Optimizing fertilization strategies is crucial for obtaining high crop yields and efficient N utilization. This study aimed to understand the potential increase in crop yield and the N utilization efficiency under biochar-based fertilizer (BF) in a maize–Chinese cabbage rotation system. Biochar-based slow-release fertilizer (BF) is an important nutrient-efficient management strategy. The yields and growth-related traits of the crops, N utilization efficiency, quality, and dynamic changes in soil inorganic N in a maize-cabbage rotation system were investigated in a pot experiment under three N fertilizer application strategies in 2019–2020; the maize stage included (1) zero-N fertilizer, i.e., control (N 0 g pot⁻¹); (2) NPK (N 5.25 g pot⁻¹); and (3) BF (N 5.25 g pot⁻¹). The Chinese cabbage stage included (1) zero-N fertilizer, i.e., control (N 0 g pot⁻¹); (2) NPK (N 6.25 g pot⁻¹); and (3) BF (N 6.25 g pot⁻¹). Compared with the CK and NPK treatments, the BF treatment had the highest average maize and Chinese cabbage yields at 86.99 g plant⁻¹ and 498.88 g plant⁻¹, respectively. BF improved the plant height, stem diameter, and ear height of maize and the leaf length, leaf width, and leaf number of Chinese cabbage, as well as increased the N utilization efficiency of maize and cabbage. BF increased the starch content of maize grain and the amino acid, sugar, and vitamin C contents of cabbage. In the critical growth stages of maize and Chinese cabbage, BF application increased the content of soil inorganic N, which coincided with the nutrient requirements in the critical growth stages of the crops. Overall, BF is an effective method to improve crop yield and N utilization in the maize–Chinese cabbage rotation systems and is a fertilization strategy with broad applicability prospects.

Solving the soil organic carbon (SOC) sequestration problem is crucial for agricultural sustainability. The main objective of our study was to assess the effects of biochar derived from different organic wastes on SOC, SOC storage, and soil aggregate fractions in a corn-Chinese cabbage rotation system. A consecutive two-year field experiment was conducted with six fertilization treatments, including nonfertilization (CK), mineral N, P, and K fertilizer (NPK), distiller-derived biochar (NPK + D), tobacco-derived biochar (NPK + T), tobacco-derived modified biochar (NPK + TM), and corn straw-derived biochar (NPK + CS). Compared to the NPK treatment, the NPK + D, NPK + T, and NPK + TM treatments significantly increased SOC by 56.3%, 58.6%, and 31.7%, respectively. Among all treatments, the NPK + T treatment had the highest SOC storage at 32.1 t ha⁻¹. Compared with CK, the NPK + T treatment increased large macroaggregates and small macroaggregates by 38.3% and 10.7%, respectively. Compared to the NPK treatment, the biochar treatments improved the geometric mean diameter (GMD) by 15.5%–25.2%. Biochar has considerable potential for enhancing crop productivity in degraded yellow soils by improving the physical environment.

Optimal potassium (K) fertilizer application in potato cropping systems can effectively increase food production and mitigate soil microbial ecosystem stress. The dynamics and sustainability of potato yield, the dynamics of potato commodity rates (CRs), and microbial community structure were explored under four different K application rates (kg K ha⁻¹ year⁻¹): 0 (control), 75 (low K), 150 (medium K), and 225 (high K). Compared with the low-K application, the medium-K and high-K applications increased potato yields by 8.08% and 11.66%, respectively. The mean CR of potato tubers during 4 years was significantly greater under the medium-K treatment than under the low-K and high-K treatments. Both medium-K and high-K applications significantly enhanced the sustainable yield index (SYI) relative to the Low-K application by 7.93% and 9.34%, respectively. Compared with the zero-K, low-K, and high-K treatments, the medium-K treatment improved the total phospholipid fatty acid (PLFA) contents by 11.91%, 16.84%, and 11.66%, respectively. Moreover, the medium-K application increased the bacterial PFLA, actinomycete PFLA, gram-positive (G⁺) bacterial PFLA, and gram-negative (G⁻) bacterial PFLA contents in the soil. Overall, application of 150 kg ha⁻¹ year⁻¹ K fertilizer represents a promising fertilization strategy in potato cropping systems in Southwest China.