HIGH PHOSPHORUS APPLICATIONS AT PLANTING IMPROVE ASPARAGUS ROOT GROWTH AND YIELD

High phosphorus (P) levels in soils are reported to stimulate early plant growth and root production. In addition, P plays a role in regulating photosynthesis and carbohydrate metabolism. In 1999, replicated trials were established in a P-deficient soil to assess the effect of increasing P levels on asparagus growth and productivity. Prior to planting, 0 to 450 kg P/ha was blended in the planting furrow. Fleshy root growth and carbohydrate content were measured each spring and fern was evaluated during the remainder of the year. Spears were harvested beginning in 2001. Increasing soil P levels had little effect on yield during the limited harvests of 2001 and 2002. By 2003 and 2004, there was a linear increase in yield with increasing P applications. This yield increase was associated with higher root biomass but not root carbohydrate content. Results suggest that a single early application of P can significantly improve asparagus establishment and subsequent productivity.