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Cover Cropping in ’Flowers
Saturday, January 1, 2022
filed under: Planting Systems
By Hans Kandel / Extension Agronomist
In my experiment, legumes were interseeded into sunflower on the day of sunflower planting, at the V4, and V10 growth stages of sunflower.
Legumes included, and their seeding rate were: hairy vetch (28.8 lbs/ac), sweetclover (9.5 lbs), alfalfa (16 lbs), black lentil (22.3 lbs) and snail medic (22.3 lbs).
The sunflower yield was reduced when legumes were interseeded at the same time as sunflower planting, except for black lentil (which produced 1,237 lbs of legume biomass). The sunflower yield, head diameter, achenes per head and 100-kernel weight were not significantly lower when legumes were interseeded at the V4 or V10 growth stages. Legume biomass was lower when the legume was interseeded at the later (V10) growth stage.
Hairy vetch produced the most biomass; but the crop is difficult to kill and may become a “weed” during a subsequent season.
Better results of cover crop establishment are achieved when the seed is covered with soil. At the drier environments, legume biomass produced was low, indicating the need for sufficient moisture for the intercrop.
Though only legumes were tried as an intercrop in this experiment, it is anticipated that other adapted species can also work. More research is needed to identify these opportunities.
This research focused on interseeding at the vegetative stage of sunflower. Experiments with corn and soybean have shown that there might be opportunities to aerially seed winter hardy cover crops at the end of the growing season. Near maturity, the sunflower canopy is opening, and light will be available for a cover crop to establish. Establishment will depend on available moisture at the time of sowing.