Effect of tillage on weed flora and seed banks in maize and sunflower

Abstract

Australian growers are reducing their use of cultivation to adopt no till cropping systems because of better timeliness of sowing crops, reduction in soil erosion, improved soil moisture conservation and savings on fuel and labour costs. In Africa, farmers still use conventional tillage (mouldboard and chisel plough) in their farming systems. These changes in tillage practices can have a major influence on the seed bank dynamics and emerging weed flora. Little published work exists in Australia on how weed seed banks and weed floras respond to these changing tillage systems. Studies in these two areas will provide information on weed species which may become problem weeds in no till systems. There is also little information on the effect of changing tillage systems on summer crop yields such as maize and sunflower under dryland conditions. Studies were conducted on the effect of tillage systems [no till (NT), chisel plough (CP) and mouldboard plough (MP)] on the vertical distribution of weed seeds, seed bank dynamics and weed seedling emergence in maize and sunflower cropping systems. Tillage effects on weed flora were assessed through seedling emergence in the field under maize and sunflower grown at two sites (mixed weed population site and grass weed site) in 2008 and repeated in 2009.