Xiuqing Cao

Controlled drainage technology in farmland not only raises groundwater levels to provide additional water directly to crops but also improves rainfall utilization efficiency, thereby helping to alleviate agricultural water scarcity. In 2002, a large-scale field research area covering 80 km² was established and equipped with controlled sluices, a weather station, groundwater observation wells, and monitoring gauges. An analysis of the impacts of controlled projects on water levels in the main drainage ditches, groundwater dynamics, drainage processes, and overall water resource regulation showed that the average water storage capacity in the main ditches increased to 1.14 m, the groundwater level rose by 0.64 m, and the total volume of water regulated through the sluice control project ac-counted for approximately 10% of the annual precipitation. Therefore, implementing controlled drainage in main ditches for agricultural water resource regulation represents an effective strategy suited to the characteristics of the Huaibei Plain. This approach not only mitigates water scarcity but also enhances the farmland ecological environment and supports the rational spatiotemporal allocation of regional water resources. Moreover, it provides valuable insights for other regions facing similar challenges.

The purpose of this study was to investigate the effects of combined treatment of Trichoderma harzianum and Phanerochaete chrysosporium on lignin degradation and humification during aerobic composting. Chicken manure (CM) and rice husk (RH) were used as organic raw materials for composting. The basic physicochemical analysis indicated that the combined addition of Trichoderma harzianum and Phanerochaete chrysosporium effectively improved lignin degradation rate (16.60%), increased humic acid (HA) content (22.70 g/kg), and the germination index (GI) reached 110.99%. Fungal community revealed that the relative abundance of Ascomycota was 37.46–68.85%, 9.57–60.35%, 58.02–91.76%, 0.98–91.60% in CK, T1, T2, T3 and Basidiomycota was 7.81–36.03%, 7.84–3.55%, 4.42–9.60%, 0.06–8.05% in CK, T1, T2, T3 (in phylum); the relative abundance of Kazachstania was 0.001–68.48%, 0.62–14.60%, 7.06–25.45%, 0.001–38.16% in CK, T1, T2, T3 and Diutina was 2.67–7.97%, 1.11–34.42%, 15.79–64.41%, 0.25–35.34% in CK, T1, T2, T3 (in genus) during the composting. Especially, the combined addition of Trichoderma harzianum and Phanerochaete chrysosporium had more negative impact on the activity of Basidiomycota compared with CK and other treatments and Trichoderma harzianum treatment had the strongest inhibitory effect on Tausonia abundance compared with CK and other treatments. Correlation analysis indicated that moisture content influenced fungal community structure (r = −0.740, p < 0.01) which affected lignin degradation (r = −0.952, p < 0.01) and compost maturity level in the composting process. Fungi Functional Guild (FUNGuild) and correlation heatmap demonstrated that T3 could enhance the relative abundance of endophyte which may had the potential to improve the degradation of lignin. This study confirmed the positive effects of the combination of Trichoderma harzianum and Phanerochaete chrysosporium in enhancing lignin degradation and promoting compost maturity, providing a foundation for a deeper understanding of the mechanisms involved in lignin degradation and humification processes influenced by the fungal community during composting, ultimately contributing to the efficient utilization of agricultural waste resources.

Due to the importance and complexity of water resources regulations in the pond irrigation systems of the Jiang-Huai hilly regions, a water allocation simulation model for pond irrigation districts based on system simulation theory was developed in this study. To maximize agricultural irrigation benefits while guaranteeing rural domestic water demand, an optimal water resources regulation model for pond irrigation districts and a simulation-based optimal water resources regulation technology system for the pond irrigation system were developed. Using this system, it was determined that the suitable pond coverage rate (pond capacity per unit area) was 2.92 × 10⁵ m³/km². Suitable water supply and operational rules for adjusting crop planting structure were also developed the water-saving irrigation method and irrigation system. To guarantee rural domestic water demand, the multi-year average total irrigation water deficit of the study area decreased by 4.66 × 10⁴ m³/km²; the average multi-year water deficit ratio decreased from 20.40% to 1.18%; the average multi-year irrigation benefit increased by 1.11 × 10⁵ RMB (16,128$)/km²; and the average multi-year revenue increased by 6.69%. Both the economic and social benefits were significant. The results of this study provide a theoretical basis and technological support for comprehensive pone governance in the Jiang-Huai hilly regions and promote the establishment of a water allocation scheme and irrigation system for pond irrigation districts, which have practical significance and important application value.