Dynamics of competition between wild oats (Avena fatua L.) and winter cereals

Abstract

Summary: This study examined the effects of competition on the growth of Avena fatua, winter wheat and winter barley. Plants were sampled at frequent intervals from replacement series experiments at two contrasting sites in the U.K. A. fatua was much slower to establish than the two cereals, but thereafter exhibited a faster rate of growth. In monoculture, it took a considerable time for A. fatua to reach a size equal to that of the cereals, but by the end of the experiments it was the largest of the three species. The change‐over from cereal dominance in mixtures to A. fatua tiominance was rapid, and in three cases coincided with cereal flag leaf emergence. In the fourth case, it appeared to coincide with the art of canopy height extension. At one site the rder of competitiveness at anthesis was A. fatua= barley>wheat, and at the other site the order was A. fatua>wheat>barley. In order to explain and predict differences between years and sites, more studies are required on morphological development in relation to abiotic variables.

Seeding rate effects in oat-berseem clover intercrops

“…Relative time of emergence has been identified as an important factor in crop-weed competition (O'Donovan et al 1985) and in legume-cereal intercrops (Tofinga et al 1993). Cousens et al (1991) concluded that the relative timing of morphological development is critical to the outcome of competition.…”

E Efficacy and Economics of Herbicidal Weed Management in Monsoon Rice of Bangladesh

“…This could be due to higher competitiveness of hybrids against weeds, development of fast and early canopy coverage with higher leaf area index values; higher root growth and crop dry weight (data not shown here). The competitive ability of crops against weeds mainly determine by higher plant height and dry matter accumulation, early canopy closure, enhanced leaf area leading to more light interception and shading over understory plant species, increased nutrient uptake, proliferate root growth, and allelopathic effects (Pavlychenko and Harrington, 1934;Balyan et al, 1991;Cousens et al, 1991;Cudney et al, 1991;Anwar et al, 2010;Bajwa et al, 2017). Early-ripening of improved rice cultivars and hybrids have the ability to acquire larger canopy coverage within a short period of time and can suppress the weed growth to a greater magnitude over traditional, open-pollinated, long-duration cultivars (Zhao, 2006;ICAR, 2007;Sardana et al, 2017;.…”

Influence of annual forages on weed dynamics in a cropping system

“…Therefore, community dominance (as determined by relative DM production) at the first harvest was with the crop, likely due to the competitiveness of the prostrate winter triticale vs. wild oats. After the first harvest, however, community dominance shifted to the weed, possibly because wild oat (which was the dominant weed) had a higher net assimilation rate than the crop (Cousens et al 1991). Finally, the dominance shifted back to the crop.…”

“…Thurston (1962) attributed effective suppression of wild oat by winter wheat (Triticum aestivum L.), winter rye (Secale cereale L.) and winter barley (Hordeum vulgare L.) silage crops to their presence in spring when wild oat was germinating. Although wild oat seedling mass remained initially smaller than the crop seedling mass, wild oat can grow faster than either winter wheat or barley (Thurston 1962), because of its higher net assimilation rate (Cousens et al 1991). Since winter rye residues are phytotoxic to some weeds (Weston 1996), allelopathy may also have played a role in the Thurston studies.…”