Abstract

FERNANDEZ, Romina; QUIROGA, Alberto; LOBARTINI, Carlos  and  NOELLEMEYER, Elke. Determinación del intervalo hídrico óptimo en usoles de la región semiárida pampeana. Cienc. suelo [online]. 2017, vol.35, n.2, pp.215-227. ISSN 1850-2067.

The Least Limiting Water Range (IHO) has not been used in the semiarid Pampas to describe the soil quality changes related to management. The objective of this work was to characterize and evaluate the IHO in soils under natural grassland vegetation (VN) and agriculture (A). The study was carried out on petrocalcic Paleustolls in the calcic plains of the central semiarid Pampas. Clay and silt, carbon and nitrogen contents, total porosity and IHO were determined on samples from upper, medium, and lower soil profile layers of a VN and an A soil. Agriculture affected IHO in the upper and medium layer, and showed more differences among layers than VN. Average IHO values for VN were 0.14, 0.15 y 0.15 cm³ cm^-3, and 0.06, 0.01 y 0.18 cm³ cm^-3 in the A soil for the upper, medium and lower layers, respectively. In both soils the IHO moist limit was determined by field capacity moisture contents, whereas the dry limit was defined by the penetration resistance curve in A and by the permanent wilting point moisture in VN. A positive relation between IHO and total soil carbon and nitrogen was observed for the upper and lower depth layers, while in the medium depth layer this relationship was not important. In general terms, it is concluded that the Least Limiting Water Range was a sensitive indicator which reflected the changes in the soil porous system under agricultural use compared to a soil with similar texture under natural vegetation.

Keywords : Soil use; Penetration resistance; Bulk density; Water availability.

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