West Usambara Plateau Sites

In this manuscript, we synthesize current and legacy data from multiple studies to better understand the distribution and diversity of soil types and their properties in the Plateau physiographic region of the West Usamabara Mountains in Northeastern Tanzania. Analysis of soil properties and soil classification in the resulting dataset of 468 sites by land use, landscape position, and elevation revealed important relationships relevant for management and land use planning. These sites occurred across a range of landscape positions and an elevation gradient from 1040 – 2240 m.a.s.l. Soil diversity at the U.S. Order and WRB Reference Group levels was higher than expected, with five U.S. soil orders and seven WRB Reference Groups described in the dataset, and the highest soil diversity occurring at lower landscape positions. We found that soil organic carbon (SOC) and pH were two master variables that were correlated most other soil properties. Sites under cultivated land uses had the lowest topsoil soil organic carbon (SOC) concentrations, and SOC generally increased with increasing elevation. Mature forest and charcoal production areas did not significantly differ in their depth distributions of SOC. Valley soils had significantly lower surface SOC concentrations but higher exchangeable bases and pH values than all other landscape positions. Soil pH decreased by an average of 3.5 units across the entire elevation gradient and decreased by 1 unit with elevation even after SOC, land use and landscape position were included in multiple regression models. Local pedotransfer functions were developed to assist with the use of pH, clay and SOC as proxies for more difficult to measure soil properties such as cation exchange capacity (CEC) and base saturation (B.S.), bulk density and total phosphorus. Phosphorus (P) and potassium (K) were

identified as the most likely limiting nutrients in West Usambaran plateau soils in general. This information is critical for sustainable land management which will be applicable to the soils of other mountain complexes in the Eastern Arc chain.

Querying over HTTP

Splitgraph serves as an HTTP API that lets you run SQL queries directly on this data to power Web applications. For example:

curl https://data.splitgraph.com/sql/query/ddn \
    -H "Content-Type: application/json" \
    -d@-<<EOF
{"sql": "
    SELECT *
    FROM \"usaid-gov/west-usambara-plateau-sites-mvxg-vsy2\".\"west_usambara_plateau_sites\"
    LIMIT 100 
"}
EOF

See the Splitgraph documentation for more information.