Resumo

GOMEZ, María Florencia; NOELLEMEYER, Elke Johanna  e  FRASIER, Ileana. Root dynamics and biological activity in different crop sequences in two soil types of the central semiarid region. Cienc. suelo [online]. 2020, vol.38, n.1, pp.56-71. ISSN 1850-2067.

The objective was to study the effect of cover crop (CC) inclusion on root dynamic and biological activity in two soils with contrasting granulometry of the central semiarid pampa region (Entisol and Mollisol). The activities were carried out in long-term trials stablished in 2010 in the Experimental Station "Guillermo Covas" INTA Anguil under no-till. Treatments were: corn-rye (C), corn-vetch (V), corn-rye+vetch (VC) and a control without CC (corn-corn). Experimental design was completely randomized blocks with 4 replicates. Aerial biomass (BA), root biomass (BR), root distribution and quality, soil water content, soil temperature and biological activity were determined at three sampling moments: at the time of silage corn cutting (time 0), 129 and 174 days later. Including CC represented an extra C input into soil. Treatments with rye contributed with more aerial and root residues, and were more efficient in water use than vetch. Root N content of CC varied between 21 y 108 kg ha^-1. Corn root-C dynamic fitted to a negative exponential model with decomposition rates in the first 20 cm of 39,7 y 29,5 kg C ha^-1 day^-1 for Entisol and Mollisol. Cover crops stimulated soil biological activity through their root inputs, and this effect was stronger when vetch which was included in the crop sequence in both soils.

Palavras-chave : decomposition; dehydrogenase activity; cover crops.

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