Post Emergent Rolling of Pulse Crops



EDMONTON - May 15/18 - SNS -- Farmers should roll pea and lentil fields after seeding to prepare the land for harvest in the fall, says Neil Whatley, crop specialist with Alberta Agriculture and Forestry.

It makes the field more level by pushing stones into the soil, breaking dirt lumps and smoothing out soil ridges.

"A level field surface improves the capture of low hanging pods, helps prevent earth tag in the seed sample, aids in harvesting lodged crops, prevents cutter bar and internal combine damage, and allows faster harvesting speed."

Research results and grower experience have provided several rolling guidelines. Rolling can be done either prior to crop emergence or post-emergently. The most appropriate time to roll pulse fields is shortly after seeding.

"However, it is not always possible to roll right after seeding due to delays from other spring seeding work or rainfall," explains Whatley. "Due to a risk of soil erosion, growers may also wish to delay rolling if the soil is very dry, is of a sandy texture, or the surface lacks residue from last year's crop."

Lentil and pea fields can be safely rolled up to the 5 to 7 node (3 to 5 true leaf) stage.

Whatley adds that since a seedling's vascular system is tightly filled with water in the early morning, its stem and branches are susceptible to breakage when rolled. "This breakage can be prevented by waiting to roll later in the morning, or in the afternoon, when plants are slightly wilted. However, experience has shown that rolling sets seedlings back when air temperatures are high, around 25 to 30 C. Given the thicker and less flexible nature of a pea seedling's stem and branching structure, be extra cautious to not roll field pea plants too early in the morning when they are stiff and turgid."

Rolling later than the appropriate node stage breaks the main stem or side-branches allowing disease entry, which reduces yield. Rolling when the plants are damp can spread foliar diseases throughout the field. Rolling when the soil is excessively wet is counterproductive.

To prevent double rolling headlands, some growers roll fields round and round, however, Whatley says some areas will be left unrolled. "If rolling fields back and forth, operators should slow down when making turns at the headlands, and use caution to not apply tractor brakes when turning."

"If the seedlings experience an additional stressor like frost or an herbicide application, wait a minimum of 3 days to roll," adds Whatley. "If a decision must be made whether to spray for weeds or roll, it is advisable to spray weeds because early weed control is of paramount importance for pea and lentil crops that compete poorly with weeds."