Spatial variability of groundwater solute concentrations at the water table under arable land and coniferous forest. Part 2: Field data for arable land and statistical analysis

作者：Jürgen Böttcher, Otto Strebel · 发表于：Zeitschrift für Pflanzenernährung und Bodenkunde · 年份：1988 · DOI：10.1002/jpln.19881510307 · 被引用次数：11 · 研究领域：Soil Geostatistics and Mapping、Hydrology and Watershed Management Studies、Soil erosion and sediment transport

Abstract The spatial variability of groundwater solute concentrations at the water table beneath a fine to medium sandy soil (Gleyic Podzol) under arable land was investigated. Samples were taken in March (within a period of high seepage) within the first decimeter below the groundwater table at horizontal intervals of 0.5 m along a 30 m transect perpendicular to the direction of plowing. At the time of sampling the field was fallow, the preceding crop was maize. Nitrate, sulfate, potassium, and calcium concentrations, as well as electrical conductivity were determined and analyzed by geostatistical and spectral analysis methods. Semivariance analysis shows spatial dependence between measurements (except for potassium) within a range of about 6 m. Spectral and cospectral analysis show a pattern of periodic variations with a period of 12 m for nitrate, sulfate, calcium, and electrical conductivity. This pattern is related to the manner in which the mineral fertilizer is spread (width of a single application = 12 m). The periodic variation of sulfate is 180° out‐of‐phase and has a phase shift of 0.4 m with respect to nitrate, calcium, and electrical conductivity, which is probably due to separate application. The concentration of potassium shows a spatial trend, presumably due to a trend in the amount of potassium fertilizer applicated from one side of the field to the other.