• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.1
• /
• pp.84-90
• /
• 2011

It is imperative to study the hydrolysis of urea in high saline-sodic condition of a newly reclaimed tidal land in order to overcome the problems associated with use of urea fertilizer. The methodology adopted in this study tried to get a convenient way of estimating rate for N transformation needed in N fate and transport studies by reviewing pH and salt contents which can affect the microbial activity which is closely related to the rate of urea hydrolysis. The hydrolysis of urea over time follows first-order kinetics and soil urease activity in reclaimed soils will be represented by Michaelis-Menten-type kinetics. However, high pH and less microorganisms may delay the hydrolysis of urea due to decrease in urease activity with increasing pH. Therefore, the rate of urea hydrolysis should adopt $V_{max}$ referring enzyme activity ($E_0$) accounting for urease concentration which is indicative for urea hydrolysis, especially in a high saline and sodic soils.

• Korean Journal of Soil Science and Fertilizer
• /
• v.42 no.3
• /
• pp.179-186
• /
• 2009

Relation between soil salinity and forage yield of five upland crops such as sudan grass, sesbania, barnyard grass, corn and soybean was studied in the three reclaimed lands of Korea during two years from 2007 to 2008. Although plant number emerged was obtained satisfactory by desalting treatment, further growth of crops was sharply affected by re-salting process according to soil drying. Soil salinity varied place by place and changed constantly, crop growth was differently responded to soil salinity according to the specific conditions of the reclaimed lands. In the Iweon reclaimed land with higher soil water conductivity and sandy soil texture, crop growth and yield sharply decrease with increase of soil salinity. Relation between soil salinity and crop growth and yield was well expressed as logarithmic function. Surface soil EC to reach at 50% of growth reduction to the tallest height of crops was $5dS\;m^{-1}$ for soybean, $6dS\;m^{-1}$ for corn and $7dS\;m^{-1}$ for sudan grass, sesbania, and barnyard grass by logarithmic function. In the Hwaong and Yeongsangang reclaimed lands with low soil conductivity and finer soil texture, plant growth response to salt stress was statistically vague by mixing of harmful influence from flooding and wet injury. However, it is observed that crop growth and yield on the place of lower salinity was better than crop growth on the place of higher salinity. It is accordingly concluded that flooding control during summer rainy season is vary important as well as desalting process for good growth of soiling and forage crops in the newly reclaimed land from tidal flat.

• Korean Journal of Soil Science and Fertilizer
• /
• v.50 no.1
• /
• pp.31-39
• /
• 2017

The effects of application of gypsum and fresh cattle manure on the yield of forage crop were investigated in Hwaong reclaimed land in Korea for 3 years from 2011 to 2013. This study was conducted to develop the practical application method of livestock manure as a fertilization source and a soil physico-chemical ameliorator for the cultivation of forage crop $Sorghum{\times}Sudangrass$ hybrid in newly reclaimed tidal land soil. Treatments with six applications were established with three replications; chemical fertilizer (CF), gypsum (G) $20Mg\;ha^{-1}$, G+fresh cattle manure (FCM) 100%, G+FCM 200%, G+FCM 300% and FCM 100% which referred to the application rate equivalent to the recommended amount of phosphate fertilization by soil test. The combined treatments of G+FCM increased soil organic matter, $Av.P_2O_5$ and exchangeable $Ca^{2+}$ contents while decreased exchangeable $Na^+$ and $Mg^{2+}$. The soil bulk density, soil hardness and soil aggregate formation were improved by G+FCM treatments. The dry matter yields of $Sorghum{\times}Sudangrass$ hybrid were significantly increased in proportion to the application rate of FCM. The phosphorus use efficiency showed the highest in the application level of G+FCM 100%, which seemed to be the results of reduced nutrient use efficiency by nutrient immobilization, leaching etc. when applied excessive amount of fresh animal manure.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.11 no.1
• /
• pp.22-29
• /
• 1991

This study was experimented to obtain the basic information on the changeable aspect and improvement of soil fertility in newly-reclaimed sloped land. Silage corn was cultivated under the six different treatments for 4 years. The relation between the amount or ratio of annual changes of soil physico-chemical properties and yield of silage corn were analyzed. Soil bulk density was decreased in 3rd year at topsoil, but that decreased in 4th year at subsoil. Soil organic matter also decreased in 2nd year at topsoil, and decreased continuously at subsoil. Bulk density and hardness of soil depths showed significant negative simple correlation with dry matter yield and cation exchange capacity showed positive. Correlation coefficient of chemical properties with dry matter yield were low. The range of annual changes of moisture percent, hardness and organic matter were wider than the other properties. The significantly different of physical properties were higher than the chemical properties, and those of topsoil were higher than subsoil. According to multiple regression between yield and physico-chemical properties of subsoil, bulk density and cation exchange capacity were in the greatest contribution at the variations, but bulk density was greatest at the ratios.

• Journal of Forest and Environmental Science
• /
• v.35 no.4
• /
• pp.263-267
• /
• 2019

Two newly recorded small orb weavers, Araneus yasudai Tanikawa, 2001 and Neoscona flavida sp. nov., with characteristic epigynal scape belonging to Araneidae are described with measurements and morphological illustrations from Korea. Both species were collected with sweep net between shrubs and bushes in mountain forest and between reeds in reclaimed land, respectively.

• Korean Journal of Soil Science and Fertilizer
• /
• v.28 no.3
• /
• pp.256-260
• /
• 1995

This study was carried out to select economic-crops according to the improvement methods of newly-reclaimed soils. Silage corn, soybean, Job's tears and sweet potato were cultivated under 6 treatments including integrated improvement plot, control plot, compost plot, subsoiling plot, phosphate plot and lime plot on the Songjeong loam from 1985 to 1988. Crop yields and soil physical properties were investigated throughout the experiment. Soil porosity in the sweet potato plots were highest. In case of cultivated years, those of 4th year were lowest. Averaged yield increasing ratios of silage corn, soybean, job`s tears and sweet potato in the integrated improvement plots were 132%, 29%, 49% and 59%, respectively. And that of 5 soil improved treatments for 4 crops were 53%, 15%, 25% and 38%, respectively. After subtraction of the total expenses of soil conditioners, the economical efficiency of soil improvements were clear in the 4 crops except the compost plot of silage corn. That of sweet potato plot was the highest.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.39 no.2
• /
• pp.175-179
• /
• 1994

This experiment was carried out to investigate the effect of improved NPK fertilizer and ameliorator application methods on job's tears yield and soil properties in the newly-reclaimed land from 1985 through 1988. Job's tears height of integrated improvement plot was higher than the other plots, and increased from the 1st and the 2nd year, but decreased from the 3rd year when soil conditioner was not applied. Average yield of the crop in the integrated improvement plot was 2.16 t /ha being increased by 49% more than the control plot, and the yield was the greatest in order of integrated improvement>subsoiling>phosphate>lime>compost>control plot. Soil bulk density and hardness of the topsoil decreased to the 3rd year, but increased in the 4th year. Soil pH of the topsoil was not changed significantly by different soil depths and cultivated years.

• Korean Journal of Environmental Agriculture
• /
• v.32 no.4
• /
• pp.332-337
• /
• 2013

BACKGROUND: Newly reclaimed land has poor soil environment for crop growth since it is high in salt concentration but low in organic content compared with ordinary soil. It is known that whole-crop-barley can grow better in the soil of relatively high salt concentration than other crops but, the growth is poor at the concentration if higher than certain amount and it is a difficulty to secure productivity. Hence, the level of soil salt concentration suitable for the production of bulky feed in newly reclaimed land has been investigated. METHODS AND RESULTS: At Saemanguem reclaimed land, the land for the soil salt concentration electrical conductivity (EC) 0.8, 3.1, 6.5, 11.0 dS/m was selected; and chemical fertilizer $N-P_2O_5-K_2O$ (150-100-100kg/ha) was tested; and forage barley 220kg/ha were sown. The soil salt concentration during the cultivation period decreased in the order of harvest season>earing season>sowing season>wintering season, and the salt concentration in harvest season is 1.4-4.2 times higher than that of the sowing season. The higher the salt concentration, the poorer the over ground growth due to poor rooting; especially at EC 11.0 ds/m there was emergence but, it blighted after wintering. The Yield from the soil salt concentration 3.1dS/m and 6.5 dS/m was 68% and 35% from that of the soil salt concentration 0.8 dS/m (8.8 MT/ha) respectively. The proline content in early life stage was more than that of the harvest season, and it increased with salt concentration. The higher salt concentration, the more $Na_2O$ and MgO content in harvest season; but the higher the salt concentration, the less the content of N, $P_2O_5$, $K_2O$ and CaO. CONCLUSION(S): When the soil salt concentration becomes higher than 3.1 dS/m, the yield becomes poor because there is serious growth inhibition of forage barley both in root part and above aerial part that results in unbalanced absorption of nutrients. Therefore, it is recommended that the salt concentration should be lowered below 3.1 dS/m by underground drainage facilities or irrigating water for the stable production of whole-crop-barley.

• Korean Journal of Soil Science and Fertilizer
• /
• v.27 no.2
• /
• pp.105-110
• /
• 1994

Field experiment was carried out to obtain the basic information on the soil improvement with different improved methods on job's tears yield and soil properties in the newly-reclaimed land from 1985 to 1988. Job's tears yield, soil properties and annual changes of soil were investigated and analyzed. Soil bulk density and hardness of topsoil decreased from 1st year to 3rd year, but those increased in 4th year. Soil pH of topsoil had no differences in different soil depths and cultivated years. Average yield of job's tears in the integrated improvement plot was 2.16ton/ha. That was increased by 49% than the control plot. Crop yield was greatest in order of integrated improvement>subsoiling>phosphate>lime>compost>control plot. Correlation coefficients of job's tears yield with soil pH and organic matter content were higher significantly. Also those of subsoil were higher than topsoil. Ratios of annual changes of soil bulk density and hardness showed significant highly with job's tears yield. Also that soil pH was significant at 5 % level in the topsoil.

• Korean Journal of Soil Science and Fertilizer
• /
• v.27 no.3
• /
• pp.189-194
• /
• 1994

This experiment was conducted to obtain basic information on the improved methods of soil physico-chemical properties and sweet potato yield cultivated on a newly-reclaimed land, a Songjeong loam soil. The crop was cultivated under the six different treatments for 4years since 1985 in the field conditions. Annual changes of soil properties and sweet potato yield were investigated and analyzed. Soil bulk density increased from the second year, and also soil hardness of topsoil increased, but that of subsoil had not tendency. Average yield of sweet potato for 4years in the integrated improvement plot was 32.68ton/ha, which is increased by 59% in comparison to that of the control plot. Crop yield was in order of integrated improvement>phosphate>subsoiling>lime>compost>control plots. The soil properties of the topsoil which showed high correlation coefficient to sweet potato yield were bulk density, hardness and cation exchange capacity(CEC), and those of the subsoil were bulk density, soil moisture and CEC. Ratios of changes of soil properties except organic matter content showed high significancy to sweet potato yield. Soil physico-chemical properties of the 4th year without soil conditioners application were worse than those of 3rd year.