Phytoliths in particulate matter released by wind erosion on arable land in La Pampa, Argentina

ROGER FUNK; JACQUELINE BUSSE; NICOLE SIEGMUND; MICHAEL SOMMER; LAURA ANTONELA ITURRI; JUAN ESTEBAN PANEBIANCO; FERNANDO AVECILLA; DANIEL EDUARDO BUSCHIAZZO

Understanding soil wind erosion and control practices in arid and semiarid environments

Frontiers in Environmental Science

Año: 2023; p. 92 - 103

Silicon (Si) is considered a beneficial element in plant nutrition, but its importanceon ecosystems goes far beyond that. Various forms of silicon are found in soils, ofwhich the phytogenic pool plays a decisive role due to its good availability. This Sireturns to the soil through the decomposition of plant residues, where they thenparticipate in the further cycle as biogenic amorphous silica (bASi) or so-calledphytoliths. These have a high affinity for water, so that the water holding capacityand water availability of soils can be increased even by small amounts of ASi.Agricultural land is a considerable global dust source, and dust samples from arableland have shown in cloud formation experiments a several times higher icenucleation activity than pure mineral dust. Here, particle sizes in the particulatematter fractions (PM) are important, which can travel long distances and reach highaltitudes in the atmosphere. Based on this, the research question was whetherphytoliths could be detected in PM samples from wind erosion events, what are themain particle sizes of phytoliths and whether an initial quantification was possible.Measurements of PM concentrations were carried out at a wind erosion measuringfield in the province La Pampa, Argentina. PM were sampled during five erosionevents with Environmental Dust Monitors (EDM). After counting and classifying allparticles with diameters between 0.3 and 32 µm in the EDMs, they are collected onfilters. The filters were analyzed by Scanning Electron Microscopy and EnergyDispersive X-Ray analysis (SEM-EDX) to investigate single or ensembles of particlesregarding composition and possible origins.The analyses showed up to 8.3 per cent being phytoliths in the emitted dust andup to 25 per cent of organic origin. Particles of organic origin are mostly in thecoarse dust fraction, whereas phytoliths are predominately transported in thefiner dust fractions. Since phytoliths are both an important source of Si as a plantnutrient and are also involved in soil C fixation, their losses from arable land viadust emissions should be considered and its specific influence on atmosphericprocesses should be studied in detail in the future.