Phosphorus availability in acidic soils of Misiones, Argentina

Abstract:

The ability to pbkp_redict phosphorus needs and make appropriate recommendations is important not only from the economic point of view but also for environmental sustainability to protect against the effects of excessive fertilizer use. The objectives of this study were to determine the best P extracting solution to estimate P availability and to establish a routine analysis for tropical acid soils. A greenhouse experiment was conducted using ryegrass (Lolium perenne L.) as the plant index, and six acid soils of Misiones, Argentine, with three levels of P. The" t" test of means showed no differences between Bray 2-P with inorganic Olsen-P, total Olsen-P modified and bioavailable-P (P-Bio). But, there were significant differences with the Mehlich 1-P, total Olsen-P, organic Olsen-P, modified inorganic Olsen-P (P-OMi) and organic Olsen-P modified (P≤ 0.05). The correlation of extracted P for the eight methods resulted in r> 0.8 (P≤ 0.01). The regression equations obtained between the evaluated methods had high r 2: 0.655 to 0.994 (P≤ 0.01). The P-Bio presented the lowest values of residual sum of squares, and achieved the best fit with the dry matter produced by aerial, roots and total parts, surpassing conventional methods and resulting in the best index of P availability for the acid soils of Misiones. The inorganic Olsen-P modified method followed in order of importance and given its analytical simplicity was selected as the most suitable method for routine analysis.

Año de publicación:

2004

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