A comparison of semi-dwarf and standard height oilseed rape varieties on N use efficiency and its components

摘要

Three winter oilseed rape experiments were established in each of2008-09 and 2009-10 growing seasons at ADAS sites High Mowthorpe, N. Yorkshire, Rosemaund, Hereford and Terrington, Norfolk. They investigated whether a semi-dwarf variety (PR45D03) hada different optimum Nitrogen (N) rate and N timing to a standard height variety (Excalibur), and whether N Use Efficiency differed between the two. It was shown that despite being up to 40 cm shorter the semi-dwarf variety required the same amount of fertiliser N to achieve optimum yield. Shorter stems did not affect the amount of N required to build each unit of green area index because lower stem biomass at flowering was compensated by a greater concentration of N in the stem. By maturity the semi-dwarf achieved similar yield levels to Excalibur and had taken up a similar amount of N. Overall, it appears that N rates and timings recommended for standard height varieties will be relevant for semi-dwarf varieties, with N uptake efficiencies and N in crop residues also similar.