• Korean Journal of Soil Science and Fertilizer
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• v.48 no.4
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• pp.240-245
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• 2015

The monitoring of soil fertility changes in orchard is very important for agricultural sustainability. Field monitoring was performed to evaluate the soil chemical properties of 140 orchard (23 sites for sandy loam, 88 sites for loam, 28 sites for silt loam, and 1 site for loamy fine sand) in Gyeongnam province every 4 years from 2002 to 2014. Soil chemical properties such as pH, electrical conductivity, amount of organic matter (OM), available phosphate ($P_2O_5$), lime requirement (LR), exchangeable potassium (K), calcium (Ca), magnesium (Mg), and sodium were analyzed. The amount of OM, exchangeable K, Ca, and Mg were significantly increased as cultivation year increases. The frequency distribution within optimum range of subsoil chemical properties in 2014 was 34.3% for pH, 35.0% for OM, 17.1% for available $P_2O_5$, 22.9% for exchangeable K, 15.7% for exchangeable Ca, and 22.1% for exchangeable Mg. In addition, the available $P_2O_5$ and exchangeable calcium were excess level with portions of 69.3% and 48.6%, respectively. The soil chemical properties in the topsoil and subsoil showed that soil pH was significantly higher in sandy loam soil than those from the loam and silt loam soils. The OM, exchangeable K, Mg, and LR of loam soil were higher than those from the sandy loam soil. These results indicated that a balanced management of soil chemical properties as affected by soil texture can improve the amount of fertilizer applied for sustainable agriculture in orchard field.

• Korean Journal of Environmental Agriculture
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• v.37 no.3
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• pp.166-171
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• 2018

BACKGROUND: Nitrogen leaching depends on the drainage pattern and nitrate content, and those are influenced by soil hydraulic properties and fertility. The purpose of this study was to confirm how soil texture contributed to leaching and balance of nitrogen, as well as to drainage. METHODS AND RESULTS: This study was performed using undisturbed weighing lysimeters which were piled up with clay loam (Songjung series) and sandy loam (Sanju series) soils in National Institute of Agricultural Science experimental field. Chinese cabbage was cultivated from August 30 to October 31, 2017. The application rates of N, $P_2O_5$, and $K_2O$ were 21.5, 7.8, and $15.0kg\;10a^{-1}$, respectively, and irrigation was supplied at -33 kPa in 30 cm soil depth. Drainage in clay loam was not noticeable, although it was increased by rainfall in early September. By contrast, the trend of drainage in sandy loam was strongly dependent upon rainfall pattern. Owing to different drainage patterns between both soil textures, nitrogen leaching was 5-fold higher in sandy loam than in clay loam. Nitrogen use efficiencies in clay loam and sandy loam were represented as 43% and 52%, respectively. CONCLUSION: The pattern of drainage and nitrogen leaching were greatly depended on clay content in soil. From this study, we carefully suggest that soil texture should be considered as an incidental factor to estimate nitrogen balance.

• Magazine of the Korean Society of Agricultural Engineers
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• v.11 no.1
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• pp.1561-1579
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• 1969

In Korea, the duty of water in paddy fields was measured at the Agricultural Experimental Station in Suwon about 60 years ago. After that time some testing has been made in several places, but the key points in its experiment were the water depth of evapo-transpiration. Improved breeds, progress in cultivation and management techniques as well as development of measuring apparatus in recent years have necessitated the review of the duty of water in paddy fields. The necessity of reviewing the conventional methods has become even more important, as no source of information has been made available through survey of water utilization on a soil use basis which requires data on peculiar features of the water depth of evapo-transpiration. For example, the duty of water in paddy field is largely affected by the water depth of evapo-transpiration in connection with the wetted paddy field, whereas in connection with the normal paddy fields without this characteristic the vertical percolation become the predominant factor in measuring the decreasing depth of water. Therefore, it becomes important. that not only the water depth of evapotranspiration but also the vertical percolation process should also be observed in order to arrive at a realistic conclusion. As the vertical percolation has aclose relationship to the height of the underground water, the change of the latter can be measured. As the conclusion of this experiment, the following subjects are indicated. 1. In order to determine the economic duty of water in paddy fields on a basis of varying soil features, the varying soil features in the benifited area should be investigated thoroughly. The water depths of evapo-transpiration(ET) ratio to evaporation in the evaporator(V) on a basis of the varying soil features are as follows: clay loam ET/V = 1.11, loam ET/V = 1.64, sandy loam ET.V = 1.63 2. The decreasing depth of water consists of the water depth of evapotranspiration, the vertical per colation and the percolation of foot path. Among these three, the percolation of foot path can be utilized again. 3. As the result of this experiment, it shows the decreasing depth of water as follows. clay loam 9.3 mm/day, loam 13.5mm/daty, sandy loam 15.3mm/day 4. On a basis of the varying soil features and the height of the underground water, the vertical percolation varies. 5. The change of the vertical percolation on a basis of the varying soil features shows as follows: clay loam $1{\sim}2$ mm/day, loam $2{\sim}3$mm/day, sandy loam $3{\sim}4$mm/day 6. The level of the underground water changes sensibly by priority of clay loam, loam, sandy loam. When it rains, the level of the underground water rises fast and falls down slowly. 7. The level of the underground water changes within the scope of 25cm 8. The transpiration ratio is given in table 8 and their value are as follows: clay loam 168.8, loam 255.6, sandy loam 272.5

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.1
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• pp.14-19
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• 1985

This study was conducted to evaluate the effects of red earth addition in sandy loam paddies. Clay contents of the red earths were 19% (loam) and 35% (clay loam). The treatments were 3 levels of red earth and 2 levels of fertilizer. The results were summerized as follows: 1. Water decrease rate was lowered with the increase of clay by the red earth application in sandy loam paddies. 2. Red earth addition increased CEC and available $SiO_2$ in sandy loam, and integrated soil improvement showed higher pH and lower Eh than standard fertilizer application. 3. Rice yields in the red earth addition of loam were decreased by 2-3% at standard fertilizer application and increased by 2-4% at integrated soil improvement. Otherwise, rice yields in the red earth application of clay loam were increased by 1-4% at standard fertilizer application and 3-8% at integrated soil improvement.

• Journal of Korea Soil Environment Society
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• v.5 no.3
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• pp.17-23
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• 2001

The adsorption and movement characteristics of herbicide pendimethalin was studied in three kinds of soil, sandy loam, silty clay and loam. The results of the batch test and columnexperimentweresummarizedasfollows. The shaking time reached to the adsorption equilibrium of pendimethalin in soils was 6 hours. The adsorption rates of pendimethalin for sandy loam, silty clay and loam were 59.6%, 77.3% and 64.0%, respectively. The adsorption isotherms with the Freundlich equation showed better consistency than that with the Langmuir one. The adsorption coefficients of pendimethalin for soils were 8.0. 16.1 and 9.5. respectively. When breakthrough point was 0.05Co, the breakthrough times reached for soils were 256 minutes, 810 minutes and 420 minutes. respectively.

• Magazine of the Korean Society of Agricultural Engineers
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• v.13 no.4
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• pp.2439-2444
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• 1971

This experiment is conducted to see the alteration in calculation of amount of duty of water in paddy fields, by the miraculous rice TONG-IL(IR667) made its appearance to us, therefore results obtained were summarized as follow. 1. In comparison with depth of evapo-transpiration and evaporation in the evaporator, the ratio is ET/V=1.84 in clay loam and ET/V=2.00 in loam, the value is larger than any vairety. 2. Comparison by growing periods of rice plants growing period 5 and Ear for mation stage (primor stage) 6 ET/V value grow larger from 3.30 to 3.77. 3. Transpiration ratio is 260.4 in clay loam and 275.0 in loam, two value are less than 300.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.628-633
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• 2015

It is necessary to assess soil physical properties and crop growth treated by compaction to establish the soil management standard. This study evaluated the bulk density, strength and crop growth after subsoil compaction for sandy loam and loam on the field in Suwon, Korea. The treatments were compaction and deep tillage. Sandy loam and loam were classified to coarse soil and fine soil, respectively, depending on clay contents. In coarse soil, bulk density of compacted plot was 8~17% greater than control and deep tilled plot. The root growth was worse in compacted plot compared with control. In fine soil, plow pan was not observed in deep tilled plot with 5~19% smaller bulk density than compacted plot and control. Deep tillage improved the crop growth. The soil physical properties by compaction were dependent on clay content and crop growth limit depended on the traffic driving.

• Korean Journal of Medicinal Crop Science
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• v.4 no.3
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• pp.205-211
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• 1996

The study was conducted to determine the effects of an optimum irrigation time as af­fected by the different soil textures in Dioscorea batatas DECNE. Water content change was decreased fol­lowing orders, non - irrigation > July 15 > Aug. 15 > irrigation of two times (July 15 following Aug. 15). It was appeared that sandy loam texture was sharply decreased compared with the loam texture in water loss. Dan-Ma was preemergenced about 6 to 8 days without soil texture. Epiphytic amounts in both Dan-Ma and Jang-Ma were about two times increased at tubberous fomation and enlargement stages comparing non - irrigation. In tuber yield without soil texture, Jang-Ma was increased compared with Dan-Ma and tuber yield in loam soil texture was promoted. As a result, it was concluded that sandy loam texture has more compatible than loam soil texture.

• 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.44 no.1
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• pp.22-28
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• 2011

With the increasing cultivation of acid-loving plants such as blueberries, the artificial acidification of soils is frequently required. This research was conducted to determine the application rates of elemental sulfur (S) required in the soil acidification for blueberry cultivation. Laboratory incubation experiment was conducted to acidify three arable soils (pH 6-7) of different texture to pH 4.5-5.0 by the addition of varying amounts of elemental S. All rates of elemental S addition reduced soil pH, although the efficacy of acidification was related to the application rate and soil characteristics. pH reduction was slow in sandy loam soil, and the final equilibrium pH was obtained after 60, 43, and 30 days of incubation in sandy loam, loam, and silty clay, respectively. Although the final pHs obtained after 93 days of incubation were not significantly different among the three soils, the equilibrium pH was relatively higher in soil of higher clay content in the application rates of 1.5-2.0 g S $kg^{-1}$ soil. The estimated amounts of elemental S required in lowering pH to 4.5-5.0 were 0.59-1.01, 0.67-1.03, and 0.53-0.88 g S $kg^{-1}$ for sandy loam, loam, and silty clay, respectively. The lowest estimated amount of elemental S in the acidification of silty clay soil was attributable to the low organic matter content. For clay soils containing optimum level of organic matter, the application rates of elemental S should be much higher than those values estimated in this research. Soil acidification did not significantly increase the available concentrations of Ca, Mg and K. Extractable Cu and Zn was not greatly affected by the acidification, but extractable Fe, Mn, and Al in the acidified soils were higher than those found in non-acidified soils. Such increases in solubility are attributable to the dissolution of oxides and hydroxides of the elements.