32 AGRICULTURAL STATISTICS 



CHEMICAL CONTROL OF WEEDS IN MONTANA WHEAT 



Over half of the acreage planted to wheat in Montana is sprayed with 

 chemicals for the control of weeds. In 1951 sprays were applied to 3,348,600 

 acres of wheat, 53 percent of the total acres seeded. This was 668,800 acres 

 more than in 1950 and exceeded the 1949 area by 583,100 acres. The acres of 

 wheat so treated in 1950 were slightly less than in 1949 due principally to a 

 smaller seeded acreage. In* 1949 about 47 percent of the acreage received 

 weed chmicals, as compared with 51 percent in 1950. 



Experimental use of chemicals for control of weeds during the early 1940's 

 led to general acceptance of this practice by grain growers in 1944. By 1947, 

 the use of sprays for weeds in winter wheat was quite general and during the 

 next two years it became prominent in controlling weeds in spring wheat, 

 barley and other grains. Many fields of flax, especially that under irrigation, 

 are now kept free of weeds by chemical sprays. 



The common weed killer (2,4-D) can be harmful to grain plants and may 

 reduce potential yields, particularly if it is applied at a vulnerable time and not 

 in proper solution. However, if the control measure was not used a consider- 

 able acreage of Montana's grains, with a preponderance of weeds, would 

 either be starved out or would be difficult to combine and thresh. Clean fields 

 and the resulting weed free grains are desired by growers. 



Since wheat is the principal crop grown in Montana and with sprays used 

 relatively more for this grain, there has been particular interest in the acreage 

 of wheat so controlled for weeds. Surveys have been made relative to acres 

 of this crop sprayed by kind and by cropping practices during 1949, 1950 and 

 1951. Data which appear on the following page and in Volume III of Montana 

 Agricultural Statistics were prepared from information supplied by approxi- 

 mately 3,100 wheat producers in the State. 



Winter wheat is sprayed in much larger proportion than spring v/heat but 

 the percentage of the acreage sprayed is increasing for spring wheat. In 1949 

 weed chemicals were applied to 68 percent of the winter wheat acreage, while 

 in 1950 and 1951 the sprayed acreage was 64 percent of the total seedings. Of 

 the winter wheat grown on summer fallowed land, 69 percent received chemi- 

 cal spray in 1949 and 65 percent in both 1950 and 1951. The acreage of winter 

 wheat grown on other dry land so treated was 53 percent in 1949, 59 percent 

 in 1950 and 46 percent in 1951. Irrigated winter wheat is sprayed less in- 

 tensively, with 41 percent in 1949 and 28 and 33 percent respectively during 

 1950 and 1951. 



Spraying for weeds in spring wheat covered 50 percent of the seeded 

 acreage in 1951, as compared with 46 percent in 1950 and 39 percent in 1949. 

 As with winter wheat, the plantings of spring wheat on fallowed land have 

 been sprayed most intensively. During 1951 about 57 percent of the fallowed 

 spring wheat was treated, as against 28 percent on other dry land and 35 

 percent on irrigated land. Since the percentages for the latter two categories 

 has changed little during the three year period, most of the increase in the 

 spraying of spring wheat has been on summer fallowed land. 



