ABSTRACT
INFLUENCE OF TILLAGE SYSTEM ON WATER REGIME IN IRRIGATED AND RAINFED SUNFLOWER PRODUCTION
G. BASCH, J.P. MENDES, M.J.G.P.R. CARVALHO, F. MARQUES and M J SANTOS Department of Crop Science, University of Evora, Evora, Portugal
Abstract Recently, sunflower production increased substantially and the crop can be found on many soils and crop rotations normally associated to cereal production. The costs for ploughing, usually performed before the sunflower, are attributed partly to the wheat crop which, however, provides similar yields using no-tillage. Reduced and no-tillage (NT) systems have proved to be feasible alternatives to the traditional tillage methods (TT) based on the mouldboard plough, both regarding economical and environmental aspects. Nevertheless, the results obtained with direct drilled sunflower in the past were less favourable as those observed with other crops, although the water saving through no-tillage is supposed to favour crop growth under a strongly limited water regime. The improvement of the performance of sunflower in relatively wet springs or when early sowing was applied indicates that there exists an interaction between the tillage system and the existing water regime. In order to study this interaction a trial with two tillage systems and 3 levels of water regime was carried out. The results are discussed on the basis of the crop parameters, soil moisture content, root length and distribution, bulk density and penetration resistance, showing that sunflower performance was affected by no-tillage both rainfed and irrigated conditions. Keywords: Irrigation, leaf area, no-tillage, penetration resistance, root growth, soil moisture, sunflower, traditional tillage.
