期刊
AQUATIC SCIENCES
卷 82, 期 2, 页码 -出版社
SPRINGER BASEL AG
DOI: 10.1007/s00027-020-0712-6
关键词
Groundwater; Surface waters; Alkalinity; Nitrogen fertilizer; Agriculture; Switzerland
资金
- Eawag (Switzerland)
- Applied Limnology Professionals LLC
In calcareous watersheds, groundwater alkalinity results largely from dissolution of carbonate minerals in soils. The alkalinity increases initially approximately in proportion to nitrate (NO3-) concentration and eventually approaches an apparent maximum of approximately 8 mmol L-1 at high NO3- concentrations. This close positive relationship between alkalinity and NO3- concentration appears to be predominantly a result of three processes: (i) mineralization of organic nitrogen fertilizer, (ii) exchange of OH- and H+ during the uptake of NO3- or ammonium by crop plants, and (iii) CO2 released by roots as a result of fertilizer-stimulated plant growth. We suggest that the asymptotic approach to a maximum groundwater alkalinity at NO3- concentrations exceeding 0.25 mmol L-1 may be caused by (i) a maximum possible areal crop production at excessive N fertilization and (ii) an increasing CO2 loss to the atmosphere due to the increasing CO2 production in the soil. Our analysis provides a general understanding and quantitative prediction of steady-state groundwater NO3- concentration, alkalinity, pH, the degree of CO2 supersaturation in the soil, and soil CO2 emissions to the atmosphere. The positive correlation between alkalinity and NO3- concentration observed in groundwaters persists in rivers and lakes. We conclude that an economically efficient agricultural practice that avoids over-fertilization might accelerate the in-soil carbonate weathering rate up to approximately threefold compared to unfertilized soils, but it will not jeopardize the use of aquifers for drinking water.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据