Producers should consider a number of factors before deciding to terminate hay land in the spring in order to seed an annual crop.
“Traditionally, forage stands have been terminated in the fall by using one of three approaches — tillage only, herbicide application combined with tillage, and herbicide application followed by direct seeding into sod,” said provincial crop specialist Mark Cutts. “The main advantage of fall termination is the ability to establish a good seedbed with tillage, or in the case of direct seeding, allowing the sod to decompose.”
While spring termination of hay land is an option, producers should be aware of a number of factors that will affect its success.
“One factor that must be managed properly is soil moisture,” he said. “In many areas of the province, conservation of spring moisture is essential for crop establishment.”
Utilizing multiple tillage operations to prepare a seedbed will reduce available soil moisture. The preferred method of establishing annual crops in spring-terminated stands is a herbicide application followed by direct seeding into sod.
Producers also need to be aware that spring termination of hay land will delay seeding, said Cutts, adding sufficient plant material must be present for herbicide applications to be effective.
Grasses should be at the three- to four-leaf stage, and legumes need to be actively growing to allow sufficient herbicide uptake to occur. Delay seeding by three to five days after the herbicide application to allow for translocation of the herbicide. Compared to a fall-terminated stand, this process will result in seeding delays of two to three weeks.
Control of the forage species in the hay stand is essential to reduce yield loss due to competition with the growing crop. A high rate of glyphosate, up to 720 grams of active ingredient per acre, can be applied to the hay stand once sufficient growth is present. If regrowth of the forage species occurs after emergence of the annual crop, producers then need to assess the weed spectrum and determine if a suitable in-crop herbicide option exists.
“Establishing good soil-to-seed contact is critical to the success of the seeded crop,” he said. “With sod seeding, the most consistent results have occurred with cereal crops compared to a smaller-seeded crop, such as canola. The larger seed size associated with cereals allows seeds to be placed beneath the thatch layer into soil where good soil-to-seed contact occurs.”
Evaluating the fertility of the soil is important as nutrient levels are commonly deficient on older hay stands and will need to be addressed when seeding an annual crop, said Cutts. He recommends producers collect a soil sample to properly evaluate fertility requirements.
“Seeding annual crops into spring-terminated hay land poses a number of challenges and is a riskier option as compared to seeding into fall-terminated hay stands,” he said. “To manage these risks, producers need to recognize these challenges and adopt the appropriate crop management techniques.”