Organic and conventional management of mixtures of wheat and spring cereals

Abstract

-Cereal mixtures may provide both organic and conventional producers with a more sustainable approach in reducing weed pressure, crop rotation flexibility, improved yield stability, buffering against pests and diseases, minimizing soil variability and increasing animal feed value. We examined the response of small grain mixtures containing wheat, oats, barley and triticale to varying degrees of natural competition and environmental stress at three locations in central Alberta, Canada. One modern and one heritage hard-red spring wheat cultivar, along with one cultivar each of oats, barley and triticale and eighteen two-way mixtures, were planted on organic and conventional land at seven location-years between 2003 and 2005. Average yields were 30% to 70% lower on organically managed sites. Monocrop barley yielded 43% and 16% higher than the site average at two organic locations. Our results suggest two main conclusions: (1) on conventionally managed land, wheat-barley mixtures exhibited potential for yield maintenance and weed suppression, and; (2) on organically managed land, competition with weeds had a large negative effect on yield (>30%). The 25:75 mixtures of wheat and oats, and all mixtures of Park (a heritage) wheat and Manny barley exhibited yield potential similar to or (up to 1.0 t ha −1 ) greater than monocrop yield. Manny barley mixtures exhibited weed suppressive capabilities.

Review: Redesigning Canadian prairie cropping systems for profitability, sustainability, and resilience

“…There is limited documented research work on grain intercropping in the NGP and the results of this research are inconsistent. Overyielding and greater yield stability have been observed in some crop combinations and under some conditions, but not in others (Carr et al 1995(Carr et al , 2004Szumigalski and van Acker 2005;Kaut et al 2008;Pridham and Entz 2008;Hummel et al 2009;Nelson et al 2012).…”

Conventionalisation of organic farming practices: from structural criteria towards an assessment based on organic principles. A review

“…Research on agronomic aspects of organic farming has shown that crop yields tend to be lower in organic farming Kaut et al, 2008), albeit less variable and less susceptible to drought (Lotter, 2003). Organic farming methods tend to increase soil organic matter and thus enhance soil fertility (Langmeier et al, 2002;Mäder et al, 2002), making it less dependent on external inputs.…”

The Sustainability of Organic Grain Production on the Canadian Prairies—A Review

“…Mixtures of Park wheat and Manny barley, for example, were shown to have equal or greater yields than monoculture wheat under organic conditions, which may be partly attributed to the weed suppressive ability of Manny barley [51]. Mixtures of AC Superb and AC Intrepid (1:1 or 1:2) wheat were found to have greater stability than AC Superb alone [53].…”

“…Crop mixtures have been considered as an agronomic approach to reducing weed pressure, protecting against pests and diseases, and enhancing yield stability [51,52]. Mixtures of Park wheat and Manny barley, for example, were shown to have equal or greater yields than monoculture wheat under organic conditions, which may be partly attributed to the weed suppressive ability of Manny barley [51].…”