Effect of tillage, cover crop and crop rotation on the composition of weed flora in a sandy soil

Abstract

The development of integrated weed management strategies requires knowledge of mechanisms that influence compositional changes in weed flora. A 9‐year study was initiated in 1988 at Delhi, Canada, on a loamy sand soil to evaluate the effect of tillage systems [conventional (CT) and no‐till (NT)] and cover crops (only in NT) on weed density, species composition and associations, and crop yield in a winter wheat (Triticum aestivum L.)/bean/winter wheat rotation. Three bean types: soyabean (Glycine max L. Merr.), white bean (Phaseolus vulgaris L.) and kidney bean (P. vulgaris L.) were included. The NT system included variations: rye (Secale cereale L.) or maize (Zea mays L.) cover crop, volunteer wheat disked after harvest and wheat stubble. Data were collected in 1994, 1995 and 1996. Tillage systems, cover crops and crop type had differential effects on weed densities, species composition and associations. Weed densities were not affected by tillage or cover crops in wheat but, in the beans, densities were greater in the CT than in the NT systems. Various associations of weed species with tillage system, cover crop and crop type were observed. Crop yields were not affected by tillage type or cover crop, except that soyabean yields were highest in plots with cover crops.

Effect of cowpea intercropping on weed control and corn yieid

“…The weeds were cut even with the ground in two randomly sorted areas delimited by a 0.5 × 0.5 m wooden frame in the net plot subplot. Weed species relative frequency (Shrestha et al, 2002) was calculated based on the information obtained from each subplot (in both 0.5 × 0.5 m areas sampled from each subplot, as previously mentioned) and was defined as the ratio between number of plots where each species occurred and total number of plots (60) in the experiment.…”

Effect of Cover Crops, and the Management Thereof, on the Weed Spectrum in a Drip-irrigated Vineyard: 1. Weeds Growing During Winter and From Grapevine Bud Break to Grapevine Berry Set

“…Facelli and Pickett (1991), as well as Shrestha et al (2002), observed that the type of plant residue cover affected the weed species composition. Consequently, there is a need for future studies to document the response of the weed flora to different cover crops and their mulches (Dastgheib & Frampton, 2000).…”

“…Treatment the cover crops (end of May) terminated the dominance of ryegrass in most of these treatments ( Swanton et al, (1999), Shrestha et al (2002) and Westra et al (2008). Stinging milkweed disappeared from all the cover crop treatments, with the exception of Nemat (MC).…”

“…It has been reported that soil cultivation practices cause changes in the weed population (Teasdale et al, 1991;Buhler et al, 1997;De la Fuente et al, 1999;Swanton et al, 1999;Shrestha et al, 2002;Westra et al, 2008). In contrast to this, however, Wrucke and Arnold (1985) indicated that the distribution of broad-leaved weeds did not differ between conventional tillage and conservation tillage, while Pollard and Cussans (1981), as well as Pollard et al (1982), indicated an inconsistency in the weed response to tillage.…”

Conservation Tillage and Weed Management

“…in glyphosate-resistant cotton CT systems. Shrestha et al (2002) concluded that long-term changes in weed flora are driven by an interaction of several factors: tillage, environment, crop rotation, crop type, and the timing and type of weed management practice.…”