The effect of row configuration on yield reliability in grain sorghum: I. Yield, water use efficiency and soil water extraction

Abstract

Four detailed field experiments were conducted in the Goondiwindi district (Queensland, Australia) over the summers of 2000-01 and 2001-02 to examine the effects of row configuration (single skip row, double skip and solid planted) on yield, yield components, biomass production, canopy architecture and light interception, water use and patterns of soil water extraction in grain sorghum hybrid MR Buster. Grain yield in skip row treatments was equal to or greater than that of solid plant treatments at yield levels below about 2.5 t/ha. Soil water measurements confirmed that this effect was due to the conservation of soil water in the centre of the skip areas for use by the crop after anthesis. A root front velocity of 2 cm/day was observed in all directions from the base of the sorghum plant. Light interception in skip row configurations was shown to be the same as in solid plant configurations between pairs of rows and up to 50 cm into the skip area. Further into the skip area, light interception was effectively nil. These results provide the basis to refine the APSIM Sorghum model to allow simulation of the effect of various row configurations over a range of climatic and soil conditions.