Effects of the super absorbent polymer (SAP) were tested on both the soil attributes and growth properties of Seidlitzia rosmarinus in the arid Emrani region of Iran in a reclamation study. A SAP concentration gradient (SAP 0 = SAP 0 g dm⁻³, SAP 1 = SAP 1 g dm⁻³, and SAP 3 = SAP 3 g dm⁻³ of soil) was coupled with 30- and 60-day irrigation intervals, and results were evaluated after two growing seasons. Results indicate that application of SAP 1 increased available water content up to 68.5% and decreased soil bulk density by 25.5% and soil infiltration rate by 21.5%. SAP enhanced growth indices and seedling establishment rates of S. rosmarinus under drought stress. In addition, the application of SAP 3 can significantly increased soil cation exchange capacity up to 31% compared to the control. This study demonstrated the increased water retention properties of SAP that leads to higher soil water storage capacity for S. rosmarinus seedlings during the first months of out-planting in arid regions. Overall, the used SAP enhanced soil and plant properties, but most assessed parameters did not differ between SAPs 1 and 3. Therefore, the 1 g application rate is recommended based on technical as well as economic considerations.

There are many conflicting reports regarding the effects of cryptogamic biological soil crusts on seed germination, seedling emergence and plant establishment. The current research investigated the effects of cryptogams (mosses and lichens) on seedling emergence and initial establishment of two vascular plants, namely Stipa barbata and S. capensis, under greenhouse conditions. For this purpose, 28 cylindrical pots were used to carefully transport field soil to the greenhouse, from two adjacent areas with similar conditions with and without cryptogams in the northeast of Golestan province of Iran. For S. barbata and S. capensis seeds planted in pots, seedling emergence, establishment and performance were evaluated over two months. The rate and percentage were higher for plants, particularly S. capensis, on soils with cryptogams than those on soils without cryptogams; such improvements could be related to the effects of cryptogams on moisture, temperature and nutrient increase in soil.