LIMING IN ACIDIFIED AGRICULTURAL SOILS OF THE PAMPEAN REGION: EFFECT ON ACTIVITY OF MYCORRHIZAL FUNGI

Abstract

Our objective was to evaluate changes in the abundance and activity of arbuscular my-corrhizal fungi (AMF) in response to the addition of calcite as a pH corrector. Three doses of calcite (0, 2000 and 6000 Kg ha-1) were applied in Mollisols of subacid pH from in French and Gardey (Buenos Aires Province) with rotations of wheat or barley / soybean-corn-soybean. Soil samples were collected prior to the start of the experiment and two years after liming (2017) when the plots were fallow (M1, April), and in plots with crops (M2, November, vegetative pre-flowering wheat in Gardey and vegetative soybeans in French). Calcite application raised soil pH (for the doses of 0, 2000 and 6000 Kg ha-1 on French pH was 6.04; 6.34 and 6.70; while for Gardey it was 5.51; 5.74; and 5.97, respecttively). Calcite application favored AMF activity associated with sporulation, although it did not affect the content of easily removable and total soil glomalin. Higher total glomalin ex-traction was attained with the sodium pyrophosphate extractant in relation to sodium citrate one (both in 50 mM concentration). The application of a 2000 kg dose of calcite ha-1 favored spontaneous mycorrhizal colonization (from 21 to 24%) of crops roots. Obtained results suggest that liming with 2000 kg calcite ha-1 could be recommended as a pH correc-tor in sub-acid soils of the region, also contributing to favor the abundance and activity of AMF, microorganisms recognized as plant growth promoters and that favor the structure and quality of the soil.