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Plant Sciences

1999

Agronomy, Horticulture and Plant Science Faculty Publications

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Sampling Weed Spatial Variability On A Fieldwide Scale, Sharon A. Clay, G. Jason Lems, Frank Forcella, Michael M. Ellsbury, C. Gregg Carlson, David E. Clay Dec 1999

Sampling Weed Spatial Variability On A Fieldwide Scale, Sharon A. Clay, G. Jason Lems, Frank Forcella, Michael M. Ellsbury, C. Gregg Carlson, David E. Clay

Agronomy, Horticulture and Plant Science Faculty Publications

Site-specific weed management recommendations require knowledge of weed species, density, and location in the field. This study compared several sampling techniques to estimate weed density and distribution in two 65-ha no-till Zea mays–Glycine max rotation fields in eastern South Dakota. The most common weeds (Setaria viridis, Setaria glauca, Cirsium arvense, Ambrosia artemisiifolia, and Polygonum pensylvanicum) were counted by species in 0.1-m2 areas on a 15- by 30-m (1,352 points in each field) or 30- by 30-m (676 points in each field) grid pattern, and points were georeferenced and data spatially analyzed. Using different sampling approaches, weed populations were estimated by …


Influence Of Deleterious Rhizobacteria On Leafy Spurge (Euphorbia Esula) Roots, Mark A. Brinkman, Sharon A. Clay, Robert J. Kremer Dec 1999

Influence Of Deleterious Rhizobacteria On Leafy Spurge (Euphorbia Esula) Roots, Mark A. Brinkman, Sharon A. Clay, Robert J. Kremer

Agronomy, Horticulture and Plant Science Faculty Publications

Rhizobacteria have been shown to be phytotoxic to leafy spurge in laboratory assays. This field study investigated the influence of two strains of Pseudomonas fluorescens [Trevisan, (Migula)], deleterious rhizobacteria (DRB), on root weight, root bud number, and root carbohydrate content of leafy spurge at three sites located in northeast and north-central South Dakota. Soils were inoculated with 2 g of starch-based granules containing no bacteria or starch granules containing 108colony-forming units (cfu)/g of either bacterial strain LS102 (Montana origin) or LS174 (South Dakota origin). Bacterial strains were detected on root samples from treated areas. Root weight and root carbohydrate content …


Influence Of Crop Rotation, Tillage, And Management Inputs On Weed Seed Production, George O. Kegode, Frank Forcella, Sharon Clay Apr 1999

Influence Of Crop Rotation, Tillage, And Management Inputs On Weed Seed Production, George O. Kegode, Frank Forcella, Sharon Clay

Agronomy, Horticulture and Plant Science Faculty Publications

Approaches to crop production that successfully reduce weed seed production can benefit farming systems by reducing management inputs and costs. A 5-yr rotation study was conducted in order to determine the effects that interactions between crop rotation, tillage, and amount of herbicide and fertilizer (management inputs) have on annual grass and broad-leaved weed seed production and fecundity. There were 10 crop rotation and tillage system combinations and three levels of management inputs (high, medium, and low). Green and yellow foxtail were the major weed species, and together they yielded between 76 and 93% of collected weed seeds. From 1990 to …