Image: Journal of Plant Nutrition and Soil Science publication: The “extra pinch” of pseudosand to enhance tropical biogeochemical processes understanding. Authors: Simone Kilian Salas1, Katharina H. E. Meurer2, Diana Boy3, Elisa Díaz García4, Susanne K. Woche4, Jens Boy4, Georg Guggenberger4, Stephan Peth4, Paul. A. Schroeder5, and Hermann F. Jungkunst1 1 - iES Landau, Institute for Environmental Science, RPTU Kaiserslautern, Landau, Germany2 - Department of Soil & Environment, Swedish University of Agricultural Sciences, Uppsala, Sweden3 - Leibniz Universität Hannover, Institute of Microbiology, Hannover, German4 - Leibniz Universität Hannover, Institute of Earth System Sciences, Section Soil Science, Hannover, Germany5 - Department of Geology, University of Georgia, Athens, Georgia, USA Abstract: Despite knowing better, water-stable aggregates like pseudosands are still disintegrated into their clay- and silt-sized bits and pieces to serve standardization in texture determination. Lacking yet a viable alternative, this deliberately committed mistake seems the contemporary best practice for modeling purposes, which is far from being ideal. Here, we propose this misconception to be a major cause for flawed process understanding of tropical soils, leading to substantial uncertainties in model development. There is enough evidence as to why pseudosands are neither sand nor the plain sum of their clay- and siltsized units and should therefore better be defined as an additional soil texture class for which properties have yet to be examined across the tropics. Keywords: sand, texture, tropical soils, water-stable aggregates Type of News/Audience: Department News Research Areas: Environmental Geosciences Sedimentary Geology Water-stable sand-sized particles under the optical microscope in the size fraction of fine sand (FS, 0.063–0.2 mm, medium sand (MS, 0.2–0.63 mm), and coarse sand (CS, 0.63–2 mm) of Brazilian Ferralsols. Circles pointing to particles potentially identified as pseudosands. Optical thin sections of the PS-mixture in the (A) fine sand (FS) fraction with cross-polarized light (left) and plane polarized light (right) and (B) an optical thin section of a pseudosand in the coarse sand (CS) fraction. (A) Secondary backscatter image of polished thin section from sample of the fine sand (FS) fraction containing pseudosand (PS-mixture) in the fine sand (FS) fraction, with (B and C) energy-dispersive spectrometry (EDS)-mapping of Si and Al highlighting the distribution of quartz-rich particles (bright blue) and gibbsite- and kaolinite-rich grains (faint blue and bright orange). (A) Precipitation (mm) in relation to simulated and measured soil water contents (vol%). (B–D) Root-mean-square error (RMSE) for soil water content (vol%) for the three periods with texture manipulation. Background colors delimit the three artificial periods after strong precipitation events (A) Precipitation (mm) in relation to simulated and measured N2O emission rates (kg ha−1 d−1). (B–D) Root-mean-square error (RMSE) for N2O emission rates for the three periods with texture manipulation. Background colors delimit the three artificial periods after strong precipitation events. Read More: Journal of Plant Nutrition and Soil Science