Observations on agronomic challenges during conversion to organic field vegetable production.

Prior to conversion, growers perceived agronomic challenges such as controlling weeds, pests and diseases as their biggest concerns. Through monitoring of commercial farms since 1997, the DEFRA-funded ‘Conversion to Organic Field Vegetable Production’ project aimed to provide information to growers on the economic and agronomic performance of farms during conversion. Many of those technical challenges of production have been successfully overcome. While there have been some problems with nitrogen availability, especially where insufficient attention has been paid to fertility building and also on lighter land, there have been few major changes in soil nutrient levels. Investment in new weeding equipment and new techniques has enabled growers to reduce costs of controlling weeds. Perennial weeds do not appear to be increasing though there have been localized problems. Seasonal effects, such as wet weather, have had a strong influence on levels of weeds, pests and diseases, and the cost of their control. All growers have had to adapt to new techniques and new crops, but those with vegetable growing experience and those growing crops they had grown before have adapted quickest to the technical challenges of production. While there are still agronomic challenges to overcome, the concerns of growers have shifted towards the marketing issues.