Crop yield and phosphorus uptake as affected by phosphorus-based swine manure application under long-term corn-soybean rotation

With increasing interest in adopting phosphorus (P)-based manure application, a good knowledge of manure form-specific agronomic performance is needed to assure crop productivity and to safeguard the environment. We evaluated the effects of three forms of swine manure (liquid, LM; solid, SM; and liquid manure compost, MC), each applied at 100 kg P ha−1 in every other year to the corn phase of a corn (Zea mays L.)-soybean (Glycine max L.) rotation, on crop yield, P uptake, and partial factor productivity of applied P (PFPP), compared with chemical fertilizer (CF) from 2004 to 2011 in a clay loam soil. The corn yield followed the order of LM > SM ≥ MC, while soybean yield did not differ amongst the three forms of swine manure. Similar patterns were observed for total P uptake and grain P removal for both corn and soybean. Manure P source agronomic coefficients calculated by dividing grain yield from the manure treatment by that from the CF treatment were 1.14, 0.85 and 0.74 for corn, and 1.00, 1.02 and 0.93 for soybean, for LM, SM, and MC, respectively. Compared with CF, the PFPP values for LM and SM were similar, but decreased by 26.3 % for MC, for corn. For soybean, the PFPP values increased linearly with year of cropping for CF and LM, while they remained unchanged over time for both SM and MC. Phosphorus-based manure application must be optimized on a form-specific basis with adoption of P source agronomic coefficients as a management tool to maximize P utilization efficiency.