Allelopathic potential of cover crops to control weeds in barley
Authors: Urbano B., González-Andrés F.1,*, Ballesteros A.
Escuela Universitaria de Ingeniería Técnica Agrícola INEA, Camino Viejo de Simancas km. 4,5. 47008 Valladolid, Spain.
The study was done to develop management practices to reduce the use of herbicides, in the semi-arid Mediterranean agricultural ecosystems of Torozos (Valladolid, Spain).
The treatments were: (i) grain sorghum (Sorghum bicolor), (ii) Sudan grass (Sorghum sudanense) and (iii) sainfoin (Onobrychis viciifolia), as cover crops, (iv) mechanical removal of weeds and v) leaving unweeded, as control.
The herbicides were not used in the experiment. Sorghum bicolor and S. sudanense proved best cover crops for weed control in succeeding barley crop. The reduction in the weeds density with S. sudanense as the cover crop was up to 75% and the increase in the barley yield was from 15.37 Q ha−1. Weed control treatments reduced the relative cover value (RCV) and the relative weight value (RWV) of only Sinapis arvensis weed, while RCV and RWV of many weeds were increased many fold over the control. Sorghum sudanense as cover crop gave the highest net profit (€302.27 per hectare) and a 7,692% marginal rate of return. The use of Sorghum sudanense or even S. bicolor as a cover crop can be recommended during the fallow year, to control weeds in the following barley season. Such a cover crop is compatible with the fallow or set-aside periods imposed by E.C. policies.
