Resiliência de plantas de cobertura à seca

Straw production from cover crops and the sustainability of no-tillage farming systems can be compromised by low rainfall during the dry off-season in Central Brazil. This study investigated the drought resilience of five cover crop species under drought stress conditions. Three irrigation levels [100% pot capacity – CV (well-watered conditions), 60% CV (moderate drought stress) and 25% CV (severe drought stress)] and five grass cover crop species [Urochloa brizantha cv. BRS Piatã, U. brizantha cv. Marandu, U. brizantha cv. Xaraés, U. ruziziensis cv. Comum and Pennisetum glaucum cv. ADR 300] were tested using a randomized block design with a 3 × 5 factorial arrangement and three replications. Canonical variable analysis (CVA) and a correlation network were established with the variables evaluated. The CVA showed that 88.6% of the total variation of the data was retained in the first two canonical variables. The plants were exposed to water stress for 25 days during the tillering and stem elongation phases. Plants of the genus Urochloa (U. ruziziensis, U. brizantha cv. Marandu, and U. brizantha cv. Xaraés) showed higher total dry matter production under normal irrigation conditions. However, under moderate water stress conditions, U. ruziziensis was the cover crop with greater resilience, since these conditions culminated in higher dry matter production.