Crop Rotational Diversity Influences Wheat–Maize Production Through Soil Legacy Effects in the North China Plain

Crop rotations can make use of plant-soil feedback (PSF) effect to improve the sustainability of crop production. Winter wheat (Triticum aestivum L.)-Summer maize (Zea mays L.) double-cropping (WM) has the largest planted area in the North China Plain. To explore sustainable planting patterns, four crop rotation modes were implemented in 2002. (1) RS: Ryegrass (Lolium perenne L.)-forage sorghum (Sorghum bicolor L. Moench) and WM rotation; (2) P: Spring peanut (Arachis hypogaea L.) and WM rotation; (3) RCP: Ryegrass–cotton (Gossypium hirsutum L.), peanut, WM rotation; and (4) SCS: sweet potato (Ipomoea batatas L.), cotton, sweet potato, WM rotation. After 15 years of crop rotation, the soil legacy effects on wheat and maize production were evaluated through field and pot experiments. Results show that yields and soil properties (soil organic carbon, total nitrogen, NO3−, pH, EC, and aggregate stability) were significantly influenced by different crop rotation systems prior to the same wheat planting. In 2018, compared to WM treatment, SCS, RCP, and P produced a higher total grain yield of wheat and maize at 27.7%, 25.1%, and 24.8%, respectively. RS produced a 6.7% lower total grain yield than WM. The crop rotational difference of wheat and maize yield was not reflected in these soil properties. The pot experiment demonstrated that soil from different cropping systems had dissimilar biotic and abiotic properties that influence crop growth. Our results show that enhanced crop rotations based on double cropping (wheat–maize) can affect wheat and maize production, and the effects were related to their specific soil legacies affected by plant-soil feedback. Including more diverse crop species in the rotation has beneficial soil legacy effects for the yield and resource utilization in agriculture systems.