Maize productivity response to combined tillage and mulching in coastal saline zones

Soil salinization is threatening sustainable crop production in coastal saline regions. An integrated approach with combined tillage and mulching may be more successful than sole management practice (e.g., rotary tillage) for reducing soil salinity and improving crop productivity in coastal saline zones. We conducted a 3-yr field experiment in maize (Zea mays L.) in the Yellow River Delta. We used four treatments: (a) rotary tillage to 15 cm (RT) (local farmers' practice), (b) deep tillage to 25-to-30-cm depth followed by RT (DT), (c) flat planting with the application of plastic mulch after DT (DM), and (d) ridge-furrow planting together with plastic mulching after DT (DMF). These treatments were intended to improve soil properties and maize productivity, while increasing net returns. Grain yields were significantly increased by 18.5-20.9% under DMF and DM, nitrogen partial factor productivity (PFPN) by 18.5-20.8%, and net returns by US$103-124 ha(-1), compared with RT. Grain yields with DMF and DM were also improved by 12.7-15.0%, PFPN by 12.8-15.0%, and net returns by $ 39-60 ha(-1), compared with DT. Compared with RT, soil electrical conductivity (EC) and Na+ concentration with DMF and DM were reduced by 16.2-75.4% and 19.0-78.2%; EC and Na+ concentration were also reduced by 6.41-64.4% and 11.1-53.7%, compared with DT. These results demonstrate that combined tillage and mulching is an efficient integrated management approach for improving soil properties, promoting maize productivity, and increasing financial benefits in coastal saline zones.