation during all growing periods show some variable phenomena, that is, amount of percolation decreases after the end of July, and it increases in end August again, also it decreases after that once more. This phenomena may be influenced complexly from water or soil temperature(night time and forenoon) as absorbtive action of rice plant roots. 5) Correlation between the amount of daytime percolation and the amount of transpiration shows high negative, amount of night percolation is influenced by water or soil temperature, but there is little no influence by transpiration. It is estimated that the amount of a daily percolation is more influenced by of other causes than transpiration. 6) Correlation between the amount of night percoe, lation and water or soil temp tureshows high positive, but there is not any correlation between the amount of forenoon percolation or afternoon percolation and water of soil temperature. 7) There is high positive correlation which is r=+0.8382 between the amount of daily percolation of planting pot of rice plant and amount and amount of daily percolation of non-planting pot. 8) The total amount of percolation through all growin. periods of rice plants may be influenced more from specific permeability of soil, water of soil temperature, and otheres than transpiration of rice plants.

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