Zhang Jing, Huang Jiacong, Pei Pengna, Feng Shuailong, Ji Yulai, Zhang Shuai, Gao Junfeng
Key Laboratory of Lake and Watershed Science for Water Security, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Key Laboratory of Lake and Watershed Science for Water Security, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; Poyang Lake Wetland Research Station, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Jiujiang 332899, China.
Sci Total Environ. 2024 Oct 10;946:174133. doi: 10.1016/j.scitotenv.2024.174133. Epub 2024 Jun 18.
Shifts for natural ecosystems were increasingly concerned due to its profound impacts on ecosystem services. Ponds within lowland artificial watersheds (polders) play a critical role in nitrogen (N) and phosphorus (P) cycling. From the perspective of N & P control in management practices, it is needed to determine an optimal pond area ratio for polders. For this purpose, our study proposed a process-based modelling framework to investigate the response of polder N & P loss to pond area, and thus to determine the threshold value of pond area ratio to achieve maximum N & P reduction for polders. The proposed framework included two process-based models (NDP and PDP) specially developed to describe N & P dynamics in lowland polders. To evaluate the proposed performance of the framework, it was applied to 171 polders in Zhong River Watershed in Lake Taihu Basin, eastern China. Our investigation results revealed that the correlation between polder N & P reduction rate and pond area ratio had an abrupt shift of 13.6 %, 14.7 % for N & P, respectively. Therefore, polders with a pond area ratio of 13.6-14.7 % had the largest N & P reduction (5.27 and 0.19 kg/ha). Polder size affected P reduction rate, with smaller polders (<200 ha) showing a higher P reduction rate, while it did not affect N reduction rate. Compared with annual precipitation, rainy-season precipitation more significantly (P<0.01) determined polder N & P reduction. This study demonstrated the use of our process-based framework in characterizing the shifts for the pond area ratio for polders, and thus provided technical support for N & P control of lowland areas in water management practices.
自然生态系统的变化因其对生态系统服务的深远影响而日益受到关注。低地人工流域（圩区）内的池塘在氮（N）和磷（P）循环中起着关键作用。从管理实践中的氮磷控制角度来看，需要确定圩区的最佳池塘面积比。为此，我们的研究提出了一个基于过程的建模框架，以研究圩区氮磷流失对池塘面积的响应，从而确定池塘面积比的阈值，以实现圩区最大程度的氮磷减排。所提出的框架包括两个专门开发的基于过程的模型（NDP和PDP），用于描述低地圩区的氮磷动态。为了评估该框架的性能，将其应用于中国东部太湖流域中河圩区的171个圩区。我们的调查结果表明，圩区氮磷减排率与池塘面积比之间的相关性分别在氮和磷方面有13.6%、14.7%的突变。因此，池塘面积比为13.6 - 14.7%的圩区氮磷减排量最大（分别为5.27和0.19千克/公顷）。圩区面积影响磷的减排率，较小的圩区（<200公顷）显示出更高的磷减排率，而对氮减排率没有影响。与年降水量相比，雨季降水量对圩区氮磷减排的决定作用更为显著（P<0.01）。本研究展示了基于过程的框架在表征圩区池塘面积比变化方面的应用，从而为水管理实践中低地地区的氮磷控制提供了技术支持。
