Potato growth, yield, and quality in response to phosphorus application rates across a range of soil test P concentrations

Increased concern for both Great Lakes water quality and potato ( Solanum tuberosum L.) phosphorus (P) requirements emphasize reviewing guidelines with regard to P fertilizer rates and potato response. Eleven field studies were conducted over a two-year period across multiple potato varieties and soil test phosphorus (STP) concentrations (64–210 mg kg −1 Bray-P1) on predominantly coarse-textured soils. Six P fertilizer rates 0, 45, 90, 135, 179, and 224 kg P 2 O 5 ha −1 were twin banded in-furrow at planting with ammonium polyphosphate 5 cm beside and 5 cm above seed pieces. Potato yield response to added P fertilizer occurred 50, 75, and 33 % of time when STP values were deficient (i.e. <75 mg kg −1 Bray-P1), optimal (i.e. 75–150), or sufficient (i.e. >150), respectively. Fertilizer P application to optimum testing soils protected again yield loss, but potato response to P was reduced as STP increased. In harmony with current literature, regression analysis indicated growers may apply up to 45 kg P 2 O 5 ha −1 as banded starter at planting regardless of STP. Mean tuber P 2 O 5 removal values were reduced 13.3 % from the current reported value (1.30 kg P 2 O 5 tonne −1 ). Results highlight the continuous need for evaluating new varieties under field conditions. Soil testing remains an important tool and best management practice for judicious P management. • 11 on-farm trials conducted on potato P response across soil test concentrations • Yield response to added P occurred 50, 75, and 33 % of time when STP was deficient, optimal, or sufficient, respectively. • Whole plant aboveground biomass at 30 DAE corresponded to total tuber yield P response • Tuber yield was a more important criterion than tuber set for calibration of P rate guidelines. • Tuber P 2 O 5 removal values decreased from the current value of 1.30–1.13 kg t −1 .