• Korean Journal of Soil Science and Fertilizer
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• v.46 no.3
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• pp.187-192
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• 2013

This study was carried out to investigate the incorporation effect of green manure crops (GMC) such as the hairy vetch on improvement of soil environment in reclaimed land during silage corn cultivation over the past two years. Plots consisted of conventional fertilization (CF) and incorporation of GMC were divided by addition rate of nitrogen fertilizer (100 kg $ha^{-1}$) with 30 - 100% of non nitrogen fertilization (NNF). Soil physico-chemical properties and growth and yield potential of silage corn were examined. The tested soils showed strong alkali and saline properties with low contents of organic matter and available phosphate while contents of exchangeable sodium and magnesium were high. Soil salinity increased during cultivation of summer crop. However, corn was not affected by salt content. The fresh weight of GMC at incorporation time was 18,345 kg $ha^{-1}$. Content of total nitrogen was 3.09% and the C/N ratio was 12.8 at incorporation time. Fresh and dry matter yield of silage corn were higher in the order of N30% reduction, CF, N50% reduction, N70% reduction, N100% reduction and NNF. Fresh and dry matter yield potential of silage corn for N30% reduction were comparable to those of CF. Bulk density of the soil decreased with incorporation of GMC, while porosity was increased. The soil pH decreased while content of exchangeable calcium, available phosphate, and organic matter increased. Also contents of exchangeable sodium and potassium decreased with incorporation of GMC. The data indicate that incorporation of hairy vetch can improve soil physical and chemical properties and reduce nitrogen fertilizer application especially for alkali saline reclaimed soil such as Saemangeum reclaimed land.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.spc
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• pp.45-46
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• 2009

This study was carried out to identify the changes of EC during desalinization due to flooding in newly reclaimed saline soil. To do this, experimental plots were made of rotary tillage+water exchanging plot, flooding plot and rainfall flooding plot. In rotary tillage+water exchanging plot, drainage, rotary tillage and flooding were conducted at the interval of 7 days. In rotary tillage+water exchanging plot and flooding plot, plots were irrigated at the height of 10 cm. After 38 days desalinization, changes of EC values at top soil (0~20 cm) were as follows. In rotary tillage+water exchanging plot, EC decreased from $21.38dS\;m^{-1}$ to $2.16dS\;m^{-1}$ and in flooding plot, EC decreased from $13.97dS\;m^{-1}$ to $2.22dS\;m^{-1}$. In rotary tillage+water exchanging plot and flooding plot, EC values decreased below the EC criterion ($4.0dS\;m^{-1}$) of saline soil. In rainfall flooding plot, EC values decreased or increased according to amounts of rainfall and rainfall time. After 38 days, EC decreased from $16.7dS\;m^{-1}$ to $12.35dS\;m^{-1}$. In flooding plot, changes of EC due to soil depth were investigated. After 38 days desalinization, changes of EC due to soil depth were as follows. At 0~10 cm depth, EC value decreased from $13.08dS\;m^{-1}$ to $0.74dS\;m^{-1}$ (94.3% of salt was desalinized). At 10~20 cm depth, EC value decreased from $14.80dS\;m^{-1}$ to $3.69dS\;m^{-1}$ (75.2% of salt was desalinized). At 20~30 cm depth, soil was desalinized slowly compared with upper soil, EC value decreased from $13.57dS\;m^{-1}$ to $6.93dS\;m^{-1}$ (48.9% of salt was desalinized).

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.spc
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• pp.14-19
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• 2009

To obtain the basic data on reclaimed tideland soils, 90 soil samples were collected from 9 tideland reclamation project areas in Korea. The soils consisted of clay (2.0 to 35.0 percents), silt (2.0 to 80.0 percents), and sand (8.0 to 95.0 percents), and were dominantly classified sandy loam and silty loam. The soils had pH of 4.5 to 9.1, organic matter of 0.50 to $19.20g\;kg^{-1}$, total nitrogen of 4 to $1,159mg\;kg^{-1}$, and avaliable phosphorus (as $P2_O_5$) of 3.5 to $147.7mg\;kg^{-1}$. The electrical conductivity in soil saturation-paste extracts (ECe) ranged between $0.62dS\;m^{-1}$ and $31.60dS\;m^{-1}$ and the concentrations of sodium and magnesium ions were higher than those of potassium and calcium ions. The magnitude of the ECe was as low as that of normal level in Nam-Po, Pu-Sa, and Kye-Hwa reclamation project areas having sandy loam texture, but was as high as that of normal level saline-sodic level in Nam-Yang and So-Po reclamation project areas having silty loam texture even though the soils were cultivated more than 10 years as a paddy. Some part of Saemangeum area was surveyed and soil textures were various; some were silt loam and some were sandy loam. The ECe values were very high in topsoil and subsoil.

• Journal of Plant Biology
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• v.14 no.3
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• pp.60-65
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• 1971

In order to observe the factors affecting light utilization efficiency in the canopy of a rice crop grown in reclaimed saline areas in Korea, 22 varieties of rice were cultured at the average salt concentration of 6.05mmhos/cm $25^{\circ}C$, (0.39%) in saline soils and non-saline silty loam soils. The inhibition of tillering ability by salt damage at the maximum tillering stage was greater than to growth in height. A significant direct correlation was observed between both ratios and salt concentration with each variety. In the salty areas the length of the flag leaf of the maturing stage showed a positive correlation with the production of rough rice while other living leaf showed a negative correlation. LAI of maturing stage was less in the salty area than in the non-salty area, while the former showed higher ratio in net assimilation and translocation to head with greater RGR before and after the heading stage.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.4
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• pp.113-120
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• 2015

The objectives of this study were to monitor and assess the effects of saline irrigation water on lettuce and carrot growth in protected cultivation. One control and 4 treatments with three replications, which were differentiated according to the level of salinity in irrigated water, were employed for each vegetable to assess the effects of the irrigation with saline water. Monitoring results showed that the use of irrigation water containing above a certain level of salinity was found to cause excessive accumulation of salts in the soil as saline irrigation water increased electrical conductivity (EC) and sodium ($Na^+$) content in both lettuce and carrot soil samples, while tap water irrigation used as control decreased the salinity in the samples. The salinity higher than the threshold level of irrigation water was found to reduce the yields of lettuce and carrot, while in less than the threshold level the higher the salinity of the irrigation water increased the yields. The salinity of the irrigation water also appeared to increase the internal salinity of the plant as the $Na^+$ content in plant increased as the salinity of irrigation water increase. Increased $Na^+$ content was analyzed to be able to increase the sugar content in carrot. This study could contribute to suggest water quality criteria for safe use of saline water in protected cultivation, although long-term monitoring is needed to get more representative results.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.5
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• pp.398-404
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• 1993

This study was conducted in order to obtain the information for yield improvement in saline paddy. Saline concentration, growth and yield of rice, being subjected to different flooding times and days to transplanting were investigated in saline paddy with 0.35 % and 0.5 % salt concentration. Saline concentration of soil was increased to 0.41 % just after rotary in the paddy with 0.35 % salinity, but decreased to 0.20 % after 3 to 4 times of flooding treatment. And also that of surface water was decreased from 0.2 % to 0.11 %. Saline concentration of soil in 5cm depth was decreased to 0.31 % by one time flooding and to 0.22% by 3～4 times flooding but salinity below 7cm depth showed slight decrease. Seedling death was exceeded 37 % when transplanted one day after rotary in the paddy with 0.35% salinity. Death ratio was decreased to 20% by three times flooding and transplanting six days after rotary. In paddy with 0.5 % salinity, death ratio was high but the tendency was very similar to 0.35 % field. In 0.35 % saline paddy field, yields were increased by 14 % by three times flooding and transplanting six days after rotary as compared to one time flooding and transplanting are day after rotary. Therefore, 3 to 4 times flooding and transplanting 5 to 6 days after rotary are desirable in high saline paddy.

• Korean Journal of Environmental Agriculture
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• v.29 no.1
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• pp.33-38
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• 2010

To improve the existing nitrogen recommendation method based on chemical properties of soils and to establish new recommendation rates of nitrogen fertilizer due to different types of soils, the application rates of nitrogen fertilizer were examined in different soils of 12 experimental rice paddy fields. The application rates of nitrogen fertilizer estimated by soil-testing were higher than the rates of nitrogen standard recommendation that has been used. The application rates for minimum rice productivity ranged from a low of 168 kg/10a in sandy soil to a high of 315 kg/10a in saline soil. Amounts of nitrogen absorption in rice were proportional to the application amounts of nitrogen fertilizer in soils. Nitrogen use efficiency was the highest, 36.7%, in immatured paddy field and it was inversely proportional to the application amounts of nitrogen. the rice tasty value was the highest in the soils without nitrogen application, and also it was the lowest in the saline soils with or without nitrogen application. As comparing with the nitrogen application rates obtained by the existing nitrogen recommendation method, optimal nitrogen application rates estimated by the standardization of nitrogen application efficiency rate, environmental index, and rice quality were 1.0 fold in the well adapted soil and sandy soil fields, 0.92 fold in the immatured soil field, and 0.83 fold in the saline soil field.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.1
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• pp.105-110
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• 1985

A incubation study was conducted to find out the effects of rice straw and gypsum as soil ameriolite on urease, nitrate and nitrite reductase activities in newly reclaimed saline sandy soil. The results obtained were summarized as follows: 1. Very low urease activities were observed in saline soil if contrast to high productive paddy soil. Urease activities were lower at 5 days than that of 25 and 50 days after incubation. Remarkably high urease activities were obtained by the application of rice straw and gypsum. 2. Comparing with NPK treatment, application of rice straw and gypsum were enhanced the activities of nitrate and nitraite reductase. 3. Positive correlation (r=0.5501 p=0.05) was obtained between urease activities and ammonium nitrogen concentration in soil. 4. Cyclic oxidation and reduction of nitrate and nitrite in soil were obtained in terms of first order microbial kinetics reaction in case of application of rice straw and gypsum, respectively. 5. Positive correlation (r=0.6296 p=0.05) was obtained between the activitie of nitrite reductase and nitrate reductase in soil.

• Asian Journal of Turfgrass Science
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• v.25 no.2
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• pp.208-216
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• 2011

The purpose of this study was to find soil-amendment materials those support the growth of Kentucky bluegrass and reduce salt accumulation at the sand based growing media in saline conditions. Rootzone profile in columns consisted of 20 cm of top soil, 20 cm coarse sand as capillary rise interruption layer and 10 cm reclaimed paddy soil as the base of the profile. Top soils were mixtures of dredged sand (DS) and amendment with compositions of 90% sand + 10% peat moss (SP), 80% sand + 10% soil + 10% bottom ash (SSoBa), 80% sand + 20% soil (SSo), 90% sand + 5% peat + 5% zeolite (SPZ), and 80% sand + 20% bottom ash (SBa). The top soil mixtures of DS and amendments were treated with and without gypsum (Gp). The columns were soaked into 5 cm depth saline water reservoir with the salinity level of $3-5dSm^{-1}$. Irrigation of $2dSm^{-1}$ saline water with rate of $5.7mm\;day^{-1}$ was applied by 3 day interval. Application of zeolite decreased SAR, application of gypsum decreased ECe of the sand amended by peat + zeolite and decreased the SAR of sand amended by bottom ash. The SP and SSoGp resulted in higher clipping dry weight of Kentucky bluegrass. The SSoGp and SPZGp showed longer root lengths. The SP and SBaGp showed higher visual quality. Addition of gypsum to soil and bottom ash treatments resulted in the increased shoot growth, whereas additional gypsum to the treatments of peat, soil and zeolite increased the root growth of Kentucky bluegrass.

• KSBB Journal
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• v.30 no.3
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• pp.97-102
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• 2015

This study aimed to evaluate the potential plantgrowth promoting effects of potassium polyacrylate, a superabsorbent polymer, and Bacillus sp. SH1RP8, a family of plant-growth-promoting bacteria. Potassium polyacrylate was selected as the polymer for use due to its high molecular weight and its ability to retain and continuously supply moisture. Plant-growth-promoting rhizobacteria (PGPR) were isolated from the soil and applied to plants growing in dry environments, such as saline conditions. The moisture absorption and retention abilities of potassium polyacrylate were evaluated at a high temperature ($50^{\circ}C$) and in a dry condition, during which time the polymer showed a water retention potential of 19606.07% after 29 days. To overcome the reaming problem in the soil environment, natural polymers (such as cellulose) were mixed with the potassium acrylate. The shoot growths of Peucedanum japonicum Thunb and Arundo donax were significantly enhanced when treated with the mixture of the isolated rhizosphere bacterium SH1RP8 and potassium polyacrylate (63.5 and 124.3%, respectively).