Effect of soil burial depth on seedling emergence of Amaranthus retroflexus

1. In The Name of God ILAM UNIVERSITY IRAN Effect of soil burial depth on seedling emergence of Amaranthus retroflexus Alireza Taab, Maryam Mottaghi Shahpar and Saghi Anbari Dept. of Agronomy and plant breeding, Faculty of Agriculture, Ilam University, 69315-516, Ilam, Iran Email: a.taab@mail.ilam.ac.ir JOINT WORKSHOP OF THE EWRS WORKING GROUPS: Weed management in arid and semi-arid climate and Weed management systems in vegetables 4-8 September 2011 Huesca, Spain

2. Introduction Weed Control Options! Crop Weed Emergence! When? And How Many? Problem ? Weed in Maize, soybean, vegetables etc. Crop yeild loss • Weed Management • - Time of weed emergence • Number of weed emergence • Depth Background Number of emerged seedling to deacrease with soil depth

3. Experiments Materials and Methodes: • Pot experiment outdoor Soil: CLAY; Organic C: 1.16% 1 Species x 4 Blocks x 6 Soil Depths x100 Seeds Depths: 0, 2, 4, 6, 8, 10cm Seed collection: 5 January 2010 Sowing date: 12 January 2010 Records: - soil temperature at 6 depths - numbers of emerged seedlings

4. Results

9. Conclusion Seedling emergence: -When mean daily soil temperature increased above ca 5ºC with ca 5 to 25ºC fluctuation -The seedling emergence was stopped when the daily soil temperature raised above 20ºC, possibly due to induction of dormancy -Maximum seedling emergence was observed for seeds at soil surface and decreased with depth but increased again at the depth of 10cm! -Seedling emerged over an extended period which make the species difficult to control -Weed control measures over an extended period with focus on larger seedling flushes

10. Thanks For Your Attention