EFEITO DE COBERTURAS VEGETAIS NO CARBONO DO SOLO E NA PRODUTIVIDADE DO MILHO EM SEMEADURA DIRETA

Abstract

The use of cover crops combined with no-till sowing increases the amount of organic material in the soil, potentially resulting in chemical, physical, and biological changes – most notably, an increase in soil organic matter. The objective of this study was to evaluate total soil organic carbon and the agronomic characteristics of maize grown under different cover crops. The experiment was conducted at the UFMS Chapadão do Sul campus (Mato Grosso do Sul) during the 2018/19 growing season, using the FS450PW maize hybrid sown in October 2018. A randomized complete block design was used, with nine treatments and four replications. The treatments consisted of the following cover crops: sunn hemp (Crotalaria juncea), pearl millet (Pennisetum americanum), forage radish (Raphanus sativus), sorghum (Sorghum bicolor), Urochloa brizantha, U. piatã, U. ruziziensis, a seed mixture (forage radish + pearl millet), and fallow. Soil samples were collected at depths of 0–10 cm and 10–20 cm, 60 days after sowing the cover crops, to determine total organic carbon (TOC) using the muffle furnace method. Agronomic characteristics and grain yield were evaluated for the maize crop. The highest organic carbon levels were observed with forage radish, sunn hemp, and the pearl millet + forage radish mixture (17.35%, 16.58%, and 16.43% at the 10–20 cm depth), while the highest grain yield (13,057 kg ha⁻¹) was obtained with pearl millet and the lowest with U. ruziziensis (9,731 kg ha⁻¹). It is concluded that cover crops affect soil organic carbon and maize productivity, with radish, Crotalaria, and pearl millet + radish increasing carbon, and pearl millet maximizing grain yield.