Location: Dairy Forage ResearchTitle: Differential survival of alfalfa varieties interseeded into corn silage
|Osterholz, William - Will|
|CASSIDA, KIMBERLY - Michigan State University|
|WILLIAMSON, JESSICA - Pennsylvania State University|
|RENZ, MARK - University Of Wisconsin|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/11/2021
Publication Date: 2/1/2021
Citation: Grabber, J.H., Osterholz, W.R., Riday, H., Cassida, K.A., Williamson, J.A., Renz, M.J. 2021. Differential survival of alfalfa varieties interseeded into corn silage. Crop Science. 61(3): 1797-1808. https://doi.org/10.1002/csc2.20465.
Interpretive Summary: Planting alfalfa in corn silage is one way to reduce and nutrient loss from cropland and improve the productivity and profitability of forage production on dairy farms in the northern USA. One barrier preventing adapting of this technique is unreliable survival of alfalfa seedlings under the corn canopy. The purpose of this study was to determine if some alfalfa varieties are better suited than others for seeding into corn. Our results revealed that some alfalfa varieties consistently exhibited either good or poor seedling survival under corn while other varieties had variable survival that was dependent on the growth environment. As observed in earlier work, application of an agrichemical called prohexadione (recently approved by EPA for use in this cropping system) substantially improved alfalfa seeding survival under more difficult growing conditions. Overall the use of a well-adaped alfalfa variety in combination with prohexadione and other management practices under development will ensure this production system can be reliably implemented on dairy farms.
Technical Abstract: nterseeding alfalfa (Medicago sativa L.) into silage corn (Zea mays L.) can increase forage yield and protect cropland, but erratic alfalfa establishment hampers on-farm adoption. This randomized complete block study evaluated seedling survival and growth characteristics of 36 alfalfa varieties differing widely in reported traits when interseeded at two Wisconsin (WI) sites in 2015 and at single sites in WI, Michigan (MI), and Pennsylvania (PA) in 2016. Subplots were sprayed with prohexadione-calcium (PHD) at 0 or 0.425 kg a.e. ha-1 to aid alfalfa establishment. After corn harvest in 2015, average stand density of varieties in WI ranged from 15 to 94 plants m-2 without PHD and from 52 to 199 plants m-2 with PHD. Stand density largely determined subsequent first cut alfalfa yield, which ranged from 1.1 to 6.3 Mg ha-1. After corn harvest in 2016, stand density of varieties averaged across PHD treatments ranged from 113 to 222 plants m-2 in MI and 132 to 248 plants m-2 in PA compared to only <1 to 49 plants m-2 in WI where PHD improved but could not ensure adequate seedling survival under wet conditions that favored vigorous corn growth and defoliation of alfalfa. Overall, establishment was poorly related to measured or reported alfalfa characteristics, but 55H94 and hybrids were consistently among the best performing varieties. Further work is needed to develop improved alfalfa germplasm and new production practices to ensure reliable establishment of alfalfa under corn.