The Effect of Different Levels of Polyacrylic and Humic Acid on Aggregates Stability and Soil Moisture Content of Saline and Sodic Soils

Saline and sodic soils have a poor structure. The chemical and physical properties of these soils can be modified using various modifiers. Consumption of organic modifiers increases aggregate stability, soil water holding capacity and percentage of usable moisture for the plant. The use of water-soluble polymers and fertilizers containing humic acid is suitable for reducing water use in agriculture and improving soil structure in salt-affected soils. The purpose of this study was to investigate the effect of polyacrylic and humic acid on aggregate stability and field capacity in saline and sodic soils. This study was conducted using four salinity levels of 10, 20, 30 and 40 dSm-1 and application of two modifiers (humic acid and polyacrylic acid) at 4 levels (0, 0.2, 0.4 and 0.8% by weight) in factorial arrangement with completely randomized design with three replications in greenhouse conditions. The results showed that the highest values of aggregates stability were at the salinity level of 10 dSm-1 and the level of 0.8% polyacrylic acid (3.13 mm) and humic acid (1.51 mm), respectively. The highest moisture content of the field capacity was measured at the salinity level of 40 dSm-1 and at the level of 0.8% polyacrylic acid (26.65%) and humic acid (25.65%), respectively.