Improving soil health and establish a deferred grazing system
Key Results and Outcomes
Soil Health Improvement: Both Set Stocked (SS) and Tall Grass Grazing (TG) systems showed limited soil health improvement. Key indicators like earthworm populations, infiltration rates, and rooting depth remained the same.
Soil Compaction: Compaction issues were observed in both systems, hindering root growth and water infiltration. Penetrometer readings consistently indicated compacted layers at various depths, impacting soil structure and overall health.
Vegetation Cover: Sward density remained low, impacting pasture quality and forage availability.
Rhizosheath Development and Nodulation: The absence of significant rhizosheath development and legume nodulation suggests low microbial activity and limited nutrient cycling within the soil.
Background
Teleri and Ned farm beef and sheep at Hafod y Llyn in Eryri, a farm owned by the National Trust. The fields are flat sandy soils, only 3m above sea level and therefore prone to flooding. They currently cut silage and buy straw for winter feeding.
The project aims to explore regenerative grassland management with 60-day rest periods and rotational grazing to improve soil fertility, reduce costs, and enhance biodiversity. Goals include year-round, high-quality grazing, increased invertebrates, improved soil health, and contributing to sustainable land management outcomes like high animal welfare and resilient ecosystems.
Purpose of work
Teleri and Ned aim to farm sustainably and efficiently at Hafod y Llyn, whilst implementing the following:
Monitor grass growth, soil health, dung beetle populations, whilst also adopting a regenerative grazing strategy.
Improve soil health to reduce runoff, enhance water quality, and increase carbon storage.
Align with SLM outcomes by promoting biodiversity, reducing GHG emissions, and improving farm resilience with minimal inputs.
What we did
The trial ran across three fields: Ffridd Ganol (1.4ha), Ffridd Uchaf (1.4ha), and Cae Terfyn (1.5ha). A soil assessment in September 2023 revealed similar compaction issues across all fields, with a notable layer below 127mm. Ffridd Ganol and Ffridd Uchaf have a high proportion of rushes and weeds, while Cae Terfyn has over 90% rushes.
Initial data collection on farm identified the following:
Soil Health:
Infiltration: Poor infiltration (30 minutes for the first inch), indicating limited water absorption.
Earthworms: Highest count of 43, suggesting improving soil biology.
Rooting Depth: Ranged from 3-5 cm, showing potential for better root growth.
Vegetation and Sward Density:
High Number of Undesirables: A significant presence of undesirable grass weeds, impacting pasture quality.
Sward Density: Generally low (3-4), but improving with management.
Soil Structure:
VESS Scores: Highlighted poor soil structure with compaction evident. Penetrometer Readings: Compaction observed at deeper layers (up to 300 PSI), suggesting the need for management to reduce compaction.
The following remedial actions were undertaken:
Mechanical Interventions: Subsoiling and spiral blade aeration to address compaction and improve soil structure.
Grazing Strategies: Rotational grazing and bale grazing to manage vegetation and promote soil health. Also comparing set stocking versus tall grass grazing in terms of their impact on vegetation and soil health.
Biodiversity Monitoring: Soil fauna, plant diversity, and dung beetles tracked using the Soilmentor App.
Soil Health Assessments: Slake tests, and infiltration rates to monitor improvements in soil quality.
Outcomes
The results of the remedial actions undertaken will be assessed over the coming months and may take years to establish their full effect.
An element of the project which focused on assessing soil health and vegetation in two different land management systems: Set Stocked (SS) and Tall Grass Grazing (TG) showed concerning trends in both systems over the observation period.
Soil Health: In both SS and TG systems, soil conditions remained poor throughout the study. Earthworm populations were low, and infiltration rates remained at 30 minutes for the first inch of soil, indicating limited soil improvement. Penetrometer readings showed signs of soil compaction, with values indicating compacted layers at varying depths (up to 24 inches in some cases). Rhizosheath development was absent, and there was no significant nodulation of legumes, suggesting poor microbial activity.
Vegetation: Basal ground cover was initially dominated by bare ground (100%) across all plots, with undesirable species increasing by the end of the observation period. Vegetation density remained low, with sparse growth of grasses, forbs, and legumes. The sward density varied from dense to sparse, with gaps becoming more evident, particularly in the TG system.
Rooting and Soil Structure: Rooting depths showed limited increase over time, with most plots having shallow roots (1.5 to 7 cm), indicating poor root penetration due to soil compaction and inadequate soil structure. VESS assessments revealed angular blocks, which further confirmed soil degradation.
Overall, the study indicates that both Set Stocked and Tall Grass Grazing systems are experiencing significant soil health issues, including compaction, poor root growth, and low vegetation cover. Immediate management interventions, such as grazing adjustments, soil amendments, and improved vegetation management, are needed to restore soil fertility and support sustainable land use practices.
To improve soil health and vegetation conditions on your own farm, follow this practical, step-by-step guide:
Assess and Monitor Soil Health
Conduct soil health tests regularly to measure compaction, earthworm populations, infiltration rates, and rooting depth.
Use a penetrometer to check for soil compaction at various depths (especially 9–24 inches).
Measure VESS (Visual Evaluation of Soil Structure) to identify soil structure issues like angular blocks or compacted layers.
Improve Grazing Management
Implement rotational grazing to prevent overgrazing and allow pastures to recover.
Adjust stocking rates based on pasture conditions, aiming for balanced grazing pressure that doesn't degrade soil or vegetation.
Use sward slitters or other aeration tools to break compacted soil and promote better root growth and water infiltration.
Encourage Vegetation Recovery
Foster diverse plant growth by encouraging the growth of grasses, legumes, and forbs. These plants improve soil fertility and reduce erosion.
Control undesirable species that may dominate the land, reducing competition for desired plants.
Enhance Soil Structure
Add organic matter like compost or manure to improve soil texture and fertility.
Consider species of various rooting depths to improve soil structure.
Monitor and Adjust Management Practices
Regularly monitor soil and vegetation health to track improvements and adjust practices as needed.
Set specific goals for soil improvement (e.g., reduce bare ground to below 10%, increase earthworm populations, improve rooting depth).