Regional Variability of Agriculturally-Derived Nitrate-Nitrogen in Shallow Groundwater in China, 2004–2014

Abstract

Abstract:Increasing diffuse nitrate loading of groundwater has long been a major environmental and health concern in China, but little is known about the spatial and temporal variability of nitrate concentrations in groundwater at regional scales. The aim of this study was to assess the spatial distribution and variation of nitrate-nitrogen (NO 3 − -N) concentrations in groundwater. We used groundwater quality monitoring data and soil physical characteristics from 21 agro-ecosystems in China for years 2004 to 2014. The results indicated that NO 3 − -N concentrations were highly variable in shallow groundwater across the landscape. Over the study period, most of the NO 3 − -N concentrations were below the World Health Organization permissible limit for drinking water (<10 mg N·L). NO 3 − -N concentrations in groundwater neither significantly increased nor decreased in most agro-ecosystems, but fluctuated with seasons. In addition, groundwater NO 3 − -N under purple soil (6.81 mg·L −1 ) and Aeolian sandy soil (6.02 mg·L −1 ) were significantly higher (p < 0.05) than that under other soil types, and it was medium-high (4.49 mg·L −1 ) under aquic cinnamon soil. Elevated nitrate concentrations occurred mainly in oasis agricultural areas of northwestern China, where farmlands with coarse-textured soils use flood irrigation. Therefore, arid and semi-arid areas are expected to sustain high NO 3 − -N concentrations in groundwater. Mitigation strategies can prevent this problem, and include control of N fertilizer input, balanced fertilization, proper rotation system, adoption of improved irrigation methods, and establishment of environmental policies.

Effect of Irrigation Level and Irrigation Frequency on the Growth of Mini Chinese Cabbage and Residual Soil Nitrate Nitrogen

“…In the process of the growth and development of crops, the absorption and utilization of N nutrients are limited. Excessive N application can inhibit the quality and yield of fruits and vegetables [8,9], leading to soil degradation [10], including simultaneous nitrification and denitrification by ammonia volatilization and N 2 O and N 2 emissions [11] and increased nitrate content in the groundwater [12], which seriously threatens the sustainable development of the vegetable industry in facilities [13].…”

Crop Structure Changes Altered the Cropland Nitrogen Balance between 2005 and 2015 on the Sanjiang Plain, China

“…Nitrogen (N) is a key element in agricultural systems if high yields are to be achieved. Nitrogen deficiency negatively affects plant growth, whereas an N surplus can substantially reduce environmental quality and human well-being [3][4][5]. As recently as the 1960s, N availability in most parts of the world was controlled by natural processes and N was deficient in cropland [6].…”

Soil Salinity and Moisture Control the Processes of Soil Nitrification and Denitrification in a Riparian Wetlands in an Extremely Arid Regions in Northwestern China

“…Intensive agricultural practices in the arid northwestern regions of China led to N pollution of surface and groundwater [1]. Riparian wetlands are ecologically important transition zones between terrestrial and aquatic ecosystems in extremely arid regions, and they play a critical role in the removal of nitrogen (N) pollution from farmland and groundwater to maintain the health of river ecosystems [2,3].…”