8 Yields of potato and alternative crops impacted by humic product application
Humic substance (HA—humic acid, fulvic acid, and humin) are a family of organic molecules made up of long carbon chains and numerous active functional groups such as phenols and other aromatics. Humic substances play dynamic roles in soil physical, chemical biological functions essential to soil health and plant growth. This chapter reviews the field trail experiments of effects of application of commercial humic products on yields of potato and several other crops conducted in the Western and Midwestern USA. Examination of these studies reveals that potato growth is more responsive to P fertilization and minimal soil fertility, less responsive to N fertilization. Whereas some observations were not always consistent, the different soil properties and qualities of humic products from different supplies might have attributed to the inconsistencies. Thus, it is recommended the benefits of commercially available humic products in potato and other crop productions should be tested locally with a specific product. Research on the impact of long-term humic application on potato production is especially needed as little such information is currently available in the scientific literature for U.S. potato regions.