Influence of sowing density and spatial pattern of spring wheat (Triticum aestivum) on the suppression of different weed species

Abstract

To better understand the potential for improving weed management in cereal crops with increased crop density and spatial uniformity, we conducted field experiments over two years with spring wheat (Triticum aestivum) and four weed species: lambsquarters (Chenopodium album), Italian ryegrass (Lolium multiflorum), white mustard (Sinapis alba), and chickweed (Stellaria media). The crops were sown at three densities (204, 449, and 721 seeds m −2 ) and in two spatial patterns (normal rows and a highly uniform pattern), and the weeds were sown in a random pattern at a high density. In most cases, the sown weeds dominated the weed community but, in other cases, naturally occurring weeds were also important. There were strong and significant effects regarding the weed species sown, the crop density, and the spatial distribution on the weed biomass in both years. The weed biomass decreased with increased crop density in 29 out of 30 cases. On average, the weed biomass was lower and the grain yield was higher in the uniform compared to the row pattern in both 2001 and 2002. Despite the differences in weed biomass, the responses of L. multiflorum, S. media, and C. album populations to crop density and spatial uniformity were very similar, as were their effects on the grain yield. Sinapis alba was by far the strongest competitor and it responded somewhat differently. Our results suggest that a combination of increased crop density and a more uniform spatial pattern can contribute to a reduction in weed biomass and yield loss, but the effects are smaller if the weeds are taller than the crop when crop-weed competition becomes intense.

Genetic Variation and Phenotypic Response of 15 Sweet Corn (Zea mays L.) Hybrids to Population Density

“…Another study using three field corn planting densities (40,000, 70,000 and 100,000 plants ha −1 ) and three weed densities resulted in up to a 50% weed biomass reduction between the low and high field corn densities [18]. Similar results have been documented in other crop species such as wheat (Triticum aestivum), barley (Hordeum vulgare), and safflower (Carthamus tinctorius) [19][20][21].…”

Phenotypic Plasticity of Chinese Sprangletop (Leptochloa chinensis) in Competition with Seeded Rice

“…If that is the case, there will be a trade-off between suppression of weeds and crop yield potential. Reduced weed biomass and crop yield loss because of increased crop density have also been reported in other crops (Lemerle et al 2004;Olsen et al 2006). Suppression of weed growth may also be achieved by delaying the emergence of Chinese sprangletop relative to rice.…”

Effect of cowpea (Vigna unguiculata) intercropping on weed biomass and maize (Zea mays) yield

“…For instance, Bulson et al (1997) found that weed biomass was significantly reduced when the densities of wheat (Triticum aestivum L.) and field bean (Vicia faba L.) intercrops were increased; and Arce et al (2009) showed that soybean seeding rates (24Á42 seeds/m 2 ) were inversely related to weed biomass. Increased seeding rates lead to quicker canopy closure, increased crop interference and greater weed suppression, resulting in increased yields (Olsen et al 2006;Kolb et al 2012). Thus, the use of increased crop density as a cultural weed management practice can complement the use of cover crops for weed suppression.…”