• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.510-516
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• 2011

Salt-affected soils are present in Pakistan in significant quantity. This experiment was conducted to assess the effectiveness of compost for reclamation and compare its efficiency with gypsum. For this purpose, various combinations of compost and gypsum were used to evaluate their efficacy for reclamation. A saline-sodic field having $pH_s$ 8.90, $EC_e$ $5.94dS\;m^{-1}$ and SAR $34.5(mmol\;L^{-1})^{1/2}$, SP (saturation percentage) 42.29% and texture Sandy clay loam, gypsum requirement (GR) $8.75Mg\;ha^{-1}$ was selected for this study. The experiment comprised of seven treatments (control, gypsum alone, compost alone and different combinations of compost and gypsum based on soil gypsum requirements). Inorganic and organic amendments (gypsum and compost) were applied to a saline sodic soil. Rice and wheat crops were grown. Soil samples were collected from each treatment after the harvest of both crops and analyzed for chemical properties (electrical conductivity, soil reaction and sodium adsorption ratio) and fertility status (organic matter, available phosphorus and potassium contents) of soil. Results of this study revealed that compost and gypsum improved chemical properties (electrical conductivity, soil reaction and sodium adsorption ratio) of saline sodic soil to the desired levels. Similarly, all parameters of soil fertility like organic matter, available phosphorus and potassium contents were built up with the application of compost and gypsum.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.15-21
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• 2011

Transport of heavy metals such as Cd is affected by several rate-limiting processes including adsorption and desorption by exchange reactions in soils. In this study, column transport and batch kinetic experiments were performed to assess Cd mobility in a double-layered soil with a reclaimed saline and sodic soil (SSS) as top soil and macroporous granule (MPG) as a bottom layer. For individual soil layer having different physical and chemical properties, Cd was considered to be nonlinear reactivity with the soil matrix in layered soils. The dispersive equation for reactive solutes was solved with three types of boundary conditions for the interface between soil layers. The adsorption of Cd with respect to the saline-sodic sandy loam and the MPG indicated that the nature of the sites or the mechanisms involved in the sorption process of Cd was different and the amounts of Cd for both of samples increases with increasing amounts of equilibrium concentration whereas the amount of Cd adsorbed in saline-sodic sandy loam soil was higher than that in MPG. The results of breakthrough curve indicating relative Cd retardation accompanied by layer material and sequence during leaching showed that the number of pore volumes to reach the maximum relative concentration of 1 increased in the order of MPG, SSS, and double layer of SSS-MPG. Breakthrough curves (BTCs) from column experiments were well predicted with our double-layered model where independently derived solute physical and retention parameters were implemented.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.717-724
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• 2012

Salt accumulated soil should be reclaimed to lower salt level for crop production. This study was carried out to investigate the characteristics of water flow and transport of mono and divalent solutes on salt accumulated soils with different head pressures. Saturated hydraulic conductivity was measured by constant and falling head methods with maintaining different head pressures. Saturated hydraulic conductivity was influenced by bulk density and organic matter contents in soils, but it had different elusion patterns between saline and sodic soil. While the quantity of water necessary for reclamation could be varies with soil type, it was considered that the supply of one pore volume of water was affordable and economic. Additional head pressure significantly increased the volume of leachate at a given time and it was more effective at low organic matter soils. The results indicate that additional head pressure would be one of the best irrigation practices on desalination method for salt accumulated soils.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.1
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• pp.93-97
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• 2012

This study was conducted to evaluate the efficiency of various inorganic and organic materials to improve physical properties of soil. Saline sodic soil (saturation percentage = 40.36%, $EC_e=5.15dS\;m^{-1}$, $pH_s=8.70$, $SAR=18.84(m\;mol\;L^{-1})^{1/2}$, bulk density =$1.49Mg\;m^{-3}$) was collected, brought to wire house and filled in pots after laboratory analysis for various parameters. Different sources of organic nutrients like farm manure (FM), press mud, compost, poultry manure and sesbania green manure were analyzed for their chemical composition. The experiment comprised of 12 treatments replicated thrice; $T_1$: control (recommended NPK), $T_2:{\frac{1}{2}}$ recommended NPK, $T_3$: FM at 1.5% by soil weight, $T_4$: pressmud at 1.5% by soil weight, $T_5$: compost at 1.5% by soil weight, $T_6$: poultry manure at 1.5% by soil weight, $T_7$: sesbania green manure at 1.5% by soil weight, $T_8:T_2$ + FM at 0.75% by soil weight, $T_9:T_2$ + pressmud at 0.75% by soil weight, $T_{10}:T_2$ + compost at 0.75% by soil weight, $T_{11}:T_2$ + poultry manure at 0.75% by soil weight, $T_{12}:T_2$ + sesbania green manure at 0.75% by soil weight. These treatments were applied using completely randomized (CR) design and appropriate time was given to decompose these organic nutritional sources. Seeds of wheat cultivar Sahar-2006 were sown. After harvesting the wheat, soil samples were collected from each pot and analyzed for various physical properties like bulk density, porosity and saturation percentage. An improvement in physical properties (bulk density, porosity and saturation percentage) of soil was noticed with the application of various organic nutritional sources but role of compost alone ($T_5$) remained prominent.

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

• Applied Biological Chemistry
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• v.44 no.2
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• pp.92-96
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• 2001

Soil physical-chemical properties and phosphorous adsorption characteristics were investigated to obtain the informations of the appropriate fertilization and soil management in Baicheng region, China, where agricultural circumstances at present forces to consider the use of land for crop production. Soils were collected from one uncultivated and three cultivated lands on August 1993. Soil $_PH$ was very higher in uncultivated land than in cultivated land, their values were 10.2 and 7.4, respectively. Regardless of cultivation, soil organic matter contents were below 2%, and concentrations of available soil phosphorus expressed as Bray 1 P and Olson P were less than 10 mg P $kg^{-1}$, however, cation exchange capacity was higher than 20 cmol(+) $kg^{-1}$. For uncultivated soil, the values of exchangeable sodium percent and calcium saturation percent were higher than 100%. The major cation of soil saturation paste extracts was Na regardless of land use type. Based on electrical conductivity and sodium adsorption ratio of saturation paste extracts, uncultivated soil was classified as saline-sodic soil and cultivated soil was classified as sodic or normal soil. The maximum adsorption capacity of phosphorus calculated by Langmuir isotherm ranged from 406 to 521 mg P ,$kg^{-1}$. The constraints of soils in Baicheng regions for agricultural cops werw high salt concentration, unfavorable soil chemical composition such as low concentration of available phosphorous, and poor drainage due to soil dispersion by high Na concentration. Therefore, the soil in Baicheng region, need the application of phosphorus fertilizer to increase the soil fertility and the proper soil management to improve the soil physical property especially permeability and soil structure.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.4
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• pp.269-274
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• 2014

Series of field experiments were conducted to evaluate the long term effect of gypsum and crop residue on crop yield and soil health in rice-wheat crop rotation system in salt affected soil. A saline-sodic field having $EC_e$ (electrical conductivity of the saturation extract) 4.77 ($dSm^{-1}$); pH ($H_2O$) 8.96; SAR 43.78 ($mmol\;L^{-1}$) and gypsum requirement (G.R.) 2.86 (Mg $acre^{-1}$) was selected on Soil Salinity Research Institute Farm. Five treatments consisting of ($T_1$) control, ($T_2$) gypsum at 100% G.R., ($T_3$) gypsum at 25% G.R. + wheat straw at $3Mg\;ha^{-1}$, ($T_4$) gypsum at 25% G.R. + rice straw at $3Mg\;ha^{-1}$, ($T_5$) gypsum at 25% G.R.+ rice and wheat straw at $3Mg\;ha^{-1}$ were replicated four times under completely randomized block design. The data indicated that grain and straw yield of rice and wheat was significantly (P<0.05) increased by all the amendments used either single or in combination. $T_2$ (gypsum at 100% G.R.) significantly (P<0.05) increased grain and straw yield of rice and wheat crops followed by $T_3$ (gypsum at 25% G.R. + wheat straw at $3Mg\;ha^{-1}$) when compared with control. Soil properties were also improved by used amendments, pronounced decreased in $EC_e$, $pH_s$ and SAR were recorded in $T_2$ followed by $T_3$. The efficiency of the treatments could be arranged in following order gypsum at 100% G.R.> gypsum at 25% G.R. + wheat straw at $3Mg\;ha^{-1}$ > gypsum at 25% G.R. + rice and wheat straw at $3Mg\;ha^{-1}$ > gypsum at 25% G.R. + rice straw at $3Mg\;ha^{-1}$ > control.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.4
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• pp.355-367
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• 2016

Soil salinization refers to the buildup of salts in soil to a level toxic to plants. The major factors that contribute to soil salinity are the quality, the amount and the type of irrigation water used. The presented review discusses the different sources and causes of soil salinity. The effect of soil salinity on biological processes of plants is also discussed in detail. This is followed by a debate on the influence of salt on the nutrient uptake and growth of plants. Salinity decreases the soil osmotic potential and hinders water uptake by the plants. Soil salinity affects the plants K uptake, which plays a critical role in plant metabolism due to the high concentration of soluble sodium ($Na^+$) ions. Visual symptoms that appear in the plants as a result of salinity include stunted plant growth, marginal leaf necrosis and fruit distortions. Different strategies to ameliorate salt stress globally include breeding of salt tolerant cultivars, irrigation to leach excessive salt to improve soil physical and chemical properties. As part of an ecofriendly means to alleviate salt stress and an increasing considerable attention on this area, the review then focuses on the different plant growth promoting bacteria (PGPB) mediated mechanisms with a special emphasis on ACC deaminase producing bacteria. The various strategies adopted by PGPB to alleviate various stresses in plants include the production of different osmolytes, stress related phytohormones and production of molecules related to stress signaling such as bacterial 1-aminocyclopropane-1-carboxylate (ACC) derivatives. The use of PGPB with ACC deaminase producing trait could be effective in promoting plant growth in agricultural areas affected by different stresses including salt stress. Finally, the review ends with a discussion on the various PGPB activities and the potentiality of facultative halophilic/halotolerant PGPB in alleviating salt stress.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.2
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• pp.59-64
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• 2006

To analyze the changes of soil physico-chemical properties after reclamation, we carried out an experiment for 75 samples of representative saline soils in South Korea. The more the years after reclamation is proceeded, the blighter the soil color is, soil horizon differentiation and structure is developed, but electrical conductivity(EC) decreased. After the soil survey, coarse textured soils were more quickly de-salined than the fine textured soils. In case of fine loamy textured Poseung series, it could be estimated that the series had Salic horizons in sub-order level of taxonomical classification. In other case of coarse loamy textured soil series, it could be estimated that the series had Sodic properties in sub-group level. Sodium contents of fine loamy textured soils were not decreased after reclamation, but those of coarse loamy textured Gwanghwal series reclaimed about 76 years ago were reclassified because of desalinization. To be desalined low to 4 dSm-1 of EC, it presumably takes about 108, or 12 years for fine loamy and coarse loamy textured soils, respectively.