At Hillier Trees, we know that healthy trees start with healthy soil. As leaders in sustainable horticulture, we’re committed to soil management practices that not only promote strong, vibrant trees, but also support environmental health. This commitment to sustainability is a cornerstone of everything we do. In this article, we’ll share our approach to soil management, emphasising its importance, our techniques, and ongoing research to improve our impact.

Why Soil Management Matter for Healthy Trees

Our approach to soil care goes beyond aesthetics; it’s about cultivating stronger, healthier trees that deliver real value to our customers. We prioritise growing robust trees with highly fibrous root systems, which allow them to adapt quickly to new environments and thrive in their final landscapes. Through careful pruning during growth, we ensure that our trees develop a fuller, balanced canopy, resulting in visually appealing and resilient specimens that provide exceptional value. Additionally, comparing a tree grown in nutrient-poor soil to one nurtured in our fertile, well-managed soil is like night and day. Healthy soil produces top-quality trees, and our soil care practices are the foundation of trees that outperform and outlast.

Our Approach to Soil Management

Our soil management practices are rooted in sustainability and science, ensuring the long-term health of our trees and the environment. Below are some of the key methods we use to sustain soil health and tree vitality.

• Comprehensive Soil-Testing and Analysis
  We conduct regular, detailed soil testing to monitor pH levels, nutrient content, nematode populations, and overall soil structure. These analyses help us maintain a balanced soil ecosystem that supports tree health and ensures nutrients are constantly available.

• Sustainable Drainage and Irrigation
  Effective soil management depends on a sustainable irrigation strategy. Our irrigation water is sourced through licensed river water abstraction and borehole extraction during the summer months. We also employ winter abstraction, which allows us to capture and store excess water in our reservoir for use in the warmer months. This winter storage not only provides a reliable water supply, but also plays a crucial role in flood management by capturing surplus water, therefore protecting soil integrity and reducing erosion.

• Soil Conservation Techniques
  To combat soil degradation and erosion, we employ mulching, cover crops, and frequent pruning. Tree matter is chopped and decomposed under the trees, adding nutrients and organic matter back into the soil. Grass is also sown between rows to stabilise soil, reduce compaction, and enhance soil fertility.

Soil Resting (Fallowing) for Nutrient Recovery

Allowing soil to rest is essential for maintaining its health. We use a three-year fallow cycle to prevent nutrient depletion and encourage natural recovery. This process, known as soil resting – or fallowing – is a crucial part of our soil management, and we dedicate significant time and effort to it. Senior Production Manager, Phil Hall, has developed some innovative techniques over the past few years to enhance this approach:

Year One:

• Decompacting the Soil: Compacted soil restricts roots and access to water and nutrients. We decompact our soil to a depth of 500mm-700mm, depending on the tree size, using a Flat Lift Subsoiler to improve drainage and aeration.
• Applying Organic Manure: Sourced from cattle on our land, this manure enriches the soil naturally.
• Sowing Biofumigant Mustard Crop: In spring, we plant mustard to reduce harmful soil organisms that may have built up during tree growth. The mustard is mulched and incorporated into the soil before seeding.
• Rolling the Soil: Rolling helps trap gases released as the mustard decomposes, adding organic matter back into the soil, restoring nutrients, and encouraging earthworm activity.

Year Two:

• Reapplying Organic Manure: We’ll continue to nourish the soil with organic manure.
• Sowing Sorghum Grass: This biofumigant reduces nematode populations and lowers levels of Verticillium wilt. We use the same drilling and cultivation techniques as in Year 1.

Year Three:

• Applying Organic Manure and Composted Green Waste: Soil health is strengthened with a mix or organic manure and composted green wate.
• Decompacting if Needed: If the land shows sign of compaction, we repeat the decompation measures.
• Sowing Sorghum Grass: We repeat the sowing process for sorghum grass as in previous years.

Innovation: Biochar Trials at Hillier Trees

We’re constantly exploring innovative ways to improve soil health. Currently, we’re conducting biochar trials to assess its potential benefits. Biochar, a carbon-rich material created through pyrolysis, is known for enhancing soil health, sequestering carbon, and reducing greenhouse gas emissions.

Our trials aim to determine whether biochar can:

• Increase tree growth rates
• Reduce susceptibility to pests and diseases
• Decrease water and irrigation needs by 20-40%
• Improve the soil’s cation exchange capacity, aiding nutrient uptake
• Enhance soil structure and aeration

To measure these outcomes, we are conducting pre- and post-trial soil analyses over a three-year period, tracking changes in nutrient levels, moisture content, and organic matter before and after trials.

At Hillier Trees, we believe our commitment to sustainable soil management practice is essential for producing high-quality trees that enrich the landscapes they’re planted in. By prioritising soil health, we’re not only supporting the environment, but also delivering trees that thrive and offer long-lasting value.

Find out more at trees.hillier.co.uk