Spatial distribution patterns of phosphorus in top-soils of Greater London Authority area and their natural and anthropogenic factors

Soil phosphorus (P) has a strong impact on soil and water quality. Soils in urban areas tend to enrich P, however, they have not been adequately investigated. A total of 6467 top-soil samples were collected and analysed by the British Geological Survey, providing basic data for studying the top-soil P distribution patterns and their environmental implications. The hotspots and cool spots were identified using the index of local Moran's I, which is a powerful methodology for discerning spatial clusters and spatial outliers. Combined with the results of one-way analysis of variances (ANOVA), a strong natural control of P was illustrated with elevated concentrations in areas of alluvium and river terrace deposits. P concentration in the lower Thames Estuary was clearly influenced by the tidal effect which has diluted the P-enriched sediments. The high concentration of Si and low pH level were linked to the low value clusters of P in Hyde Park and Richmond Park. Besides the natural control, the high value clusters concentrated in the city centre and built-up area, which indicated soil P content was strongly affected by human activities. The results of a t-test also showed the significant distinction of P concentrations between urban area and non-urbanised area, implying that urbanization and built-up materials accounted mostly for the locations and magnitude of the P pool. To conclude, the spatial patterns of P observed in the study area were controlled by both natural (parent materials (PMs) and geomorphology) and anthropogenic (urbanization) factors

Heterogeneity of Soil Nutrients: A Review of Methodology, Variability and Impact Factors

Soil nutrient heterogeneity highly correlates to plant growth and development of environmental quality. In order to better understand nutrient cycling, heterogeneity of soil nutrients and their driving mechanism in different land use types were summarized from 1945 to 2016. By grouping keywords indexed in the titles of articles from the data base of Web of Science, two hundred and thirty one publications related to our topics were used for analysis. Soil sampling and statistical method were compared, and spatial dependence and the impact factors for soil organic matter (SOM), Nitrogen (N), Phosphorus (P) and Potassium (K). The results showed that soil nutrient heterogeneity was influenced by different factors at different scales. The spatial dependence of SOM, N and P were mainly at the moderate level (48.9-59.0%) and strong level (33.3-42.2%), while for K was at strong level (63.6-84.6%) and moderate level (15.4-36.4%). This was mainly influenced by topography, soil loss, weather condition, parent material, soil type, soil texture, land use, human activities, soil moisture, mineral element, soil structure, animal and plant. These impact factors were summarized separately, and the influence of factors at different spatiotemporal scales was discussed. At the end of the review, the ideas for further research were postulated

Heterogeneity of Soil Nutrients: A Review of Methodology, Variability and Impact Factors

Soil nutrient heterogeneity highly correlates to plant growth and development of environmental quality. In order to better understand nutrient cycling, heterogeneity of soil nutrients and their driving mechanism in different land use types were summarized from 1945 to 2016. By grouping keywords indexed in the titles of articles from the data base of Web of Science, two hundred and thirty one publications related to our topics were used for analysis. Soil sampling and statistical method were compared, and spatial dependence and the impact factors for soil organic matter (SOM), Nitrogen (N), Phosphorus (P) and Potassium (K). The results showed that soil nutrient heterogeneity was influenced by different factors at different scales. The spatial dependence of SOM, N and P were mainly at the moderate level (48.9-59.0%) and strong level (33.3-42.2%), while for K was at strong level (63.6-84.6%) and moderate level (15.4-36.4%). This was mainly influenced by topography, soil loss, weather condition, parent material, soil type, soil texture, land use, human activities, soil moisture, mineral element, soil structure, animal and plant. These impact factors were summarized separately, and the influence of factors at different spatiotemporal scales was discussed. At the end of the review, the ideas for further research were postulated