Resumen

BELTRAN, Marcelo Javier et al. Calidad de la materia orgánica y disponibilidad de macro y micronutrientes por la inclusion de trigo como cultivo de cobertura. Cienc. suelo [online]. 2016, vol.34, n.1, pp.67-79. ISSN 1850-2067.

Cover crops appear as an option to improve the balance of carbon (C) and its quality. The aim of this study was to study the effect of wheat as a cover crop on the dynamics of organic matter and the availability of some macro and micro nutrients under different crop rotations. This work was carried out in a long-term experiment under non-tillage system. Treatments were: soybean-soybean (S-S), soybean-cover crop-soybean (S-CC-S), corn-soybean-wheat/soybean (C-S-W/S) and corncover crop-soybean-wheat/soybean (C-CC-S-W/S). As principal results, it was observed that the fraction of organic carbon between 53 and 105 mm (COPf) was significantly increased when CC were added to soybean monoculture. The carbon fraction of less than 53 mm (COa), was higher when cover crop were incorporated to the rotations. Soybean monoculture had a value of total organic carbon (COPg + COPf) of 11.1 g kg^-1, being the lowest value of all treatments and significantly lower than S-CC-S (17 g kg^-1). Soil macronutrients concentration had no differences between treatments. Rotations with grasses and legumes (M-S-T/S) determined in general a greater accumulation of zinc (Zn) and manganese (Mn) (2.2 and 63 mg kg^-1 respectively) than soybean monoculture (1.4 and 50 mg kg^-1) in the depth of 0-5 cm. The concentration of these micronutrients was positively correlated with organic matter content. In this year of study, the CC did not seem to have affected the concentration of micronutrients, thus successive analysis should be performed in order to study the effect of CC in micronutrients dynamics in time.

Palabras clave : Organic fractions; Nutrient availability; Crop rotations.

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