Response to Phosphorus of Cranberry on High Phosphorus Testing Acid Sandy Soils
- L. E. Parent * and
- S. Marchand
The fertilized sand-grown cranberry (Vaccinium macrocarpon Aiton cv. Stevens) could be at risk for water contamination by P during seasonal flooding and drainage, especially in high-P soils. The P diagnosis is usually conducted from soil and tissue tests but should also include water-extractable P (PW) as an environmental index. Although the Bray-1 P (PBray1) test is the current test for cranberry soils, the Mehlich-III (M-III) test is now commonly used in Quebec and the mid-Atlantic USA as an agri-environmental index with specified thresholds. Our objective was to relate the (P/[Al+Fe])M-III molar ratio to PW and PBray1 and to evaluate this ratio against yield and tissue P responses to added P in high-P sand-grown cranberry crops. Fertilizer trials were conducted during the 2001 to 2004 period at rates of 0, 13, 26, and 39 kg P ha−1 yr−1 on permanent plots at five locations in central Quebec. The slope of the relationship between the (P/[Al+Fe])M-III molar ratio (range: 0.024–0.094) and PBray1 (60–235 mg P kg−1) was 0.0004 (R 2 = 0.92). There were significant site and year effects but no significant effect of added P on berry yield. There were significant linear effects of added P on tissue P concentration in the range of 0.9 to 1.4 g P kg−1 but no critical value could be defined. The simulated (P/[Al+Fe])M-III environmental threshold (9.7 mg PW kg−1) was 0.113. The (P/[Al+Fe])M-III molar ratio could be used interchangeably with PBray1 in Quebec sand-grown cranberry crops but the provisionary environmental threshold must be ascertained from drainage water monitoring.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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