Nitrate Contamination in Groundwater: Evaluating the Effects of Demographic Aging and Depopulation in an Island with Intensive Citrus Cultivation
Nitrate Contamination in Groundwater: Evaluating the Effects of Demographic Aging and Depopulation in an Island with Intensive Citrus Cultivation
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DOI：
10.3390/w14142277
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发表时间：
2022-07
期刊：
影响因子：
3.4
通讯作者：
S. B. Kimbi;S. Onodera;T. Ishida;M. Saito;M. Tamura;Y. Tomozawa;I. Nagasaka
中科院分区：
文献类型：
--
作者：
S. B. Kimbi;S. Onodera;T. Ishida;M. Saito;M. Tamura;Y. Tomozawa;I. Nagasaka
尽管日本人口老龄化和人口减少迅速，但地下水硝酸盐污染仍然构成严重的环境问题。导致日本地下水源硝酸盐含量升高的主要因素之一是农业集约化，通常是因为化肥使用量增加。我们调查了人口老龄化和人口减少对地下水硝酸盐污染的影响，日本西部的一个岛屿，有广泛的柑橘种植。与平均年龄为73岁的奥乔村相比，库比村的农民平均年龄略高，为76岁，从2005年到2015年的十年中，农业用地减少了46%。奥乔有830名居民，是库比的两倍。与Ocho（4.8 mg/L）相比，Kubi村的平均NO3−−N浓度更高（6.6 mg/L）。使用稳定氮同位素和贝叶斯同位素混合模型确定了Kubi和Ocho的NO3−−N污染源。这些源分布与社会和土地利用因素有更强的相关性。据信，Kubi的老年农民使用大量化肥，导致植物吸收氮的效率低下，导致渗漏增加，地下水污染比Ocho更多。
Despite rapid population aging and depopulation in Japan, groundwater nitrate contamination still poses serious environmental problems. One of the main factors contributing to elevated nitrate levels in Japanese groundwater sources is agricultural intensification, frequently because of increased fertilizer use. We investigated the impact of population aging and depopulation on groundwater nitrate contamination on a western Japanese island that has extensive citrus farming. In comparison to Ocho village, where the average age of farmers is 73 years, Kubi village’s farmers are slightly older on average, at 76 years, and agricultural land has decreased by 46% over the past ten years, from 2005 to 2015. Ocho had 830 residents, which was twice as many as Kubi. In comparison to Ocho (4.8 mg/L), Kubi village had higher average NO3−−N concentrations (6.6 mg/L). NO3−−N contamination sources in Kubi and Ocho were determined using stable nitrogen isotopes and a Bayesian isotope mixing model. These source distributions were more strongly associated with social and land use factors. It was believed that the older farmers in Kubi employed a significant quantity of chemical fertilizers, which caused inefficient nitrogen uptake by plants, leading to increased leaching and more groundwater contamination than in Ocho.