Results of a 35-year ploughless tillage experiment at Changins (1970-2004). Part III: Weeds, diseases, pests and slugs.

摘要

A tillage experiment was established in 1969 at Changins, Switzerland, to investigate the long-term effects of different ploughless tillage treatments. A crop rotation of winter wheat, winter oilseed rape, winter wheat and maize was established on a clay humic and on a loamy soil. Three ploughless techniques were compared with conventional mouldboard ploughing: deep cultivation with a chisel plough (25-30 cm depth), shallow cultivation with a cultivator (10-15 cm), and minimum tillage with a rotary harrow (5-7 cm depth), occasionally replaced by direct drilling (wheat and rape) and strip tillage (maize). From 1991 to 2003, a general increase in the seed bank was observed in the soil, which was more pronounced under ploughless treatments. No significant correlation was observed between the abundance of annual weeds and tillage treatments, except for the group oil seed rape (Brassica napus) and wild mustard (Sinapis arvensis), which showed a significant decrease under minimum tillage. Perennial weeds were efficiently controlled by target-aimed herbicides. Wheat ear Fusarium disease (Fusarium graminearum [Gibberella zeae] and F. poae) only caused few damages because of the tolerant wheat cultivar used and unfavourable climatic conditions for the disease. On oil seed rape, infection by phoma (Phoma lingam [Leptosphaeria maculans]) did not vary between the tillage treatments. During a season with high contamination by stemkanker (Sclerotinia sclerotiorum), infection of rape plants was greater in minimum-tilled plots than in ploughed plots. Insect pests and slugs could be controlled using either chemical products or biological methods if available over the whole experimental field..