Key Messages (2025):

• Repellency increased from pre-sowing to post-harvest at all three sites, confirming SWR is dynamic and seasonal.
• Large differences in repellency were observed within paddocks, often greater than differences linked to previous management treatments.
• Surface soil moisture did not reliably predict repellency severity across sites.
• Soil moisture probes showed less repellent zones responded more rapidly to rainfall and achieved greater infiltration.

Project Background

Soil water repellency (SWR), or non-wetting soils, remains a major constraint across sandy and gravelly soils in the WA Wheatbelt. Repellent soils reduce water infiltration, delay crop emergence, increase patchiness, and reduce crop productivity, particularly in dry seasons.

Growers use strategies such as claying, inversion ploughing, wetters, and stubble management to reduce repellency. However, SWR varies greatly between paddocks, within paddocks, and between seasons. This variability makes long-term management difficult and increases uncertainty around treatment effectiveness.

Project Summary

In 2025, Facey Group joined a national GRDC investment led by Murdoch University to investigate the drivers of spatial and temporal variation in SWR. The Wickepin monitoring sites contribute regional data to improve understanding of how seasonal conditions, soil type, landscape position, and management influence repellency over time.

Three monitoring sites were established across the Wickepin region in 2025:

• Facey 1 – South Wickepin (sandy gravel, Jurien lupin)
• Facey 2 – Tincurrin (sand, Bannister oats)
• Facey 3 – East Wickepin (sand, Renegade TT canola)

At each site, soil samples were collected pre-sowing and post-harvest to assess seasonal changes in soil water repellency. Soil moisture probes were installed to monitor rainfall infiltration and soil moisture dynamics during the season.

The project aims to build a multi-year dataset to better understand how repellency changes across seasons and landscapes, and how it influences water movement and crop establishment.