Adding Biochar to a Fertile Temperate Soil Has No Impact on the Growth and Very Little on the Quality of Sunflower ( Helianthus annuus L.) and Ancient and Modern Wheat Varieties ( Triticum spp.)

We checked the effect of biochar addition to a fertile temperate soil on plant growth and the quantity and quality of seeds of four varieties of wheat ( Triticum spp., two “ancient” varieties, Verna and Senatore Cappelli , and two “modern” varieties, Bologna and Claudio ) and a high oleic hybrid of sunflower ( Helianthus annuus L.). Relatively novel is the qualitative investigation of the marketable product, as few are the works on this topic. We tested three different doses of biochar—1, 4, and 20 t ha −1 —versus an untreated soil (“control”) in a 2-year open field trial in Central Italy, where wheat was grown the first year and sunflower the second year. Biochar addition did not change the soil characteristics save for the carbon content, which increased significantly with the highest dose of biochar. Also, we did not find any significant biochar-induced effect on plant growth and yields of both wheat and sunflower. Regarding the qualitative aspects, adding biochar to the soil implied an increase in total polyphenols in the middlings and bran of wheat and, with the highest dose of biochar, also in total proteins and in flavonoids and caffeic acid derivatives. Instead, no difference in carotenoids concentration and antiradical activity was observed in middlings or bran. As for the sunflower, no significant difference in seeds’ composition was detected at any of the biochar doses. The addition of biochar to a fertile, well-drained soil as the one we investigated is not detrimental to the quantity and quality of wheat and sunflower seeds. Rather, the concentration of some polyphenols in wheat appears to be positively affected by biochar addition.