Rural Reflections: Lava rock nourishes Hawaiian ag industry

Farm Forum

When temperatures drop to minus 35 and the snow swirls across the Northern Plains, it’s a good time to head to a tropical island. Even in paradise, some areas of the landscape can appear harsh and unable to provide any base for life. Dale and I visited Hawaii a few weeks ago with SDARL alumni and were fascinated by the “land” in that state and the many faces of its agriculture.

In Hawaii, soil, or what is referred to as soil, all originates with the volcano, either millions of years ago or 200 years ago. On the Big Island of Hawaii, land near the road on the west side of the island looked like a barren wasteland while other areas were green and lush with foliage. We were told that all climate types were on the island except for two.

Each day we live and work on top of a substance that we take for granted. This last year, I’ve attended some workshops that look at our South Dakota soil and learned ways to minimize degradation. Grabbing a fistful of dirt is a good way to understand some of the properties of the substance that we depend on in agriculture. It took me a while to understand the soil that makes up the islands.

Shiny black volcanic rock lined the roads near Kona on the Big Island of Hawaii. We learned that the lava contains metals and micro-nutrients such as copper, zinc and silicon. In this place, erosion by wind and water turns the cooled lava eruptions into soil. That process evolves over thousands of years. Living organisms along with the environment take the lava from a hard, unyielding substance into soil that can sustain life. The stark areas were relatively “young,” as the lava flow was from the 1800s.

As the lava rock breaks down, the result absorbs and holds heat and water, making a great habitat for growth. A secondary benefit is that it is a natural deterrent for insects.

The deteriorated lava rock provides a superb base for all sorts of agriculture on the island state today. Pineapple is still grown on Oahu but nowhere near the acreages there used to be in the state. Sugar remains on Maui only, once the largest crop in the state. During our visit, we learned that the sugar cane fields and pineapple plantations have mostly moved their operations to South America where labor is cheaper.

High-value is definitely the key for most crops grown, whether that is seed, vegetables, orchard crops, etc. Propagating seed corn for the mainland has become the number one ag crop for Hawaii.

In a land where almost anything grows, we were surprised not to see fields of corn and soybeans. We were told the biggest reason for people not growing corn and soy are input costs. There’s a premium on all inputs and labor on top of the water cost, which might be anywhere from $0.55 to $2.00/1000 gallons. All equipment has to be brought to the islands, and the support system isn’t there. There have been some hay and silage operations, but they have not typically been sustained. Storage of grain is also a problem in the humid environment.

Agriculture is flourishing. We saw small operations raising coffee, cacao for chocolate, grapes for wine, bushes for teas, mushrooms, avocadoes, mangos, vegetables, basil and nuts. We also visited aquaponic facilities where the water from tilapia raised in tanks is used to fertilize the head lettuce and salad mix. Row after rows of these plants float on Styrofoam sheets in tubs with the water filled with nutrients nourishing the roots. In the fields, water from the heavens ranges from 15 inches to 50 inches of rain.

Huge ranches take advantage of the lush grasses. On the Ponoholo ranch, the land rises from the ocean beaches to the mountain tops, stretching 10 miles from top to bottom. Rainfall near the ocean is 15 inches while up the mountain, it is 150 inches.

Near the Kilauea volcano, we visited a winery. The manager told me that in order to plant the vines, they used jackhammers to carve out a 2-foot wide trench in the volcanic rock. They put in compost, and then added some dirt and the vine cuttings. The jackhammer cracks the rock so the roots can take hold. They are near enough to the volcano that sometimes, when the winds are from the wrong direction, the blossoms on the vines are affected from the sulfur gasses from the volcano.

Our ancestors built a life for their families in South Dakota. With a plow, they carved their mark on the land as they turned the sod to grow crops for their families. It was fascinating to get a glimpse of the process in this island state where lava rock now nourishes the agriculture industry. Aloha!