Effect of rate and method of phosphorus application on the growth and development of 'Pasja' crops

Abstract

‘Pasja’ (Brassica campestris x napus) was grown at Lincoln in 2008, with banded or broadcast phosphorus (P) fertiliser applied at 0, 20, 40 or 60 kg/ha at establishment on a Templeton silt loam soil of moderate fertility (Olsen P of 9-17 mg/ kg range for individual plots). Total dry matter (DM) production, leaf to stem ratios and leaf area development were measured over time and related to the biophysical environment. Final DM yield increased with P rate from 3,730 kg DM/ha for the control to ~5,000 kg DM/ha at 60 kg P/ha. The leaf to stem ratio declined from between 22 and 31 at 17 days after emergence to 10.3 at the final harvest. Leaf area index (LAI) for the control crops was lower than for those that received P fertiliser, but there were no differences among the P fertilised crops. Total accumulated intercepted solar radiation (RIcum) was 8% greater when P was applied compared with the control. This difference was the main contributor to differences in total dry matter yield and was independent of the application method. Keywords: Brassica