Key Points
- Cultivation serves a number of purposes but excessive cultivation is costly and can damage soil structure.
- Three cultivation trials were conducted during the 2008-09 season. The Waikato and Central Hawke’s Bay (CHB) trials compared conventional tillage with strip tillage. The Taranaki trial compared conventional tillage with direct drilling. The trials were monitored regularly for plant biomass, plant N and soil mineral N.
- Tillage type did not affect maize silage yield in Waikato and ChB. In Taranaki, yields tended to be lower due to lower plant population resulting from pest pressure
- The total amount of N released over the season was greater under conventional tillage than strip tillage. Soil mineral N was greater under conventional tillage early in the season. Soil moisture was greater under strip tillage.
- Using contractor costs, strip tillage is between $20 and $110/ha cheaper than conventional cultivation. Direct drilling is between $260 and $310/ha cheaper.
- These trials demonstrate that reduced tillage can offer benefits but crops must be managed well. Particular attention should be given to fallow time, planter accuracy, weed control and pest control.