53rd Squadron – Athena Squadron

[Atreides2]

Soil Analysis of Pittsburgh and Preliminary Data (53-444560-B)

Our teams on Pittsburgh have collected some soil sample from the planet.

A number of twenty soil samples (to a depth of 10 cm) were collected randomly from each of the four sites from planet Pittsburgh, along the mining operations and the industrial zones.

Ten samples were stored at 5 °C (but extracted within 24 h) and the remaining ten samples were air‐dried at room temperature, ground, and sieved through a 2‐mm mesh. The air‐dried soils were slowly saturated with water over a 2 day period. Sub-samples of 25 g were centrifuged for 30 min at 12000 rpm in a HS Centrifuge. Concentrations of K, Ca, Mg, Fe, and Na were measured using a AA‐55875 S atomic absorption spectrophotometer. The anions Cl, SO4 and NO3 were measured using ion chromatography.

Where there are minerals present and industry present that work with materials based on aluminium, in the soil there is usually enough aluminium to buffer the pH at around 4 and to subject non‐tolerant plants to aluminium toxicity. When aluminium is not present, as in organic soils, the aluminium buffering is lost, the pH can fall to well below 4 and H+ ions dominate the composition of the soil solution.

If this interpretation is correct then the existence of plant races separately adapted to H+ toxicity or Al3+ toxicity is predicted on the surface of the planet.

Factors associated with soil acidity is also considered to be limiting plants in many parts of Pittsburgh. This work was undertaken to investigate the role of the toxicity of hydrogen (H+) which seems to have been considered by Crayterian ecologists as an explanation of the reduced plant growth observed.

It must be emphasized that in this study very acid organic soils (pH<4.0) have been distinguished from acid mineral soils (pH 4.0–5.0) where the major yield‐limiting constraint is generally considered to be Al toxicity or H deficiency.

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