Abstract:
In Lyon County, Kansas, there were 12,140 hectares (approximately 30,000 acres) of old fields (abandoned croplands). To reduce the 80 to 85 years of secondary succession required to establish tall grass prairie in old fields there are certain recommended mechanical methods of seeding old fields. These mechanical methods have disadvantages, including: erosion, phytotoxic effects from grain sorghum, and competition from the seed bank. To overcome the problems of the mechanical methods, this research was done to determine if a successful stand of desirable grasses including big bluestem, little bluestem, indian grass, switchgrass, and sideoats gramma could be established by spraying old fields with a herbicide then seeding directly into the dead weeds and litter. The method involved spraying the old fields with 1.75 liters "Roundup", 0.56 kilograms 2,4D, and 187.05 liters water carrier per hectare (24 ounces "Roundup", 8 ounces 2,4-D, and 20 gallons water per acre). The study areas were then seeded with the grass mixture at a rate of 8.52 kilograms per hectare (7.60 pounds per acre) at Study Area A (Whitney) and 11.22 kilograms per hectare (10.0 pounds per acre) at Study Area B (Senn) of pure live seed (PLS). At the end of the second growing season, the seedlings were counted. The results were: 1.87 seedlings per 929 square centimeters (one square foot) at Study Area A (Whitney); and 1.34 seedlings per 929 square centimeters (one square foot) at Study Area B (Senn). This rated a good (the highest rating) according to the standards of the Great Plains Agricultural Council (1966). This method is successful as the results show. The planted species were not only successful, but they set seed during the second growing season. The only unwanted perennial grass remaining was smooth brome, which can be reduced in density by using an earlier spraying date prior to seeding or by post-seeding burning. Finally, this method should be a recommended alternative to the mechanical methods of establishing tall grass prairie in old fields.
