Abstract

ZUBIAGA, Luciano et al. STUBBLE STRUCTURE AND AVAILABLE WATER UNDER NO-TILLAGE IN THE SEMI-ARID SOUTHERN PAMPEAN REGION. Cienc. suelo [online]. 2023, vol.41, n.1, pp.89-120.  Epub Nov 30, 2023. ISSN 1850-2067.

Critical processes related to water dynamics occur mainly at the soil-atmosphere interface. The structure of crop stubble cover, both in quantity and distribution, affects the soil surface microclimate and, consequently, on the degree of water conservation. The aim of this work was to evaluate changes in the soil-atmosphere interface and their impacts on soil water as affected by different crop residue structures. The experiment was carried out at the Experimental Station of the National Institute of Agricultural Technology in Hilario Ascasubi, Villarino, Buenos Aires. Three winter cereals (wheat, rye, and oats) were evaluated as preceding crops of wheat from June 2017 to December 2020, that is, two consecutive cycles of biannual agricultural rotations with winter cereals. Dry biomass quantification, its distribution by strata, and the stem area index were used to evaluate stubble structure at the end of fallow. In addition, soil temperature, relative wind speed, and water dynamics in the fallow were determined. Although preceding winter crops and mainly their stubble arrangement showed differences in biomass contribution and cover structure, similar soil cover was achieved. Soil temperature and wind speed were affected by stubble arrangement but were unaffected by the preceding crop. Stubble arrangement modified fallow efficiency, moisture at seeding of the subsequent crop, and soil moisture evolution up to 13 days after a rainfall event. The stubble arrangement and winter cereal preceding crops impacted on the soil-atmosphere interface and, consequently, on soil water dynamics.

Keywords : Winter crops; soil-atmosphere interface; water conservation; Hilario Ascasubi..

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