Enhancement of wheat establishment with modified sowing and fallow management techniques

Abstract

Modified fallow management practices and modified sowing techniques were used to enhance wheat (Triticum aestivum) establishment in dry conditions. The effects of tillage, stubble management, deep sowing and press wheel pressure on wheat establishment were examined at various periods after rain. Experiments were conducted on two contrasting soil types: an Entic Pellustert and a Typic Natrustalf.

On the Entic Pellustert, both tillage during the fallow and the use of a press wheel at sowing increased wheat establishment. Responses to tillage and the press wheel occurred even when there was enough post-sowing rain to wet the soil to the level of seed placement. Increase in sowing depth from 67 to 88 mm reduced establishment in most sowings. On the Typic Natrustalf, there was little establishment response to tillage, a mulch of wheat stubble or the use of press wheel pressure at sowing. However, an increase in sowing depth from 54 to 74 mm maintained a given level of establishment for an additional 10 days of soil drying after rain. Deep furrow sowing (placement of seed over 100 mm below the original soil surface) did not improve establishment on either soil type. On both soil types, soil matric potential and establishment at a particular sowing depth were significantly correlated (R2 = 0.91 and 0.68, respectively), indicating that differences in establishment were caused primarily by the impact of the treatments on seed bed water levels.