Ridge Tillage Increased Halophyte Fine Root Production and Turnover Rates by Altering Soil Properties in an Abandoned Farmland in Northwest China

Ridge tillage is a common tillage practice used for farmlands and afforestation. However, the mechanisms by which ridges affect halophyte fine root dynamics in abandoned farmlands are still unknown. A field experiment was conducted to evaluate the effect of ridge tillage on root dynamics in an abandoned farmland over three consecutive years using a minirhizotron method. The rate of fine root production varied from 27 to 44 mm cm-2 each year, and the root turnover rate was between 7.46 and 16.99 times per year. Ridge tillage significantly decreased 0-1 mm diameter root production and root lifespan (28.98% and 19.77%, respectively) while increasing root mortality by 18.74%. Conversely, there was no significant effect of ridge tillage on roots within the 1-2 mm diameter range. Ridge tillage resulted in increased root production and root lifespan, which was mainly due to an increase in soil moisture. Clear seasonal patterns were observed for fine root production, root standing crop and root mortality due to increases in soil organic matter, soil water content and soil salt content in the abandoned farmland. Our results demonstrated that ridge tillage not only accelerated halophyte root production and lifetimes but also improved belowground productivity, providing a potential way to replant in the saline-alkaline soils of abandoned farmlands.