Potato Response to Phosphorus Fertilization at Two Sites in Nova Scotia, Canada

Abstract

Identifying phosphorus (P) requirements and P-use efficiency is crucial to a sustainable potato industry in Eastern Canada. In a three-year study (2013–2015) conducted in Nova Scotia, Canada, we assessed the potato (CV Superior) yield response to P fertilization on two different soils in the Annapolis Valley. Soil organic matter ranged from 3.0% to 4.1% and from 2.0% to 2.5% at the Kentville and Sheffield sites, respectively. Initial soil phosphorus was higher at Kentville site, ranging from 81 to 162 mg kg−1 than at Sheffield site ranging from 75 to 109 mg kg-1. A randomized complete block design was used with five P rates (0, 17.5, 35, 52, and 79 kg P ha−1) applied at planting. Tuber yields were assessed at harvest, and P-uptake efficiency characteristics were measured before vine senescence. Total and marketable yields were not impacted by P rates. Marketable yield was 68% and 57% greater for Kentville than for Sheffield in 2013 and 2015, respectively and were significantly affected by P rates × year interactions at a 5.4% probability level. Quadratic functions were used to describe tuber yield responses to P rates (0.61 > R2 < 0.85) and P rates corresponding to the maximum yields were 17.5 kg P ha−1 in 2013 and 2015 and 35 kg P ha−1 in 2014 when data from both sites were pooled together. Phosphorus uptake efficiency ranged from 0.47 to 0.54 g DM mg−1 P offtake at Kentville and from 0.45 to 0.49 g DM mg−1 P offtake at Sheffield and was 13% and 7% greater at Kentville than at Sheffield in 2013 and 2015, respectively. While further studies are still needed for recalibration, results from this study provide some of the first information regarding potato response to P fertilization in Nova Scotia. Based on current P recommendations in the region for the same soil P levels, our results suggest that current P rates can be reduced without impacting potato yield.