Influence of fertilizer management and soil fertility on tuber specific gravity: A review

Tuber specific gravity is a measure of potato internal quality and is used by the potato processing industry for assessing crop acceptability. Potato growers, therefore, have an interest in understanding how nutrient management practices influence specific gravity. This paper provides a review of research on fertilizer and soil fertility influences on specific gravity. Excessive application rates of nitrogen and potassium, along with excessive soil levels of either nutrient, may reduce tuber solids. Phosphorus applications may improve specific gravity when soil test phosphorus levels are low. Fertilizer materials with higher salt indices will decrease specific gravity more than fertilizer materials with lower salt indices.