• Title/Summary/Keyword: Different soil layers

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Soil Properties Under Different Vegetation Types in Chittagong University Campus, Bangladesh

  • Akhtaruzzaman, Md.;Roy, Sajal;Mahmud, Muhammad Sher;Shormin, T.
    • Journal of Forest and Environmental Science
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    • v.36 no.2
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    • pp.133-142
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    • 2020
  • Soil physical and chemical properties at three layers such as top (0-10 cm), middle (10-20 cm) and bottom (20-30 cm) layers under three different vegetation types were studied. Soil samples were collected from Acacia forest, vegetable and fallow lands of Chittagong university campus, Chittagong, Bangladesh. Results showed that sand was the dominant soil particle followed by clay and silt fractions in all soil depths under different vegetation types. Soils of fallow land showed the highest values of bulk density while forest soils had the lowest values at three depths. Acacia forest soil having lowest values of dispersion ratio (DR) is less vulnerable while fallow soil with highest DR values is more vulnerable to soil erosion. The lower pH value at all soil layers in three ecosystems represented that soils under study are acidic in nature. Contents of organic matter, total nitrogen, exchangeable cations (Ca2+, Mg2+, K+ and Na+) and cation exchange capacity (CEC) were observed higher in Acacia forest soils compared to vegetable and fallow soils. Only soils of vegetable land had higher level of available phosphorus in three layers than that of other two land covers. The study also revealed that different soil properties were observed in three different vegetation types might be due to variation in vegetation and agronomic practices.

Analysis of Soil Moisture Characteristics in Nut Pine Forest about Seasons and Soil Layers (잣나무림에서의 시기별 토층별 토양수분 특성분석)

  • Hong, Eun-Mi;Choi, Jin-Yong;Yoo, Seung-Hwan;Nam, Won-Ho
    • Journal of The Korean Society of Agricultural Engineers
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    • v.54 no.4
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    • pp.105-114
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    • 2012
  • Soil moisture plays a pivotal role in hydrological processes, especially in the forest which covers more than 64% of the national land. Soil moisture was monitored to analyze soil moisture change characteristics in terms of time and soil layers in this study. 2 Years soil moisture change data was obtained from the experimental nut pine forest and statistical analysis including auto-correlation and cross-corelation among soil moisture data from different soil layers was conducted. Using the monitored soil moisture data, a relationship between soil moisture change and precipitation was analyzed and seasonal soil moisture change characteristics were analyzed. From the result of inter-relationships among soil layers in terms of season and time lag, soil moisture change characteristics in the nut pine forest were upper soil layers were much sensitive than lowers, and seasonal variation if soil moisture for upper soil layers were bigger than lowers showing low correlation with precipitation in winter and spring due to freezing and snowfalls.

Soil properties and molecular compositions of soil organic matter in four different Arctic regions

  • Sujeong, Jeong;Sungjin, Nam;Ji Young, Jung
    • Journal of Ecology and Environment
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    • v.46 no.4
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    • pp.282-291
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    • 2022
  • Background: The Arctic permafrost stores enormous amount of carbon (C), about one third of global C stocks. However, drastically increasing temperature in the Arctic makes the stable frozen C stock vulnerable to microbial decomposition. The released carbon dioxide from permafrost can cause accelerating C feedback to the atmosphere. Soil organic matter (SOM) composition would be the basic information to project the trajectory of C under rapidly changing climate. However, not many studies on SOM characterization have been done compared to quantification of SOM stocks. Thus, the purpose of our study is to determine soil properties and molecular compositions of SOM in four different Arctic regions. We collected soils in different soil layers from 1) Cambridge Bay, Canada, 2) Council, Alaska, USA, 3) Svalbard, Norway, and 4) Zackenberg, Greenland. The basic soil properties were measured, and the molecular composition of SOM was analyzed through pyrolysis-gas chromatography/mass spectrometry (py-GC/MS). Results: The Oi layer of soil in Council, Alaska showed the lowest soil pH and the highest electrical conductivity (EC) and SOM content. All soils in each site showed increasing pH and decreasing SOC and EC values with soil depth. Since the Council site was moist acidic tundra compared to other three dry tundra sites, soil properties were distinct from the others: high SOM and EC, and low pH. Through the py-GC/MS analysis, a total of 117 pyrolysis products were detected from 32 soil samples of four different Arctic soils. The first two-axis of the PCA explained 38% of sample variation. While short- and mid-hydrocarbons were associated with mineral layers, lignins and polysaccharides were linked to organic layers of Alaska and Cambridge Bay soil. Conclusions: We conclude that the py-GC/MS results separated soil samples mainly based on the origin of SOM (plants- or microbially-derived). This molecular characteristics of SOM can play a role of controlling SOM degradation to warming. Thus, it should be further investigated how the SOM molecular characteristics have impacts on SOM dynamics through additional laboratory incubation studies and microbial decomposition measurements in the field.

Phylogenetic characterization of bacterial populations in different layers of oak forest soil (상수리나무림의 토양 층위별 세균군집의 계통학적 특성)

  • Han, Song-Ih
    • Korean Journal of Microbiology
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    • v.51 no.2
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    • pp.133-140
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    • 2015
  • We have examined the correlation between the physicochemical and microbiological environment variables for the different layers of oak forest soil in Mt. Gyeryong, Korea. The result shows that there is a high correlation in the environment variables between the soil parameters of the fermented (F) layer and humus (H) layer. In particular, the pH level in the F layer shows a high correlation with C and N, while the various organic acids of the H layer turns out to be closely correlated with soil bacteria density. As we evaluated phylogenetic characteristics of bacterial populations by DGGE analysis with DNA extracted. Total of 175 bands including 43 bands from litter (L) layer, 42 bands from F layer, 43 bands from H layer and 47 bands from rhizosphere (A) layer were selected as the major DGGE band of oak forest soil. Based on the 16S rRNA gene sequences, 175 DGGE bands were classified into 32 orders in 7 phylum. The heat map was analyzed in order to compare the quantity of the base sequences of each order and based on the clustering of the different layers of oak forest soil, the result confirms that the F layer and H layer belong to a different cluster from that of L layer and A layer. Furthermore, it also showed that approximately 50% of the total microbial population in different layers is ${\alpha}$-proteobacteria, which indicates that they belong to the dominant system group. In particular, Rhizobiales, Burkholderiales and Actinobacteriales were observed in all the seasons and layers of oak forest soil, which confirms that they are the indigenous soil bacterial community in oak forest soil.

Interpreting in situ Soil Water Characteristics Curve under Different Paddy Soil Types Using Undisturbed Lysimeter with Soil Sensor

  • Seo, Mijin;Han, Kyunghwa;Cho, Heerae;Ok, Junghun;Zhang, Yongseon;Seo, Youngho;Jung, Kangho;Lee, Hyubsung;Kim, Gisun
    • Korean Journal of Soil Science and Fertilizer
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    • v.50 no.5
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    • pp.336-344
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    • 2017
  • The soil water characteristics curve (SWCC) represents the relation between soil water potential and soil water content. The shape and range of SWCC according to the relation could vary depending on soil characteristics. The objective of the study was to estimate SWCC depending on soil types and layers and to analyze the trend among them. To accomplish this goal, the unsaturated three soils were considered: silty clay loam, loam, and sandy loam soils. Weighable lysimeters were used for exactly measuring soil water content and soil water potential. Two fitting models, van Genuchten and Campbell, were applied. Two models entirely fitted well the measured SWCC, indicating low RMSE and high $R^2$ values. However, the large difference between the measured and the estimated was found at the 30 cm layer of the silty clay loam soil, and the gap was wider as soil water potential increased. In addition, the non-linear decrease of soil water content according to the increase of soil water potential tended to be more distinct in the sandy loam soil and at the 10 cm layer than in the silty clay loam soil and at the lower layers. These might be seen due to the various factors such as not only pore size distribution, but also cracks by high clay content and plow pan layers by compaction. This study clearly showed difficulty in the estimation of SWCC by such kind of factors.

Growth and yield responses of rice varieties to various soil water deficit conditions under different soil types

  • Kikuta, Mayumi;Samejima, Hiroaki;Magoti, Rahab;Kimani, John M.;Yamauchi, Akira;Makihara, Daigo
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2017.06a
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    • pp.322-322
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    • 2017
  • To avoid drought stress under rainfed upland conditions, it is important for rice to efficiently utilize water at shallow soil layers supplied by rainfall, and access to water retained in deer soil layers. The root developmental characteristics of rice, which play important role in the adaptability to drought conditions, vary depending on the variety. Moreover, water availability for plant differs depending on the soil types that have different physical properties such as water holding capacity, permeability, capillary force, penetration resistance, etc. In this study, we evaluated growth and yield responses of rice varieties to various soil water deficit conditions under three different soil types. The experiment was conducted in a plastic greenhouse at the Kenya Agricultural and Livestock Research Organization-Mwea from October 2016 to January 2017. Two upland varieties (NERICA 1 and 4) and one lowland variety (Komboka) were grown in handmade PVC pots (15.2 cm diameter and 85.0 cm height) filled with three different types of soil collected from major rice-growing areas of the country, namely black cotton (BC), red clay (RC), and sandy clay (SC). Three watering methods, 1) supplying water only from the soil surface (W1), 2) supplying water only from the bottom of the pots (W2), and 3) supplying water both from the soil surface and the bottom of pots (W3), were imposed from 40 days after sowing to maturity. Soil water content (SWC) at 20, 40, and 60 cm depths was measured regularly. At the harvesting stage, aboveground and root samples were collected to determine total dry weight (TDW), grain yield, and root length at 0-20, 20-40, 40-60, and 60-80 cm soil layers. Irrespective of the watering methods, the greatest root development was obtained in RC, while that in BC was less than other two soils. In BC, the degree of yield reduction under W1 was less than that in RC and SC, which could be attributed to the higher water holding capacity of BC. In RC, the growth and yield reduction observed in all varieties under W1 was attributed to the severe drought stress. On the other hand, under W2, SWC at the shallow soil depth in RC was maintained because of its higher capillary force compared with BC and SC. As the result, growths and yields in RC were not suppressed under W2. In SC, deep root development was not promoted by W2 irrespective of the varieties, which resulted in significant yield losses. Under W1, the rice growth and yield in SC was decreased although shallow root development was enhanced, and the stomatal conductance was maintained higher than RC. It was suspected that W1 caused nutrients leaching in SC because of its higher permeability. Under rainfed conditions, growth and yield of rice can be strongly affected by soil types because dynamics of soil water conditions change according to soil physical properties.

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Effects of Materials of Drainage Layer at the Reclaimed Soil Base on Tree Growth at the Open Space of Saemangeum Sea Dike (새만금 방조제 개활지의 준설토 기반에 대한 배수층재 처리가 수목 생육에 미치는 효과)

  • Lee, Hanna;Lim, Joo-Hoon;Koo, Namin;Bae, Sang-Won
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.18 no.1
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    • pp.13-23
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    • 2015
  • This study was performed to compare the effects of different drainage layers on tree growth at the exposed sites of Saemangeum sea dike. 4 types of drainage layers including control(dredged soil), specially prepared bark, gravel, and wood chip were set in 150~165cm depth of soil. Pinus thunbergii and Celtis sinensis were planted after 9 months of soil treatment. Electrical conductivity(EC) of soil in all treated plots were decreased under $4dS{\cdot}m^{-1}$, and NaCl(%) was decreased under 0.05% after 1 year from soil treatment. Soil moisture at the 120cm depth of the bark treated plot was higher than that of the 180cm soil depth, below the drainage layer. It is considered that vertical mobility of water was inhibited. Organic matter(OM) at the 120cm soil depth increased at bark and wood chip treated plots. Survival rates after 4 years of P. thunbergii and C. sinensis were 100% in all treatments. The height of P. thunbergii was not significantly different among the treatments while the height of C. sinensis was significantly different among the treatments and it was highest at the bark treated plot.

Studies on the Root Rot of Ginseng(III) (인삼근부병에 관한 연구 3)

  • 이민웅
    • Korean Journal of Microbiology
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    • v.12 no.4
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    • pp.153-158
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    • 1974
  • Around and in the area of Wolgot-Muon, Gimpo-Gun, Kyunggi province, I examined total bacteria, general Pseudomonas spp., fluorescent Pseudomonas spp., in soil layers and also in different kinds of soil of respective diseased, uncultivated, and healthy areas, and found the followings. 1. In the diseased and uncultivated areas, the content of moisture and silt was greater than in the healthy area. 2. Contrary to the above, the healthy area contained a greater amount of inorganic elements such as $P_2O_5$, K, Ca and of soil particle such as Cs and Fs. The degree of pH and content of Mg were even in three types of soils. 3. Total bacteria were found in abundance in the healthy soil. It was observed that in all types of areas, bacteria reside in abundance in the rhizosphere, i.e., 10-15 cm layers and that the closer the surface, the greater the numbers of the bacteria. 4. General Pseudomonas spp. were also found to the greater in number on the surface of the soil, especially so in the rhizosphere, with the numbers decreasing as the soil layers increase. Numbers of this bacteria in all types of area were nearly uniform. 5. A great number of fluorescent Pseudomonas spp. were found in the diseased area, especially so in the rhizosphere.

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강변여과수 개발부지 지하수의 수리지화학적 특성 -Preliminary results

  • 현승규;우남칠;신우식;함세영
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2003.09a
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    • pp.579-582
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    • 2003
  • This study is a part of the project to identify water-quality degradation mechanism due to Fe and Mn in the river-bank infiltration system in the Changwon city, Kyungsangnam-Do. Results of hydrogeochemical logging indicated that the matrix of the river bank affects groundwater quality, probably related with the hydraulic conductivities of the different layers of bank deposits. Electric conductivity logging data clearly show various layers of groundwater flows. Further studies are necessary to identify mechanisms of increasing dissolved oxygen contents with depths at some monitoring wells.

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Application of Analysis Models on Soil Water Retention Characteristics in Anthropogenic Soil (인위적으로 변경된 토양에서의 수분보유특성 해석 모형의 적용)

  • Hur, Seung-Oh;Jeon, Sang-Ho;Han, Kyung-Hwa;Jo, Hee-Rae;Sonn, Yeon-Kyu;Ha, Sang-Keun;Kim, Jeong-Gyu;Kim, Nam-Won
    • Korean Journal of Soil Science and Fertilizer
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    • v.43 no.6
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    • pp.823-827
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    • 2010
  • This study was conducted to assess the propriety of models for soil water characteristics estimation in anthropogenic soil through the measurement of soil water content and soil water matric potential. Soil profile was characterized with four different soil layers. Soil texture was loamy sand for the first soil layer (from soil surface to 30 cm soil depth), sand for the second (30~70 cm soil depth) and the third soil layers (70~120 cm soil depth), and sandy loam for the fourth soil layer (120 cm < soil depth). Soil water retention curve (SWRC), the relation between soil water content and soil water matric potential, took a similar trend between different layers except the layer of below 120 cm soil depth. The estimation of SWRC and air entry value was better in van Genuchten model by analytical method than in Brooks-Corey model with power function. Therefore, it could be concluded that van Genuchten model is more desirable than Brook-Corey model for estimating soil water characteristics of anthropogenic soil accumulated with saprolite.