On-Farm Research Investigates New Cover Crop Options
Posted: September 21, 2009
Ron Hoover, Penn State's On-Farm Research Coordinator, plants the cover crop demonstration plots in Franklin County. (Photo by Jonathan Rotz)
Cover crops are one of the keys to success when it comes to improving soil quality and reducing the impact of agriculture on the environment. Many farmers are already using cereal rye but wonder if there are other species that should be tried. The questions being raised include: are there opportunities to include a legume, possibly as part of a mixture, to produce more nitrogen for succeeding crops? How late can I plant some of these species? What can be planted late and still provide soil protection? Is there such thing as planting too early (after small grain harvest)? Is there a fit for a non—winter hardy species (oats) in my rotation? What species are better as nutrient scavengers?
With these questions in mind, a team of Penn State Crop Management Extension Group county educators and state specialists planned a network of cover crop demonstration plots in counties across the Commonwealth. Ron Hoover, Penn State’s On—Farm Research Coordinator, and county agronomy extension educators planted the plots on two dates at each site, one in early September and one in late September. The demonstration sites are in the following counties (towns): Jefferson (Reynoldsville), Westmoreland (Crabtree), Northumberland (Milton), Dauphin (Gratz), Lancaster (Manheim), Franklin (Chambersburg), York (Loganville), Berks (Fleetwood), Northampton (Pen Argyl), Montgomery (Royersford), and Bradford (Canton).
Twelve different species of cover crops were planted either alone or in mixtures. The cover crops will be monitored for fall growth vigor, winter hardiness, early spring vigor, aboveground biomass prior to destruction in the spring, and nutrient content on some entries. Phacelia, sunhemp, and persian clover are three cover crops planted in the demonstration plots that are new to Penn State’s research program.
Phacelia (Phacelia tanacetifolia) is an annual broadleaf that is a native of semi—arid regions in the U.S. and Mexico. It has been used in Europe and is now being re—introduced as a cover crop in the U.S. Phacelia is not a legume, but is plant with beautiful purple flowers, which attract insects. Phacelia is a long—day plant, flowering only when days are longer than 13 hours (May—Sept). It germinates at temperatures above 37F and winterkills at 18F. It produces large amounts of biomass, but little of this residue will likely remain in the spring because phacelia residue degrades quickly.
Sunnhemp (Crotelaria juncea) is a tropical legume originally from India. It is known for its rapid growth: when grown as a summer annual, sunhemp can produce over 5,000 pounds of biomass and 100 pounds of nitrogen per acre. It can produce this amount within 60 to 90 days, so it has the potential to build organic matter levels and sequester carbon in the soil. It is known to suppress nematodes. It is a short—day plant, producing yellow flowers.
Persian clover (Trifolium resupinatum) is a winter annual legume that has been evaluated as a forage in the southern U.S. It is adapted to poorly drained soils, but is sensitive to weed competition. As a forage, it can be grazed or harvested although bloat can be a problem. Persian clover dies in late spring/early summer after it has produced small purplish/pink flowers and seed. The idea is that it will reseed itself. It is not likely to survive if temperatures decrease below 10F.
Penn State Extension Educators and Specialists will be present at field days and cover crop walks held at these demonstration plots and others around the state this fall.