28/01/24
A new study from the Czech Republic has reinforced the remarkable benefits of surface-applied compost on soil health.
Unlike traditional methods that involve tilling compost into the soil, this approach reinforces known benefits by applying stable, mature compost directly to the surface—a method that has shown significant improvements in soil properties over just two growing seasons.
A Simpler Way to Improve Soil
The study, conducted across two agricultural sites with different soil textures (loam and silty clay loam), examined the effects of surface-applied compost on plots growing wheat, maize, and intercrops.
Compost was applied in two variations: smaller, repeated doses (30 tonnes a hectare) and a single large dose (200 t/ha). These were compared to untreated control plots over the 2023 and 2024 growing seasons.
Major Findings
- Soil Organic Matter Soars
- Organic matter levels increased by 58.1% with the single large dose, compared to a 27.8% increase with the smaller doses. This dramatic improvement supports better crop growth and overall soil fertility.
- Water Retention Improves
- The single large dose boosted saturated water content by 11%, almost double the 5.3% improvement seen with smaller doses. This translates to better resilience against dry spells.
- Stronger Soil Structure
- Water-stable aggregates increased by as much as 30% with the larger dose, whereas smaller doses saw a maximum increase of 6%. Robust soil structure helps prevent erosion and promotes root growth.
- Reduced Soil Compaction
- Bulk density dropped by 15.7% with the single large dose, compared to 10.5% with smaller applications. Looser soil allows for better root penetration and air movement.
- Better Water Flow
- Saturated hydraulic conductivity improved by 28.6% only with the larger dose, showcasing its superior ability to enhance water movement through the soil.
- Improved pH and Nutrient Availability
- Both methods improved pH and electrical conductivity, but the single large dose had a more pronounced impact on nutrient uptake.
Key takeaways for gardeners
The study adds to a considerable body of evidence for a no-till, no-dig approach to gardening. No-dig gardening, a method I have personally used almost exclusively for the last ten years, enables you to both improve soil health and structure and to reduce the amount of work needed to maintain your garden.
Do note that while the heavy compost application had the biggest impact, No-Dig experts like Charles Dowding recommend only using a heavy application of compost on a new vegetable patch, followed by a yearly lighter application of compost around 1 inch in depth.
Source
Miháliková, M., Báťková, K., Dvořák, P., Kara, R. S., Almaz, C., Král, M., Badalíková, B., Hejátková, K., Mašán, V., Burg, P., & Plíva, P. (2024). Effect of surface-applied compost on soil properties. Soil and Water Research, Czech Academy of Agricultural Sciences.