A characterization study of two by-products from the cork stopper industry was conducted to assess their suitability as components of growing media (substrate). Granulate of natural cork stopper (GNCS) and granulate of technical cork stopper (GTCS) were studied, evaluating their chemical composition, fractionation, effects on physical and chemical properties, mineral elements, and phytotoxicity. The two by-products were granulometrically classified into four categories: very fine fractions (≤1 mm), fine fractions (>1 and ≤2 mm), intermediate fractions (>2 and ≤5 mm), and coarse fractions (>5 and ≤10 mm). The highest proportion of granulates was observed within the intermediate fraction (>2 and ≤5 mm). GTCS presented significant limitations regarding the assessed properties, while the very fine fractions (≤1 mm) were the most attractive in both granulates. Therefore, selecting raw materials and their fractionation are vital for predicting the performance of growing media and establishing their suitability for promoting plant growth and productivity. Thus, these two by-products of the cork stopper industry have desirable characteristics as components of growing media.
Freitas et al. (Wed,) studied this question.