Effect of pit-seeding on changes in soil seed bank (Case study: Sisab, North Khorasan)

This study was conducted to investigate the changes in the soil seed bank of Sisab region due to the pit-seeding operation. To recognize the seed bank potentials, sampling was done using a randomized-systematic method at tow depths of 0-5 and 5-10 cm in winter 2016. Two transects of 500-m length were stablished in the pit-seeding region and in the control area and 10 plots of 1m2 were used along each transect. To study the effects of pit-seeding and soil depth as well as their interaction on the soil seed bank characteristics, a factorial design was applied. In the case that the interaction between pit-seeding and depth was significant, the unpaired T-test was applied to study the seed bank characteristics in each depth of the pit-seeding and control regions. A paired T-test was also used to compare the seed bank characteristics between the two depths. The results showed that pit-seeding had significant effect on soil seed bank characteristics and caused to increased density, diversity, and species richness of seed bank.  In addition, all characteristics of the soil seed bank were significantly higher in the top soil. Our results clearly showed that the pit-seeding operation not only increased the forage production in the study area but also increased the diversity and seed density, whose ultimate result could improve the rangeland ecosystem function.