• Korean Journal of Agricultural Science
• /
• v.49 no.2
• /
• pp.239-247
• /
• 2022

The physico-chemical properties of agricultural soil are factors that affect crop productivity and soil fertility. In Korea, agricultural environment change surveys have been conducted every four years since 1999. The purpose of this study is to investigate the status and changes in the physico-chemical properties of agricultural soil in Chungcheongnam-do. Samples were collected from the exact location of the aforementioned environment survey, and environmental variables (land use, type of crop cultivated) were investigated in relation to the samples. Soil collection was conducted using a core sampler and a single gouge auger. The bulk density of the soil generally increased up to a depth of sampling of 40 cm but decreased thereafter to a depth of 60 cm. Additionally, the bulk density was highest in the upland soil case and stood at 1.59 g·cm^-3, while the lowest value of 1.52 g·cm^-3 was obtained from orchard soil samples. Conversely, the porosity and moisture gradually decreased at soil depths of 0 - 40 cm and increased at depths of 40 - 60 cm. Most of the soil chemical properties generally decreased with an increase the soil depth from 0 to 70 cm, but electrical conductivity (EC) increased up to a depth of 40 cm. Therefore, it is judged that it is necessary to lower the bulk density by supplying organic matter for agricultural land in Chungcheongnam-do.

• Korean Journal of Soil Science and Fertilizer
• /
• v.46 no.6
• /
• pp.585-592
• /
• 2013

To estimate the effect of long-term fertilization on metabolically active bacterial communities in a rice field, RNA was extracted from endosphere (rice root), rhizosphere, and bulk soil that had been subjected to different fertilization regimes for 59 years, and the 16S rRNAs were analyzed using the pyrosequencing method. The richness and diversity of metabolically active bacteria were higher in bulk soil than in the endosphere and rhizosphere, and showed no significant difference between non-fertilized and fertilized plots. Weighted UniFrac analysis showed that each compartment had characteristic bacterial communities and that the effect of long-term fertilization on the structure of bacterial community was more pronounced in bulk soil than in the endosphere and rhizosphere. The 16S rRNAs affiliated with Alphaproteobacteria and Firmicutes were more abundant in the endosphere than in bulk soil while those affiliated with Chloroflexi and Acidobacteria were more abundant in bulk soil than in the endosphere. Several dominant operational taxonomic units (clustered at a 97% similarity cut-off) showed different frequencies between non-fertilized and fertilized plots, suggesting that the fertilization affected their activities in the rice field.

• Journal of Korean Society on Water Environment
• /
• v.23 no.4
• /
• pp.518-526
• /
• 2007

There have been serious soil erosion and water pollution problems caused by highland agriculture practices at Doam-dam watershed. Especially agricultural activities, chemical and organic fertilizer and pesticide applications, soil reconditioning to maintain soil fertility are known as primary causes of soil erosion and water qaulity degradation in the receiving water bodies. Among these, soil reconditioning can accelerate soil erosion rates. To develop soil erosion prevention practices, it is necessary to estimate the soil erosion from the watershed. Thus, the Universal Soil Loss Equation (USLE) model has been developed and utilized to assess soil erosion. However, the USLE model cannot be used at watershed scale because it does not consider sediment delivery ratio (SDR) for watershed application. For this reason, the Sediment Assessment Tool for Effective Erosion Control (SA TEEC) was developed to assess the sediment yield at any point in the watershed. The USLE-based SA TEEC system can estimate the SDR using area-based SDR and slope-based SDR module. In this study, the SATEEC system was used to estimate soil erosion and sediment yield at the Doam-dam watershed using the soil properties from reconditioned agricultural fields. Based on the soil sampling and analysis, the US LE K factor was calculated and used in the SA TEEC system to analyze the possible errors of previous USLE application studies using soil properties from the digital soil map, and compared with that using soil properties obtained in this study. The estimated soil erosion at the Doam-dam watershed without using soil properties obtained in the soil sampling and analysis is 1,791,400 ton/year (123 ton/ha/year), while the soil erosion amount is 2,429,900 ton/year (166.8 ton/ha/year) with the use of soil properties from the soil sampling and analysis. There is 35 % increase in estimated soil erosion and sediment yield with the use of soil properties from soil reconditioned agricultural fields. Since significant amount of soil erosion are known to be occurring from the agricultural fields, the soil erosion and sediment yield from only agricultural fields was assessed. The soil erosion rate is 45.9 ton/ha/year without considering soil properties from soil reconditioned agricultural fields, while 105.3 ton/ha/year after considering soil properties obtained in this study, increased in 129%. This study shows that it is very important to use correct soil properties to assess soil erosion and sediment yield simulation. It is recommended that further studies are needed to develop environment friendly soil reconditioning method should be developed and implemented to decrease the speed of soil erosion rates and water quality degradation.

• Korean Journal of Soil Science and Fertilizer
• /
• v.47 no.5
• /
• pp.319-323
• /
• 2014

This study investigates the prediction of soil chemical properties (organic matter (OM), pH, Ca, Mg, K, Na, total acidity, cation exchange capacity (CEC)) on 688 Korean soil samples using the visible-near infrared reflectance (VIS-NIR) spectroscopy. Reflectance from the visible to near-infrared spectrum (350 to 2500 nm) was acquired using the ASD Field Spec Pro. A total of 688 soil samples from 168 soil profiles were collected from 2009 to 2011. The spectra were resampled to 10 nm spacing and converted to the 1st derivative of absorbance (log (1/R)), which was used for predicting soil chemical properties. Principal components analysis (PCA), partial least squares regression (PLSR) and regression rules model (Cubist) were applied to predict soil chemical properties. The regression rules model (Cubist) showed the best results among these, with lower error on the calibration data. For quantitatively determining OM, total acidity, CEC, a VIS-NIR spectroscopy could be used as a routine method if the estimation quality is more improved.

• Korean Journal of Soil Science and Fertilizer
• /
• v.49 no.5
• /
• pp.434-439
• /
• 2016

Anthropogenic soil in cropland is formed in the process of subsoil reversal and the refill of soil into cropland. However, there was little information on the chemical properties within soil profiles in anthropogenic soil under rice paddy near the river. In this study, we investigated the chemical properties within soil profiles in the anthropogenic soil located at 4 sites in Gumi, Kimhae, Chungju, and Euiseong to compare with the natural paddy soil near the river. Among particle sizes, the sand content decreased under soil profiles but the silt and clay contents increased compared to the natural paddy soil in soil profiles. Organic matter content in topsoil of anthropogenic soil was lower than in that of natural soil, which was shown the contrary tendency within soil profiles. Also, the soil pH, available $P_2O_5$, and exchangeable cations were higher in anthropogenic soil compared to natural paddy soil at topsoil, which was maintained these tendency into soil depth. Nutrients may be equally distributed in anthropogenic soil during the process of refill in paddy soil near the river. This results indicated that anthropogenic soil would contribute to carbon sequestration, the mitigation of compaction, and reduction of fertilizer application in paddy soil. Therefore, characteristics of anthropogenic soil can be used for the soil management in cropland.

• Korean Journal of Environmental Agriculture
• /
• v.37 no.2
• /
• pp.141-145
• /
• 2018

BACKGROUND: Agricultural soils are vulnerable from contamination of heavy metal derived from industrial waste. Monitoring on heavy metals on agricultural soils around industrial complexes and evaluation on distributional state on the concentrations of heavy metals in soil have been carried out for problem assessment on soil condition. METHODS AND RESULTS: Soil samples of 1,200, were collected from sixty site of industrial complexes located Gyounggi, Chungbuk, Cheonbuk, and Gyoungnam provinces. Total concentration of Cu, Pb, Zn, Ni, and As were analyzed. Heavy metal concentrations in most soil samples were below warning criteria, except 1 site of Pb, Ni, and As, separately. The comparison of mean values of heavy metal concentrations between soils around industrial complexes and paddy soils, showed similar levels of heavy metals, except Pb. The concentrations of lots of heavy metals were distributed between from warning criteria to one fifth level of warning criteria. However, in the case of Cu and Pb, more than 30% were distributed below one twenties level of warning criteria. These results were very similar with the distribution state of heavy metals in upland soils. The concentrations of heavy metals in surface soil and subsoil were similar among the heavy metals in soils around industrial complexes. CONCLUSION: The concentrations of heavy metals in soils around industrial complexes were distributed close to warning criteria. Long term and continous monitoring and evaluation on heavy metals in agricultural soils are required for food safety and sustainable soil management.

• Korean Journal of Agricultural Science
• /
• v.41 no.4
• /
• pp.369-377
• /
• 2014

This study was carried out to evaluate the effect of rice husk (RHB) and food waste biochar (FWB) on upland soil with sandy loam texture, in terms of physico-chemical analysis, lettuce seed germination test, and orgainc carbon leaching experiment. RHB and FWB had different physico-chemical properties each other. Carbon to nitrogen ratio (C/N ratio) of RHB was 32, showing two times higher than that of FWB. FWB had high salt and heavy metal content, compared to RHB. This is probably due to different ingredients and production processing between two biochars each other. Results of germination test with Lettuce showed lower germination rate when FWB was applied because of higher salt concentration compared to control and RHB. Organic carbon leaching test using saturated soil column (${\Phi}75{\times}h75mm$) with $10MT\;ha^{-1}$ biochar application rate, showed higher saturated hydraulic conductivity in rice husk biochar treatment column, compared to control and food waste biochar treatment. The highest total organic carbon concentration in column effluent was lower than those in both of rice husk biochar and food waste biochar, whereas the differences was negligible after 9 pore volumes of effluent. Consequently, biochars from byproducts such as rice husk and food waste in sandy loam textured upland soil could enhance a buffer function such as reduction of leaching from soil, but the harmful ingredient to crops such as high salt and heavy metals could limit the agricultural use of biochars.

• Korean Journal of Soil Science and Fertilizer
• /
• v.48 no.6
• /
• pp.588-592
• /
• 2015

Soil testing is one of the major strategies for establishing sustainable agricultural practice as it analyzes nutrient contents of soil and determines the amount of nutrients required for crop growth. Soil testing for the field cultivating regional major crops in Korea has been conducting by National Academy of Agricultural Science (NAAS), provincial agricultural research & extension services and agriculture technology centers since 2000. 1,006,227 soil samples were analyzed and uploaded on Korean soil information system (http://soil.rda.go.kr) from 2003 to 2013. Soil pH has changed from 6.1 to 6.2. Organic matter (OM), available (Avail.) phosphate and exchangeable (Exch.) K have decreased from 24 to $23gkg^{-1}$, 541 to $399mgkg^{-1}$ and 0.90 to $0.72cmol_ckg^{-1}$ between 2003 and 2013, respectively. Especially, Exch. Ca contents decreased to $5.7cmol_ckg^{-1}$ in 2009 and increased to $6.2cmol_ckg^{-1}$ in 2013. Ratios of optimal ranges for cropping were 48% for pH, 22% for OM, 26% for Avail. phosphate, and 23, 16, 22% for Exch. K, Ca and Mg in 2013. Ratios of optimal ranges for pH increased and low ranges for OM, Avail. phosphate and Exch. K increased. Frequency distribution was 64% for pH 5.5~7.0, 65% for OM $10{\sim}30gkg^{-1}$, 48% for Avail. phosphate under $300mgkg^{-1}$ and 23, 29, 22% for Exch. K 0.2~0.6, Ca 4.0~6.0 and Mg $1.0{\sim}1.5cmol_ckg^{-1}$.

• Korean Journal of Agricultural Science
• /
• v.41 no.4
• /
• pp.391-398
• /
• 2014

Identifying soil water content as a major factor for evaluating irrigation and water resource is a primary module to develop a prediction model. A variety of PTFs (Pedo-Transfer Functions) are applied in the models to estimate soil water content, the analysis techniques, however, which compare the estimated from models and the measured by instruments, are not reached at the level to demonstrate the effectiveness of the PTFs in Korea. Many soil physicians such as Eom, Peterson, Rawls, Saxton, Bruand, Baties, Tomasella & Hodnett (T&H), and Minasny, have developed analytic models using PTFs. Soil data for the analysis used soil water contents on 347 soil series (10 kPa), 358 soil series (33 kPa), 356 soil series (1,500 kPa) established by NAAS (National Academy of Agricultural Science). A coefficient of determination on soil water content at 10, 33 and 1,500 kPa was the highest as 0.5932 in EM (Eom model), 0.6744 in REM (Rawls model) and 0.6108 in REM, respectively. In conclusion, it is strongly suggested that the use of EM or REM is suitable for estimating soil water content in Korea although SM (Saxton model) has been widely used.

• Korean Journal of Soil Science and Fertilizer
• /
• v.47 no.6
• /
• pp.553-557
• /
• 2014

The steady increase in livestock industry has greatly required the stable production of food and forage crops. As an alternative, rice-forage cropping system has been attempted in several southern areas. The present study was performed to understand whether an application of cattle-manure compost affects soil chemical properties and crop productivity in rice-forage cropping system, rice ${\rightarrow}$ summer oat ${\rightarrow}$ rye, in Jangheong county, south Jeolla province from 2013 to 2014. Treatments was composed of control (no compost), CM1 (compost application before rice transplanting), and CM2 (two-times compost application, before rice transplanting and after rice harvest), and inorganic fertilizers (N, P, and K) were equally dressed in all plots. Yields of rice were not significantly different between treatments, however, oat production was 1.25-fold higher in CM1 and CM2. Nutrient uptake amounts of rye were higher in CM2 than CM1 and control. Total nitrogen in soil was maintained stable level during crop cultivation. And soil organic matter contents in all treatments were increased by crop residue. Available P_2O_5$ and exchangeable K were increased by cattle manure application. Therefore, it suggested that the amount of nutrient by forage crop residue should be considered in rice-forage multiple cultivation.