• Korean Journal of Soil Science and Fertilizer
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• v.49 no.4
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• pp.327-334
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• 2016

In order to compare phosphorus (P) behavior of livestock manure compost (LMC) and chemical fertilizer (CF) applied to the sea-reclaimed land soils, incubation experiments were conducted for five weeks. Four soils differing textural classes, sandy loam and clay loam, and electric conductivity (EC) value, high and low, were applied with CF and LMC. LMC was applied at the level of 0, 1, 2, and 3% on the soil weight basis and CF was applied at the same levels of P as LMC. The results showed that increase of P application rate of CF and LMC led to linearly increase available $P_2O_5$ and $0.01M\;CaCl_2$ extractable P contents regardless of soil texture and EC. However, 0.01M $CaCl_2$ extractable P from soil applied with CF was significantly higher than with LMC. Correlation analysis between $0.01M-CaCl_2$ extractable P and fractionated P by different extraction methods showed that $0.01M-CaCl_2$ extractable P positively correlated with KCl-P (soluble and exchangeable P) and HCl-P (Ca and Mg bound P). However, NaOH-P (Fe and Al bound P and organic P) and residual P was adverse. The amount of NaOH-P significantly influenced to the amount of 0.01M $CaCl_2$ extractable P of CF and LMC in the soils. The application of LMC at sandy loam soil could be carried out in the consideration of nutrient leaching and crop uptake.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.6
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• pp.712-719
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• 2016

Understanding N mineralization dynamics in soil is essential for efficient nutrient management. An anaerobic incubation experiment was conducted to examine N mineralization potential and N mineralization rate of the organic amendments with different C:N ratio in paddy soil. Inorganic N in the soil sample was measured periodically under three temperature conditions ($20^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$) for 90 days. N mineralization was accelerated as the temperature rises by approximately $10%^{\circ}C^{-1}$ in average. Negative correlation ($R^2=0.707$) was observed between soil inorganic N and C:N ratio, while total organic carbon extract ($R^2=0.947$) and microbial biomass C ($R^2=0.824$) in the soil were positively related to C:N ratio. Single exponential model was applied for quantitative evaluation of N mineralization process. Model parameter for N mineralization rate, k, increased in proportion to temperature. N mineralization potential, $N_p$, was very different depending on C:N ratio of organic input. $N_p$ value decreased as C:N ratio increased, ranged from $74.3mg\;kg^{-1}$ in a low C:N ratio (12.0 in hairy vetch) to $15.1mg\;kg^{-1}$ in a high C:N ratio (78.2 in rice straw). This result indicated that the amount of inorganic N available for crop uptake can be predicted by temperature and C:N ratio of organic amendment. Consequently, it is suggested that the amount of organic fertilizer application in paddy soil would be determined based on temperature observations and C:N ratio, which represent the decomposition characteristics of organic amendments.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.4
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• pp.373-381
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• 1994

This experiment was conducted to investigate the effects of nitrogen fertilizer level on forage yield and feed value, and to clarify the optimum nitrogen fertilizer level of rye in middle west area when cultured in paddy field. The field experiment treated 5 levels of nitrogen fertilization was carried out at Yesan from Oct. 1990 to June 1991. The fresh and dry weight increased with increased nitrogen fertilizer level by 30kg /10a, but dry matter ratio decreased. The ratio of leaf blade and leaf sheath in rye plant increased with increased nitrogen fertilizer level, but the ratio of stem and inflorescence decreased. The content and yield per unit area for protein, total digestible nutrient(TDN). Minerals, and energy increased with increased nitrogen fertilizer level, while acid detergent fiber(ADF) and neutral detergent fiber(NDF) decreased. The ratio of available protein among crude protein became higher with increased nitrogen fertilizer level. The optimum clipping time for net energy gain(NEG) and net energy maintenance(NEM) were 10 days earlier than milk stage for conventional items including TDN and proteins.

• Korean Journal of Organic Agriculture
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• v.18 no.1
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• pp.83-92
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• 2010

Organic farming is a type of agricultural practices based on naturally occurring processes excluding or strictly limiting the use of synthetic fertilizers, pesticides, and other chemicals. This study was conducted to investigate the influences of agro-based materials, effective microorganisms (EM), liquid silicate (LS), and organic liquid fertilizer (OLF) for water dropwort (Oenanthe stolonifera DC.) cultivation. Soil pH, soil organic matter, and plant available phosphorous decreased with LS application. Exchangeable Ca and Mg decreased with EM application, and electrical conductivity and exchangeable Ca and K decreased with OLF application. Most of essential nutrient contents in water dropwort were reduced with the treatments of LS, EM, and OLF as compared with those in control plot, except nitrogen and phosphorus. However, diseases and insect pests were almost not observed in the water dropwort in the agro-based material application plots, except cluster caterpillar (Spodoptera litura). Productivity of water dropwort tended to be reduced: its higher productivity in the OLF and EM+LS plots and lower in the LS and control plots.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.2
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• pp.134-142
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• 2017

Crop production in rice paddy fields is of great importance because of declining rice consumption and the low self-sufficiency ratio for field crops in Korea. A controlled drainage system (CDS) is recognized as an effective means to adjust water table (WT) levels as needed and control soil water content to improve the soil environment for optimum crop growth. The present study evaluated the effects of a CDS on soil characteristics, including soil water distribution and soybean development in paddy fields. The CDS was installed with two drain spacing (3 m and 6 m) at the experimental paddy field at the National Institute of Crop Science, Miryang, Korea. It was managed with two WT levels (0.3 m and 0.6 m) during the growing season. Soil water content, electrical conductivity and plant available nitrogen content in the soil were significantly greater in the 0.3 m WT management plots than in the 0.6 m plot and the control. At the vegetative stage, chlorophyll content was significantly lower with higher WT control because of excess soil moisture, but it recovered after the flowering stage. Soybean yield increased with WT management and the 0.6 m WT treatment produced the greatest grain yield, $3.38ton\;ha^{-1}$, which was 50% greater than that of the control. The CDS directly influenced outflow through the drains, which significantly delayed nutrient loss. The results of this study indicated that WT management by CDS can influence soil characteristics and it is an important practice for high yielding soybean production in paddy fields, which should be considered the crop growth stages for stable crop production.

• Journal of Ginseng Research
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• v.13 no.1
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• pp.105-113
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• 1989

This study was conducted to determine the cause of the occurence of marginal leaf chlorosis in ginseng plants (Panax ginseng C.A. Meyer), and to determine its emersion in fields (practically) and in pots (experimentally). The following results were obtained. In the Present investigation, ginseng plants raised in acidic soil containing a high a moue t of Mn showed marginal leaf chlorosis. Henre it Ivas suggested that the shoot growth and root weights became grad gractually lower. The leaves having marginal leaf chlorosis contained low amounts of N, P,. Ca, Mg, and Na and the Fe/Mn ratios were low. There was a corresponding increase in Mn uptake. It was founrl that in soils where marginal leaf chlorisis occured the pH urar brlolv 4.2 to 4.9 and the Ca, Mg and Na content was decreased thus effectively increasing the available manganese in the soil. The Mn/Fe ratios in the yellow leaf margins of ginseng Plants affected by the Mn toxicity was over 2.0 compared to the general Mn/Fe ratio of 0.50 for healthily leaves, stems and roots. Typically when ginseng plants grow fields having soil with a pH below about 5.0, there tenor to be an uptake of excess Mn. When ginseng plants are grown in a nutrient sand culture solution It with an increased Mn concentration, they accumulate large amounts of Mn in the roots and in the shoots. In both casts marginal leaf chlorosis appeared in the emersions. In the Present investigation, ginseng plants raised in acidic soil and containing a high amount of Mn showed marginal leaf chlorosis.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.1
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• pp.25-30
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• 1993

It is common that in the vegetable cultivation areas, the farmers tend to continue the heavy fertilization to maximize the crop yields in short term. This results in the accumulation of fertilizer elements in the soil and increase in the electrical conductivity of soil. Disregarding these, farmers continue to apply heavy doses of fertilizers. A field experiment was conducted to find out on such a soil whether fertilizer application taking the quantity of nutrients accumulated in the soil into account would save the fertilizer without losing the yield of crop, using Chinese cabbage and spinach as test crops. The findings of the experiment is summarized as following. 1. The yield of Chinese cabbage was not affected by reduction of $19kg\;P_2O_5/10a$ and $7kg\;K_2O/10a$ as compared to farmers doses, and in case of spinach the yield rather was increased under the reduction of $22kg\;P_2O_5/10a$ and $22kg\;K_2O/10a$. 2. The reduction of fertilizers according to plant nutrient status of soils did not affect the inorganic nutrient contents of the crops significantly, in both Chinese cabbage and spinach. 3. A trend was observed that the reduction in the P and K fertilizers application would shorten the storage period of Chinese cabbage. 4. The reduction in P and K fertilizers application resulted in the reduction in available P, exchangeable K, EC and $NO_3-N$ in the soil after the harvest of the crops.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.4
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• pp.283-291
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• 2000

The beneficial effects of mycorrhizal fungi on plant growth has largely been attributed to higher uptake of P and other mineral nutrients. However, the effects of mycorrhizal colonization on uptake of mineral nutrients are conflicting in various past investigations. This study was carried out to investigate the effect of P application rate on mycorrhizal colonization and nutrient uptake of Poncirus trifoliata (trifoliate orange) seedlings grown in non-cultivated volcanic ash soil of Cheju island. Five levels of P (40, 573, 1,106, 1,373. $1,640mg\;P\;kg^{-1}$) were applied with double superphosphate. Seedlings inoculated with mycorrhizal fungi were grown for 5 month in a greenhouse. As the level of P application increased, mycorrhizal colonization in the seedlings decreased, and the colonization was significantly reduced when available P was higher than $150mg\;P\;kg^{-1}$ levels. There was a significant correlation between mycorrhizal colonization and P uptake by trifoliate orange seedlings at lower P applications. The effectiveness of mycorrhiaze on P uptake was more significant at lower P applications. Uptake of N, K, Ca, Mg an Zn by trifoliate orange seedlings also increased as mycorrhizal colonization increased, but mycorrhizae could not enhance the uptake of Cu by trifoliate orange seedlings in volcanic ash soil of Cheju island.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.4
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• pp.220-227
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• 2004

Phosphorus desorption study is essential to understanding P behavior in agricultural and environmental soils because phosphorus is considered as two different aspects, a plant nutrient versus an environmental contaminant. This study was conducted to determine soil P buffering power related to P desorption quantity intensity (Q/I) parameters, $Q_{max}$(an index of P release capacity) and $l_0$(an index of the intensity factor), and to investigate the characteristics of relationship between the P desorption Q/I parameters and the soil properties. Soil samples were prepared with treatments of 0 and $100mg\;P\;kg^{-1}$ applied as $KH_2PO_4$ solution. The P desorption Q/I curves were obtained by a procedure using anion exchange resin beads and described by an empirical equation ($Q=aI^{-1}+bln(I+1)+c$). The P desorption Q/I curves for the high available P (${\g}20mg\;kg^{-1}$ of Olsen P) soils were characteristic concave trends with or without soil P enrichment, whereas for the low available P (${\lt}20mg\;kg^{-1}$ of Olsen P) soils, the anticipated Q/I concave curves could not be obtained without a proper amount of P addition. When the soils were enriched in phosphates, the values of desorbed solid phase labile P and solution P, such as $Q_{max}$ and $I_0$ respectively, were increased, but the ratio of $Q_{max}$ versus $I_0$ was decreased. Thus, the slope of desorption Q/I curve represented as phosphorus buffering power, $|BP_0|$, is decreased. The $|BP_0|$ values of the high available P soils ranged between 48 and $61L\;kg^{-1}$ in the P untreated samples and between 18 and $44L\;kg^{-1}$ in the P enriched samples. Overall $|BP_0|$ values of both low and high available P soils treated with $l00mg\;P\;kg^{-1}$ ranged between 14 and $79L\;kg^{-1}$. The $Q_{max}$, values ranged between 71.4 and $173.1mg\;P\;kg^{-1}$, and the lo values ranged between 0.98 and $3.82mg\;P\;L^{-1}$ in the P enriched soils. The $Q_{max}$ and $I_0$ values that control the P buffering power may be not specifically related to a specific soil property, but those values were complicatedly related to soil pH, clay content, soil organic matter content, and lime. Also, phosphorus release activity, however, markedly depended on the desorbability of the applied P as well as the native labile P.

• Weed & Turfgrass Science
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• v.4 no.2
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• pp.144-150
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• 2015

Silicate fertilizers known to be effective in improving the growth and density of zoysiagrass. Most silicate fertilizers being used in Korea are slag-originated silicate fertilizer, but some water soluble silicate fertilizers are commercially available recently. This study was conducted to know the effect of water soluble silicate fertilizer, on the growth of zoysiagrass and the change of soil chemical properties in Wagner pot and field experiment. Root length, fresh and dry weight of shoots and stolons, the number of shoots and stolons, total of stolons length and the $SiO_2$ content of internal plant were significantly increased by the $SiO_2$ content but chemical properties of the soil were not significantly changed by the $SiO_2$ content. The $SiO_2$ contents of 18 and $36{\mu}lml^{-1}$ did not show significance difference, and therefore a reasonable application the content of $SiO_2$ was thought to be $18{\mu}lml^{-1}$. Foliar spray of water soluble silicate fertilizer is believed to enhance the growth and density of zoysiagrass than soil application.