Agronomic evaluation of substrates for microgreens cultivation.
Healthy food; Brassica oleracea; Compost.
Composting is an efficient technology for the reuse of organic waste from economic activities, offering potential socio-economic and environmental benefits. With the growing interest of the population in healthier lifestyles, more nutritious and contaminant-free products, organic foods have become highly sought after by this consumer profile, with microgreens standing out. The aim of this study is to evaluate the agronomic viability of substrates developed for the cultivation of Purple Cabbage microgreens (Brassica oleracea var. capitata f. rubra), derived from a blend of compost produced from Gliricidia pruning (Gliricidia sepium (Jacq.) Steud.) and sawdust, with commonly used conditioning materials in organic agriculture. The composting process took place in a heap with dimensions of 2.0 x 1.2 x 0.9 m. The evaluated substrates consisted of mixtures of vermiculite, perlite, and sphagnum peat moss with the compost in proportions of 25%, 50%, and 75%, along with three reference treatments: 100% compost, 100% commercial substrate Carolina Soil©, and washed sand. pH, electrical conductivity (EC), dry bulk density, total N, P, K, Ca, Mg contents, and available P, K, Ca, Mg, CO2 and NH3 emissions from compost and substrates were evaluated, excluding washed sand which was considered inert. The agronomic performance of the produced inputs was evaluated through the cultivation of purple cabbage. Fresh weight, dry weight, and seedling height were assessed after 15 days of cultivation. The experiment was developed in a factorial design (3x3) + 3, with a completely randomized experimental design. It was observed that compost production based on Gliricidia and sawdust and the substrates produced with conditioning materials meet current organic legislation and yielded good results in microgreen production. The formulated substrates showed superior performance for the fresh weight parameter compared to the commercial substrate Carolina Soil© and washed sand, except for those derived from compost mixtures with 75% perlite and sphagnum peat. The results highlighted the possibility of using these materials in the production of microgreens.