Pig Proof Turf for Hawaii’s Commercial and Residential Landscapes.
Posted on Dec. 12, 2023 / Plant Pests / Subscribe 0
By: Dr. Joseph DeFrank
Feral pigs are destructive agents for Hawaiian turf grass in both commercial and residential landscapes. Wild pigs plow through turf in search of grubs and worms to add much needed protein to their omnivore diet, refer to Figure 1. Both homeowners and commercial turf managers have suffered with this constant threat to the integrity of their turf and have little recourse to prevent future damage.
Figure 1. Wild pigs plow through turf in search of grubs and worms. Major repair efforts are needed to return this site to a mowable turf surface. Pig damge stops where gravel-filled geocells start.
As with most useful discoveries, my pig-proof turf revelation was an indirect result of my need for an all-weather work surface for the preparation of large landscape palms for off-farm plantings, refer to Figure 2. Many land managers know that simply laying down a 3-4 inch layer of loose gravel will only provide a measure of clean large equipment operations during dry weather. However, rainy conditions will turn a gravel surface into a muddy mess when large equipment is used to maneuver heavy loads and gravel is pushed into a wet subsoil.
Figure 2. Turf covered gravel-filled geocell areas provide an all-weather surface for the movement of large-scale equipment moving very heavy loads.
Pig-proof turf sites have been installed at my nursery on the Big Island through the use of geocell panels filled with fine gravel with an underlying layer of woven polypropylene fabric (often referred to as “weed mat”). Geocell panels are honeycomb-shaped plastic cellular confining systems filled with aggregates of various materials such as blue-stove gravel or course volcanic cinder. Geocells have many uses in road construction and armoring waterways, allowing for heavy stormwater flow without loss of the gravel layer in-fill, see Figure 3. In 2000, geocell panels filled with sand were used at Waimea Bay on Oahu to build an emergency road across the beach after a dangerous rockslide closed Kamehameha Highway.
Figure 3. Gravel-filled geocells can accept stormwater with a minimal loss of in-fill while also allowing for immediate vehicular traffic once water levels recede.
My pig-proof turf covered staging area was installed in 2003, refer to Figure 4. Geocells filled with a mix of very fine gravel with larger pieces make a well-drained all-weather work surface and receptive medium for healthy turf growth. In Figure 5, wild pig damage to the turf area (left side of image) stops where the gravel-filled geocells start.
Figure 4. Geocell filled with a mix of fine and coarse blue-stone gravel. Gravel-filled geocell areas, underlaid with woven geotextile fabric, provide the foundation for a pig-proof turf for all-weather parking lots, farmer's markets, and stormwater collection structures.
Figure 5. Wild pig damage to turf area stops where the gravel-filled geocells start, see upper right image for geocell boundary.
Gravel-filled geocell areas can be grassed over with sprigs planted during installation. Commercial turf sites such as farmer’s markets, church parking lots, or open spaces that accept stormwater runoff are ideal uses gravel-filled geocells where pig damage is limited to surface scrapping of the turf. A 4-inch deep gravel-filled geocell, planted with a hard stemmed grass like Zoysia, can provide a pig-proof turf with all-weather traffic potential and distant memories of pig ravage landscapes.
GEOTECH SOLUTIONS, INC ( https://www.geotechsolutions.com/ ) is a local distributor of geocell products located on Oahu. Amazon (https://www.amazon.com/) also carries a variety of geocell products with a wide variety of choices in cell depth and overall size.
Dr. Joseph DeFrank, Research Emeritus and CEO of Ulu Wehi Agronomics.
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