Richard Chynoweth, FAR
Herbage and vegetable seed growers and their associated industries face many issues during each production season. These range from crop establishment to in-season weed and pest control, and include the ever-increasing demands from regulatory bodies and consumers alike.
Growers are under pressure to produce economically sustainable seed yields of certified, weed-free seed while reducing crop inputs and/or their reliance on agrichemicals. Restrictions of agrichemical use are influenced by the end-user of the seed, or residue (e.g. straw), or in the future by public perception or a third party end user e.g. European supermarkets. Herbicide options and activity will reduce as products are removed either globally, or from New Zealand, and as the incidence of herbicide resistance increases. This will see the return to an emphasis on crop rotations, spot spraying, cover crops and non-chemical weed control. Or do we just
need to rethink weed management and ‘live’ with ground cover e.g. inter-row cover crops as opposed to bare ground?
Environmentally, how do seed crops, particularly those sown in wide rows or with slow growth rates, influence nitrate leaching? Can catch crops be incorporated to aid with the rapid uptake of residual nitrogen from the previous crop or nitrogen mineralising from decaying plant material? Do we need to rethink autumn establishment methods to ensure nutrient uptake before winter?
The industry must explore all options to maintain viability, including looking at the mistakes and successes of others and collaborating with other countries and production sectors. For example, can the stem rust model developed in Oregon, USA, reduce fungicide inputs on grass seed crops? What other models/knowledge can be developed to assist growers? Are there management/biological products that could replace fungicide usage on some crops? Can the use of certain rotations reduce weed or slug pressure? What slug biocontrol agents are currently active in New
Zealand? These are all issues/questions the seed industry must investigate to remain internationally competitive and both socially and economically viable.