Review of: "Mineral stabilities in soils: how minerals can feed the world and mitigate climate change"

Potential competing interests: No potential competing interests to declare.Enhanced rock weathering (ERW) is potentially a climate change mitigation wedge, and the current state of the science is leading to increasing deployment of this technology in croplands, pasture lands, and forested lands.The article by Manning (2022) is a literature review that aimed to cover the mineral weathering aspects of ERW by compiling relevant literature available at the time of writing.Mineral weathering is a mature science, so it is not surprising that the review included papers spanning over a century, from 1922 until 2022.The review covers several aspects of geochemistry and some aspects of mineralogy, including: ΔG rxn (Figure 1) of several weathering reactions (Table 1);The expected solubility of Si and Al as a function of pH (Figure 2); Mineral weathering data in Figure 3 and Table 2 ( which contains a critical mistake, to be discussed below); SEM images exemplifying the microbial role during weathering in soils (Figure 4); A schematic illustration of the oxygen and carbon isotope compositional range of soil carbonates (Figure 5); and A unique analysis of the expected silicon release from silicate weathering (rock-forming minerals in Figure 6 and clay minerals in Figure 7) compared to the expected Si intake of wheat during a crop season.The review article by Manning (2022) is timely and largely useful for researchers and practitioners involved in ERW.However, as it contains one important mistake, the rest of this post-publication review will focus on rectifying this.Below is the main issue found in Manning (2022).The original Figure 3 (and corresponding values also shown in Table 2) showed values that were reported to be "mineral dissolution rates", in log units.However, those values are in fact mineral dissolution rate constants (in log units), which we can term k.The values of log k are meant to be used in equations developed by Palandri and Kharaka (2004) to first calculate log A values, and then calculate log W r values, where W r is the "mineral dissolution rate".In fact, W r is a function of pH and temperature, so W r values can be readily calculated for conditions expected to be found in soils, while k being a constant, actually represents a theoretical weathering rate at pH of 0 (zero) and 25°C.Manning (2022) actually realizes this later in the review, when presenting the data of Figures 6 and 7, but when presenting Figure 3 and Table 2, which are more likely to be used by readers, the correct terminology and meaning of the presented values is missing.To rectify this, I have reproduced Figure 3 below, with the original figure on the left, now clearly indicating that those are log k values for the acid mechanism, and a modified figure on the right, where the values are calculated log W r 's based on pH of 6.0 and temperature of 20°C and using the most appropriate Qeios, CC-BY 4.0

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.