Excessive nitrogen (N) fertilizer input has become a common phenomenon among most farmers in the winter wheat–summer maize rotation system of north-central China, and has resulted in low nutrient use efficiency and environmental pollution. Controlled-release urea (CRU) is proposed as a solution to excessive fertilization because CRU achieves high yields and reduces N losses. Therefore, CRU mixed with normal urea at rates based on the Nutrient Expert (NE) system was used as fertilizer in a 4-year field experiment to test the preference in crop yields, economic benefits, nitrogen use efficiencies, and N losses. The following fertilizer treatments were established: local farmers’ practices (FP); normal urea fertilizer at the rate recommended by the NE system (NE); mixed CRU and normal urea at ratios of 60:40 (CRU1) and 75:25 (CRU2) based on the NE system; and 80% of the recommended N rate of the NE, CRU1 and CRU2 treatments (80%NE, 80%CRU1 and 80%CRU2). The results showed that, compared with the NE treatment at the same application rate of N, mixed CRU and urea increased yields and net benefits while reducing N loss. The application of CRU at 60% for maize and 75% for wheat had the best overall effects. Compared with FP, the average grain yield, recovery efficiency of N fertilizer and net benefits increased by 8.5%, 10.9% and 11.3%, respectively, for maize with CRU1, and increased by 4.5%, 15.1% and 10.3%, respectively, for wheat with CRU2. Furthermore, mixed CRU and urea at the recommended N rate significantly reduced N loss from 38.5% to 40.3% but increased soil NO₃⁻-N and NH₄⁺-N contents at 0–30 cm, although opposite results (NO₃⁻-N) were observed deeper in the soil (30–90 cm). In the treatments 80%CRU1 and 80%CRU2, the maize yield and overall economic benefits were equivalent to those in the FP treatment, but apparent N loss was significantly reduced. Thus, these results confirmed that the combination of the CRU and the NE system for winter wheat–summer maize in north-central China is efficient and valuable, and has the potential to improve yield, nitrogen use efficiency and net benefit with low N losses.

Objectives: The substitution of chemical fertilizers with organic alternatives presents a viable strategy for enhancing soil quality and boosting agricultural productivity. However, the question remains whether organic–inorganic compound fertilizers (COIFs) can sustain improved soil quality and crop yields while reducing chemical fertilizer use. The underlying mechanisms of COIF’s impact still warrant further exploration. Methods: In this study, a long-term fertilization trial was conducted from 2020 to 2023 at two sites with different soil textures and types in the Huang-Huai-Hai Plain, China. The experiment involved three fertilization treatments, each replicated three times: (1) LCF (conventional fertilizer treatment); (2) COIF1 (COIF applied at 90% of the recommended rate); and (3) COIF2 (COIF applied at 80% of the recommended rate). The objective was to assess the effects of COIF on summer maize growth, grain yield, nutrient uptake and utilization, and soil quality. Results: Compared to LCF, COIF1 in Yantai and Dezhou increased biomass by 6.4% and 8.1%, grain yield by 5.9% and 4.12%, PFP (N, P, and K) by 17.6% and 15.7%, and soil quality by 563.6% and 462.5%, respectively. No significant differences in biomass and grain yield were observed between COIF2 and LCF, yet COIF1 in Yantai and Dezhou enhanced PFP (N, P, and K) by 19.7% and 18.6%, and soil quality by 109.1% and 175.0%, respectively. In conclusion, COIF improved soil quality by enhancing soil organic matter (SOM), available nutrients, pH, and other soil indices. It promoted summer maize growth, increased grain yield, and improved nutrient utilization. COIF was a practical and effective measure to reduce chemical fertilizer use, enhance field soil quality, and ultimately increase maize yield and nutrient utilization.

Controlled-release nitrogen fertilizer (CRNF) has been proven to surpass common urea by mitigating nutrient losses, enhancing soil quality, and improving crop productivity. However, the long-term effects of CRNF on soil biological properties are not well understood. Here, a 12-year field experiment was conducted with five treatments: no N fertilizer (PK); the split application of urea at the farmer’s practice rate (FP) and the optimal rate (OPT); the one-time application of CRNF at the same rate as the OPT (CRNF); and a 20% reduced rate of the OPT (0.8CRNF). Soil samples were collected during the maize tasseling and filling stages; high-throughput sequencing and the PICRUSt2 method were employed to determine the bacterial community and its functional potential. The results showed that CRNF significantly increased alkaline hydrolysis N by 14.10% and 9.45% compared to OPT during the tasseling and filling stages, respectively. This increase in soil available N resulted in a significant increase in bacterial diversity of 2.09% and 2.35% compared with the FP and OPT, respectively. The bacterial community in the FP and OPT changed markedly between the tasseling and filling stages, with many bacterial species at the ASV and genus levels showing variations in relative abundance. In contrast, CRNF and 0.8CRNF exhibited stable N-cycling functions, as indicated by the lower variations in nitrate reductase and predicted N-cycling functional genes between the tasseling and filling stages. The obtained results suggest that CRNF application can enhance soil N supply, promote the formation of stable bacterial communities, and maintain stable N-cycling functions.

The paper presents a newly developed nonlinear tube-ball mill model for model based on-line condition monitoring. This mathematical model is derived through analyzing energy transferring, heat exchange and mass flow balances. Evolutionary techniques are adopted to identify the unknown system parameters using the on-site measurement data. The identified system parameters are then validated using multiple on-line measurement data. Validation has been conducted by comparing the measured and simulated values. The results indicate that the model can represent the coal mill dynamics and can be used to predict the mill dynamic performance. Then the model is implemented on-line and it can run on-line along with the real milling process. It is then adopted for on-line condition and safety monitoring, fault detection, and control to improve the efficiency of combustion.

Coastal saline–alkali soils represent one of the most challenging agroecosystems due to coupled chemical, physical, and biological constraints. Although humic acid (HA) and microbial fertilizers (MFs) are recognized as effective amendments, the mechanisms linking soil improvements to yield gains remain unclear. Here, a 2-year field experiment was conducted in the Yellow River Delta to assess the effects of HA, applied alone or in combination with Bacillus subtilis and Trichoderma harzianum, on soil salinity, nutrient availability, aggregate stability, microbial communities, and wheat yields. Results showed that HA application alone reduced soil electrical conductivity (EC) and total soluble salts (TSS), and enhanced aggregate mean weight diameter (MWD), leading to 40.94–55.64% higher yields. Co-application with MFs further amplified these improvements, lowering EC and TSS up to 77.04% and 73.83%, enhancing MWD by 122.50%, and raising yields by 75.79%. Soil enzyme activities (e.g., catalase, β-glucosidase, urease, and alkaline phosphatase) and fungal diversity were substantially enhanced, whereas bacterial diversity showed no significant change. Co-occurrence network analysis demonstrated that application of HA with MFs (particularly with B. subtilis) reshaped microbial networks by enriching modules linked to nutrient provisioning, aggregate stability, and enzyme activity, while suppressing modules associated with salinity tolerance. Keystone species such as Lysobacter and Massilia were significantly enriched and closely associated with soil chemical and aggregate improvements. Structural equation modeling further revealed that yield gains were mainly explained by reduced salinity and enhanced aggregate stability rather than nutrient provisioning. These findings provide mechanistic evidence that HA improves soil quality and wheat productivity in coastal saline–alkali soils through integrated chemical, physical, and biological pathways, and that these benefits are strengthened when combined with microbial fertilizers.