Performance of Winter Wheat Varieties in White Clover Living Mulch

Abstract

The choice of variety for agricultural systems with multiple crops may differ from the one used in sole crop because of the changes in environmental conditions brought about by interspecific plant competition. Information about varietal performance under living mulch conditions as well as the suitability of the results of the official variety testing, conducted under conventional cropping conditions, for such systems is lacking for small grain cereals such as winter wheat (Triticum aestivum L.). In the current study, nine different winter wheat varieties were established in an existing living mulch of white clover (Trifolium repens L.) in three trials in the Swiss Midlands in the years 2003 and 2004. The winter wheat was directly sown in widely spaced rows (0.375 m) at a density of 450 viable grains m -2 . Grain yield varied between 1.83 and 4.11 Mg ha -1 . Plant height was correlated (r = 0.92, p < 0.001) with the grain yield, suggesting that varieties with long shoots may have an advantage because of the more intense shading of the white clover plants. However, the best yielding varieties were also those with the most intense tillering. Recorded values of grain quality traits (grain weight, test weight and protein content) for the tested varieties were analogous under the living mulch conditions of the current trials to those obtained in the official variety testing. This analogy was not observed for the grain yield, except for one trial, where the competitive strength of the white clover was reduced by mechanical interference prior to the seeding of the wheat, which positively affected tillering and hence grain yield. Thus, the use of better yielding varieties of winter wheat in living mulches is at the cost of decreased grain quality. The combination of yield and quality goals in living mulch systems will rather depend on the minimization of the competition of the cover crop on the wheat plants than on the variety choice following recommendations based on trials conducted under conventional cropping conditions.

Field scale functional agrobiodiversity in organic wheat: Effects on weed reduction, disease susceptibility and yield

“…The living mulch affected crop performance independently of cultivars effect, unlike observed by e.g., Hiltbrunner and Liedgens (2008). This may be linked to the concurrent sowing of our living mulch and wheat, unlike the systems studied in Central and Western Europe.…”

“…The living mulch system tested in our trials has original features, compared to the currently adopted system design in studies on cereal-legume intercropping. Living mulches are often established before wheat sowing (Hiltbrunner and Liedgens, 2008;Hiltbrunner et al, 2007aHiltbrunner et al, , 2007bThorsted et al, 2006). This is frequent in experiments carried out in Central-Northern Europe, where the living mulch is mainly aimed at optimizing N use efficiency and weed reduction.…”

Functional agrobiodiversity and agroecosystem services in sustainable wheat production. A review

“…In intercropping and living mulch systems, wheat performance is highly linked to competitive relationships between wheat and the companion crop (Den Hollander 2012;Hiltbrunner et al 2007a). To maximise weed control while minimising side effects, focus must be set on interaction factors such as sowing design (Thorsted et al 2006a), mechanical regulation of the living mulch (Thorsted et al 2006b), sowing densities (Hiltbrunner et al 2007c), and wheat cultivar performance in a living mulch system (Hiltbrunner and Liedgens 2008).…”

“…Once stated the main objective of these practices, e.g. weed suppression (Hartwig and Ammon 2002) or increased N use efficiency (Tosti and Guiducci 2010), the most important decision mainly addresses the functional identity of the two components, usually a cereal cultivar (Hiltbrunner and Liedgens 2008) and a legume species (Hiltbrunner et al 2007b) or cultivar (Davis and Woolley 1993). Instead, it is less clear which mechanisms should we focus on when dealing with genetic diversity.…”

“…In some intercropping and/or living mulch designs, the cereal crop is sown in a previously established stand of a perennial legume. In many of the cited experiments ran in central and northern Europe, the living mulch was sown as a cover crop during summer (Hiltbrunner et al 2007a, b, c;Hiltbrunner and Liedgens 2008;Thorsted et al 2006a, b). In Bergkvist (2003), white clover was undersown in barley followed by two consecutive seasons of wheat-living mulch.…”