Productivity and nitrogen benefits of late-season legume cover crops in organic wheat production

Abstract

Cicek, H., Entz, M. H., Thiessen Martens, J. R. and Bullock, P. R. 2014. Productivity and nitrogen benefits of late-season legume cover crops in organic wheat production. Can. J. Plant Sci. 94: 771–783. When full-season cover crops are used in stockless organic rotations, cash crop production is compromised. Including winter cereals in rotations can widen the growing season window and create a niche for late-season cover crops. We investigated the establishment and biomass production of relay-cropped red clover (Trifolium pratense L.) and sweet clover (Melilotus officinalis L. ‘Norgold’) and double-cropped cowpea (Vigna unguiculata L. ‘Iron and Clay’), hairy vetch (Vicia villosa L.), lentil (Lens culinaris L. ‘Indianhead’), soybean (Glycine max L. ‘Prudence’), pea (Pisum sativum L. ‘40-10’), and oil seed radish (Raphanus sativus L.) as well as wheat response to these crops under reduced tillage (RT) and conventional tillage (CT) at three locations in Manitoba, Canada. Red clover, sweet clover and pea produced from 737 to 4075 and 93 to 1453 and 160 to 2357 kg ha−1of biomass, respectively. All double crops, with the exception of soybean at 2 site years, established successfully under both RT and CT. The presence of cover crops increased wheat N uptake at stem elongation, maturity and yield, even when the biomass production of cover crops was modest. We conclude that late-season cover crops enhance the following wheat yield and facilitate reduced tillage in organic crop production.

Late-season catch crops reduce nitrate leaching risk after grazed green manures but release N slower than wheat demand

“…Additionally, there are two major differences between the present experiment and the two previous Manitoba studies (Thiessen Martens et al, 2001;Cicek et al, 2014a). One difference is the crop type: non-legumes in the present study versus legumes in the previous Manitoba studies.…”

“…In the first study, growth rates of four late season legumes ranged from 2 to 18 kg ha À1 d À1 (Thiessen Martens et al, 2001). In the second study, growth rates of legumes under organic management ranged from 3 to 32 kg ha À1 d À1 (Cicek et al, 2014a). While growth rates of late season crops in the experiment 1 were much higher than two Manitoba studies, the rates were similar in experiment 2.…”

“…Thiessen Martens et al (2001) reported 750 and 630 kg ha À1 of biomass production for chickling vetch (Lathyrus sativus L.) and lentil (Lens culinarus L.), respectively, when double cropped after fall rye. Cicek et al (2014a) reported that among the eight late season cover crops tested, only relay cropped red clover (Trifolium pretense) and double cropped forage pea produced acceptable amount of biomass from mid August to early October. Double cropped oilseed radish in their study produced up to 350 kg ha À1 Table 3 Effect of catch crop species (barley and oilseed radish) and seeding management (direct seeding and conventional seeding) on catch crop dry matter biomass production, daily growth rate, N uptake and N concentration for experiments (Exp) 1 and 2. when seeded after tillage, but produced only 70 kg ha À1 when no-till seeded.…”

Cover Crop Biomass Production in Temperate Agroecozones

“…Under vegetables, spring seeding CCs (5.7 to 8.1 Mg ha -1 ) produced as much biomass as fall or summer seeding (up to 6.1 Mg ha -1 ) depending on termination date. The greater CC biomass production with early seeding could be primarily due to optimum moisture conditions (Cicek et al, 2014) and temperature for germination. The early seeding gives CCs an advantage over late summer or fall growth compared to CCs drilled after harvest.…”

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

“…In Manitoba, red clover and alfalfa (Medicago sativa L.) were successfully established as spring-seeded relay crops in fall-seeded winter cereals Martens et al 2005;Cicek et al 2014a). In Alberta, red clover, alfalfa, and winter pea (Pisum sativum L.) were established successfully with winter cereals in both fall and spring plantings (Blackshaw et al 2010).…”