Effect of Soil Conditioners on Cation Ratio of Soil Structural Stability, Structural Stability Indicators in a Sodic Soil, and on Dry Weight of Maize

The relative effects of Na (+) and K (+) on soil structural stability due to application of some conditioners in sodic soils are not clearly defined by the existing literature. In this research, a completely randomized design experiment was performed to quantify the effect of some conditioners on physical properties in a loamy sodic soil. Five treatments included no conditioner as a control, urban solid waste compost (MC), Vermi-compose (VC), poultry manure (PM), and gypsum powder (G). The amount of each soil amendment was 10ton/ha and each treatment consisted of 3 replications. The most important structural stability indicators including air capacity (AC), water dispersible clay (WDC), the slope of the retention curve at the inflection point (S ( gi ) index), and mean weight diameter of aggregates (MWD) were measured. The results showed that compared with the control, soil conditioners improved soil structural stability indicators significantly (P<0.05). Due to application of studied conditioners, the values of AC, WDC, S ( gi ) index, and MWD increased. In addition, it was demonstrated that there was a negative and significant correlation between CROSS and SAR and structural stability indicators. By increasing SAR and Cation Ratio of Soil Structural Stability WDC, S ( gi ) index, AC, and MWD values were decreased and as a result of these processes and improvement the physical condition of seedbeds, the dry weight of maize was increased.