Mineral amendments to improve plant growth after soil sterilization in allelopathy experiments

This study aimed to ameliorate the soil physicochemical properties and plant growth after soil autoclaving by adding mineral amendments. Agricultural soil was mixed with sand and perlite in 2 ratios (1:1 and 1:2, w/w), creating 4-treatments that were sterilized by autoclaving. Thereafter, 4 plant species [Zea mays, Lactuca sativa and Sinapis alba (crops) and Amaranthus retroflexus (weed)] were individually grown in pots containing the autoclaved soil mixtures. At the end of the assay, physicochemical parameters of soil mixtures (pH, soil texture and structure) and plant morphological traits (leaf area, fully developed leaves, emergence, length, biomass, and rhizosheath) were measured. There was a significant increase in soil pH and a decrease in soil particle density after the addition of perlite. Plant growth (shoot length, root length or biomass) seedling emergence, leaf area and rhizosheath were significantly increased with the use of mineral amendments, especially perlite. The use of inexpensive amendments effectively ameliorated soil physicochemical properties and plant growth after soil autoclaving. Improving the soil properties after sterilization by using mineral amendments would be useful to standardize soil physicochemical conditions and thus, reducing the undesired interference in the evaluation of allelopathic effects.