The Nitrogen Budget of Coastal Eastern Guangdong in the Last 15 Years

Song Song,Yongsong Su,Zhenyu He,Lichun Xie

doi:10.3390/hydrology8020081

Abstract

Nitrogen pollution has caused severe ecological and environmental crisis, especially in densely populated coastal regions. Using a mathematical model based on statistical data series from industry, agriculture, environmental protection, and population in 2000, 2005, 2010, and 2015, this paper aims to estimate the nitrogen income and expenditure of coastal Eastern Guangdong, to reveal the temporal variation of the nitrogen budget in the coastal region with high agriculture intensity, and to suggest a management strategy for the local nitrogen control. The results show that: coastal Eastern Guangdong is a nitrogen surplus region, with nitrogen load and nitrogen flux varying in the range 276.01–299.60 kg N ha−1 yr−1 and 221.26–239.06 kg N ha−1 yr−1, respectively, during the period 2000–2015; from 2000 to 2015, the overall nitrogen surplus and the nitrogen surplus unit area showed an obvious upward trend, indicating that nitrogen pollution in the area was deteriorating; agricultural used fertilizer serves as the main contributor to nitrogen input, while water nitrogen accounts for the highest portion of nitrogen output; despite the fluctuation of nitrogen input and output, water nitrogen output steadily increased, suggesting a stronger water environment management requirement. This research provides reference for researchers and decision-makers in the ecological and environmental domains.

Highlights

Nitrogen participates in the biogeochemical cycle of the ecosystem and plays an important role in life maintenance [1,2,3]
Previous studies have shown that more than 66% of lakes and reservoirs in China are in a state of eutrophication, of which 22% are rich or super-rich in nutrients [4]
The main objective of this study is to clarify the main sources of nitrogen in the region, to evaluate the nitrogen budget, and to link the relationship between agriculture and the environment in coastal areas

Summary

Introduction

Nitrogen participates in the biogeochemical cycle of the ecosystem and plays an important role in life maintenance [1,2,3]. With the intensification of the anthropogenic impact on the ecological environment, the nitrogen cycle has been interfered with severely. Nitrogen continuously enters the environment, either accumulates on land, or enters rivers, lakes, reservoirs, and other water bodies with flowing water, causing land degradation and water pollution to differing extents. Eutrophication and its environmental influence has become one of the major water crises in China’s lakes in recent decades [4]. The global biochemical circulation of nitrogen results in the deterioration of the terrestrial system, as well as the oceanic system, especially in coastal regions [5]. About 60% of the world’s population lives in coastal regions [6]. The increase in population and in industrial and agricultural development has placed unprecedented environmental pressure on coastal regions

Objectives

Methods

Results

Conclusion