|LAURIAULT, LEONARD - New Mexico State University|
|GULDAN, STEVEN - New Mexico State University|
|POPIEL-POWERS, FERNANDA - New Mexico State University|
|STEINER, ROBERT - New Mexico State University|
|MARTIN, CHARLES - New Mexico State University|
|HEYDUCK, ROB - New Mexico State University|
|FALK, CONNIE - New Mexico State University|
|MAY, TAMMY - New Mexico State University|
Submitted to: Open Agriculture Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/25/2018
Publication Date: 7/2/2018
Citation: Lauriault, L.M., Guldan, S.J., Popiel-Powers, F.G., Steiner, R.L., Martin, C., Heyduck, R., Falk, C., Petersen, M.K., May, T. 2018. Relay intercropping with cover crops improved autumn forage potential of sweet maize stover. Open Agriculture Journal. 8(7):103-115. https://doi.org/10.3390/agriculture8070103.
Interpretive Summary: Farmers globally must consider all options to produce more food with less land. Crop residues, such as maize (Zea mays) stover after grain harvest, are used throughout the world as winter feed for livestock. In two years of randomized complete block studies with 3 replicates at New Mexico State University's Alcalde Sustainable Agriculture Science Center, sweet corn (also Zea mays) was left intact (corn-alone) or relay intercropped with oat (Avena sativa; corn-oat) or turnip (Brassica rapa; corn-turnip) and grazed in late autumn. Turnip topgrowth had higher crude protein (CP) and 48-h in vitro dry matter disappearance (48-h IVDMD) than oat topgrowth (119 and 186 g CP kg-1 for oat and turnip, respectively, P<0.001, and 422 and 623 g IVDMD kg-1 for oat and turnip, respectively, P<0.0001). Relay intercropping with turnip improved sweet corn whole stover IVDMD, averaging 443, 439, and 515 g IVDMD kg-1 for corn-alone, corn-oat, and corn-turnip, respectively (P<0.0001), likely due to complementarity of root system dynamics. Relay intercropping increased beef heifer average daily gain over grazing corn stover alone (0.36, 0.52, and 0.59 kg d-1 for corn-alone, corn-oat, and corn-turnip, respectively, P<0.02). These results demonstrate that relay intercropping oat or turnip into sweet corn is viable for extending the use of sweet corn stover to support cattle gains. Additional research should determine if digestibility improvement by relay intercropping with turnip or other brassica species would occur with grain or silage corn or other summer cereal forage species.
Technical Abstract: Maize (Zea mays L.) stover is used globally as winter feed for livestock but the nutritive value is low, requiring supplementation. A 2-year randomized complete block study with three replicates at New Mexico State University’s Alcalde Sustainable Agriculture Science Center compared sweet maize (Zea mays var. rugosa; maize-alone) with sweet maize relay intercropped with oat (Avena sativa L.; maize-oat) or turnip (Brassica rapa L.; maize-turnip). Relay intercropping had no effect (p > 0.05) on sweet maize stover dry matter (DM) yield and there was no difference in aboveground biomass DM yield of the intercropped species. Turnip aboveground biomass had greater crude protein concentration and 48-h in vitro dry matter disappearance (IVDMD) than oat aboveground biomass. Relay intercropping with turnip improved sweet maize stover IVDMD (443, 439, and 515 g IVDMD kg''1 for maize-alone, maize-oat, and maize-turnip, respectively, p < 0.0001). Intercropping increased animal gains compared to maize-alone (0.36, 0.52, and 0.59 kg/day for maize-alone, maize-oat, and maize-turnip, respectively, p < 0.02), likely due to provision of additional crude protein. Relay intercropping oat or turnip into sweet maize is viable for improving sweet maize stover for fall forage. In addition turnip, specifically, had a positive effect on stover nutritive value.