Long-term trials on the experimental station Dahnsdorf in special consideration of weed control

Abstract

The long-term trial “Comparing strategies for environmentally sound plant protection” was established in autumn 1995. The period of investigation covered 12 years. The influence of the herbicide intensity was investigated. The development of weed infestation and cereal yields was examined for a crop rotation with two-third cereals and three different herbicide applications. The permanent application of half of the situation-related herbicide dose caused a step by step increase in weed infestation compared to the situation-related dose. In the first six years the occurrence of Apera spica-venti, Viola arvensis and Matricaria spp. increased particularly. At the end of the second crop rotation after 12 years, an increase in the density of Centaurea cyanus and Matricaria spp. was found. The differences of yield increase caused by herbicide application were mostly low during the first crop rotation for both herbicide doses. For the second crop rotation, the application of half of the situation-related herbicide dose did only partially prevent yield losses. The application of situation-related herbicide doses in contrast led to significant higher yield increases in wheat and barley.

In the long run the permanent application of reduced herbicide doses can only be successful if the herbicide dose is situation-related and between 50 to 100% of the authorised dose. Reliable assessments of the sustainability of reduced herbicide doses are attainable in long-term trials only.

The period of investigation should be at least ten better twenty years. This depends on the local conditions, the weed infestation at the beginning, soil tillage and crop rotation.

DOI: 10.5073/JfK.2010.07.02, https://doi.org/10.5073/JfK.2010.07.02