Olive prunings: shredding and returning them to soil
Shredded branches and leaves can provide surface cover and food for organisms decomposing plant residues.
Food for decomposers
Wood contains complex compounds that decompose gradually. Saprotrophic fungi grow through residues and break down resistant components. Carbon and nutrients pass through microbial life and return to soil cycles. Residue availability and suitable moisture support this activity.
Cover reduces soil loss
Mulch protects against raindrop impact and particle movement. In a two-year trial on a steep clayey olive grove in southern Italy, pruning mulch reduced soil loss by 75–80% and runoff coefficient by 20–32% relative to mechanical tillage. These results apply to the tested rates and conditions.
Combining prunings and living cover
A 2025 olive grove study used simulated rain at two intensities. Spontaneous vegetation, pruning mulch and their combination reduced soil loss by more than 95% relative to tilled surfaces. Combined vegetation and prunings gave the most complete cover. These are simulated-rainfall results illustrating surface protection during erosion events.
Amount and distribution matter
A few scattered fragments do not provide the protection of an adequate layer. A four-year study in a super-high-density Córdoba grove associated larger pruning quantities with more surface soil carbon. Moisture effects varied with season and residue condition.
When material is limited, concentrating it in selected strips may provide more effective cover than spreading it very thinly everywhere.
Our field work
We plan to use shredded prunings as mulch and woody compost feedstock, following fungal activity and decomposition in accordance with our Soil Food Web School training.
Sources and further reading
- USDA NRCS, Soil Tech Note 7A: Fungi
- USDA NRCS, Soil Health Management
- Mulching as best management practice to reduce surface runoff and erosion in steep clayey olive groves
- The Use of Pruning Residue Mulch and Spontaneous Groundcovers to Control Erosion and Carbon Loss in Olive Orchards (2025)
- Opportunities of super high-density olive orchard to improve soil quality: Management guidelines for application of pruning residues (2021)