3 Factors to Consider if You Want to Build a Native Soil Natural Grass Field
Sporting fields can be classified according to the soil type over which the field is built. In this regard, there are sand-based fields which remove all native soil and replace it with a drainage layer of stone and root zone of sand for better drainage. Native soil fields are classified as true native fields which only use the soil already present on the site, and modified native fields have things like compost, porous ceramics, peat and sand added for various effects. Choosing the soil base is one of the most important aspects that must be decided early on in the design phase. These are some of the considerations that you can use to inform your decision when considering native soil fields:
Soil analysis is imperative before any more considerations are made. This is because not every soil type is capable of supporting the constant usage that many athletic fields are subjected to. You will need the input of a field design professional or soil engineer to test the soils and give professional recommendations. You can build a native field if your land is located in temperate climatic areas with moderate amounts of rainfall and soil that has balanced amounts of silt, clay and sand to facilitate growth of natural grass. Native soils are also ideal since they have better nutrient-preservation ability and water retention compared with sand-based fields. This means less expense in irrigation and fertilization.
Of course, native soil fields are preferred since they are much cheaper to construct, followed by modified native fields and sand-based fields respectively. For many organizations, particularly small ones, native fields are the only option. When budgeting, do not fail to account for maintenance needs depending on the soil types, level of traffic/usage and other factors.
For native fields, any variation from the ideal (moderate rainfall and balanced soil) will demand for soil modification at the time of construction, as well as more investment towards maintenance to keep the field looking spick and span. A poorly-maintained field can increase risk of injury to athletes during play.
Planning for drainage
A major problem with native soil fields relates to compaction – a natural process that occurs with usage where the fields become more compact (denser), affecting growth of natural grass. Native soil fields are also more prone to drainage problems especially during periods of heavy rainfall and after some time once compaction has occurred. This is circumvented by adding a gentle slope to allow water to flow from the field through prescribed drainage pathways when there's more water than the soil can absorb. This is done through inclusion of a collection drain around the perimeter so that the areas to where the water flows are not left muddy. However, this slope must be put very carefully, as excessive sloping can have a negative impact on the athletes' performance during play, particularly for sports relying on ball roll like field hockey and football.