Title: Impact of sunflower on land productivity in the semiarid steppe of the United States Author
Submitted to: Grain
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 14, 2012
Publication Date: January 21, 2013
Citation: Anderson, R.L. 2013. Impact of sunflower on land productivity in the semiarid steppe of the United States. Grain. 73:416-421. Interpretive Summary: Producers in Ukraine are exploring no-till cropping systems. With the change to a market-driven economy, producers now have freedom to choose their crop rotations. One crop that currently has favorable economics is sunflower; some producers are growing sunflower 3 years in a row. However, research in the United States has shown that sunflower can be damaging to soil health, consequently reducing land productivity. In this paper, we describe a series of experiments that explain how sunflower affects soil factors such as porosity, organic matter levels, and soil water storage. A sequence of sunflower-fallow is especially damaging. We encouraged producers in Ukraine to consider more complex rotations, and provide examples of successful rotations used by U.S. producers that have eliminated the detrimental impact of sunflower on soil health.
Technical Abstract: Sunflower (Helianthus annuus) is widely grown in the steppe region of Ukraine and Russia because of favorable economics. Sunflower is also grown in the steppe of the United States. Sunflower, however, has damaged soil health in the U.S. steppe because of its low after-harvest residue levels, thus reducing land productivity. A winter wheat (Triticum aestivum)-sunflower-fallow (W-S-F) rotation reduced soil organic carbon 17% and soil aggregate stability 36% in 9 years compared with winter wheat-corn (Zea mays)-fallow (W-C-F). Consequently, winter wheat yield declined across time in W-S-F. Furthermore, sunflower yield and after-harvest residue was reduced by disease and insect injury when sunflower was grown once every 2 or 3 years. Because of its impact on soil health, sunflower production in the U.S. has shifted into regions with higher precipitation (> 500 mm per year) so that crops can be grown successfully the year following sunflower. Also, producers grow sunflower in long rotations (5 or 6-year sequences with sunflower grown only once) established with no-till. Rotations include crops that produce high levels of after-harvest residues, such as winter wheat and corn. With these changes, U.S. producers are growing sunflower without damaging soil health and land productivity.