Phosphorus mobility in acidic wild blueberry soils in Québec, Canada.
Lafond, J. et Ziadi, N. 2018. Phosphorus mobility in acidic wild blueberry soils in Québec, Canada. Affiche présentée à la NABREW, 13-14 août, Orono, Maine, USA .
In the province of Quebec, more of 35 000 ha of land are cultivated in wild lowbush blueberry (Vaccinium angustifolium Ait.). Blueberry fields are managed on acidic soils, well drained, and with low nutrient contents. To insure and maintain high crop productivity, fertilizers are applied in the spring of the sprout year. The objective of this project was to determine the effect of fertilizer applications on soil phosphorus (P) mobility under field conditions. Experiments were conducted in commercial stands of wild blueberries between 2004 and 2008 in Lake St. Jean area, Quebec, Canada. Four nitrogen rates (0 to 90 kg N ha-1) and four P rates (0 to 90 kg P2O5 ha-1) were applied in May of the sprout year. Soil P was determined after Mehlich 3 (PM3) extraction in the 0-5, 5-15 and 15-30 soil layers. Soil PM3 increased significantly after P application in soil surface and in the 5-15 cm soil layer in the sprout and production year. Phosphorus addition had no significant effect in the 15-30 cm soil layer. The (P/[Al+Fe])M3 molar ratio reached 10.7 % in the soil surface with the highest P application. In the other soil layers, this ratio was below 3.10%. Under field conditions, P leaching was limited in the 5-15 cm soil layer but a P build-up occurred in soil surface. Furthermore, the (P/[Al+Fe])M3 molar ratio measured in soil surface was very closed to the critical value (11.3%) beyond which there is a risk of surface water contamination.