A comparison of different tillage-seeding systems: the interaction of tillage and time of sowing on sandplain soils in Western Australia

Abstract

The effects of tillage-seeding method and 2 times of sowing on yields of wheat (Triticum aestivum) were examined on the sandplain soils in the northern wheatbelt of Western Australia. Four methods were compared: sowing after cultivation, sowing followed by deep ripping, direct drilling (i.e. single-pass seeding with a tined drill), sowing with a new cultivation depth modified drill (CDM) modified to cultivate up to 14 cm deep while sowing at 4 cm. Crops direct-drilled with the CDM produced more grain than crops established with conventional direct drilling or 'crops sown later using the cultivate-sow method and had similar yields to late-sown deep-ripped crops, where appropriate cultivars were used. Early sowing followed by deep ripping produced the highest grain yield. However, increasing the depth of soil disturbance while sowing early with the CDM in a 1-pass system resulted in a progressive increase in grain yield. When the cost of the extra ripping or cultivation operation is taken into account, early direct drilling with the CDM drill is likely to be more profitable than either conventional direct drilling or sowing with deep ripping or cultivation.