Monday, November 13, 2006

The Interactive Effects of Row Configuration, Nitrogen Input and Sowing Rate on the Behaviour of Australian Spring Wheats Differing in Physiological Background.

Tom Giles1, Nicholas Paltirdge2, and David Coventry1. (1) Univ of Adelaide, Roseworthy Campus, Adelaide, Australia, (2) Univ of Adelaide, Roseworthy Campus, Adelaide, Australia

As part of a study monitoring water and nitrogen use in wheat-legume intercropping systems, field experiments (2004-05) were undertaken at Roseworthy (South Australia) to evaluate the yield performance with different row configurations, seeding rates and nitrogen inputs. The two spring wheat cultivars used, Frame and Wyalkatchem, differ in vegetative structure and maturity. Row configurations were based on standard 0.175m spacings and included double skip (DSA) and single skip (SSA) arrangements, as well as sole crop configuration (Sole). SSA provided the higher yields in both the 2004 and 2005 compared with DSA, consecutively receiving only 10% and 14% yield reductions when compared to the sole arrangement, whereas the DSA treatment showed 20% and 21% penalties. The relationship between row configuration and seeding rate was interactive in 2005 (p<0.05) and evidently associated with opportunistic adjustment by SSA plants at the highest seeding rate. Nitrogen input x cultivar interactions was also significant (p<0.05) with Wyalkatchem showing a 32% greater response to the application of nitrogen. The lower yields of the DSA treatment suggest a reduction in the horizontal accessibility of resources, therefore improving their availability for summer active forage legumes grown as an inter-row crop. More-over, the increased space afforded by this sowing arrangement, accompanied by the adoption of guidance technology, may allow the use of various practical applications including inter-row weed control.