Continuous ridge-furrow film mulching enhances maize root growth and crop yield by improving soil aggregates characteristics in a semiarid area of China: An eight-year field experiment

Aims Film mulching has been widely used for increasing crop yields in semiarid areas, but its long-term impact on crop performance and soil quality remains poor. This study aims at investigating the long-term effects of different mulching methods on the crop root growth and soil aggregates stability. Methods A continuous experiment for eight years was set to assess the effects on the soil aggregates stability, root traits, and yield under five different treatments: (i) control method comprising flat planting without mulching (CK), (ii) flat planting with half film mulching (P), (iii) film mulching on ridges and planting in narrow furrows (S), (iv) full film mulching on double ridges (D), and (v) film mulching on ridges and planting in wide furrows (R). Results The soil quality improved significantly after continuous film mulching for eight years. Compared with CK, mulching decreased the soil bulk density, and increased the soil porosity, soil macroaggregate content (7.39%-22.92% by dry-sieving, and 8.49%-21.67% by wet-sieving), and soil aggregate stability, especially under S and D. Mulching could promote the root growth (root length, root diameter, root surface area, and root volume) distinctly, while S and D increased the average root biomass by 17.27% compared with R and P. The improved soil structure and root traits under mulching increased the yield (29.98–63.96%), and the average yield under S was 1.32%, 25.7%, and 26.14% higher than those under D, R, and P, respectively. Conclusions In general, the best improved soil aggregate fractions and stability was found under film mulching on ridges and planting in narrow furrows (S), which was significantly associated with the root traits improvement, and thus increasing the crop yield. Therefore, it can be considered an effective mulching pattern for increasing and stabilizing the crop yield in the Loess Plateau region of China.