An integrated agricultural system of rice (Oryza sativa L.) planting and crawfish (Procambarus clarkia) breeding has been widely practiced in southern China due to its important economic benefits. Evaluating effects of this new agricultural model on the soil physicochemical properties of paddy fields is vital for sustainable rice production. Consequently, a field experiment was carried out to examine the impacts of the durations of rice-crawfish (RC) rotations on soil pH, bulk density, porosity, soil organic carbon, total nitrogen (N), available nutrients, cation exchange capacity (CEC), and the total quantity of reducing substances at soil depths of 0-20 cm, 20-40 cm, and 40-60 cm.The rice yield and its components were also determined. The mid-season rice monoculture was set as CK. The durations of the RC rotations were 1, 7, 13, 18 and 23 years, designated RC1, RC7, RC13, RC18 and RC23, respectively. The results showed that the soil organic carbon, total N, available nutrients (N, phosphorus and potassium), porosity, and CEC in the 0-20 soil depths all increased with an increase in the time of the RC rotation. This suggests that a long-term RC rotation could improve the soil carbon and nutrients. However, the soil bulk density, and total amount of reducing substance decreased with the continuation of RC rotations. The RC rotations of 7-23 years significantly increased effective panicle number, spikelet number and grain filling percentage, and consequently produced greater grain yield. However, the long-term of RC rotations increased total amount of soil reducing substance below 20 cm depth. Therefore, rice-crawfish rotation for more than 7 years could improve soil physicochemical properties in the plough layer (0-20 cm soil depth) of paddy fields and grain yield of rice, but increase the risk of soil gleying below 20 cm depth.

Nitrogen fertilization serves as an effective approach to alleviating abiotic stresses, including drought, waterlogging, and heat stresses. Nevertheless, the interactive impacts of nitrogen application rates and waterlogging durations on biomass accumulation, translocation, and root growth remain largely unknown. To address this knowledge gap, a two-year (2018 and 2019) field experiment was conducted to investigate the impacts of varied waterlogging durations (0, 5, 10, and 15 days, denoted as W0, W5, W10, and W15) at the early flowering stage and nitrogen application rates (0, 240, and 360 kg N ha-1, denoted as N0, N1, and N2) on cotton biomass accumulation and translocation, soil nitrogen status, root traits, and lint yield. The results showed that waterlogging stress significantly delayed cotton phenology by 1-6 days, inhibited plant biomass accumulation and translocation, reduced soil nitrate nitrogen content, suppressed root growth and nitrate reductase activity, and ultimately decreased lint yield by 37-83 %, with the reduction proportional to waterlogging durations. Nitrogen input effectively alleviated waterlogging stress on cotton growth, and increased lint yield by 139-306 %. Compared to N1, N2 more effectively mitigated the adverse effects of W10 waterlogging by increasing root length density in deeper soil layers (40-100 cm), enhancing overall biomass production, and facilitating dry matter translocation from vegetative parts to reproductive structures. In contrast under W15 conditions, no significant differences were found between N1 and N2 in root traits, biomass translocation, or lint yield, indicating the 15-day waterlogging stress at early flowering caused irreversible damage to cotton growth. Consequently, tailoring nitrogen application rates according to waterlogging intensity is of great significance for improving nitrogen use efficiency and alleviating waterlogging stress.

Restoration of degraded sandy soils is often constrained by impaired microbial functioning and disrupted nutrient cycling, making effective fertilization management essential for ecosystem recovery and plant growth. We investigated how combined organic and inorganic fertilization influences microbial community composition, functional potential, and soil multifunctionality in rhizosphere and bulk soils of a walnut orchard in the Yarlung Zangbo River Valley, and how these changes relate to walnut growth. Combined fertilization significantly increased soil fertility; specifically, organic matter and total nitrogen in the rhizosphere increased by 29%, while available phosphorus increased by 48%. Furthermore, enzyme activities related to carbon cycling (β-glucosidase) responded strongly, increasing by 193% and 252% in the rhizosphere and bulk soils, respectively. It also altered microbial community composition, with fungi showing stronger sensitivity to fertilization than bacteria, as reflected by greater increases in ACE richness. Metagenomic analysis revealed marked compartment-specific functional responses. In the rhizosphere, combined fertilization increased the abundance of genes related to carbon fixation and degradation, indicating greater microbial functional potential for C cycling. Whereas the up-regulation of nitrogen fixation genes and down-regulation of denitrification genes suggested improved nitrogen retention and acquisition. By contrast, bulk soils exhibited greater phosphorus mineralization potential. These responses increased soil multifunctionality and improved walnut performance. Compared to conventional fertilization, plant height and ground diameter under combined fertilization increased by 22% and 17%, respectively, while crown width exhibited a substantial 66% increase. Association analyses further showed that microbial community shifts, functional gene enrichment, and soil nutrient accumulation were closely coupled, indicating a coordinated soil–microbe–plant response to integrated fertilization. Our findings reveal the microbial-mediated pathways through which combined organic and inorganic fertilization improves soil functioning and plant growth in degraded sandy land, and provide a mechanistic basis for sustainable orchard management and ecological restoration in dry valley agroecosystems.

ABSTRACT Rice–crayfish farming (RCF) system represents an effective ecological agricultural model characterized by the cyclical spatiotemporal integration of rice farming and crayfish aquaculture. However, the effects of farming mode and stage on soil microbial community structure over time remain insufficiently explored. In this study, we investigated taxonomic and functional changes in soil microbiomes and their associations with soil nutrient fertility in both RCF and rice monoculture (RM) systems. Our findings demonstrated that RCF significantly increased soil pH, total nitrogen (TN), and soil organic carbon (SOC) compared to RM across multiple growth stages (P < 0.05). Two-way analysis of variance showed that both mode and stage affected the Chao1 index, while the Shannon index was only affected by stage. Microbial community analysis revealed clear structural differences between the two systems (P < 0.001). Functional prediction indicated lower chemoheterotrophy but higher photoheterotrophy, aromatic degradation, and sulfur cycling in RCF, along with reduced nitrogen cycling function. Co-occurrence network analysis further showed a longer average path length and higher modularity in RCF than in RM. Modules 3 and 6 in RCF were positively correlated with pH, TN, and SOC. Overall, RCF stabilizes the soil environment and selects for specific functionally sensitive taxa, thereby promoting the formation of a highly modular microbial network, which ultimately maintains the synergistic stability of soil nutrients and the microbial community.IMPORTANCEThe present study comprehensively compared two different farming modes in terms of their soil microbiome structures and the associations between the microbiomes and soil nutrient fertility. Rice–crayfish farming (RCF) model-specific microbial taxa were identified, and their modularity was found in RCF. These findings provide valuable insights into microbial community responses and regulation in ecological agriculture, establishing a robust microbiological foundation for optimizing rice-aquatic animal integrated farming management and advancing sustainable agricultural practices.

Rainfall-adapted irrigation (RAI), the application of controlled-release nitrogen fertilizer (CRNF), and deep placement of nitrogen fertilizer can contribute to the improvement of resource utilization efficiency. Nevertheless, the interactive effects of these factors on nitrogen loss via runoff and leaching from paddy fields remain ambiguous. Consequently, a two-year field experiment was conducted to evaluate the interactive effects of four nitrogen management strategies on nitrogen losses through runoff and leaching from paddy fields and rice yield under RAI when compared to conventional flooding irrigation (CI). Compared to CI, RAI significantly reduced total nitrogen loss via runoff (−49.8%) and leaching (−35.9%) by lowering volume of runoff and leaching. Compared to conventional nitrogen application (surface application of common urea with 240 kg N ha−1), deep placement of CRNF with 192 kg N ha−1 decreased floodwater nitrogen concentration, reducing total nitrogen loss by 46.8% via runoff and 50.9% via leaching. Importantly, RAI combined with deep placement of CRNF with 192 kg N ha−1 minimized nitrogen losses through leaching and runoff from paddy fields and maximized grain yield (8251 kg ha−1) by improving nitrogen accumulation in rice. Collectively, RAI combined with deep-placed CRNF with an 80% nitrogen rate could reduce non-point source pollution from paddy fields.

ABSTRACT Zooplankton are key regulators of trophic interactions and nutrient cycling in shallow eutrophic lakes and are sensitive indicators of ecological responses to anthropogenic pressures. This study was conducted to understand ecosystem dynamics in Changhu Lake, a typical shallow eutrophic lake in China. We conducted monthly surveys from June 2023 to May 2024 in Changhu Lake. Our work involved identifying zooplankton species and analyzing their assemblages. We used redundancy analysis (RDA), a neutral community model, and structural equation modeling (SEM) to identify key environmental drivers and understand community assembly processes. We identified 102 zooplankton species. The assemblages showed marked spatiotemporal variations, with small‐bodied taxa dominating most seasons and sites, while large crustaceans remained scarce and peaked only locally in spring. Diversity peaked in autumn and declined sharply in summer. Compared to data from 2012 to 2013, total zooplankton abundance increased and small taxa became more dominant. RDA identified total phosphorus, chlorophyll a, ammonium nitrogen, and water temperature as key environmental drivers. Neutral community modeling indicated a higher migration rate in spring (R2 = 0.610, Nm = 47) versus dispersal limitation in winter (R2 = 191, Nm = 15). The community structure had a direct positive effect on ecosystem stability, whereas diversity had an indirect negative effect. The findings indicate a limited recovery of large‐bodied species despite ongoing restoration initiatives. This study provides mechanistic insights into community assembly and resilience, offering valuable guidance for the adaptive management of lakes facing intensifying anthropogenic pressures.

This study evaluated the multi-scale spatial heterogeneity of soil fertility in walnut orchards in the middle and lower reaches of the Yarlung Zangbo River valley. The investigation focused on Jiacha, Lang, and Milin counties, covering four river terrace levels and three soil depths within the 0-60 cm layer, and further examined the effects of such heterogeneity on walnut fruit quality. Using integrated multivariate statistical approaches and fuzzy comprehensive evaluation, 321 paired soil and fruit samples collected in September and October of 2023 were analyzed. Overall soil fertility was moderate (0.4 <= IFI < 0.6) with a mean integrated fertility index (IFI) of 0.527, but showed pronounced spatial variation. PCA-based composite scores indicated the highest fertility in Milin County, followed by Lang County, with Jiacha County ranking lowest. Soil fertility across 11 towns was classified into five grades. Cluster analysis based on ten standardized soil fertility indicators revealed clear regional aggregation patterns, where close towns exhibited similar fertility conditions. Third-level river terraces exhibited significantly higher fertility than other terrace levels. Available phosphorus was widely deficient, while exchangeable magnesium and available zinc were also low, representing key limiting nutrients with strong regional variability. Spatial differences in soil enzyme activities reflected variation in microbially mediated nutrient cycling, with phosphatase activity negatively correlated with available phosphorus, suggesting potential microbial responses to phosphorus-stressed environments. Soil fertility significantly influenced walnut fruit quality, with alkaline hydrolyzable nitrogen, phosphorus, potassium, and exchangeable calcium and magnesium identified as key drivers. These findings provide a theoretical basis for suggesting a zoned precision fertilization strategy, where prioritizing P, Zn, and Mg inputs in deficient areas could be considered alongside organic fertilisation. Such site-specific management strategies are suggested to support the sustainable development of the walnut industry along the Yarlung Zangbo River valley.

The ecological restoration of degraded sandy land in the Yarlung Zangbo River Valley is constrained by the metabolic functions of soil microorganisms. This study investigates the dynamic mechanisms of microbial elemental use efficiency in walnut plantations, with a focus on seasonal variations in soil chemical stoichiometry, extracellular enzyme activity, and microbial nutrient efficiency in rhizosphere and bulk soils. This paper explores the effects of conventional organic fertilizer (CF) and organic-inorganic compound fertilizer (OIF) on microbial nutrient use strategies and their seasonal dynamics. The results showed significant seasonal fluctuations in soil active nutrients and microbial biomass, while the total nutrient content remained stable. OIF enhanced microbial chemical stoichiometric homeostasis but simultaneously triggered a "carbon-phosphorus metabolic trade-off", leading to a restraint of microbial carbon use efficiency (CUE) during the growing season. Microbial elemental use efficiency (EUE) exhibited clear seasonal differentiation: CUE was higher in summer, promoting biomass accumulation, whereas NUE and PUE increased in winter and spring, reflecting a nutrient conservation strategy. The EUE pathways were decoupled between rhizosphere and non-rhizosphere microenvironments. The rhizosphere was more directly driven by soil chemical stoichiometry and microbial biomass, while the non-rhizosphere was influenced by nutrient limitation states, represented by vector characteristics. This study provides insights into the seasonal adaptability and microenvironmental heterogeneity of microbial metabolism during the restoration of cold sandy land. It is suggested that future ecological management should focus on N-P balanced fertilization and consider the differential responses between rhizosphere and non-rhizosphere zones to enhance ecosystem productivity and soil carbon, nitrogen, and phosphorus sequestration potential.

Ponds within paddy field watershed have been proved to be effective in controlling runoff, sediment, and nutrient loss. However, the optimal area and distribution of these ponds are not always achieved at watershed scale. To address this, optimizing pond area and allocation is crucial for effective diffuse pollution control in water management. This study presented a Decision Support System (DSS) that integrated a pond measurement database (POND database), the Non-dominated Sorting Genetic Algorithm II (NSGA-II) for optimization, and the Soil and Water Assessment Tool (SWAT) for simulation. This DSS aims to identify cost-effective conservation strategies to meet desired water quality goals. Results showed that, with constraints on water quality and available area, the implementation of ponds in paddy field watersheds led to reductions of 8.4 % to 36.9 % in diffuse nitrogen (N) and 11.12 % to 45.7 % in phosphorus (P) loss. As the desired reduction rates increased, stricter controls on diffuse pollution necessitated a significant increase in pond system area. Under the optimal allocation scenario identified by the DSS, total nitrogen (TN) and total phosphorus (TP) losses could be reduced by 24.27 % and 29.45 %, respectively. Annual precipitation had a negative impact on the pond system's efficiency, with effective water quality management achievable with annual rainfall below 1150 mm. These findings evaluated the potential of pond systems in managing diffuse pollution. The proposed DSS framework offered valuable technical support for optimizing pond area and allocation, enhancing the effectiveness of water quality management in paddy field watersheds. This research contributes significantly to understanding and implementing effective conservation strategies for evaluating water quality.

In China, rice-crayfish farming (RCF) is a resource-efficient and eco-friendly agricultural model that demonstrates significant potential for soil organic carbon (SOC) storage. However, the impact of RCF on SOC accumulation and its associated microbial characteristics remains unclear. In this study, we conducted an experiment in rice fields with five years of RCF. We investigated surface SOC content and its components, as well as soil microbial community and its functions over two consecutive years. Compared to rice monoculture (RM), SOC in RCF increased by 24.13 % to 32.40 %. Labile organic carbon I (LOC I) and recalcitrant organic carbon (ROC) in RCF increased by 25.84 % to 39.07 % and 30.98 % to 60.87 %, respectively. While RCF reduced dissolved organic carbon (DOC) by 33.24 % to 45.83 %, it increased particulate organic carbon (POC) and easily oxidizable carbon (EOC) by 92.28 % to 132.61 % and 66.42 % to 69.76 %, respectively. The activities of (3-xylanase (BX), (3-glucosidase (BG) were significantly decreased and (3-1,4-N-acetylglucosaminidase (NAG) was significantly increased in RCF. Additionally, RCF decreased the proportion of chemoheterotrophy and aerobic chemoheterotrophy of prokaryotic communities, while increased the proportion of dark sulfide oxidation and the dark oxidation of sulfur compounds. RCF also exhibited a high proportion of wood saprotroph functions of fungal communities. The structural equation models revealed that soil properties and prokaryotic communities were the main factors contributing the accumulation of SOC by enzyme activities in RCF. Overall, the practice of RCF increased the content of LOC I and ROC, altered soil prokaryotic community structure and predicted functions, led to a reduction of soil enzyme activities involved in the decomposition of organic matter, and consequently enhancing the accumulation of SOC.

In the context of global climate change, frequent summer heavy rainfall events act as significant disturbances to the ecosystem functions of shallow lakes. This study examined the response of phytoplankton community structure and dynamics to heavy rainfall in Lake Changhu, a shallow eutrophic lake, through monthly monitoring during the summer months (June–August) of 2020–2022. The results revealed that heavy rainfall induced substantial water level fluctuations and shifts in key environmental parameters. Marked interannual variations were observed in the phytoplankton community, with the highest species richness in summer 2021 and lowest in 2022. While Chlorophyta dominated in species composition, Cyanobacteria overwhelmingly dominated in abundance, with key taxa including Dolichospermum flos-aquae L., Pseudanabaena limnetica L., Oscillatoria princeps V., Microcystis wesenbergii K., and Merismopedia minima B. Both phytoplankton abundance and biomass peaked in summer 2021. Community diversity indices were consistently lower in June compared to July–August, indicating higher environmental stress and a more simplified community structure during the initial rainfall period. A comprehensive water quality evaluation suggested that Lake Changhu was in a lightly to moderately polluted state. Correlation and redundancy analyses (RDA) identified rainfall, water temperature, and nutrient concentrations as the primary environmental drivers shaping phytoplankton community succession. These findings systematically elucidate the mechanistic responses of phytoplankton to heavy rainfall disturbances, offering a scientific foundation for ecological resilience assessment and adaptive management of shallow lakes under climate change.

Climate change is expected to drive significant alterations in rainfall patterns, which will pose considerable threats and pressures on aquatic ecosystems. Phytoplankton, as a critical component of these ecosystems and a reliable biological indicator of environmental health, may respond variably to such climatic changes. However, our understanding of how phytoplankton communities respond to climate change remains limited. In this study, we investigated the response of phytoplankton functional groups to rainfall patterns and their relationships with environment factors in a subtropical eutrophic lake (Changhu Lake, China) from May 2020 to April 2022. Our findings indicate that changes in phytoplankton functional structure over time were influenced by rainfall patterns. A total of 119 genera, 21 functional groups, and 15 dominant functional groups were identified, with the dominant functional groups exhibiting strong seasonal variations. Notably, shifts in rainfall patterns led to a transition in dominant phytoplankton functional groups: from taxa tolerant of mixing and low nitrogen levels (e.g., H1, J, and S1) during the rainy season to taxa that thrive under eutrophic and stratified conditions (e.g., X2, C, N, and W1) during the dry season. The use of phytoplankton functional approaches simplifies identification and reflects environmental conditions effectively. Redundancy analysis (RDA) revealed strong correlations between changes in phytoplankton functional groups and environmental factors such as water temperature, precipitation, water level, and nutrient availability. The insights from this study improve our understanding of how aquatic ecosystems shift under climate change and demonstrate the potential of phytoplankton functional responses as a valuable tool for water management and conservation.

Despite increasing concerns over recurrent phosphorus (P) pollution, the Ju River—a small tributary of the Yangtze River—has received limited scientific attention. To correct this, the present study integrates field-based observations with the Hydrological Simulation Program—FORTRAN (HSPF) model to comprehensively assess the conjunct effects of urban expansion and changing precipitation patterns on watershed hydrology and phosphorus dynamics at the small-catchment scale. A total of five urban expansion scenarios and three precipitation enhancement scenarios were simulated to capture both seasonal and event-driven variations in daily discharge and total phosphorus (TP) concentrations. The model was calibrated and validated using in situ water quality data, ensuring high reliability of the simulations. The results indicate that agricultural non-point sources are the primary contributor to total phosphorus (TP) loads. During the overlapping period of intensive farming and heavy rainfall (June–July), TP concentrations more than doubled compared to other months, with these two months accounting for over 70% of the annual TP load. Urban expansion significantly amplified hydrological extremes, increasing peak discharge by up to 224% under extreme rainfall, thereby intensifying flood risks. Although increased precipitation diluted TP concentrations, it simultaneously accelerated overall phosphorus export. This study offers a novel modeling–monitoring framework tailored for small watersheds and provides critical insights into how land use transitions and climate change jointly reshape nutrient cycling. The findings support the development of targeted, scenario-based strategies to mitigate eutrophication risks in vulnerable river systems.

Land-use type is a key factor influencing soil properties, microbial community composition, and plant nutrient status. In this study, five land-use types (Tibetan barley, rapeseed, walnut, wheat, and weeds) were investigated in a river valley of southeastern Tibet to compare their effects on soil chemical characteristics, microbial communities, and plant nutrients. Soils under walnut trees had significantly higher available phosphorus and microbial biomass phosphorus but lower soil organic matter. Rapeseed fields had higher levels of available potassium and were dominated by the fungal genus Tausonia; rapeseed leaves also contained the highest nitrogen and potassium concentrations. Weed plots supported a distinct fungal community dominated by Helvella. Tibetan barley and wheat increased overall bacterial and fungal diversity, with wheat soils with the highest microbial biomass carbon and nitrogen. Redundancy analysis indicated that soil total nitrogen, available nitrogen, and organic matter were the main drivers of plant nutrient variation, together explaining 93.5% of the total variance. These findings demonstrate how land-use type regulates soil–microbe–plant interactions in alpine valleys and provide empirical references for agricultural management and soil improvement on the Qinghai–Tibet Plateau.

Aromatic rice has gained significant attention due to its high economic and nutritional value. 2-Acetyl-1-pyrroline (2-AP), a key aroma compound in aromatic rice, plays a crucial role in elucidating the aroma characteristics of aromatic rice. However, there is no report on the effect of aromatic rice in rice–potato rotation on aroma characteristics. In order to study the influences of winter-planted potatoes on the yield, quality, and 2-AP biosynthesis of aromatic rice grains, the commonly cultivated aromatic rice variety Meixiangzhan-2 and the potato cultivar Huashu-5 were selected as experimental materials for a three-year consecutive field experiment with different tillage patterns consisting of rice–winter fallow as the control group (CK) and rice–potato rotation as the experimental group (RP). The results indicated that the RP treatment enhanced the soil nutrient content and decreased the bulk density. Compared with CK, RP treatment increased the effective panicle number by 10.88% and grain number per panicle by 8.82%, thereby increasing the yield by 11.99%. Meanwhile, RP treatment improved the brown rice rate by 2.61%, milled rice rate by 4.53%, head milled rice rate by 7.51%, and crude protein content by 6.98%. Regarding 2-AP biosynthesis in grains, in contrast to CK, the RP treatment raised the levels of related precursors (Δ1-pyrroline, Δ1-pyrrolidine-5-carboxylic acid, and proline increased by 8.95%, 18.14%, and 13.75%, respectively) and enzymes (proline dehydrogenase, ornithine transaminase, and diamine oxidase increased by 18.37%, 14.61%, and 11.36%, respectively) in its synthesis pathway, thereby facilitating the accumulation of 2-AP. Furthermore, we also observed a more stable yield and grain 2-AP content in aromatic rice under RP treatment. Overall, with regard to enhancing the aromatic rice yield and aroma, the rice–potato rotation system can be contemplated for vigorous promotion.

Background & Aim:Milu(Père David's deer,Elaphurus davidianus)is a national key protected wild animal.Since its reintroduction in 1980,research on the diet composition of Milu has been a focus of researchers.We summarized the main feeding plants of Milu in the Beijing Milu Ecological Research Center,the Dafeng Milu National Nature Reserve,and the Shishou Milu National Nature Reserve.And we reviewed the common research methods of diet composition for animal including direct observation,utilization method,stomach content analysis,fecal microanalysis,stomach content or fecal DNA analysis and stable isotope technology and compared in terms of temporal scale,diet resolution,diet from the consumed stage,major strengths and major limitations.And,we analyzed the effects of ecological factors such as self-factors,plant nutrients and availability,and human activities on the diet composition of Milu.The analysis of the diet composition of Milu and common diet composition research methods aims to clarify the current progress of Milu diet composition research for promoting ex-situ conservation and natural return of Milu. Review results:The main food source of Milu is plants.The food selection of Milu is influenced not only by self-factors,but also by the nutrient content and availability of feeding plants and anthropogenic factor.Physiological variation and alteration of energy requirements due to self-factors can influence the diet composition of the deer.Plant nutrients including crude protein,soluble sugars,and fiber are important factors influencing diet composition.Plant availability and anthropogenic factors further influence diet composition by changing food diversity and abundance.The comparative analysis of common diet composition research methods shows that different methods reflect different time scales and food resolutions in resolving diet composition,and there are corresponding advantages and limitations in the face of large endangered ungulates such as Milu. Perspectives:We recommend that researchers should clarify the purpose and target population of the study.On this basis,researchers should reasonably assess the strengths and limitations of the available research methods,select appropriate sampling and data analysis methods to establish a reasonable diet composition research program.In future studies on the food composition of Milu,should focus on integrating the results of related studies on Milu,using a combination of methods to analyze diet composition,and comprehensively analyzing the food selection mechanism of Milu.This will not only guide the response of Milu to habitat fragmentation,wetland degradation and anthropogenic disturbance during reintroduction,but also further promote the development of Père David's population and long-term conservation efforts.

Continuously feed-based aquaculture leads to excessive nitrogen and phosphate loads, degrading the culture environment. In this study, lotus (Nelumbo nucifera Gaertn) was planted in yellow catfish (Pelteobagrus fulvidraco Richardson) culture ponds to construct an integrated agriculture–aquaculture system to reduce nutrient accumulation and remediate the aquacultural environment. Results showed that additional lotus cultivation significantly reduced TN and TP concentrations in the pond water by 51.81

Soil CO2 and CH4 concentrations are crucial determinants of crop physiology and the soil environment. However, the intricate relationships among soil respiration, soil nutrients, enzyme activities, and winter wheat growth in the presence of shallow groundwater remain enigmatic. This study aimed to investigate the dynamics of soil CO2 and CH4 concentrations and their correlations with soil nutrient content, enzymatic activities, and wheat root biomass to better understand the influence of shallow groundwater on soil environmental conditions. Lysimeter experiments were conducted at five groundwater depths (20, 40, 50, 60, and 80 cm) and three fertilizer application rates (low, 75%; normal, 100%; high, 125%). Soil CO2 (soil layer > 10 cm) and CH4 concentrations significantly decreased with increasing groundwater depth. The maximum values of root parameters and shoot biomass were mainly concentrated at 50–60 cm at the high fertilization level (except root length density, which was higher at the normal fertilization level), and were 0.36–77.4% higher than other treatments. Soil CO2 concentration showed positive correlations with organic matter and total N content, enzyme activities, and root biomass. Soil CH4 concentration had significant correlations with soil organic matter, total N, and available K. Compared to the fertilization level, groundwater depth emerged as a crucial factor as it affected soil physicochemical properties, soil enzymatic activities, root respiration, and winter wheat growth in shallow groundwater.