Relationship between soil P fractions and microbial biomass in an oligotrophic grassland‐desert scrub system

Abstract

Phosphorus (P) is an essential element of the biosphere, both as a constituent of living organisms and as a regulator of biological processes. The Cuatro Ciénegas Basin in the central Chihuahuan Desert of Mexico is characterized by extreme P oligotrophy. The aim of this study was to quantify P distribution in soil P fractions, P sorption capacity, and P in microbial biomass in a desert scrub and grassland soil system in the Churince area of the Cuatro Ciénegas Basin over summer and winter seasons. Our objective, as part of an exploration of ecosystem functioning, was to ascertain the relationship between soil P fractions and P in microbial biomass. Our results demonstrate a scarcity of P, mainly in grassland, and also a higher P sorption capacity in grassland soil than in desert scrub. Desert scrub soil retained more P (228 ± 5 μg g−1 dry soil) than grassland soil (87 ± 10 μg g−1 dry soil), mainly in inorganic forms, but grassland soil retained more P in accessible organic forms. We suggest that biotic controls regulated by access to water shape the dynamics of soil P availability in the Churince grassland‐desert scrub system.

Spatial heterogeneity of physicochemical properties explains differences in microbial composition in arid soils from Cuatro Cienegas, Mexico

“…All soil samples in this study had high alkalinity produced by the elevated concentrations of ions, which is a general pattern in desert soils ( Titus, Nowak & Smith, 2002 ). The high pH decreases P availability, which is very scarce in these soils and it is bonded to Ca 2+ and Mg 2+ ( Cross & Schlesinger, 2001 ; Perroni et al, 2014 ). It is worth to mention that ions varied spatially in identity in this small plot: quadrats A and B were significantly high in anions, while quadrats C and D were significantly high in cations.…”

How To Live with Phosphorus Scarcity in Soil and Sediment: Lessons from Bacteria

“…P forms in ecosystems include mineral P (e.g., in rocks, soil, and sediment), dissolved and particulate organic P, and dissolved inorganic phosphate (PO 4 3Ϫ , here P i ) (8). P i is the main P source for microorganisms and plants, but its availability in soil, sediment, and water is very low due to its high reactivity with calcium, iron, and aluminum (9). Since primary productivity and growth rates in ecosystems are highly P dependent (10), microbes have evolved numerous mechanisms for uptake and storage of P i in response to nutrient scarcity (11,12).…”

Peer Review #2 of "Spatial heterogeneity of physicochemical properties explains differences in microbial composition in arid soils from Cuatro Cienegas, Mexico (v0.1)"

“…All soil samples in this study had high alkalinity produced by the elevated concentrations of ions, which is a general pattern in desert soils (Titus et al, 2002). The high pH decreases P availability, which is very scarce in these soils and it is bonded to Ca 2+ and Mg 2+ (Cross & Schlesinger, 2001;Perroni et al, 2014). It is worth to mention that ions varied spatially in identity in this small plot: quadrats A and B were significantly high in anions, while quadrats C and D were significantly high in cations.…”