2020 Crown Nut Company Hulls & Shells Research Summary

Almond hulls, shells, and mixes of the two materials are annually stockpiled at Crown Nut Company processing facility. These materials are a source of accessible, nutrient-rich organic matter amendments that are used on nearby orchards. During processing, materials are separated into Nonpareil/Independence hulls, shells from all varieties, and a mix of hulls and shells from pollinizer varieties. There is a need to find new waste streams for hulls and shells since growth in the almond industry is outpacing the dairy industry where these materials are typically sold as cattle feed. In recent years, Crown Nut Company has spread excess shells along roadsides and in orchard alleyways as a mulch. This helps reduce dust and facilitates field access of machinery after rain. In addition to the benefits provided by mulching, almond hulls and shells contain significant amounts of potassium and other nutrients. Following nitrogen, potassium is the nutrient in second highest demand for almond trees. The highest fertilizer costs in almond production tend to be associated with potassium. This research trial asks the question: Can almond hulls and shells be used as a soil amendment over almond tree roots to supply potassium for crop uptake?