Wild Oat (Avena fatua) Competition with Spring Wheat: Effects of Nitrogen Fertilization

Abstract

Field experiments were conducted to determine the effect of nitrogen fertilization on competition between wild oat (Avena fatuaL. # AVEFA) and spring wheat (Triticum aestivum‘Anza’). Nitrogen fertilizer treatments were applied over several wild oat-wheat density combinations. Wheat grain yield in wild oat-infested plots generally declined with fertilization while the density of wild oat panicles increased. Apparently, in competition with wheat, wild oat was better able to utilize the added nitrogen and thus gained a competitive advantage over the wheat. The increased competitiveness of wild oat resulted in reduced crop yields. Under the conditions of these experiments, nitrogen fertilization resulted in positive wheat yield response only when the wild oat plant density was below 1.6 percent of the total plant density.

Competition, Morphology and Canopy Structure in Wheat (Triticum aestivum L.) and Wild Oat (Avena fatua L.) Exposed to Enhanced Ultraviolet-B Radiation

“…However, the competitive outcome between these two species may differ, depending on factors such as density (Carlson & Hill, 1985;Martin & Field, 1987), the relative timing of seedling emergence of crop and weed (Chancellor & Peters, 1974;O'Donovan et al, 1985), and soil nutrient levels (Henson & Jordan, 1982;Carlson & Hill, 1986). In any case, the emphasis of the present study concerns the influence of UV-B on competitive balance rather than the outcome of competition, per se.…”

Weed community composition after 43 years of long-term fertilization in tropical rice–rice system

“…Balanced fertilization promotes the growth of crops, resulting in closed crop stands and light limitation for the weed communities growing underneath, thereby affecting weed species diversity (Yin et al, 2006;Nie et al, 2009). Carlson and Hill (1986) showed the dry weight of weed, wild oat (Avena fatua L.) was increased by fertilizer application in wheat production system. This discrepancy in the effect of fertilization on crop-weed competition may be attributed to the difference in the response to soil fertility levels among weed species.…”

Crop Rotation and Intercropping Strategies for Weed Management

“…Yields of soybeans grown in weed-free plots indicated that soybeans had not responded to the residual N. The weeds' greater responsiveness to N fertility resulted in greater reductions in soybean yield in the residual N treatments than in unfertilized treatments. Although such an effect is not universal (see, for example, Staniforth [1957] or Thurston [1959]), studies in a variety of cropping systems, including rice (Oryza sativa L.) (Okafor and De Datta 197 6), sugar beet (Scott and Wilcockson 1976), wheat (Carlson and Hill 1985), faba bean , and barley/pea intercrops (Liebman 1989), have also indicated that N fertilization under weed-infested conditions may not increase yield but result instead in increased weed growth and, in some cases, decreased crop yield.…”