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Soil ’n’ survival: matter of inches

It is eye-opening when you work with the best soil formation in the world here in Iowa, and then elsewhere see soil with only a few inches of depth and scratch through it with your hand to find bedrock! That’s how I, an Iowa State University Extension agronomist, sum up my recent visit to Guam, a small island nation in the Pacific Ocean.

Recently, I was in Guam attending a soil carbon conference organized by the University of Guam. Guam is a small island nation in the Pacific Ocean. Scientists from the U.S., China and other Pacific Rim islands attended and presented at the conference. We had a chance to visit several research farms and farmers’ fields.

The island is equivalent in size to a small Iowa county, approximately 32 miles long and 17 miles wide. The temperature was a constant 90 degrees F day and night, and humidity was over 50% at all times. The conditions reminded me of Iowa weather during the month of July.

However, a significant difference from Iowa is the absence of well-developed soil. Their soils are only a few inches deep and sit on volcanic bedrock. The soils of Guam are characterized by a lack of nutrients, high aluminum content and extremely low pH. It reminded me not only how fortunate we are to have, arguably, the best soil formation in the world, but also how we take our soils here in Iowa for granted in the way we often manage the resource.

Healthy soil, healthy people

The chemical and physical conditions of soil in Guam present significant production and health challenges — yes, human health challenges for the island’s native inhabitants. The majority of agriculture production is tropical fruits, with a few acres in vegetable production. The side effects of the soil chemical makeup are not only poor crop yields, but also negative human health effects.

In the early 1950s, studies suggested trace metal toxicity and exposure to these metals from food and water derived from the soil were the cause of the disease Amyotrophic Lateral Sclerosis-Parkinson Dementia Complex. This neurological disorder was linked to high concentrations of aluminum and manganese in the southern part of the island’s soil, where the cycad tree grows. The people in that region used its fruit seeds as part of their diet. The discovery of this disease has lead researchers to link it to a high concentration of aluminum in spinal cords of patients who used cycad seeds as part of their diets.

The people of Guam developed soil management skills over generations and kept the few inches they have despite the harsh chemical and physical soil conditions that have both negative health and environmental effects. The magnitude of challenges that Guam’s people face are huge in managing their soils. In particular, the soil conditions dramatically affect human survival. The few inches of soil are not suitable to support crop production systems. In some cases, you can scratch the soil surface by hand and hit the bedrock!

Our soil is a source of survival for not only the people in our state, but also globally. Iowa’s agriculture, completely dependent on our soil, is feeding people across the Pacific and around the world either directly or indirectly. Despite all the weather challenges we face here in Iowa, such as the recent floods and drought in different parts of the state, it is imperative that we double our efforts in promoting soil conservation practices to protect our precious soils and sustain their quality.

We have great soil resources in Iowa and must manage our soil and keep it in its unique and productive condition. We, too, need to manage it by the inch in order to have healthy, productive people and a safe environment. 

Al-Kaisi is an ISU Extension agronomist and soil management specialist at Ames. He recently visited Guam, a small island nation in the Pacific Ocean.


IS THIS IOWA? No, it’s Guam. “The soil resources of Guam are quite a contrast to the deep, rich soils of Iowa,” says ISU’s Mahdi Al-Kaisi. “We must manage Iowa’s unique soils to keep them productive and save them from erosion.”

This article published in the October, 2011 edition of WALLACES FARMER.

All rights reserved. Copyright Farm Progress Cos. 2011.