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ARS Home » Midwest Area » St. Paul, Minnesota » Plant Science Research » Research » Publications at this Location » Publication #300677
Title: Alfalfa stand length and subsequent crop patterns in the upper Midwestern United States

Author
item YOST, MATT - University Of Minnesota
item Russelle, Michael
item COULTER, JEFFREY - University Of Minnesota
item BOLSTAD, PAUL - University Of Minnesota

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/29/2014
Publication Date: 8/1/2014
Citation: Yost, M.A., Russelle, M.P., Coulter, J.A., Bolstad, P.V. 2014. Alfalfa stand length and subsequent crop patterns in the upper Midwestern United States. Agronomy Journal. 106(5):1697-1708.

Interpretive Summary: Although rotations of perennial and annual crops are known to be important for farm profitability and environmental protection, there is very little quantitative information available about these rotations. This reports the first in-depth analysis of crop rotations with the perennial legume, alfalfa, for a 6-state region in the North Central US. The length of time alfalfa was kept in a field tended to be shorter in the Corn Belt areas of Iowa, Minnesota, Nebraska, and South Dakota, and in much of Wisconsin, but longer in the western parts of the Dakotas and Nebraska. A surprising finding was that between 10 and 70% of the fields were kept in alfalfa for 7 or more years, depending on the state and soil texture. Corn was the most frequently chosen first crop after alfalfa, except in North Dakota, where small grains, like wheat, were grown. The second crop after alfalfa also tended to be corn, but soybean and small grains also were selected frequently in the Dakotas and Minnesota. The detailed maps generated by this research provide the first regional look at how crop rotations with alfalfa are managed, and will help researchers focus their work on this important rotation.

Technical Abstract: To gain perspective on alfalfa (Medicago sativa L.), annual crop rotations in the upper midwestern United States, USDA-National Agricultural Statistics Service (NASS) cropland data layers (CDLs) and USDA-NRCS soil survey layers were combined for six states (North Dakota, South Dakota, Nebraska, Minnesota, Iowa, and Wisconsin) and 7 yr (2006-2012). Geographic location and soil texture class both affected alfalfa phase length (stand age). In general, alfalfa was kept in production longer outside the Corn Belt area of this six-state region and soil texture effects on alfalfa phase length varied by state. Corn (Zea mays L.) was the most frequent first- and second-year crop following alfalfa (comprising 79 and 61% of cases, respectively) in all states except North Dakota (35%). Soybean [Glycine max (L.) Merr.] frequency was 11 and 28% for the first- and second-year crop following alfalfa, respectively, across states. Small grains frequency as the first-year crop was 29% in the Dakotas and 6% in the other four states, and frequency as second-year crop was 26% in North Dakota and 5% in the remaining five states. Alfalfa phase length, soil texture class, and year all affected the first- and second-year crop following alfalfa, and effects differed by state. These results should aid in the improvement of alfalfa production and rotation practices that maximize net return to growers and utilize the large N supply following alfalfa termination. This approach to analyzing crop rotation patterns also may prove useful for other rotations with perennial and annual crops.