Effects of no-tillage and non-inversion tillage on weed community diversity and crop yield over nine years in a Mediterranean cereal-legume cropland

Both no-tillage and non-inversion tillage systems have been proposed within the context of 'conservation agriculture' as alternatives to conventional tillage for weed management and soil conservation. However, little information is available regarding their influence on weed community diversity and crop yield in Mediterranean cereal steppelands. Type of tillage represents a crop abiotic factor that largely influences the environmental conditions at the field scale to which weed communities may respond. The present paper examines the effect of no-tillage, subsoil tillage and minimum tillage (the latter two being non-inversion systems), on arable weed community diversity and composition in a cereal-legume crop rotation over 9 years. Their effects on crop yield are also explored. Inter-annual environmental variability was found to be more important than the tillage system in determining weed species diversity and assembly. None of the studied tillage systems exerted consistent effects, neither on weed community diversity nor on crop yields. In addition, the effect of tillage system on weed community diversity was crop-type dependent. The main effects of tillage systems were related to the composition of weed communities. Less common species resulted particularly affected while core species were consistent across tillage systems.