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Huangshui is a typical organic wastewater in Chinese Baijiu production, with high pollution and valuable ingredients. Conventional wastewater treatment leads to resource-wasting and environmental pollution. It is urgent that the demand for effective Huangshui treatment with the development of the Baijiu-making industry. This review systematically summarizes recent studies, revealing the main characteristics and application of Huangshui, focusing on the application of the rich microbial resources and flavor substances, which provides a practical approach to cascade and full use of Huangshui in medicine, cosmetic, functional food, fertilizer, and wastewater treatment fields. Further research suggested that Huangshui can also be used as an external carbon source for the denitrification system or as an organic liquid water-soluble fertilizer for more fruits and grains. The applications favor improving production efficiency and lowering pollutant emissions and introduce novel concepts for the sustainable development of related industries. Thus, Chinese Baijiu plants can achieve the near-zero emissions of wastewater and cleaner production. [ABSTRACT FROM AUTHOR]

This paper addresses the problem of decentralized safety control (DSC) of constrained interconnected nonlinear safety-critical systems under reinforcement learning strategies, where asymmetric input constraints and security constraints are considered. To begin with, improved performance functions associated with the actuator estimates for each auxiliary subsystem are constructed. Then, the decentralized control problem with security constraints and asymmetric input constraints is transformed into an equivalent decentralized control problem with asymmetric input constraints using the barrier function. This approach ensures that safety-critical systems operate and learn optimal DSC policies within their safe global domains. Then, the optimal control strategy is shown to ensure that the entire system is uniformly ultimately bounded (UUB). In addition, all signals in the closed-loop auxiliary subsystem, based on Lyapunov theory, are uniformly ultimately bounded, and the effectiveness of the designed method is verified by practical simulation. [ABSTRACT FROM AUTHOR]

In this paper, the safe optimal control method for continuous-time (CT) nonlinear safety-critical systems with asymmetric input constraints and unmatched disturbances based on the adaptive dynamic programming (ADP) is investigated. Initially, a new non-quadratic form function is implemented to effectively handle the asymmetric input constraints. Subsequently, the safe optimal control problem is transformed into a two-player zero-sum game (ZSG) problem to suppress the influence of unmatched disturbances, and a new Hamilton–Jacobi–Isaacs (HJI) equation is introduced by integrating the control barrier function (CBF) with the cost function to penalize unsafe behavior. Moreover, a damping factor is embedded in the CBF to balance safety and optimality. To obtain a safe optimal controller, only one critic neural network (CNN) is utilized to tackle the complex HJI equation, leading to a decreased computational load in contrast to the utilization of the conventional actor–critic network. Then, the system state and the parameters of the CNN are uniformly ultimately bounded (UUB) through the application of the Lyapunov stability method. Lastly, two examples are presented to confirm the efficacy of the presented approach. [ABSTRACT FROM AUTHOR]

The application of green manure is considered a sustainable management approach to improve soil quality and crop yield in agricultural production. However, few studies have focused on the effects on soil properties and the microbial community when varied green manure rates are applied in rice cropping systems. We examined the soil and microbial properties in paddy soil and evaluated rice productivity and sustainable yield index in response to Chinese milk vetch (MV) application at various rates (0, 22.5, 30, 45, and 60 Mg ha−1, labeled MV0, MV22.5, MV30, MV45, and MV60, respectively) in a seven-year (2014–2020) field experiment. For all treatments, MV application significantly improved rice yield by 22.5–29.7% and sustainable yield index by 10.3–13.0% compared with no MV application, and the highest average yield across the 7 years of the study was found in MV60, followed by MV45, MV30, and MV22.5. Compared with MV0, MV45 and MV60 treatments significantly reduced soil bulk density (BD), increased soil organic carbon (SOC), total nitrogen (TN), total potassium (TK), and alkali solution nitrogen (AN), particularly in MV45. Moreover, compared with MV0, a marked decrease in the alpha diversity (Shannon index) of the bacterial community and a significant increase in the relative abundance of Firmicutes were observed under MV45. The alpha diversity of the fungal community did not vary across treatments, but MV45 significantly reduced the relative abundance of Ascomycota and Chytridiomycota compared with MV0. In addition, redundancy analysis indicated that the fungal community structure was significantly related to soil BD, and random forest classification analysis demonstrated that SOC and AN were the most important factors for rice yield in this study. Overall, these results indicated that MV application at 45 Mg ha−1 should be recommended to simultaneously achieve the improvement of rice yield and soil quality in the South China. [ABSTRACT FROM AUTHOR]

Phosphorous (P) fixation in saline soils is a concern worldwide. To investigate optimization strategies for P fertilizer application that improve P use efficiency (PUE) and crop yield in saline soil, in terms of P sources and rates, we conducted a two year field experiment in the coastal saline area of China to investigate the effects of P rates and sources, including superphosphate (SSP), monoammonium phosphate (MAP) and ammonium polyphosphate (APP) on yield, aboveground P uptake, agronomy efficiency (AEP), and soil available P of winter wheat (Triticum aestivum L.). Wheat yield, under the three P sources, increased with P rates and reached a plateau under 20 kg P ha−1 SSP,18 kg P ha−1 MAP, and 17 kg P ha−1 MAP, respectively. The application of SSP increased the wheat yield by 9–11% compared to MAP and APP. The aboveground P uptake of winter wheat under SSP was 14% and 13% higher than MAP and APP, respectively, under the optimal P application rate. The AEP under SSP was higher than the other two P sources under the same P rate. SSP increased the soil Ca2+ concentration by 20–42%, but decreased the Na+ concentration by 14–18% at the P rate of 26 kg P ha−1 in all soil layers, including 0–20, 20–40, 40–60 cm, compared to CK (0 kg P ha−1). The soil Olsen-P concentration under APP was higher than the other P sources. This study suggests that optimizing P sources and rates can improve wheat yield, PUE, and soil quality in the coastal saline soil. [ABSTRACT FROM AUTHOR]

In this paper, a new adaptive critic design is proposed to approximate the online Nash equilibrium solution for the robust trajectory tracking control of non-zero-sum (NZS) games for continuous-time uncertain nonlinear systems. First, the augmented system was constructed by combining the tracking error and the reference trajectory. By modifying the cost function, the robust tracking control problem was transformed into an optimal tracking control problem. Based on adaptive dynamic programming (ADP), a single critic neural network (NN) was applied for each player to solve the coupled Hamilton–Jacobi–Bellman (HJB) equations approximately, and the obtained control laws were regarded as the feedback Nash equilibrium. Two additional terms were introduced in the weight update law of each critic NN, which strengthened the weight update process and eliminated the strict requirements for the initial stability control policy. More importantly, in theory, through the Lyapunov theory, the stability of the closed-loop system was guaranteed, and the robust tracking performance was analyzed. Finally, the effectiveness of the proposed scheme was verified by two examples. [ABSTRACT FROM AUTHOR]

As efforts to close crop production yield gaps increase, the need has emerged to identify cost-effective strategies to reduce yield losses through soil improvement. Maize (Zea mays L.) production in coastal saline soil is limited by high salinity and high pH, and a limited number of soil amendment options are available. We performed a field experiment in 2015 and 2016 to evaluate the ability of combined flue gas desulfurization gypsum and furfural residue application (CA) to reduce the maize yield gap and improve soil properties. We carried out the same amendment treatments (CA and no amendment as a control) under moderate (electrical conductivity (EC1:1) ≈ 4 dS m−1) and high (EC1:1 ≈ 6 dS m−1) salinity levels. Averaged over all salinity levels and years, maize yields increased from 32.6% of yield potential in the control to 44.2% with the CA treatments. Post-harvest CA treatment increased the calcium (Ca2+) and soil organic carbon (SOC) contents while decreasing the sodium (Na+) content and pH in the upper soil layer. Corresponding nitrogen, phosphorus, potassium, calcium, and magnesium accumulations in maize were significantly increased, and Na accumulation was decreased in the CA group compared with the control. The economic return associated with CA treatment increased by 215 $ ha−1 at the high salinity level compared with the control, but decreased at the moderate salinity level because of the minor increase in yield. The results of this study provide insight into the reduction of yield gaps by addressing soil constraints. [ABSTRACT FROM AUTHOR]

Certain minerals possess structures that convey properties which improve soil quality; however, their application in coastal saline areas has been poorly studied. In this study, we explored the effects of combining mineral amendments on the improvement of wheat yield and soil properties in a two-year field experiment in mildly saline coastal soil areas of the Yellow River Delta, China. Five mineral materials were combined into the following four treatments: zeolite + rock phosphate (ZP), zeolite + silica calcium soil conditioner (ZC), vermiculite + rock phosphate (VP), and vermiculite + medical stone (VS). For all treatments, combined mineral amendments increased wheat yield compared to the control, with similar increases in yield following treatment with VP (45.7%), ZP (43.5%), and ZC (43.6%), and a significantly smaller increase following VS treatment (26.3%). These increases in grain yield were attributed to larger dry matter accumulation and higher grain numbers per ha. Compared to the control, ZP and ZC application substantially reduced soluble magnesium (Mg) and sodium (Na) contents, electrical conductivity (EC), and sodium adsorption ratio (SAR), and increased soil organic carbon (SOC) at a soil depth of 0–20 cm. VP application increased soil available phosphorus (P) by 34.7% and soluble potassium (K) by 69.3% at a soil depth of 0–20 cm. VS application slightly increased the SOC, total nitrogen (N), available P, and soluble K compared to the control. Overall, these results indicate that combining mineral amendments significantly increases wheat yield and improves soil properties in a saline area. Thus, we recommend the use of mineral amendments in saline coastal areas. [ABSTRACT FROM AUTHOR]