Cover Cropping and Double Cropping following an Over-wintered Cash Crop South of the 43rd Parallel

Options for growing overwintered cash crops in relatively cold and dry climates have improved over the past ten or so years. Beyond the standbys of winter rye, winter wheat, and triticale, some other small grains and brassica oilseeds can now be grown as overwintered cash crops. The harvest of overwintered cash crops in locations north of the 43rd parallel usually happens in late July or early August, leaving insufficient time to follow overwintered cash crops with a cover crop or another cash crop. In this scenario, practices that maximize post-harvest residue are one of the most effective ways to protect the soil surface until the following spring planting season.

Overwintered cash crops south of the 43rd parallel are typically harvested in late June or early July. These relatively early harvest dates of overwintered cash crops means that there is sufficient time to raise a warm season cover crop or a short season cash crop following harvest – provided there is sufficient soil moisture available from rainfall or irrigation. In places where winter wheat has long been a primary staple crop, stubble was typically left fallow until the following growing season. This leaves a 3-4 month window for weeds to grow and set seed and it leaves high-cost farmland idle. Cover crops or cash crops could help to reduce late summer and fall weed growth, provide additional residue, and provide additional sources of revenue beyond a single cash crop.

Single-species cover crop trials from South-Central Nebraska have shown that sunflowers, radish, and sorghum-Sudangrass produce the most biomass for common warm season cover crops following winter wheat. Warm season, multi-species cover crops mixes can also be grown as a dual use cover crop/forage crop for late summer and fall livestock grazing. There are a number of options for short season cash crops following an early summer winter cash crop harvest. These include dry beans (varieties that can be straight-cut), soybeans, sunflowers, corn, proso millet, and buckwheat.

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