Rhizosphere phosphorus depletion in three crops differing in their phosphorus critical levels

GERARDO RUBIO; V. FAGGIOLI; J.D. SCHEINER; FLAVIO H. GUTIERREZ BOEM

JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE-ZEITSCHRIFT FUR PFLANZENERNAHRUNG UND BODENKUNDE

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2012 vol. 175 p. 810 - 817

1436-8730

Rubio, G., V. Faggioli, J.D. Scheiner & F.H. Gutiérrez Boem. 2012. Rhizosphere phosphorus depletion in three crops differing in their phosphorus critical levels. Journal of Plant Nutrition and Soil Science, 175, 810?817.It has been reported for many soils that maize (Zea mays L.) has a higher soil-P critical levelthan soybean (Glycine max L.) and sunflower (Helianthus annuus L). The objective of this workwas to compare the rhizosphere P depletion in these three species in order to investigate if theydiffer in their capacity to acquire soil P. Sequential P fractionation and pH were determined in rhizosphere and nonrhizosphere soil samples from field and greenhouse experiments. Neither sunflower (the species with highest rhizosphere acidification) nor soybean or maize showed a significant relationship between P depletion and rhizosphere pH. The labile P fraction and the NaOHPifraction had lower values in the rhizosphere than in the bulk soil in 38% and 77% of the studiedcases, respectively. Sunflower and especially maize presented a more intense Pi depletionthan soybean. The comparison between sunflower and maize revealed that neither of them tooka clear advantage over the other in terms of P depletion. Rhizosphere Pi depletion was associatedwith the amount of P acquired by the plants. We conclude that the accessibility to differentP pools does not explain the differences in soil-P critical levels among the three species.