Reducing High Sodium in Salt-Affected Soils and Improving Drainage Case Study
Summary
A low-lying coastal paddock with elevated sodium levels showed significant improvement in soil structure and drainage over a two-year period. Soil sodium reduced from 2.44 g Na per 100 g soil to 0.70 g Na per 100 g soil, alongside improved pasture establishment and root growth.
The Problem: High Sodium in Coastal Soil
This paddock was located on a low-lying coastal property where elevated sodium levels were contributing to:
Poor drainage and slow infiltration
Soil sealing after rainfall
Restricted root growth
Reduced pasture response despite fertiliser inputs
Coastal soils can be more prone to sodium accumulation due to marine influence, shallow water tables, and limited natural drainage.
Initial soil testing recorded:
Sodium: 2.44 g Na per 100 g soil
At this level, excess sodium can disperse clay particles, reducing aggregation, air-filled pore space, and overall soil function.
The Approach
DCT soil conditioning products were applied as part of a soil function programme focused on:
Improving soil aggregation
Supporting calcium balance
Stimulating soil biology
Enhancing nutrient cycling
No major drainage earthworks or structural modifications were undertaken during the monitoring period.
The objective was to improve soil function so sodium could move out of the root zone more effectively under natural rainfall conditions.
The Measured Results
After 12 Months
Sodium reduced to 1.34 g Na per 100 g soil
(Approximately 45% reduction)
After 24 Months
Sodium reduced to 0.70 g Na per 100 g soil
(Approximately 71% reduction from baseline)
The grower also reported:
Improved drainage in tight areas
Better soil workability
Stronger pasture establishment
Improved root depth
Why High Sodium Soils Limit Productivity
In coastal and low-lying soils, excess sodium weakens soil structure by dispersing clay particles. This reduces:
Drainage and infiltration
Oxygen availability in the root zone
Root penetration depth
Fertiliser efficiency
As sodium levels declined and aggregation improved:
Soil structure stabilised
Drainage improved
Root systems extended deeper
Pasture performance became more consistent
How DCT Supports Improvement in Salt-Affected Soils
DCT soil conditioning products support the biological and structural processes that influence sodium behaviour in soil by:
Improving soil aggregation and pore structure
Supporting calcium function within the soil cation balance
Stimulating microbial activity that contributes to stable soil structure
Enhancing water movement through the soil profile
When soil structure improves, sodium is less likely to dominate exchange sites and can move more effectively through the profile under rainfall.
Important Context
This case reflects measured changes in a specific low-lying coastal soil under defined management. Results will vary depending on soil type, rainfall, drainage capacity, and existing soil chemistry.
DCT products support soil function but do not replace appropriate drainage management where required.
Concerned About High Sodium in Your Soil?
If your soil test shows elevated sodium or exchangeable sodium percentage (ESP), particularly in coastal or poorly drained land, send your results through for review.
We can assess whether a soil function approach may help improve structure, drainage, and productivity.