ABSTRACT
I. INTRODUCTION Zero-tillage (ZT) seeders used for cereal crops in Australia typically involve a machine with a mass of approximately 120 kg per row pulled by a tractor that is rather heavier than the seeder, providing an engine power of around 2 kW per row. At first sight, this appears to be an excessive engineering requirement for the apparently straightforward job of inserting approximately one g/m of seed 30-60 mm below the soil surface into soft, moist soil. The idea that this task is overengineered is reinforced by the observation that many ZT seeders are based on frames similar to those of the heavier units of conventional tillage (CT) equipment.
