Economic Losses Caused by Weed Competition in Manitoba Grain Fields: Ii. Effect of Weed Competition on the Protein Content of Cereal Crops

Abstract

Economic losses caused by weed competition in Manitoba grain crops were studied on 142 farm fields during a 3-year period, 1956 to 1958 inclusive. Ten paired plots were located in each farm field, one-half of each paired plot being kept weed-free throughout the growing season. Per cent protein was determined on wheat, barley and oat samples collected from 60 of these farm fields. Significant increases in protein content were obtained following weed removal in 22 of the 60 grain fields studied and small increases were noted in most other fields. In the combined analysis of all fields, removal of weeds resulted in significant increases (P =.01) in both protein content and yield of wheat, barley and oats. This suggests that weeds compete very effectively with grain crops for available nitrogen and that reductions in crop yields resulting from weed competition are generally accompanied by reductions in protein content as well.

The Biology of Canadian Weeds.: 27. Avena Fatua L.

“…Protein content of wheat and bailey seeO may be decreased (Friesen et al 1960) or unaffected (Bell and Nalewaja 1968b (Baum 1968). Mason (1853) stated that oats were cultivated in Newfoundland in 1622, according to Coffman (1961), and wild oats occurred as an impurity in the grain.…”

Effects of herbicide and nitrogen fertilizer application on grain yield and quality of wheat and barley

“…The increase in percentage grain N, hence grain protein content, in the 1989 spring barley and 1990 spring wheat crops, suggests that weeds reduce the crop's ability to take up and utilize N. Friesen et al (1960) found significant increases in grain protein following weed removal in several of the crops they studied. They concluded that weeds compete very effectively with grain crops for available N and that reductions in grain yield resulting from weed competition are generally accompanied by reductions in protein content as well.…”

Nitrogen

“…It can be observed that it increases with the rate of nitrogen fertilizer. However, the use of herbicide did not cause any change in the levels of grain N. Nevertheless, since the weight of the wheat grain significantly increased as a result of using the herbicide, protein production per area increased, bearing out Friesen et al (2).…”