16 February 1996

Raise inputs, hybrid rape men are told

HYBRID rape growers are being urged to treat crops as having a 5t/ha (40 cwt/acre) yield potential and increase inputs accordingly.

According to CPB Twyford oilseeds breeder Liz Williams last years best yields came from crops that had above normal levels of inputs. "While a hybrid – like traditional rapes – has good powers of compensation, unless you feed and protect it properly, youll fail to exploit its in-built vigour," she says.

Poor nutrient availability, exacerbated by the drought, caused pod abortion and fewer seeds per pod in farm crops in the Midlands and South East, she claims. The result was disappointing yields.

In general Synergy after cereals should get 280kg/ha (224 units/acre) of nitrogen, and after set-aside 220-280kg/ha (176-224 units/acre), CPB Twyford advises. The first split may need to be earlier than usual to service the crops greater vigour.

Sulphur availability in the right form at the right time may be even more important. "Get the nitrogen right and ignore the sulphur and youll still significantly restrict yield," stresses Miss Williams.

Use 80-140hg/ha (64-112 units/acre) as sulphur trioxide (SO3) to supply 35-56kg/ha (28-45 units/acre) S to the growing plant, she says.