On-Farm Evaluation of Direct Seeding of Cover Crop Effects on Soil C and N Reserves and Greenhouse Gas Emissions in a Cauliflower Production System

Abstract

Vegetable production primarily relies on the conventional tillage system (CTS), which leads to soil degradation through erosion and reduced soil health. The use of no-tillage vegetable systems (NTVS) aims to mitigate these issues; however, information about the impact of this management system on soil health and greenhouse gas (GHG) emissions remains limited. Thus, the objective of this study was to conduct an on-farm evaluation of the effects of no-tillage and cover crop use on soil C and N contents and stocks, soil bulk density (SD), mean geometric diameter (MGD) of aggregates, soil temperature, volumetric soil moisture (VM), plant yield, and GHG emissions in cauliflower production under NTVS compared to CTS in a subtropical ecosystem in southeastern Brazil. Chemical and physical properties were assessed at depths of 0–5, 5–10, and 10–30 cm. GHG emissions, particularly nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4) were measured using closed static chambers and gas chromatography. NTVS with cover crop mixes had higher yield than CTS without cover crops (25.1 and 18.4 Mg ha−1, respectively). NTVS exhibited increased MGD and VM and reduced SD. Soil temperature in the 0–5 cm layer was lower in NTVS than in CTS. Soil C and N stocks were higher in NTVS, but high N2O emissions offset this advantage compared to CTS. Overall, NTVS emitted more CO2 and N2O than CTS, while both systems showed soil CH4 uptake. NTVS maintained sufficient carbon equivalent reserves (0–30 cm) to offset GHG emissions, making it a viable alternative for plant yield and soil quality; however, its environmental impact on GHG emissions requires further attention.