Short-term effects of nitrogen deposition on nitrogen spatial and temporal distributions in a Calamagrostis angustifolia wetland of the Sanjiang Plain.

Jian Liu,Xiaoling Fu,Hongwei Ni,Jifeng Wang,Jianbo Wang,Fang Ma,Yingnan Liu

doi:10.1371/journal.pone.0232767

Jian Liu, Xiaoling Fu + Show 5 more

Open Access

https://doi.org/10.1371/journal.pone.0232767

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Abstract

Nitrogen (N) availability is an important factor regulating the feedback mechanisms of global change. This research uses a small Calamagrostis angustifolia wetland i = on the Sanjiang Plain of Northeast China as the research object and 15N tracer technology to study the effects of different nitrogen deposition levels (0 gN/m2, 4 gN/m2, and 8 gN/m2) through in situ controlled field experiments. Temporal and spatial distribution patterns of nitrogen in plants and soils and their short-term effects on nitrous oxide emissions fluxes were studied. The results showed that 1) the nitrogen content in the stems, leaves and roots of C. angustifolia decreased slowly with the growing season. Nitrogen application significantly increased the absorption of tracer nitrogen in the aboveground and underground plant parts (P<0.01), and the more nitrogen applied, the larger the absorption amount was (P<0.01). The absorbed amount accounted for 52%-86% of the total tracer nitrogen. 2) The tracer nitrogen in the soil did not show a significant change; the more nitrogen that was applied, the more nitrogen that was retained in the soil, and the tracer nitrogen adsorbed by the soil was mainly ammonium nitrogen. 3) The variation in the 15N-labeled nitric oxide emissions flux under different nitrogen treatments was consistent; nitrogen application increased the 15N-labeled nitric oxide emissions flux, but the difference between the low-nitrogen and high-nitrogen treatments was not significant (P>0.05).

Highlights

With the increase in chemical fertilizer consumption and the continuous utilization of fossil fuels, excessive nitrogen has been deposited in the plant ecosystem through the atmosphere and stored in the soil through leaching, as part of the nitrogen cycle of the ecosystem [1,2]
Nitrogen is absorbed from the air through photosynthesis in tissues, causing nitrogen accumulation in various organs of plants, such as stems and leaves [3,4] Most scholars consider soil nitrogen storage, absorption, and loss and soil microbial nitrification and denitrification to determine the impact of the nitrogen cycle on ecosystems
This study used the typical wetland of the Sanjiang Plain, a C. angustifolia wetland, as the research object and used the 15N tracer technique to study the spatial and temporal distribution patterns of nitrogen in plant-soil systems under different nitrogen deposition levels

Summary

Introduction

With the increase in chemical fertilizer consumption and the continuous utilization of fossil fuels, excessive nitrogen has been deposited in the plant ecosystem through the atmosphere and stored in the soil through leaching, as part of the nitrogen cycle of the ecosystem [1,2]. The Sanjiang Plain contains the most intact and well-maintained original wetland in China This wetland has high biodiversity and is an important representative of wetland ecosystems and a wetland of international significance [10]. This study used the typical wetland of the Sanjiang Plain, a C. angustifolia wetland, as the research object and used the 15N tracer technique to study the spatial and temporal distribution patterns of nitrogen in plant-soil systems under different nitrogen deposition levels. The short-term effects of N2O emissions fluxes and the nitrogen allocation strategies in plant-soil-atmosphere systems are of great theoretical and practical significance for studying global climate change trends and comprehensively and realistically evaluating wetland nitrogen cycling

Overview of research sites

Experimental design

Measurements of the N2O effluxes

Results and analysis

Discussion