Malama Puʻuloa is working on several restoration efforts to restore abundance to Puʻuloa and reconnect community to place. Over time, Mālama Puʻuloa observed that some plants wouldn’t grow in certain areas, leading to the questions: What is in our soil? Is it safe to eat food grown here? What can we do to improve our soil?

What is soil?Soil is alive! It is a complex mixture of minerals, water, air,

organic matter, and countless organisms that are the decaying remains of once-living things.

Soil series describe the composition of the soil and are often named after places. In Hawai’i, there are 190 soil series. The three sites in Puʻuloa where we conducted soil tests are each

in different soil series, speaking to the differences of each area despite their proximity.

Got Soil?Mālama Puʻuloa: Understanding Soil Condition and Recommendations for

Restoration

To better understand the soil condition at Puʻuloa, we conducted three soil tests:

Soil health is the biological, chemical and physical properties of the soil, which allow it to sustain life.

Soil fertility determines the nutrient content of the soil and its ability to provide nourishment for plants, as well as excess nutrients which may restrict plant growth.

Soil toxicity determines the concentration of metals in soil that are needed in small quantities for plant growth or known to cause human health problems.

Knowing what is in soil is the foundation of knowing what can grow, what is safe to eat, and the first steps of

restoring abundance to Puʻuloa.

https://soilhealthhawaii.org/

Mauʻu ʻakiʻakiFimbristylis cymosa

Honouliuli StreamSoil series: Keaau Clay

Constraints:Due to its proximity to the ocean and stream, soils are very saline (high salt content), and often saturated with water, possibly restricting what plants can survive.

There are additional concerns including runoff from agriculture and development bringing certain pollutants down stream.

Removing mangroves has opened up the area but led to increased erosion with higher chance of stream sedimentation as it flows into Puʻuloa.

Considerations:Planting coastal adapted native plants such as paʻu o hiʻiaka, native sedges, hala, milo, etc. are recommended as they can survive high salt levels and wet soil. Native plant species also help in decreasing erosion and runoff and can act as phytoremediation solutions, ie. remove pollutants from soil and water.

At this site:Mālama Puʻuloa is working on stream restoration, removing mangroves, and restoring fishponds. They have cut back mangroves to open up the area and increase water flow, and outplanted native plants on both sides of the stream.

Paʻu o HiʻiakaJaquemontia sandwicensis

HalaPandanus tectorius

NaupakaScaevola taccada

Kapapapuhi Point ParkSoil series: Helemano Silty Clay

Constraints:Due to its proximity to the ocean, soils are very saline (high salt content), restricting what plants can survive.

There are additional concerns including runoff from agriculture and development bringing certain pollutants to the shores around the park.

Soil is very dense and compacted, it is very hard to dig holes and plant.

Considerations:Planting coastal adapted native plants such as ʻākulikuli, pohinahina, naupaka, kou, milo, etc. are recommended as they can survive high salt levels and dry soil. Native plant species also help in decreasing erosion and runoff and often can act as phytoremediation solutions, ie. remove pollutants from soil and water.Augers are a great tool to loosen soil around planting sites.

At this Site:Mālama Puʻuloa is restoring Kapapapuhi Point Park - a public access coastal park. They have removed mangrove on the shoreline, which increases visibility, allows for more fishing and native plant outplanting.

ʻAkulikuliSesuvium portulacastrum

PōhinahinaVitex rotundifolia

Ulu - BreadfruitArtocarpus atilis

Uala - Sweet PotatoIpomea batatas

Maiʻa - BananaMusa spp.

Constraints:While soil in this area is less saline, many food plants will require added soil nutrients in the form of fertilizer to enhance food productivity.

Cadmium, Chromium, and Arsenic concentrations were above desirable levels and could pose a potential human health concern if they are uptaken into food crops

Considerations:Use natural fertilizers, compost and decomposing material to enhance soil quality around areas for food crops.

Before consumption, testing of fruit and vegetables should be done. In addition, wash all plant parts before consumption as this urban food forest is exposed to localized and air pollution.

Food ForestSoil series: Pearl Harbor Clay

At this Site:Mālama Puʻuloa is creating a linear community garden along the Pearl Harbor Historic Bike Path. They are cleaning areas along the bike path and intend to plant food crops to feed the Puʻuloa community and restore relationship between people and place.

Hawai’i Soil Health Soil Sampling Protocol:

● Collect at least 10 soil cores per 1 composite sample● Between composite samples, rinse tools with alcohol and then

rinse thoroughly DI water● Remove overlying vegetation ● Use pickaxe or sharpshooter shovel to dig small pit to 8 inch

depth● Use trowel to collect vertical slice from side of pit 6 inch deep,

2-3 inch thick● Transfer all ~10 cores to bucket and mix to create 1 composite

sample● Place bagged sample in cooler with frozen cold packs● Store samples in fridge until ready for shipping

*Different soil testing labs may have different procedures.*

Hawai’i Soil Health Testing:

https://soilhealthhawaii.org

Soil Fertility and Metals Testing:

https://www.cropnutrientsolutions.com