Publication Date


Advisor(s) - Committee Chair

James Worthington, W.C. Normand, L.D. Brown

Degree Program

Department of Agriculture

Degree Type

Master of Science


No-tillage production of crops has developed and become widespread since the late 1950/s. No-till is dependent upon the use of broad spectrum herbicides to kill weeds already growing at planting time. Until recently, this has almost exclusively been paraquat (1,1'-dimethy1-4,4'-bipyridinium ion). Glyphosate [N-(phosphonomethyl)glycine] is a new herbicide which has great potential for use in no -tillage production.

Soybeans (Glycine max L.) were planted in the stubble after wheat (Triticum aestivum L.) was harvested. All plots received applications of the residual herbicides alachlor [2-chioro-2',6'-diethyl-N-(methoxymethyl)acetanilide] and linuron [3-(3,4-dichlorophenv1)-1-methoxy-1-methylurea]. Each plot also received either paraquat or glyphosate or was designated as a check. Glyphosate was appiied at three different volumes and paraquat at only one volume. All mixtures were applied at two spraying pressures. Applications were made to areas where straw was undisturbed after combining and to areas where the straw had been removed.

Ratings taken 10 days and six weeks after herbicide application indicate that glyphosate performs as well as or better than paraquat. The ratings also indicate that glyphosate performs as well at 187 L/ha as it does at 574 L/ha. Spraying pressure and removal of straw seem to have little effect on the degree of weed control.


Agriculture | Agronomy and Crop Sciences | Life Sciences | Plant Sciences | Weed Science