Allelopathic Potential of Winter Cereals and Their Cover Crop Mulch Effect on Grass Weed Suppression and Corn Development

Abstract

Field experiments were conducted to study the effect of three rye (Secale cereale L.) populations, six triticale (3Triticosecale Wittm.) cultivars, and two barley (Hordeum vulgare L.) cultivars, used as cover crops, on the emergence and growth of barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.], bristly foxtail [Setaria verticillata (L.) P.Beauv.], and corn (Zea mays L.). Moreover, bioassay studies were conducted to assess allelopathic potential of the winter cereal extracts on both weed species and corn. All winter cereal extracts reduced barnyardgrass and bristly foxtail seed germination and growth, but none of them had any effect on corn. Bristly foxtail was affected more by all extracts than barnyardgrass, and growth of both weed species was reduced more by the extract of barley cultivar Athinaida. In field, 4 wk after corn planting, barnyardgrass and bristly foxtail emergence was reduced by 27 to 80% and 0 to 67%, respectively, in winter cereal mulched plots compared with that in winter cereal mulch-free plots. On the contrary, corn emergence was not affected by any cover crop mulch. At harvest, corn grain yield increased by 45% in no herbicide treated barley cultivar Athinaida mulched subplots as compared with that in respective mulch-free subplots. This corn yield in no herbicide treated Athinaida mulched subplots was similar with that obtained in respective herbicide-treated subplots. The results of this study suggest that some winter cereals such as barley cultivar Athinaida could be used as cover crop for annual grass weed suppression in corn and consequently to minimize herbicide applications. MATERIALS AND METHODS Laboratory Experiment Extract PreparationPlants of three rye populations originated from Albania, Germany, and Greece, as well as six triticale cultivars (Thisvi, K.

Corn Nitrogen Fertilization Requirement and Corn-Soybean Productivity with a Rye Cover Crop

“…However, delay in RCC control occurred at some site-years due to wet soil conditions. The intent was also to wait a minimum of 7 d after RCC control to plant corn in an attempt to avoid potential negative effects (Dhima et al, 2006), and plant soybean at or within 7 d after rye control.…”

“…That was not the case in our study, where reduced yield was potentially due to an allelopathic effect from the RCC on corn growth or differences in soil properties between no-RCC and RCC during the growing season. Also, RCC biomass can create a surface mulch that would change soil moisture and temperature patterns and negatively affect corn growth (Dhima et al, 2006). Waiting only 7 to 10 d for planting corn after RCC control has been reported to be enough to avoid the allelopathic effect of RCC on corn growth (Duiker and Curran, 2005).…”

“…Allowing more time for RCC to grow in early spring increases RCC biomass production and residual N uptake, but also increases the risk of RCC allelopathic effects (Raimbault et al, 1990;Dhima et al, 2006;Krueger et al, 2011) and delays corn planting, both of which can reduce corn growth and yield (Wagger, 1989). The effect of RCC on plant available N (PAN) and crop yield can also depend on fertilizer N rate and soil supply of PAN (Duiker and Curran, 2005), RCC management (Sainju et al, 2007), and soil moisture and temperature to promote microbial activity (Hoorman, 2009;Maltas et al, 2009).…”

Winter Rye Cover Crop Biomass Production, Degradation, and Nitrogen Recycling

“…Additional potential benefits from cover crops include improved infiltration, decreased erosion, enhanced microbial biomass, increased weed suppression, and improved C sequestration and soil organic matter (Kaspar et al, 2001;Franzluebbers, 2005;Sainju et al, 2005;Dhima et al, 2006;Hoorman et al, 2009;Olson et al, 2010;Bernstein et al, 2011;Mirsky et al, 2013;Tabaglio et al, 2013;Moore et al, 2014;McDaniel et al, 2014). An issue with cover crops in the upper Midwest, however, is the cold and generally short period for growth between harvest and spring planting of annual crops (Dinnes et al, 2002).…”

“…Negative RCC effects on corn growth and yield (Johnson et al, 1998;Thelen and Leep, 2002;Kramberger et al, 2009;Pantoja et al, 2015) make farmers reluctant to use an RCC or to allow adequate time to grow in the spring (Tollenaar et al, 1993;Vaughan and Evanylo, 1998;Dinnes et al, 2002;Dhima et al, 2006). Lamarca (1996) found that when accumulated cereal cover crop biomass was less than 3000 kg DM ha -1 , the strongest negative effect on corn growth was for the 4-wk period after cover crop termination; however, greater cover crop biomass resulted in an extended negative effect.…”