Conventional, integrated and organic winter wheat production in The Netherlands in the period 1993-1997

In order to assess possible changes in occurrences of pests and diseases in winter wheat as a result of differences in farm management, a monitoring study was carried out between 1993 and 1997 in The Netherlands to assess pest and disease incidence in winter wheat produced by conventional, integrated and organic methods. For the characterization of the different management types and for the interpretation of differences in pest and disease levels among management types information was gathered by yearly questionnaires on field characteristics, crop rotation, tillage, seeding, fertilizers, growth regulators, fungicides; insecticides and weed control in 558 fields. This paper reports on these various aspects of crop management at the conventional, integrated and organic farms investigated. Two groups of integrated farms were hereby distinguished; a group of pioneer farmers (Innovation project (IP)) and a later-started group (A2000 project). Winter wheat cultivation on conventionally managed farms was very similar to cultivation at the integrated farms run under the A2000 project. By comparison, the IP integrated farms used a greater range of seed mixtures, sowed later and made less, and less frequent, use of growth regulators and pesticides. At both conventional and integrated farms there is an ongoing intensification of fertilizer and pesticide use. Management at 'integrated' farms is consequently increasingly similar to that at conventionally managed holdings. The organic farms differ in virtually every aspect of their management, and their management regime shows little variation over time. In the discussion the representativeness of the farms studied and the differences between, and the changes within, the IP and A2000 integrated farms are considered. It is concluded that the IP integrated farms meet the government's environmental targets with respect to pesticide use, but not with respect to pesticide dependence