Potato Phosphorus Response in Soils with High Value of Phosphorus

Phosphorus (P) is an element that is potatoes require in large amounts. Soil pH is a crucial factor impacting phosphorus availability in potato production. This study was conducted to evaluate the influence of P application rates on the P efficiency for tuber yield, specific gravity, and P uptake. Additionally, the relationship between soil pH and total potato tuber yield was determined. Six rates of P fertilization (0-280 kg P ha(-1)) were applied at twelve different sites across Northern Maine. Yield parameters were not responsive to P application rates. However, regression analysis showed that soil pH was significantly correlated with total potato tuber yield(R-2=0.38). Sites with soil pH values < 6 had total tuber yields, marketable tuber yields, tuber numbers per plant, and total tuber mean weights that were all higher than these same parameters at sites with soil pH >= 6. All sites with soil pH< 6 showed a highly correlated relationship between P uptake and petiole dry weight (R-2=0.76). The P application rate of 56 kg P ha(-1)was the best at sites with a soil pH < 6, but 0-56 kg P ha(-1)was the best at sites with soil pH >= 6.