It has long been hypothesised by landholders in Australia, that Distichlis spicata var. yensen-4a (NyPa Forage) improves the soil properties when grown in saline discharge zones. This hypothesis was tested by sampling soil where D. spicata had been grown for 8 years at Wickepin in Western Australia.

Soil samples were collected from the site in July 2005. The site had been established to D. spicata 8 years prior to sampling, with an adjacent area that was not planted for comparison. Soil samples were also taken from the spreading margin of the stand of D. spicata, where it was estimated that the D. spicata had been growing for 2 years. Intact soil cores were sampled at 0-6, 10-16 and 20-26 cm depth with 6 replicates to determine differences in saturated hydraulic conductivity and root density. Destructive soil samples were taken from 0-10, 10-20, 20-30 and 30-50 cm depth with 6 replicates to determine water stable aggregates and soil organic carbon.

Results show that soil saturated hydraulic conductivity increased significantly in the top 6 cm of soil under the D. spicata, increasing from 0.5 cm/hr in the control to 7.5 cm/hr after 8 years of D. spicata.. This trend continued down the soil profile. Soil carbon was also increased under the D. spicata, increasing from 0.4 to 0.75%, with this trend shown down the soil profile. Eight years of D. spicata growth improved the stability of the soil aggregates in the top 10 cm of the soil; approximately 75 % of the aggregates remained larger than 2 mm in diameter after 5 minutes of wet sieving. These results demonstrate that D. spicata is able to improve the soil physical properties when grown in a saline discharge site.