Weed seeds in long-term dryland tillage and cropping system plots |
| |
| Authors: | Unger Miller & Jones |
| |
| Institution: | USDA-ARS, Conservation and Production Research Laboratory, PO Drawer 10, Bushland, TX 79012 USA,;Plant, Soil and Insect Sciences Department, University of Wyoming, University Station, Laramie, WY 82071 USA |
| |
| Abstract: | Successful crop production depends on effective weed control. Weed seedbanks were determined after 12 years of dryland cropping with winter wheat and grain sorghum under different tillage methods (no- and stubble mulch) and cropping sequences. Seeds of 12 species were detected. Amaranthus retroflexus was most abundant, but seed numbers were similar under all conditions. Portulaca oleracea , Panicum capillare , Setaria viridis and Sorghum halepense seed numbers differed because of some factors, with those for P. oleracea being greatest. For others, seed numbers were low (≤0.11 kg?1 soil), except for Digitaria sanguinalis with 7.8 kg?1 soil and Bromus japonicus with 1.3 kg?1 soil. Most seeds were near the surface with both tillage methods, with enough present under most conditions to cause a problem if proper control measures were not used, especially with continuous cropping. When a weed problem occurs under conditions as in this study, the results indicate that it could be reduced by growing winter and summer crops in rotation, which permits controlling weeds with tillage and/or herbicides when a crop is not growing. Other possibilities for controlling weeds under conditions as in this study are to alternate between dicotyledonous and monocotyledonous crops, which would permit use of a wider range of herbicides, and to use selective in-crop herbicides. |
| |
| Keywords: | weed seed dryland cropping system no-tillage mulch tillage wheat sorghum |
|
|
