Mingye Zhang , Shuchen Liu , Yu An , Dongjie Zhang , Jianghao Tan , Le Wang , Yifan Li , Ming Jiang , Haitao Wu , Shouzheng Tong
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引用次数: 0
Abstract
Agricultural utilization of wetlands has witnessed a continuous upward trend, with the semi-arid regions being especially prominent in this regard. These wetlands under human management have consequently emerged as crucial constituents within the agricultural ecosystem. Grazing is considered a predominant land use practice profoundly impacting nutrient cycling and redistribution in semi-arid wetlands, and exogenous nitrogen (N) from atmospheric deposition and agricultural water discharge simultaneously participated these processes. Nevertheless, the impacts of exogenous N input and grazing on phosphorus (P) distribution patterns remain nebulous, especially in the semi-arid Songnen Plain of China, where P limitation prevails. In order to address this knowledge gap, the study conducted a field experiment with four grazing intensities (natural, light, medium, and heavy) and two N addition levels (with and without) in semi-arid wetlands. The results show that grazing and N addition together affect P content in soil and plant organs. Grazing intensity generally reduces soil P, regardless of N addition, while N addition promotes soil P accumulation in natural wetlands. P content in plant organs increases with grazing intensity. Soil organic carbon (SOC), soil water content (SWC), electrical conductivity, and soil N are positively correlated with soil P but negatively correlated with P in stems and leaves. RDA shows that SWC and SOC are key factors influencing P distribution in soil and plant organs. Plant growth strategies create a positive correlation between root and soil P contents, and a negative correlation between P in stems, leaves, and soil. SEM further shows that grazing significantly affects P levels in soil and plant organs, while N addition boosts P uptake in roots and its transfer to aboveground organs, mediated by SWC and SOC. These findings show that exogenous N input alters P acquisition strategies and distribution in plant organs and soil in grazed wetlands of semi-arid regions. This study enhances understanding of P cycling and offers practical guidelines for sustainable wetland management.
期刊介绍:
Agriculture, Ecosystems and Environment publishes scientific articles dealing with the interface between agroecosystems and the natural environment, specifically how agriculture influences the environment and how changes in that environment impact agroecosystems. Preference is given to papers from experimental and observational research at the field, system or landscape level, from studies that enhance our understanding of processes using data-based biophysical modelling, and papers that bridge scientific disciplines and integrate knowledge. All papers should be placed in an international or wide comparative context.