Soil tillage on farms may significantly reduce in crops the availability of ergothioneine (ERGO), an amino acid produced by certain types of soil-borne fungi and bacteria that is known as a “longevity vitamin” due to its potent antioxidant properties, according to new research by an interdisciplinary team at Penn State. The study is among the first to demonstrate that soil disturbance can directly impact a key dietary factor associated with long-term human health. “Research suggests that a lack of ergothioneine in the diet may result in increased incidences of chronic diseases of aging, such as Parkinson’s Disease and Alzheimer’s Disease, and reduced life expectancy,” said Robert Beelman, professor emeritus of food science. Beelman noted that ERGO is produced by fungi, which is why mushrooms are among the leading dietary source of this amino acid. However, ERGO produced by soil borne fungi also make its way into plants.
“Research has demonstrated that tillage of agricultural soils can disrupt fungi populations in the soil and compromise the availability of this important amino acid,” said Sjoerd Duiker, professor of soil management and applied soil physics. “This led us to speculate that agricultural soils that receive minimal or no tillage may have higher levels of fungi, and therefore, crops grown in these soils may have higher ERGO levels than crops grown with aggressive tillage.” To study the effects of tillage on ERGO content of crop plants, the team turned to an ongoing tillage study that began in 1978 at the Russell E. Larson Agricultural Research Center at Rock Springs in central Pennsylvania. The study comprises a randomized complete block design with three tillage treatments—mouldboard ploughing/disking/harrowing (MB), which represents the most intense tillage; chisel ploughing/disking/harrowing (CD), which represents a medium amount of tillage; and no-till (NT)—each replicated four times. The crops grown in the study include maize, soybeans and oats. The team collected grain samples from each of the treatments, ground them into powder and used liquid chromatography and mass spectroscopy to analyse their ERGO content.
The researchers found that ERGO concentrations declined as tillage intensity increased. Specifically, from NT to MB, ERGO content declined by 32% for maize, 33% for soybeans and 28% for oats. In addition to being associated with reduced ERGO concentrations, increased tillage also was associated with reduced crop yields.