Effect of phosphorus fertilizer form, opener spread and rate of application on biomass yield, P uptake and recovery in a canola-wheat-pea rotation under controlled environment conditions

The form and opener configuration used to apply phosphorus fertilizer can influence its effectiveness and crop response. A growth chamber study was conducted to examine the response of crop (canola, wheat, and pea grown in rotation) and soil to P fertilizer form (monoammonium phosphate and struvite), opener spread (narrow versus wide), and rate treatments of 0, 20, 40, and 60 kg P₂O₅ ha⁻¹ added to canola (<i>B. napus</i>) in the seed-row, followed by wheat and pea without P fertilization to examine residual effects. Crop emergence, 30 days above ground biomass yield, uptake of P and apparent recovery of fertilizer P were determined, along with labile soil residual P concentrations at the end of the rotation. Both MAP and struvite produced similar crop biomass yield and P uptake response. The narrow opener spread (1”) performed better in canola yield response to added P and in recovery of P fertilizer compared to the wide (3”) spacing and did not appear to reduce canola emergence even at the highest rates of added P fertilizers.