Search National Agricultural Library Digital Collections

NALDC Record Details:

Cropping systems alter weed seed banks in Pacific Northwest semi-arid wheat region

Permanent URL:
http://handle.nal.usda.gov/10113/43127
File:
Download [PDF File]
Abstract:
Arable land weed seed banks are dynamic and reflect cropping history, current management, and environment. Changes in crop rotation and tillage system can alter weed seed density and species composition. In the semi-arid region of the Pacific Northwest, USA, no-till spring cropping is being studied as an alternative to the traditional winter wheat (Triticum aestivum L.)/dust-mulch fallow (WWF) rotation. Weed seed bank density and species composition were assessed during the first 6 years of an ongoing cropping system study comparing WWF with three no-till rotations; spring wheat (Triticum aestivum L.)/chemical fallow (SWF), continuous spring wheat (CSW), and spring wheat/spring barley (Hordeum vulgare L.) (SWSB). Soil cores were collected at depths of 0-8, 8-15, and 15-23 cm in all plots during August each year following crop harvest. Weed seeds were washed from the soil, dried, and germinated in a glasshouse. Weed species most associated with the 0-8 cm depth was Bromus tectorum L., the major winter annual grass weed in WWF. Species most associated with 8-15 cm depth was Chenopodium leptophyllum (Moq.) Nut. ex S. Wats, a native warm season broadleaf weed that may have long seed bank persistence. An initial high density of B. tectorum was reduced with no-till spring crops and in WWF with intensive management strategies. In comparison an initial low weed seed density of B. tectorum remained low with no-till but increased in WWF with less management. Broadleaf weed species did not become management problems in no-till; however, seed bank weed shifts occurred where winter annual broadleaf species remained following reduction of high densities of B. tectorum. Summer annual broadleaf weed seeds such as C. leptophyllum and Salsola tragus L. were present but not at high densities. Summer annual grass weed seeds were not present and are not typical in this region. In this research, no-till spring cereal based systems did not result in an increase in total seed density at the soil surface. Results from this research show that no-till spring crop rotations are effective at controlling winter annual grass weeds as well as broadleaf weeds normally associated with WWF.
Author(s):
Thorne, M.E. , Young, F.L. , Yenish, J.P.
Subject(s):
arid lands , semiarid zones , weeds , Bromus tectorum , Chenopodium , buried seeds , spatial distribution , crop rotation , Triticum aestivum , winter wheat , no-tillage , fallow , soil depth , plant density , botanical composition , Washington
Format:
p. 1121-1134.
Note:
Includes references
Source:
Crop protection 2007 Aug., v. 26, issue 8
Language:
English
Year:
2007
Collection:
Journal Articles, USDA Authors, Peer-Reviewed
Rights:
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.