Alkali soils have undesirable properties for crop production. However, these problematic areas can be reclaimed and regained for cultivation. Mulch materials have been used in the past to decrease salinity damage in saline soils. But information about using mulch materials for alkali soil reclamation is rare. The aim of this study was to determine the combined effects of different levels of gypsum applied with straw or pumice mulch materials on the reclamation of an alkali soil. Results obtained from soil extracts during the leaching water cycles showed that gypsum and mulch materials caused significant differences in sodium adsorption ratio (SAR) and electrical conductivity (EC) values. Major reclamation parameters of soil samples were also determined after the addition of 140 cm of leaching water. The exchangeable sodium percentage (ESP) significantly decreased from 18.43 in the initial soil to as low as 2.31 in 0-15 cm soil depth samples and 10.53 at 15-30 cm (P < 0.05). The various treatments were related to significant decreases in SAR, EC, and lime content in reclaimed soils. The amount of water stable aggregates (WSA) increased significantly after reclamation. Although hydraulic conductivity values also increased, the increase was not statistically significant. The fastest water flow rate was observed in the 100% gypsum requirement (GR) and straw mulch treatment. In contrast, the slowest water flow rate was found in the 50% GR and unmulched treatment, and the differences in means were significant. Overall, the 100% GR and straw mulch treatment was most effective in decreasing soil alkalinity, improving soil structure, and reducing reclamation time.

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&lt;p&gt;Soil cohesion (Co) is one of the most important physical soil characteristics and it is closely related to the basic soil properties and physical distribution forces (e.g. particle size distribution, pore sizes, shear strength) and so it is mostly determined by experimentally approaches with the help of other soil properties in general terms. Instead of using these assumptions, the fluidized bed approach provides an opportunity for direct measurement of intrinsic soil cohesion. In this study, soil cohesion development for different soil types was investigated with the fluid-bed method by which pressure drop in soil mass measures under increasing water pressures until the cohesion between particles disappears. For this purpose, 20 different soils varying with a wide range of relevant soil physical properties were sampled; such that clay, silt and sand contents varied between 2% and 56%, 1% and 50%, and 1% and 97%, respectively while porosity values were between 0.38 and 0.92. By those textural diversities of the soils, obtained cohesion values changed between 5203 N m&lt;sup&gt;-3&lt;/sup&gt; and 212276 N m&lt;sup&gt;-3&lt;/sup&gt;. Given results from regression analysis, a significant relationship was found between cohesion values of the soils and their porosity and silt fractions (R&lt;sup&gt;2&lt;/sup&gt;: 86.6).These findings confirm that the method has a high potential to reflect differential conditions and show that soil cohesion could be modeled by such basic and easily obtainable parameters as particle size distribution and porosity, as well.&lt;strong&gt;&amp;#160;&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Key words&lt;/strong&gt;; &lt;strong&gt;Mechanical soil cohesion, particle size distribution, fluidized bed approach, porosity&lt;/strong&gt;&lt;/p&gt;

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