Soil Health Principles
/ by Winstone Gypsum
Just like us soil is a living organism that needs air, water and essential nutrients to thrive.¹ Well maintained soil provides good soil structure, water retention and nutrient availability to crops.¹ When soil aeration and water availability are ideal, plant health and plant growth benefit.²
Characteristics of a healthy soil ³
· Cycles nutrients effectively
· Provides good aeration to promote root growth
· Regulates the flow of water and rainfall
· Reduces run off and erosion
· Resilient to drought, heavy rainfall events, and temperature extremes
· Resilient to disease and pest problems
· Contains a well rounded microbial community
A healthy soil includes it’s biological, physical and chemical properties.
A biologically healthy soil harbours a multitude of different organisms with most helpful to plants, enhances availability of nutrients and produces chemicals that stimulate plant growth.²
A soil’s physical condition is also critical to soil and plant health. Soils that are well aggregated and have adequate levels of organic matter will facilitate aeration, improve rainfall infiltration, drainage of excess water, and water holding capacity 4. Well aggregated soils also encourages proper root development. ²
The important chemical determinants of a soil’s health are it’s pH, salt content and levels of available nutrients. Healthy soils have adequate but not excessive nutrients. ²
A guide to managing a range of soil types
Sandy Soils³
These soils have a low capacity to hold organic matter so plan to add organic matter regularly to maintain biological activity, improve soil structure and stability. Sandy soils also have a low cation exchange capacity, it is recommended to lime little and often to maintain pH as well as manage nutrients to match supply and demand.
Medium Soils³
These soils are slow to change organic matter content so it is best to monitor and add organic matter regularly to maintain biological activity. This soil has some capacity to buffer changes in pH and nutrients, but do monitor pH, phosphorus and potassium regularly and manage nutrients to match supply and demand. To prevent compaction and minimise damage to soils in wet weather minimise tillage where possible. Adopt practices such as crop rotation to improve soil health.
Heavy (clay) soils³
These soils are naturally high in organic matter, to maintain biological activity it is best to top up organic matter regularly. Develop good rotational strategies for clay soil and manage lime, phosphorus and potassium applications. Aim to optimise soil quality to maximise nutrient use efficiency. Ensure proper drainage as waterlogging of clay soils can be an issue especially in soils without active roots.
Applications of calcium and gypsum
Calcium plays a critical role in maintaining and improving soil properties. Calcium cations bind clay minerals into micro aggregates required for root health. Soil testing to assess calcium as well as all essential nutrients will help in determining a complete balanced nutrition programme that will aid in keeping soils healthy.
Applications of agricultural lime are used to adjust soil pH and will increase soil calcium levels over the long term. Agricultural lime releases calcium slowly as it weathers in the soil and is considered a long term calcium source.
Gypsum is a source of plant available calcium in the short to medium term. Gypsum is an ideal option to top up soil reserves of calcium during high demand periods of plant growth such as establishment, flowering and fruit set.
Gypsum can be included in lime blend at a ratio of 60% lime: 40% gypsum blend.
Talk to your local fertiliser advisor about applying gypsum to your farm.
Gypsum is a naturally occurring mineral. Winstone Gypsum is BioGro certified.
References
1. Principles to improve soil health | AHDB
2. Building Soils for Better Crops - SARE