Sweet potato production on the Hamakua Coast
It’s time to test your soil!
By Chantal Vos, Researcher, and Norman Arancon, Associate Professor of Horticulture.
![Norman stands in large sweet potato field.](https://hilo.hawaii.edu/nihopeku/wp-content/uploads/2018/06/Norman-in-sweet-potato-field.jpg)
Sweet potato (Ipomoea batatas, L.) production along the Hamakua Coast can be increased by addressing nutrient imbalances in the soil. Sweet potato is an important crop in Hawai‘i both for local consumption and as an export crop and more than 90 percent is produced along the Hamakua Coast on the island of Hawai‘i (Miyasaka and Arakaki, 2010). Most commercial sweet potato farmers on Hawai‘i Island do not test their soil or crops on a regular basis for potential nutritional problems. Fertilizers are often applied indiscriminately based on prior experience or current practice from other growers, whether these areas have been cropped for many years or are newly cleared for cultivation. Soil fertility is often not optimal, even on land that has never been cultivated with sweet potato (virgin land). During crop production, available nutrients are lost through leaching, run-off, and crop harvest. Nutrient balances are distorted, and fallow periods have demonstrated limited capacity to adequately restore and build soil fertility. This being said, fallows will generally reduce many disease and pest problems (Bennett et al., 2012).