Fertilizer management impacts on stand establishment, disease, and yield of Irish potato

Excessive fertilizer application in North Carolina, USA results in high residual soil levels of P, K and total soluble salts in potato fields. Our objectives were to determine the salt sensitivity of three common cultivars (Atlantic, Snowden and Superior), and the effects of planting density and fertilization on stand establishment, soilborne disease, and yield. Greenhouse results suggest that potato growth and emergence, but not shoot initiation, are reduced by high salinity. On a Portsmouth fine sandy loam, high fertilizer rates did not reduce stands of cv. Atlantic in the field in 1996 or 1997. Excess N resulted in more Rhizoctonia stem canker in 1996, and lower yields at the lower planting density in 1997. Yield compensation for reduced plant density occurred in 1997 at the lower N rates (56 and 112 kg N ha(-1):) and at the high PK rate (49 kg P and 139 kg K ha(-1)).