Resumen

POSE, Nélida Nancy et al. Agronomic and environmental phosphorus parameters in molisolls with different soil uses in the province of Buenos Aires, Argentina. Acta Agron. [online]. 2016, vol.65, n.4, pp.375-382. ISSN 0120-2812.  https://doi.org/10.15446/acag.v65n4.52186.

The dynamic change occurred in the soil due to different uses can be estimated by monitoring sensible variables. There is no agreement about the most appropriate phosphorus (P) parameter for this purpose. The aim of this work was to evaluate the usefulness of soil tests for P availability, risk of P loss and P retention capacities (P-Bray1, P-CaCl₂, P₇₅, PSI and DPS) in order to differentiate changes in soil P content related to soil uses, and to establish the relationship between these techniques. Two soil depths in two sites at the southeast of Buenos Aires province were analyzed. Different soil uses were considered: natural grasslands (PN), forest systems (FO), secondary grassland (PS) and different agricultural sequences (A). All techniques significantly differentiated between management systems; however, these differences were affected by soil depth. There were close correlations between the techniques, but there were dependent of soil use, P-Bray1 to P-CaCl₂ (R² = 0.89), P₇₅ to PSI (R² = 0.79) and DPS_P75 or DPS_PSI to P-CaCl₂ (R² = 0.82 and 0.83 respectively). The A systems increased P availability (P-Bray1), decreased P retention capacities ( P₇₅ and PSI) and generated an increased risk of P losses (P-CaCl₂). The FO and the PS had better P availability with respect to the PN, more P retention capacity and lower risks of P losses by runoff. Based on these results, a given P form could be estimated based on the analytical determination of another P form, but differentially by soil use.

Palabras clave : DPS; PSI; Land use; P-Bray1; P-CaCl₂.

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