Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Plant Science

First Advisor

W.E. Arnold


Chlorsulfuron (2-chlor-N- (((4-methoxy-6-methyl-1, 3,5-tri azin-2-yl)amino)carbonyl)benzenesulfonamide] controls a wide variety of broadleaf weeds and some annual grasses in cereals and flax (Linum usittatissimum L.). It belongs to a class of compounds known as the sulfonylureas which also contains metsulfuron [methyl 2- ((methoxy-6-methyl-1,3,5-triazine- (2-yl)amino) carbonyl)amino)sulfonyl)benzoate] and sulfometuron methyl [2-carbomethoxy-N- ((4,6-dimethylpyrimidin-2-yl)amino carbonyl)benzenesulfonamide]. A characteristic of these compounds is high phytotoxic activity when applied at extremely low rates. In many cases, application of less than 0.01 kg active ingredient per hectare (kg ai/ha) of chlorsulfuron postemergence has provided control of 90% or better on a variety of weed species. Control of grassy weeds such as Setaria spp. and Canada thistle (Cirsim arvense (L.) Scop.) may require higher rates. An important aspect of chlorsulfuron is excellent crop tolerance. Many small grain herbicides must be applied within very specific growth stages to minimize the risk of crop injury. Chlorsulfuron can be applied from preplant to early boot stage of spring wheat (Trisicum aestivum L.) at several magnitudes the labeled rate without yield reduction. This level of crop tolerance at various growth stages allows growers greater flexibility in planning a weed control. program. Under certain conditions, chlorsulfuron can persist in soil for more than one growing season to control some weed species. The long persistence of chlorsulfuron is an advantage to producers in cereal-fallow rotations, but a distinct disadvantage to producers interested in rotating to chlorsulfuron sensitive crops. Chlorsulfuron represents an advance in weed control because of its wide spectrum of weeds controlled at low rates combined with excellent crop safety and low mammalian toxicity. However, the possibility of carryover limits its usefulness. These studies were conducted to: 1) Evaluate the effects of chlorsulfuron soil residues on several crops which are commonly grown in the Northern Great Plains; 2) Determine how the soils and climate of two different locations might affect chlorsulfuron carryover; and 3) Examine the effects o1 alachlor [2-chloro-2 ' ,6' -diethyl-N- (methoxymethyl) acetanilide], chloramben [3-amino-2,5-dichlorobenzoic acid], and trifluralin [a,a,a - trifluoro-2,6-dinitro-N, N-depropyl-p-toluidine] on chlorsulfuron carryover injury to soybeans (Glycine max (L.) Merr.) and sunflowers (Helianthus annuus L.).

Library of Congress Subject Headings

Weeds -- Control
Crop rotation
Crops and soils -- South Dakota



Number of Pages



South Dakota State University


No Copyright - United State