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Effects of Forest Fire on the Physicochemical Properties of Top Soils of Adjacent Agricultural Land
Yongseon Zhang,Dong-Jin Kim,Hee-Rae Cho,Young-Ho Seo,Hyub-Sung Lee,Soon-Sun Kim 한국토양비료학회 2020 한국토양비료학회지 Vol.53 No.2
Combustion of agricultural topsoil leads to reduced organic sources, a transformation of soil structure, a formation of water repellent soil layer, and changes in balance and availability of nutrients. Therefore, in order to evaluate the change in soil environment of adjacent agricultural lands affected by forest fires, we investigated the physicochemical properties of the topsoil of agricultural lands in Goseong and Gangneung, Gangwon Province in 2019. The forest fire damaged agricultural land adjacent to forests do not have sufficient combustion sources like forest land. So there are no root burning, ash penetration, soil structure transformation, and water repellent soil layer, which can cause the soil to be thermally damaged. There was no statistically significant difference in the physical (bulk density, porosity, soil moisture, and soil three phase) and chemical (pH, EC, organic matter, available phosphate, and exchangeable cations) properties of the agricultural land damaged by wildfire and the control agricultural land. Based on this, there appears to be no combustion damage that affects the soil environment of farmland.
Yongseon Zhang,Kangho Jung,Hye-Rae Cho,Kyeong-Hwa Han,Min-Kyeong Kim,Yeon-Kyu Sonn 한국토양비료학회 2016 한국토양비료학회지 Vol.49 No.2
This experiment was conducted in Suwon and Iksan city from 2012 to 2014 to evaluate soil erosion and nutrient loss from irrigated paddy fields during cropping period. Rainfall amount and rainfall erosivity of EI30 were, on average, 1,026 ㎜ and 3,922 ㎜ ㏊<SUP>-1</SUP>yr<SUP>-1</SUP>hr<SUP>-1</SUP> for the cropping period, respectively, and the rainfall event with maximum EI30 occurred in July. Annual average of runoff was 2,508 MT ㏊<SUP>-1</SUP>yr<SUP>-1</SUP> in Suwon and 3,375 MT ㏊<SUP>-1</SUP>yr<SUP>-1</SUP> in Iksan, accounting for 36% of rainfall of the cropping period. Nutrient loss by runoff, on average, was 7.0 ㎏ N ha<SUP>-1</SUP>yr<SUP>-1</SUP>, 1.3 ㎏ P ㏊<SUP>-1</SUP>yr<SUP>-1</SUP>, and 16.6 ㎏ K ㏊<SUP>-1</SUP>yr<SUP>-1</SUP> ; N, P, and K loss were 5.0, 0.6, and 8.3 ㎏ ㏊<SUP>-1</SUP>yr<SUP>-1</SUP>, respectively, in Suwon and 8.9, 1.9, and 16.7 ㎏ ㏊<SUP>-1</SUP>yr<SUP>-1</SUP> in Iksan. Soil loss in Korean paddy rice was evaluated as 0.33 MT ㏊<SUP>-1</SUP>yr<SUP>-1</SUP> ranging from 0.05 MT ㏊<SUP>-1</SUP>yr<SUP>-1</SUP> to 0.88 MT ㏊<SUP>-1</SUP>yr<SUP>-1</SUP>. Amount of soil loss, however, depended on areas and year influenced by variation of rainfall amount and intensity. Interestingly, soil erosion in Iksan in 2012 was remarkably greater than those in other periods due to heavy rainfall between late May and June with soil flake dispersion right after the rice-planting season.
Yongseon Zhang,Yong-Hee Moon,Yeon-Kyu Sonn,Kangho Jung,Hye-Rae Cho,Kyeong-Hwa Han 한국토양비료학회 2015 한국토양비료학회지 Vol.48 No.5
In highland crop fields, saprolite is piled up approximately every three years as deep much as 20 to 30 cm because farmers expect that adding new materials may improve productivity and mitigate hazards by continuous cultivation of a single crop. Piling saprolite, however, has been reported to induce poor soil drainage. Effects of deep ploughing with a spading machine and an excavator were studied in sites located in Daekwanryeong-myeon, Pyeongchang in which soil physical properties were deteriorated by piled saprolite. The soil made of parent material of Samgag series was piled up over surface soil of Haggog series naturally developed in the area. Carrot was cultivated in the field. Productivity and growth factors of carrot were compared among control and deep ploughing by a spading machine and an excavator. Effective soil depth extended to 60 cm or greater by 60 cm deep ploughing by an excavator or 50 cm deep ploughing by a spading machine. On the other hand, effective soil depth was within 50 cm at control plot. Productivity of carrot responded to amelioration of soil physical properties. The productivity was greater in deep ploughing treatments than that of control or 30 cm ploughing. It suggested that increased productivity by deep ploughing was mainly related to breaking plough pan which inhibited extension of rooting zone.
Yongseon Zhang,Yeon-Kyu Sonn,Yong-Hee Moon,Kangho Jung,Hye-Rae Cho,Kyeong-Hwa Han 한국토양비료학회 2014 한국토양비료학회지 Vol.47 No.4
Farmers in highlands in South Korea pile up 20 to 30 cm of saprolites, mostly granite- or granitegneiss-weathered materials, on surface of arable lands every three to five years to compensate eroded soil and sometimes to discontinue soil-borne diseases. Immediate increases of infiltration and percolation rates are expected with coarse textured saprolites while soil drainage becomes poorer in a long-term. In this study, we analyzed mineralogical characteristics and micro-morphology of plow pan to investigate processes making impermeable layers. Soil samples were collected from plow pan, usually located at approximately 20 cm soil depth and at the lower part of piled saprolites, in arable lands in Hoenggye 5-ri, Daekwanryeong-myeon, Gangwon-do (N37.7, E128.7) in which saprolites were added 2, 4, and 8 years ago; saprolites were transported from similar areas. The saturated hydraulic conductivity decreased over time. Based on soil thin section pedography, quartz and feldspar accounted for a majority of minerals. The size of feldspar decreased and macropores became filled with clay or silt particles over time, which implies that macropores were packed with particles weathered from feldspar. The X-ray diffraction (XRD) analysis indicated that intensity of feldspar decreased over time and the reverse was true for kaolinite and illite, indicating that feldspar and mica weathering induced formation of kaolinite and illite. Conclusively, deteriorated drainage by formation of impermeable layers in farms with piled saprolites was caused by accumulation of clay minerals such as kaolinite and illite in macropores; illite and kaolinite can be formed by weathering of mica and eldspar, respectively.
Study on the Standards of Proper Effective Rooting Depth for Upland Crops
Yongseon Zhang,Kyunghwa Han,Kangho Jung,Heerae Cho,Mijin Seo,Yeonkyu Sonn 한국토양비료학회 2017 한국토양비료학회지 Vol.50 No.1
The study was performed to determine effective soil depth with crop type. Lysimeters, filled with three types of soils (sandy loam, loam and clay loam), were used. Effective soil depths for 25 cm, 50 cm, 75 cm, and 100 cm were considered for each soil. Six crops were investigated for plant height and yield, and rooting depths: Chinese cabbage, maize, lettuce, potato, red pepper, and soybean. Experiment was conducted at the National Institute of Agricultural Sciences in Suwon from 2012 to 2014. Effective rooting depth including 70% of root ranged from 19 cm to 29 cm for Chinese cabbage, from 24 cm to 38 cm for maize, from 17 cm to 24 cm for lettuce, from 27 cm to 32 cm for soybean, and around 50 cm and 30 cm for potato and red pepper. The maximum depth was 60 cm for soybean, 50 cm for Chinese cabbage, lettuce, and potato, and 75 cm for maize and red pepper. Each crop showed high yield in the treatment with soil depth over maximum rooting depth under all soils.
Optimum Range on Soil Physical Indicators Under Plastic Film House
Yongseon Zhang,Heerae Cho,Kyunghwa Han,Junghun Ok,Seonah Hwang,Kangho Jung 한국토양비료학회 2018 한국토양비료학회지 Vol.51 No.4
The water and nutrients in the soil can be absorbed by the crop root. The soil physical properties affect the growth and penetration of crop root. The objectives of this study were to determine soil physical indicators that could inhibit the crop growth under plastic film house, and to establish the appropriate soil physical criterion depending on crop types. The soil physical (including effective rhizosphere, soil three phase, and bulk density) and chemical (including pH, EC, organic matter content, and available phosphate) properties were investigated in the mainly cultivated area for greenhouse crops including lettuce, strawberry, cucumber, tomato, oriental melon, and water melon from 2015 to 2017. For plastic film house, soil physical indicators were commonly chosen as bulk density, air porosity, and effective root depth. The optimum ranges for plastic film house soil were as follows; deeper than 50 cm for effective root depth, less than 1.5 Mg m<SUP>-3</SUP> for bulk density and more than 10% gas phase.
Micromorphological Features of Pan Horizon in the Soils Derived from Different Parent Materials
Yongseon Zhang,Yeon-Kyu Sonn,Yong-Hee Moon,Kangho Jung,Hye-Rae Cho,Kyeong-Hwa Han 한국토양비료학회 2014 한국토양비료학회지 Vol.47 No.4
We have five soil series of pan soils in South Korea out of 391 series: Gangreung, Bugog, Yeongog, Jangweon, and Pogog. Productivity decreases in pan soils as pan horizons impede percolation and capillary rise of water and interrupt root extension. This study was performed to investigate pedogenic processes of pan soils mainly located in footslope and river terrace by analyzing physicochemical properties and soil micro-morphology. Korean pan soils belong to Alfisols, Ultisols, or Inceptisols and have udic or aquic soil moisture regime, mesic temperature regime, and mixed mineral substances. Texture of pan horizons selected for the present study was mainly silty clay loam with clay contents ranging from 26.3 to 45.3%. Bulk density of the pan horizons ranged from 1.4 to 2.1 Mg m<SUP>-3</SUP> and their soil structure were subangular or angular structure. In terms of micromorphological structure, Bt horizon of Gangreung series was formed as platy and striated b-fabric structure possibly affected by uplift of coastal terrace following clay sedimentation by flood. Jangweon series showed micro-morphology of massive structure and crystallic b-fabric as macropores between coarse debris established by debris fall in slope were filled with silt-sized particles. The Bt horizons having massive structure and striated b-fabric in Yeongog, Pogog, and Bugog series implies that those horizons experienced horizontal mass flow after clay accumulation.