Influence of tillage systems on weed seedling emergence pattern in rainfed rice

Differences in weed seedling emergence patterns due to agronomic practices, such as tillage, have implications for weed competition and weed management strategies. The effect of different tillage systems, including conventional tillage, minimum tillage and zero-tillage, on the emergence pattern of different weed species was evaluated in a field experiment in the wet (rainfed) seasons of 2007 and 2008. In both years, seedling emergence of Digitaria ciliaris, Echinochloa colona, Eleusine indica, Ageratum conyzoides, Eclipta prostrata and Portulaca oleracea was greater in zero-tillage compared with either conventional or minimum tillage where the seedling emergence was similar. The emergence of Rottboellia cochinchinensis was not influenced by the tillage system. Tillage had different effects on Mimosa pudica emergence in the two seasons. The results will facilitate improved decision making with respect to the timing of weed control and contribute to the development of integrated weed management practices for dry seeded, rainfed rice. (C) 2009 Elsevier B.V. All rights reserved.