ISHS Acta Horticulturae 446: VI International Symposium on Vaccinium Culture
PHOSPHORUS FORMS, RATES, AND TIMING IN MASSACHUSETTS CRANBERRY PRODUCTION |
| Authors: | C. J. DeMoranville, Joan R. Davenport |
| Keywords: | Vaccinium macrocarpon Ait., productivity, phosphate rock, triple superphosphate, organic fertilizer, soil and plant tissue phosphorus |
| Abstract:
The effect forms, rates, and timing of phosphorus applied to cranberries grown on relatively high P soils was studied in field plots for three years at six locations, two each for three cultivars. Despite high soil test P, tissue P levels were at or below the critical level. All cultivars responded similarly to the treatments. Triple super phosphate (TSP), foliar P, and phosphate rock (PR) all supported similar cranberry yields, greater than that when no P was applied. Slow-release N-P-K fertilizer was as effective as soluble N-P-K in supporting cranberry productivity, but tissue P was less in the slow-release plots. Organic P forms (fish, chicken manure, bone meal) were associated with decreased yield. Four rates (0, 22.5, 45, and 67 kg P/ha) and five timings (three- or four-way split based on developmental stage) of P application were compared. Yield did not vary with application timing. Yield was higher when P was applied (compared to 0 kg P/ha) but yield among the other rates was similar. P was necessary to sustain cranberry production but high rates were not required. Based on this research, P applications of 20 kg/ha are recommended for producing cranberry bogs. Higher P rates or foliar P treatments may increase tissue P levels but there is no evidence that yields will improve beyond those with the moderate P rate. Foliar P applications were associated with increased field rot and extremely high soil test P levels (>100 mg/kg) were associated with lowered yield. P should be split-applied if a soluble material such as TSP is used to minimize P fixation or leaching loss. Slow-release forms or PR may be applied in a single early season application. | |
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