abstract

The segetal vegetation of wheat and barley fields in Veneto (NE Italy).
The segetal vegetation of autumn-winter crops in Veneto (NE Italy) was investigated by means of 72 phytosociological relevés treated with multivariate analysis procedures. Original relevés were also compared with published data. Drastic changes in plain agroecosystems induced the disappearing of the coenoses described about 50 yeras ago and its substitution with Papaveretum apuli which is subdivided into two subassociations: typicum subass. nov. and veronicetosum triphylli subass. nov., this latter occurring on sandy soils of fluvioglacial origin. In the foodplain two other association are present: Echinochloo-Setarietum pumilae as result of watered corn crop and Matricario chamomillae-Polypogonetum monspeliensis ass. nov. growing in the coastal belt where soils laying under sea level are influenced by salt water. On calcareous hill belt Euphorbio-Biforetum detected in the ’60 is still the valid association whereas on basaltic substrates a new one is proposed: Anthemido arvensis-Trifolietum arvensis ass. nov. The material collected from acid to neutral soils of Montello is considered insufficient to tipify another cluster of relevés (Persicaria maculosa-Silene gallica community).

keywords

autumn-winter cereals, north-eastern Italy, phytosociology, Veneto, weed coenoses