ABSTRACT

Polyethylene screens have been widely used in leafy vegetable production system, but there is no research of this technology in bunching onion growing during the summer season. This study aimed to evaluate the association of reduced soil disturbance with shading screens in bunching onion successive cropping in the summer. The experiment was established in split-plot scheme, comprising two soil management strategies (1= disc harrow + leveling disc harrow + rotary tilling and 2= disc harrow + leveling disc harrow) in the plots and environmental management strategies (1= black screen 35%; 2= black screen 50%; 3= silver screen 35%; 4= silver screen 50% and 5= full sun) in the subplots. The responses of bunching onion cropping in shading screens or full sunlight differed with meteorological conditions in the summer. Plants growing in high temperatures and less rainfall presented similar yield regardless the use of polyethylene screens or cultivation under full sun conditions. In the opposite situation, bunching onion growing under full sun is more productive. Bunching onion height increased in plants growing under polyethylene screens. There was positive effect of shading screens in maintaining soil moisture, especially on the surface. Disc harrow + leveling disc harrow presented higher water retention at all soil depths evaluated. However, the yield decreased 21.7% (first crop) and 14.9% (second crop) in relation to disc harrow + leveling disc harrow + rotary tilling.

Keywords:
Allium fistulosum; shading-net; soil tillage.