Short-Term Effects of Mustard (Sinapis alba L.) Cover Crop on Soil Quality in a Maize Production System

Soil health is vital for food security and ecosystem services supporting climate change mitigation. Cover crops (CCs) improve soil quality and crop yields in intensive agriculture. This study assessed the impact of Sinapis alba L. as a CC on ten physical, chemical, and biological soil indicators before maize planting. Three management systems were compared: (i) CC with conventional tillage (CT), (ii) CC under no tillage (NT), and (iii) tilled fallow without CC (TF). Measurements were taken at 60 and 90 days after sowing (DAS) at 0–6 and 0–20 cm depths. The Soil Quality Index (SQI) was higher at the surface under NT (0.69 at 60 DAS; 0.65 at 90 DAS). At 0–20 cm, SQI values increased at 90 DAS but did not differ among treatments. TF also showed improvements (up to +18% at 0–20 cm). Dissolved organic matter increased significantly (1.7–2.5 times), especially under NT and CT. NT enhanced structural stability (+70%) and reduced bulk density (−47%). All glomalin fractions decreased at 90 DAS; however, NT retained higher concentrations of recalcitrant glomalin in the 0–6 cm layer compared to the other treatments. These findings highlight S. alba under no tillage as a promising strategy to improve soil quality, though long-term studies are needed.