Rate,Timing,Placement and Enhanced Fertilizer Sources for Improving Phosphorus Use Efficiency.

Phosphorus (P) fertilization is essential for sustaining society. However, plant P uptake is inefficient due to poor soil P solubility, especially in potatoes (Solanum tuberosum L.). This is due to poor rooting efficiency and high demand. Phosphorus use efficiency (PUE) improves approximately two to three fold with correct rate, timing, placement, and by using enhanced efficiency fertilizer products (EEF) as evidenced by several dozen studies conducted over nearly two decades. But how do these efficiencies work in concert with each other and with EEF products? Our findings show that various technologies and management systems account for the interactions between these factors. For example, research on two EEF products showed they were no better than traditional P sources at standard rates. However, reducing the P rate by approximately 50% increased yield and crop quality by 5-8% compared to traditional fertilizer applied at the same rate. In another example, failing to account for high residual soil test phosphorus levels resulted in poor PUE and even reductions in yields when EEF products were used in these conditions. Alone or in combination, these techniques offer an opportunity to increase PUE. A review of our findings shows yields increased an average of 6.2% when EEF were used at the correct rate, timing, and placement.