Suitability of Mulch and Ridge-furrow Techniques for Maize across the Precipitation Gradient on the Chinese Loess Plateau

Mulch and ridge-furrow are effective techniques to improve water harvest, reduce evaporation and increase crop productivity in dry rainfed areas. We collected grain yield data of maize (Zea mays L.) across the precipitation gradient on the Loess Plateau under three treatments- (1) CK, flat plot without mulch; (2) HM, half-mulch flat plot, i.e. alternating mulched row and bare row without ridge-furrow; and (3) DRM, double ridges and the furrow fully mulched with plastic film. Maize grain yields were highest in the DRM treatment and lowest in the CK treatment. Mulch or ridge-furrow with mulch have increased maize grain yield significantly. The highest increase was found in low growing season precipitation regimes. Grain yields of the three treatments trended to converge in high growing season precipitation regimes. Regressions between grain yields and growing season precipitation for the three treatments showed that maize yields increased linearly with precipitation for CK; statistically significant quadratic models were found for HM and DRM treatments. The economic net incomes were calculated based on yields and inputs of capital and labor for the three treatments. Considering both water resource and economic outcome, we recommend that a precipitation range of 196-532 mm is most suitable for mulch and ridge-furrow techniques for maize on the Loess Plateau. Spatially, CK and HM treatment were most suitable for small parts of the southeast part of the plateau and DRM was suitable for most of (87%) the plateau.