Data from: Legacy effects of alfalfa monocultures or annual crop/alfalfa mixtures on subsequent corn yield and quality

Interseeding annual crops into existing alfalfa (Medicago
sativa L.) stands is gaining interest, and one reason may be that
alfalfa lowers nitrogen requirements for subsequent crops. However, little
is known about the legacy impact of this practice on subsequent corn (Zea
mays L.) production. An experiment involving interseeding annual
cool‐season crops into alfalfa was conducted between 2017 and 2021, which
serendipitously allowed us to evaluate the legacy impact of this practice
on subsequent corn grain production. This follow‐up study compared corn
grain yield and quality of corn planted subsequently on positive control
plots (alfalfa monoculture), negative control plots (annual crop
monoculture), and experimental treatment polyculture plots (annual crops
planted into alfalfa). We found that corn yield was lower following annual
monocultures compared to corn following alfalfa monoculture and
polyculture plots. The treatments did not have a significant effect on
grain protein or starch percentage, but grain oil percentage was higher
following polyculture compared to annual monoculture. Corn grain zinc
concentration was positively associated with previous alfalfa density and
corn ear leaf chlorophyll concentration. These findings indicate that
alfalfa monoculture and alfalfa‐annual crop polycultures can have
different positive legacy effects on corn yield, near‐surface soil
attributes, and grain quality. Future research aimed at evaluating the
legacy of crop/alfalfa mixtures on subsequent corn crops in the northern
Great Plains in multiple locations over several years are needed.