Continuous maize cultivation with high nitrogen fertilizers associated with the formation of dried soil layers in the semiarid farmland on the Loess Plateau

Abstract

• Different land use types were chosen to determine soil desiccation. • Long-term maize cultivation with high yield caused a DSLs in the deep soil layers. • Crop rotations are recommended for maize production in the semiarid environment. Sustainable agriculture ensures food security and combats climate change by minimizing reliance on water resources. Maize ( Zea mays L.) is commonly grown with plastic mulching practice on the Loess Plateau of China, but its impact on soil desiccation is not well understood. We compared the effects of different land-use, including 17-year continuous wheat cultivation, 19-year pea-wheat rotations, 12-year continuous maize cultivation (high yield), 30-year multi-crop rotations, and 9-year continuous maize cultivation (varying yield) under four nitrogen (N) fertilization rates (i.e., 0, 100, 200, and 300 kg N ha −1 ). Average crop evapotranspiration during 2009–2020 for long-term continuous wheat, pea-wheat rotation, high-yielding maize, and multi-crop rotations was 222, 201, 277, and 393 mm, respectively, while average effective precipitation from March to September was 329 mm for all treatments. Continuous high-yielding maize cultivation formed a dry soil layer (DSL) in the deep soil profile (>400 cm), which was not found in other cultivation modes. After 9-year continuous high-yielding maize cultivation, 300 kg N ha −1 applying (20.9 Mg ha −1 biomass yield) formed the DSLs in the 360–960 cm soil profiles, while under 200 kg N ha −1 (20.1 Mg ha −1 biomass yield), the soil water content was almost close to the threshold of DSL in the 600–740 cm soil depth; while under 0 and 100 kg N ha −1 (<15 Mg ha −1 biomass yield), the DSL was not found along the soil profile, indicating that DSL formation under continuous maize cultivation was is driven by high N rates (or high yield level). These results suggest that long-term high-yielding maize cultivation with plastic mulching causes severe soil water depletion, resulting in the formation of a DSL in the deep soil profile. To maintain productivity, farmers should not be encouraged to carry out long-term continuous cropping of high-yielding maize in the semiarid environment on the Loess Plateau.