Efeito de coberturas mortas vegetais sobre o desempenho da cenoura em cultivo orgânico

Abstract

The effect of soil mulch with different plant species was evaluated in relation to the performance of organically grown carrots and to weed population levels. The experiment was carried out at the Integrated Agroecological Production System located in Seropédica, Metropolitan Region of Rio de Janeiro State (Baixada Fluminense), Brazil, using a randomized blocks design comprising four treatments replicated six times. These treatments consisted of soil mulch with chopped and dried above-ground biomass of Cameroon grass (Pennisetum purpureum), gliricidia (Gliricidia sepium), and pigeon pea (Cajanus cajan) compared to uncovered plots (control treatment). Carrot marketable yield and root characteristics (weight, length, and major diameter) were determined at harvesting. Reinfestation by weeds was estimated through the total number of individuals per square meter of cultivated area and the assessment carried out at 20, 50 and 80 days after sowing. Carrot (cv. Brasília) showed significantly increased values regarding all the variables (except for root length) in the plots treated with legume amendments (pigeon pea and gliricidia). As for the Cameroon grass mulch, results were statistically equivalent to the control treatment. Weed populations by cultivated area unit reached levels up to 300% higher in the non-mulch plots compared to the ones covered with plant residues.