• Korean Journal of Soil Science and Fertilizer
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• v.42 no.spc
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• pp.47-50
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• 2009

Nutrient losses, especially nitrogen and phosphorus, in agricultural runoff can contaminate surface and ground water, leading to eutrophication. Thus, erosion control is crucial to minimizing nutrient losses from agricultural land. Assessments of various erosion control practices were carried out under various cropping system, soil management practices, and slope conditions by means of a lysimeter study and under artificial rainfall. Soil and nutrient losses were monitored in a small agricultural field to evaluate the soil conservation practices. Nutrient losses occur in runoff and leachate (dissolved nutrient) and in sediments (particulate nutrient). Dissolved nitrates accounted for the majority (about 90%) of nitrate transport within the soil. Particulate phosphate in sediments represented the majority (60% to 67%) of phosphate transport. Recently, engineering and agronomic erosion-control practices haver been used to reduce erosion problems in fields on slopes. These practices reduced soil loss, runoff, and nutrient loss to 1/6, 1/2,and 1/3 their original levels, respectively. Bioavailable particulate phosphate in sediments represents a variable but longterm source of phosphate for algae. Dissolved nitrate and phosphate are immediately available for algal uptake, so reducing fluxes of these nutrients should also reduce the risk of eutrophication.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.3
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• pp.270-274
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• 1992

This study was observed to find out the relationship of soil microorgaism physico-chemical properties and yields on the continuous cultivation of peanuts soil in the difference 20 farmes field located in Gochang, Chonbuk area. The results obtained was summarized as follows : 1. Soil hardness and volume of soild and liquid of peanut continuous cultivation soil were higher than those of one year cultuvation. 2. The exceeding optimum level of phosphorus and potassium appeared factors affecting and reduction of peanut continuous cultivation soil. 3. Number of microorgaisms in continuous cultivation soil was high but the ratio of bacteria/fungi (B/F) and actinomycetes/fungi (A/F) ratio were low. 4. The number of soil nematodes in continuous cultivation soil were higher than that of alternative cultivation soil.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.3
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• pp.1-10
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• 2017

The aim of this study is to investigate the chemical properties and heavy metal concentration of soils in conventional and organic paddy. We sampled and analyzed topsoil (0~15 cm) and subsoil (15~30 cm) of conventional and organic paddy fields in Yongin and Anseong, South Korea. The statistical significance between groups was determined by Duncan's multiple range test and correlation between soil properties was also analyzed. The results show that organic matter (OM) and T-N of conventional paddy soil were higher than those of organic paddy soil. However, higher T-P concentration was observed in organic paddy soil than conventional paddy soil. As, Pb, and Zn concentration in organic paddy soil were statistically lower than those in conventional paddy soil. The couple of water content (WC) & As, OM & T-N, T-P & $P_2O_5$, T-P & Zn, $P_2O_5$ & Zn, and Cr & Ni had a good positive correlation but the couple of WC & T-P, WC & Zn, T-P & As, and As & Zn had a strong negative correlation. It can be concluded that organic farming is beneficial to soil environment by reducing the amounts of organic matter, T-N, As, Pb, and Zn concentration in paddy soil when compared to conventional farming.

• Current Research on Agriculture and Life Sciences
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• v.20
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• pp.77-82
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• 2002

This study was carried out in order to produce useful material for the forest multiple use and forest protection by physico-chemical soil analysis of studied area in Sokwang-ri Forest Genetic Resource Protection Forest which was divided into in standard plots include Tricholoma matsutake and Sarcodon aspratus production forest. The result of physico-chemical soil analysis represented as following. The soil type of T. matsutake production forest was Dry brown forest soil(B1), while on the other hand the soil type of S. aspratus production forest was Moderately moist brown forest soil(B3). Between T. matsutake and S. aspratus production forest did not result in significant changes in soil pH(5.22-5.60) and soil depth(47cm), but available phosphorus, carbon, and nitrogen contents were different results. CN ratio of the fairy ring of T. matsutake was quite lower than that in S. aspratus production forests, which indicated that T. matsutake production forest was built up in the relatively immature soils which contain little organic matter. Generally, it was predicted that Pinus densiflora for. erecta forest succeeded to deciduous tree forest in stable soil environments. To conserve these T. matsutake and S. aspratus production forest, the contents of available phosphorous and exchangeable cation should be increased by continuous soil environment management and it should be established the secondary growth forests of old aged Pinus densiflora for. erecta trees as soon as possible.

• Korean Journal of Environmental Biology
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• v.22 no.1
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• pp.93-100
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• 2004

The content of nutrients such as organic carbon, nitrogen, phosphorus and potassium accumulated on soil layers in Quercus mongolica forest of Mt. Songnisan National Park located at central part of Korea was measured, and then the decomposition constants and decay times of the nutrients were also calculated by the negative coefficience model(O1son,1963). The quantities of organic carton of L-layer, F-layer, H-layer and $A_1$-layer of the forest stand were 231.25 g $m^{-2}$, 291.50 g $m^{-2}$,166.91 g$m^{-2}$ and 174.51 g $m^{-2}$, respectively. The content of organic carbon and nitrogen contained in L-layer and F-layer showed large quantity than those of other layers. The large amount of phosphorus and potassium was observed at the B-layer and $A_1$-layer. On the other hand, the decomposition constants(k) of soil organic matter were as follows : organic carbon (k = 0.3657), nitrogen (k = 0.3319), phosphorus (k = 0.2050), and potassium (k = 0.0934) and the decay times needed to 99% decomposition of nutrients in soil organic matter were as follows: that is, organic carton, nitrogen, phosphorus and potassium was 13.94 years, 15.18 years, 24.79 years, and 55.11 years, respectively. By the application of Turbo Pascal Program on the inflowed and outflowed nutrients to the forest stand,87.67% (714.84 g $m^{-2}$) of organic carbon inflowed was decomposed and 81.62% (1,594.62 g $m^{-2}$) of organic carbon accumulated was decomposed. And 84.98% of nitrogen inflowed was decomposed and 70.26% of nitrogen accumulated was also decayed.50.00% of phosphorus input and 40.31% of potassium input were decomposed, and 38.40% of phosphoyus and 33.03% of potassium accumulated were also decayed, respectively. Therefore, it is suggested that Quercus mongolica forest surveyed in the present study is maintaining in steady state because input and output amounts of nutrients is shown a similar pattern.

• Korean Journal of Environmental Agriculture
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• v.18 no.2
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• pp.140-147
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• 1999

Since the national land area is small and the fanning land occupies only 24% of total land area in Korea, the promotion of agricultural productivity is urgent. In this process, the application rate of chemical fertilizer, which is the major pollution factor at agricultural non-point sources, has been increasing in every year. The present study examined difference of runoff loading of nitrogen and phosphorus by rainfall intensity(above 100mm, 80-100mm, 50-80mm and 30-50mm). Runoff loading of nitrogen and phosphorus by rainfall intensity has differences under similar rainfall intensity. We are considering that these results were affected by rainfall intensity as well as hydrological condition, soil management, whether or not fertilizer application, cropping, rice straw and plowing.

• Journal of Microbiology and Biotechnology
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• v.30 no.1
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• pp.118-126
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• 2020

Silicon and phosphorus are elements that are beneficial for plant growth. Despite the abundant availability of silicate and phosphate in the Earth's crust, crop nutritional requirements for silicon and phosphorus are normally met through the application of fertilizer. However, fertilizers are one of the major causes of heavy metal pollution. In our study, we aimed to assess silicate and phosphate solubilization by the bacteria Enterobacter ludwigii GAK2, in the presence and absence of phosphate [Ca₃(PO₄)₂] or silicate (Mg₂O₈Si₃), to counteract cadmium stress in rice (Oryza sativa L). Our results showed that the GAK2-treated rice plants, grown in soil amended with phosphate [Ca₃(PO₄)₂] or silicate (Mg₂O₈Si₃), had significantly reduced cadmium content, and enhanced plant growth promoting characteristics including fresh shoot and root weight, plant height, and chlorophyll content. These plants showed significant downregulation of the cadmium transporter gene, OsHMA2, and upregulation of the silicon carrier gene, OsLsi1. Moreover, jasmonic acid levels were significantly reduced in the GAK2-inoculated plants, and this was further supported by the downregulation of the jasmonic acid related gene, OsJAZ1. These results indicate that Enterobacter ludwigii GAK2 can be used as a silicon and phosphorus bio-fertilizer, which solubilizes insoluble silicate and phosphate, and mitigates heavy metal toxicity in crops.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.1
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• pp.99-105
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• 1993

This study determined the macro-mineral levels in plants and sheep, at different times during the year, at three farms in northern China. Samples of plants, animal tissues and faeces were collected at 5 to 8 times during the year from each site. They were analysed for calcium, sodium, phosphorus, magnesium and potassium. Sodium concentrations in plants were below those recommended for optimum animal production at all sites for all or part of the year (0.01-1.66 g/kg DM). Low concentrations of sodium in faeces were measured and signs of sodium deficiency (soil ingestion) were observed on one farm. There were seasonal trends in other mineral levels in plants and animals. Plants were lowest in potassium (2.3-13.4 g/kg DM), magnesium (1.28-4.82 g/kg DM) and phosphorus (0.24-1.62 g/kg DM) in winter and spring. However, high levels of these elements were supplied in the feed supplements used at this time of the year. During the periods of rapid pasture growth, in summer and autumn, supplements of feed and salt are often not provide even though pasture concentrations of phosphorus and sodium are low. It may be at these times that sheep will be most susceptible to deficiencies of these elements.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.1
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• pp.47-58
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• 2002

Much of the plastic film house soils in the southern part of the Korean peninsula are managed using a upland-paddy rotation culture system (hereafter, RS) to prevent salt accumulation in soil. However, information on the effects of RS on soil properties and environmental conservation is limited. In order to determine the effects of RS on soil properties, 22 fields under RS and 20 fields under a non-rotation system (hereafter, NRS) in plastic film houses were selected in Chinju, in southern Korea, and the P distribution characteristics were investigated, including the chemical properties. The RS contributed to the removal of water-soluble salts in the surface layer and to the redistribution of organic matter evenly in the soil profile. In the AP horizon, available phosphorus levels were $1,611mg\;kg^{-1}$ in RS and $1,789mg\;kg^{-1}$ in NRS, which markedly exceeds the optimum range for plant cultivation. Total P was lower in RS (average $4,593mg\;kg^{-1}$) than in NRS (average $5,440mg\;kg^{-1}$) and this decrease was taken to be an effect of RS. Inorganic P was the predominant form of P in both systems, followed by organic P and residual P. A soil profile showed that total and inorganic P concentrations decreased with depth in both systems. However, organic P increased withdepth in RS, which was in contrast to that noted in NRS. The increase in organic P with depth in RS implied that organically rather than inorganically derived phosphate moved through the soil. The concentrations of water-soluble P, Ca-P and Al-P were higher in NRS than in RS soil profiles, but the Fe-P concentration was higher in RS than in NRS, which might be affected by the anaerobic conditions found in paddy soils. In both systems, the Al-P form of extractable P predominated in the surface layer, followed by Ca-P, Fe-P and water-soluble P. With increasing depth, the composition rate of Ca-P to extractable P decreased to less than 10% in the 60-70cm depth, as Fe-P dominated at this level. The content of water-soluble P, potentially the main source of eutrophication, was higher in NRS than in RS. These results indicated that the RS used in plastic film houses contributed to the removal of water-soluble salts but only slightly decreased the phosphate concentration.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.457-464
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• 2011

Livestock manure compost (LC) generally contains high content of phosphorus, therefore can be a substitute for phosphorus fertilizers. In this experiment of the cultivation of lettuce in green house, the possibility of LC as a subsitute for phosphorus fertilizer was investigated and the fertilizer efficiency of nitrogen and potassium in LC as compared with chemical N fertilizer (urea) and K fertilizer (potassium chloride) was examined. In proportion to the increase in the application rate of nitrogen fertilizer, soil pH declined, whereas EC and $NO_3$-N content became higher. The application of LC appeared to increase the soil content of organic matter, available phosphate, exchangeable calcium, magnesium and sodium more than that of chemical fertilizer. Supplementation of the K fertilizer by the lack amount from the application of LC resulted in the same exchangeable potassium content in soil with NPK plot in which N, P and K fertilizers were applied by the amount of soil test recommendation. The relationship between soil $NO_3$-N content and nitrogen application rate from fertilizer and compost showed as y=0.57717a+0.19760b+74.65 ($R^2$=0.6347) in which y is the soil $NO_3$-N content (mg $kg^{-1}$), a is nitrogen application rate from fertilizer and b is nitrogen application rate from compost (kg $ha^{-1}$), respectively. From this equation, the supply ability of $NO_3$-N into soil of LC exhibited about 34% (pig manure compost 37.0, chicken manure compost 34.7, cattle manure compost 23.3) of nitrogen fertilizer (urea).