Ciencia del suelo
versión On-line ISSN 1850-2067
DIVITO, Guillermo Adrián; SAINZ ROZAS, Hernán y ECHEVERRIA, Hernán Eduardo. Phosphorus fertilization strategies in a Buenos Aires southeast crop rotation. Cienc. suelo [online]. 2010, vol.28, n.1, pp. 47-55. ISSN 1850-2067.
In the soils of southeast Buenos Aires, fertilizer phosphorus (P) forms medium to high solubility products, making it possible to define different fertilization strategies based on application frequency. The effect of P application rates capable of fulfilling all crop requirements in intensive rotations in the region is unknown. The objectives of this work were to: (1) assess yields in crops fertilized with P annually and once during the crop rotation and (2) determine P use efficiency and P recovery for each fertilization strategy. The experiment was conducted at the E.E.A. I.N.T.A. Balcarce on a Typic Argiudoll and Petrocalcic Paleudoll complex, under no-tillage and with high P-Bray (Bray & Kurts, 1945) content (28.7 mg kg-1). During the two rotation cycles for maize, soybean, and double wheat/soybean crop, three treatments were assessed: application of P annually, application once during the rotation cycle, and a control without P application. The experimental design was in randomized blocks with four repetitions. No crop yield differences were found between annual and rotation fertilization strategies across the two cycles evaluated. The control crop yield did not differ from the fertilized crop during the first rotation cycle but did during the second. The crop rotation P use efficiency (EUProt) did not differ between nutrient applications strategies (19.4 and 32.4 kg kg-1 during the first cycle and 32.9 and 37.4 kg kg-1 during the second for annually and rotation fertilized treatments respectively). There were no differences between strategies in the crop P use efficiency of each crop (EUPcult). In contrast, during the first cycle, the applied P recovery efficiency (ERP) was higher for the rotation fertilized treatment than the annual application (0.13 and 0.03 kg kg-1), while there were no differences in the second cycle (0.16 and 0.17 kg kg-1 for annual and rotation application respectively).The correlation between the annual change in soil P-Bray and the P balance of the crop sown that year was low. A model was developed to predict the available-P decline in soils without P application, considering initial P-Bray level and crop P exportation as variables.
Palabras clave : Annual phosphorus application; Rotation phosphorus application.