The Effect of Phosphorus and Soil Moisture Levels on Yield and Processing Quality of ‘Centennial’ Sweet Potatoes1

Abstract

‘Centennial’ sweet potatoes (Ipomoea batatas (L.) Lam.) did not respond to increasing levels of P over an 8 year period probably due to the low soil pH and relatively high native P levels. Increasing the available soil moisture to above 25% resulted in a 3.4 MT/ha increase in yield of marketable roots over that obtained with natural rainfall but increasing the available moisture had no influence on yield. The P rate had no effect on dry matter and/or carotenoid content, firmness and splitting of processed roots. Protein content as percent of dry weight was reduced with increased P rate. Increasing the available soil moisture resulted in lower dry matter, protein, and carotenoid contents but had no influence on fiber content, firmness, or splitting.