Continuous wheat-maize rotation (WM) has caused soil degradation and yield reduction in the North China Plain (NCP). To explore sustainable crop systems, four diversified rotations were conducted over three 2-year cycles from 2015 to 2021: (ⅰ) Maize → WM, spring maize-WM; (ⅱ) Millet → WM, spring millet-WM; (ⅲ) Peanut → WM, spring peanut-WM; and (ⅳ) Soybean → WM, spring soybean-WM. During the third rotation cycle (2019–2021), we investigated variations in soil nutrients and enzyme activities in the 0–40 cm layer throughout wheat growth stages (sowing, regreening, jointing, anthesis, and maturity stage) among different rotations and assessed their impacts on wheat production and soil quality. Results indicate that diversified 2-year rotations reduced nitrogen loss by lowering soil mineral nitrogen during wheat growth stages compared to WM. The heightened activities of nutrient-acquisition (carbon, nitrogen, and phosphorus) enzymes in diversified 2-year rotations contributed to an improvement in soil quality index (SQI) by 4.1 %-8.7 % ( < 0.05) and 9.8 %-18.9 % in the 0–20 cm and 20–40 cm soil layers, respectively, compared to WM. However, the SQI in the 0–20 cm was significantly lower in Peanut → WM compared to Soybean → WM. Diversified 2-year rotations also increased wheat yield by 45.7 %-66.4 % ( < 0.05) compared to WM. The stoichiometry of enzymes revealed that diversified 2-year rotations exacerbated soil microbial carbon limitation during wheat growth stages. This issue, however, was effectively addressed by increasing dissolved organic carbon to fulfill the crop's carbon requirements. The findings highlight the potential of incorporating diverse spring crop species, whether leguminous or non-leguminous, into wheat-maize rotation as a promising crop pattern to enhance soil quality and increase wheat yield in the NCP.

中文翻译：

---

华北平原通过多种轮作提高土壤质量和小麦产量


连续的小麦-玉米轮作（WM）导致华北平原（NCP）土壤退化和减产。为了探索可持续作物系统，从2015年到2021年，在三个两年周期内进行了四次多样化轮作：（ⅰ）玉米→WM，春玉米-WM； (二)小米→WM、春小米-WM； (ⅲ)花生→WM、春花生-WM； (ⅳ)大豆→WM、春大豆-WM。在第三个轮作周期（2019-2021年）中，我们调查了不同轮作期间小麦整个生长阶段（播种、返绿、拔节、开花和成熟期）0-40 cm层土壤养分和酶活性的变化，并评估了它们的差异。对小麦产量和土壤质量的影响。结果表明，与 WM 相比，多样化的两年轮作通过降低小麦生长阶段的土壤矿质氮来减少氮素损失。在多样化的两年轮作中，养分获取（碳、氮和磷）酶的活性增强，导致土壤质量指数 (SQI) 提高了 4.1 %-8.7 % ( < 0.05) 和 9.8 %-18.9 %与 WM 相比，分别在 0-20 cm 和 20-40 cm 土层。然而，与大豆 → WM 相比，花生 → WM 中 0-20 cm 的 SQI 显着较低。与西小麦相比，多样化的两年轮作也使小麦产量提高了 45.7 %-66.4 % ( < 0.05)。酶的化学计量表明，多样化的两年轮作加剧了小麦生长阶段土壤微生物碳的限制。然而，通过增加溶解有机碳以满足作物的碳需求，这个问题得到了有效解决。 研究结果强调了将多种春季作物品种（无论是豆科还是非豆科）纳入小麦-玉米轮作中的潜力，作为一种有前途的作物模式，可提高NCP的土壤质量和增加小麦产量。