• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.2
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• pp.195-202
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• 1995

This experiment was performed to characterize the optimum water table level for the growth and yield of barley(var. Olbori) and wheat(var, Grumil), Olbori and Grumil were grown in the 550 liter plastic pot filled with silt loam or sandy loam, During the whole growth period, the water table adjusted to be 20, 30, 40, 50, and 70cm, Higher water table was resulted in the decrease in plant height and top dry weight, but in the increase of the ratio of top to root dry weight, especially in barley, This suggested that high water table level affected more the growth of top than that of root, The number and area of green leaves were decreased as the water table was higher than 30 to 40cm at the late growth period(May 18, 1993), The largest number and area of green leaves were shown at 50cm of water table in sandy loam and at 70cm in silt loam, As the water table was high, the leaf chlorophyll content was low, And barley was affected more significantly than wheat by soil texture, The photosynthetic activity was decreased remarkably at 20cm water table, Heading period was 2 to 3 and 4 days earlier at the 20cm water table of sandy loam in barley and wheat, respectively, However this earlier heading was not shown in silt loam, Grain filling was accelerated 5 to 7 days earlier in barley and 10 days in wheat grown at 20cm water table, The highest yield was present at 50 and 70cm water table, The yield was decreased remarkably at 20cm water table, resulting that yield reduction ratio of barley was 71.1% and 72, 2%, and that of wheat was 41.0% and 60, 0% in sandy loam and silt loam, respectively, High water table decreased the number of spike per unit area, but increased the seed weight per spike in barley, However, High water table reduced the seed weight per spike in wheat. There was significant correlation between yield and leaf chlorophyll content in wheat and barley, Yield was correlated significantly with green leaf area in barley, and with top dry weight, ratio of top to root dry weight chlorophyll content and photosynthetic activity in wheat. The optimum water table was 50 to 70cm in wheat and barley, They grew fairly well at 30cm water table of sandy loam, and at 40cm of silt loam.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.1
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• pp.16-25
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• 1992

A pot experiment was conducted to understand effect of soil temperaute on soybean shoot and root growth, and its relations to nutrient uptake including phosporus and potassium. Pregerminated soybean seedlings, Paldal cultivar, were planted for 43 days on the pots with Ihyeon silt loam and Samgag sandy loam in the temperature controled water baths at 17, 25 and $32^{\circ}C$. Shoot and root samples were taken at four times and analyzed. Shoot and root dry matter weights were heavier as higher soil temperaure. The root dry matter increased faster than shoot at earlier period. Shoot dry matter weights grown at 17 and $25^{\circ}C$ showed little difference between two soils, however, those grown in silt loam at $32^{\circ}C$ were heavier than sandy loam. The total lengths of roots were longer as higher soil temperature, and longer in silt loam than sandy loam. The roots grown in sandy loam at low temperature were thicker than the roots grown in silt loam at high temperature. The uptakes of phosphorus and potassium were higher as higher tempeature with same trend with dry matter. The uptake rate of unit root surface area was higher in sandy loam soil than silt loam. The uptake rates showed strong dependence on soil temperature as well as dependence of water uptake rate. Based on Dalton and Gardner model, at high temperature the dependence trend of phosphorus and potassium on soil temperature showed with active uptake model, while at low temperature the dependence showed without active uptake model.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.spc
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• pp.14-19
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• 2009

To obtain the basic data on reclaimed tideland soils, 90 soil samples were collected from 9 tideland reclamation project areas in Korea. The soils consisted of clay (2.0 to 35.0 percents), silt (2.0 to 80.0 percents), and sand (8.0 to 95.0 percents), and were dominantly classified sandy loam and silty loam. The soils had pH of 4.5 to 9.1, organic matter of 0.50 to $19.20g\;kg^{-1}$, total nitrogen of 4 to $1,159mg\;kg^{-1}$, and avaliable phosphorus (as $P2_O_5$) of 3.5 to $147.7mg\;kg^{-1}$. The electrical conductivity in soil saturation-paste extracts (ECe) ranged between $0.62dS\;m^{-1}$ and $31.60dS\;m^{-1}$ and the concentrations of sodium and magnesium ions were higher than those of potassium and calcium ions. The magnitude of the ECe was as low as that of normal level in Nam-Po, Pu-Sa, and Kye-Hwa reclamation project areas having sandy loam texture, but was as high as that of normal level saline-sodic level in Nam-Yang and So-Po reclamation project areas having silty loam texture even though the soils were cultivated more than 10 years as a paddy. Some part of Saemangeum area was surveyed and soil textures were various; some were silt loam and some were sandy loam. The ECe values were very high in topsoil and subsoil.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.3
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• pp.249-255
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• 1995

This study was conducted to investigate the effects of some soil conditioners, such as polyacrylamide(PAM), polyvinylalcohol(PVA) and Bitumen emulsion, on aggregate formation and stability, wetting angle, sorptivity and penetrability of the soil with different textures : sand, sandy loam, loam and clay loam. A pot experiment was carried out to find out the effect of treatment on the germination and growth of lettuce with three textures : sand, sandy loam and silt loam. Soil aggregates larger than 2mm in untreated soils at dry condition were naught in sand, 45% in sandy loam, 80% in loam and 90% in clay loam. Treatments of soil conditioners tended to increase the occurrence of soil aggregate larger than 2mm, which were 20~25% in sand, 55~75% sandy loam, but not affected greatly aggragate occurence in loam and clay loam. The aggregate instability was decreased by the soil conditioner treatment. The wetting angles of the soils were greatly changed by hydrophobic of Bitumen, but those were changed slightly by PVA and PAM application. The sorptivity and penetrability data indicated that the effects of different materials on these parameters differed depending upon soil texture. Application of PVA and PAM were no effect exceptive in sand. Application of Bitumen revealed that water movement was not showed in all soils. The germination rate, root weight and top plant weight of lettuce were increased in all soils by PAM treatment as compared to untreated soils. Particularly the greater effect was occurred in sand soil than in sandy loam and silt loam. PAM increased greatly the moisture content and air phase of soils.

• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.E
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• pp.1-11
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• 1992

Increasing national concern on nonpoint source pollution of surface and ground water Systems has led researchers and policy makers to develop certain agricultural Best Management Practices. As an initial step of broad study program above mentioned, this study reflected the effects of different tillage practice on bulk density and degree of saturation on two regional soils, namely Tama silt loam and Catlin silt loam. Results may help to clarify some of the conflicting findings on the impact of tillage systems on these parameters and it may also explain some of the reasons for specific role that different tillage systems play regarding nonpoint source pollution from agricultural fields.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.3
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• pp.290-295
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• 1993

To evaluate rice yield and changes of soil properties, 3 tillage methods including no tillage was tested in different soil textures, such as silty clay, sandy loam and silt loam fields. Hwaseongbyeo was transplanted by machine at May 28. Water and soil temperature of no tillage were lower than other plots, but differences of temperature were not larger in different treatments. Mean water requirement in depth of sandy loam field was larger than other textures, but that of silty clay field was smaller. The water requirement in depth of no tillage was larger by 1.4～2.2mm / day than the other plots. In the silty clay field, mineral contents, except Na$_2$O content, of rice plant of no tillage plot at the harvesting stage was higher than the other treatments. The rice yields in the no tillage plot were decreased by 18% in sandy loam, by 7% in silty clay and by 1% in silt loam respectively than the power tiller plots.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.6
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• pp.398-404
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• 2000

We examined the effect of soil:water ratio on the equivalent concentration of individual electrolyte species and the electrical conductivities (EC) of the diluted extracts of 24 soil samples (loam or silt loam) collected from rose-cultivated plastic houses to estimate the EC of saturated soil-paste extracts (ECe) from diluted soil extracts. With increasing volume ratio of water (higher dilution), the equivalent concentrations of each electrolyte species and their sum increased. The relative contribution to the EC, however, was highest for $NO_3{^-}$, irrespective of soil:water ratio. The measured ECe was 6.36 for loam and $8.09dS\;m^{-1}$ for silt loam soils and the corresponding soil:water ratio was 0.38 and 0.50, respectively. The EC_e estimated from the EC of diluted extracts at 1:1, 1:2, or 1:5 soil:water ratios using their corresponding uniform diluted factors was lower than the measured EC_e and this difference was greater with higher dilution and EC values. Therefore, the alternative diluted factors (y) for each soil: water ratio were obtained following the definition of diluted factor and were correlated significantly with volume ratios of added water (x): y=1.55x+0.5 for loam and y=1.21x+0.48 for silt loam soils. On the other hand, correlation analyses of the EC of soil extracts (y) to the volume ratio of added water (x) on log-log scale yielded linear models: logy = -0.805logx + logb, SD of slope=0.05, b=sample specific constant, n=24). With known saturation percentage of a sample representing a group and and the EC of diluted extract of a given soil, the EC_e could be predicted using the proposed logarithmic equation.

• Korean Journal of Agricultural Science
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• v.38 no.4
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• pp.631-639
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• 2011

This research was conducted to investigate potential use of New Zealand spinach (Tetragonia tetragonoides) as a new vegetable crop which will be cultivating in salt-affected soils including reclaimed land. Traditionally New Zealand spinach has been studied to explore functional compound or salt removing potential. To cultivate the crop species in the salt-affected soil widely, it is essential to obtain salt and soil texture responses under the controlled environment. Fifty nine New Zealand spinach ecotypes native to Korean peninsula first collected over seashore areas, and primitive habitat soil environment was evaluated by analyzing soil chemical properties from 32 locations. Different textures of sandy, silt loam, and sandy loam soils were prepared from nearby sources of sea shore, upland and paddy soils, respectively. Target salinity levels of 16.0 dS/m, 27.5 dS/m, 39.9 dS/m, and 52.4 dS/m in electrical conductivity (ECw) were achieved by diluting of 25, 50, 75, 100% (v/v) sea water to tap water (control, 0.6 dS/m), respectively. Various measurements responding to soil texture and irrigation salinity included plant height, root length, fresh weight (FW), dry weight (DW), leaf parameters (leaf number, leaf length, leaf width), lateral branching, and inorganic ion content. was found to adapt to diverse habitats ranging various soil chemical properties including soil pH, organic matter, exchangeable bases, EC, and cation exchange capacity (CEC) in Korea. Responding to soil texture, New Zealand spinach grew better in silt loam and sandy loam soil than in sandy soil. Higher yield (FW and DW) seemed to be associated with branch number (r=0.99 and 0.99, respectively), followed by plant height (r=0.94 and 0.97, respectively) and leaf number (r=0.89 and 0.84, respectively). Plant height, FW, and DW of the New Zealand spinach accessions were decreased with increasing irrigation salinity, while root length was not significantly different compared to control. Based on previous report, more narrow spectrum of salinity range (up to 16 dS/m) needs to be further studied in order to obtain more accurate salinity responses of the plant. As expected, leaf Na content was increased significantly with increasing salinity, while K and Ca contents decreased. Growth responses to soil texture and irrigation salinity implied the potential use of New Zealand spinach as a leafy vegetable in salt-affected soil constructed with silt loam or sandy loam soils.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.4
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• pp.373-377
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• 1985

This experiment was designed to find out the soil properties to control the soil erodibility. Two kinds of soil conditioners, hydrophilic Uresol and hydrophobic Bitumen were treated to sandy loam and silt loam. Soil erodibility was tested during a simulated rainfall in a soil pan which was covered with a 2cm layer of treated and untreated aggregates (< 5.36mm) on a soil layer. The runoff starting time was delayed 8-20 minutes by Uresol treatment and it was hasten 1-21 minutes by Bitumen treatment. Runoff rates were reduced by Uresol to 62.5% in sandy loam and 93.7% in silt loam, but it was increased by Bitumen treatment. Erosion from the Uresol treated soil was remarkably reduced to 1.7-23.6% of that in the untreated soil. In case of the Bitumen treatment, the soil loss from silt loam was reduced to 55.5% of the control, but it was increased in sandy loam soil by 52% over the control. The ratio of soil loss and runoff, sediment concentration in runoff, was noticeably increased when the soil structure was unstable. There was significant correlation between soil loss and logarithm of wetting angle-stability index. Soil loss was greatly increased when the index was less than 0.2.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.162-168
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• 1999

This study was performed to analyze dealinization effects on gypsum treatments in reclaimed tidelands and to obtain the basci data for developing prediction techniques f desalinization to be applicable in the begining of tideland reclamation. In this study , the reclamation experiments with 4 treatments were conducted through the leachig method, using the samples of silt soil and silt loam soil collected in 5 units of tideland reclamation projects. The electrical conductivity , exchangeable sodium percentage and hydraulic conductivity were analyzed in order to investigate the effects of desalinizatino for reclaiming the tidelands with high salt concentration.