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seeding oat for weed control

Pest Management

Affordable biomass. With good growing conditions and sound management (including timely planting), expect 2,000 to 4,000 pounds of dry matter per acre from late-summer/early fall-seeded oats and up to 8,000 pounds per acre from spring stands.


Allelopathic (naturally occurring herbicidal) compounds in oat roots and residue can hinder weed growth for a few weeks. These compounds also can slow germination or root growth of some subsequent crops, such as lettuce, cress, timothy, rice, wheat and peas. Minimize this effect by waiting three weeks after oat killing before seeding a susceptible crop, or by following with an alternate crop. Rotary hoeing or other pre-emerge mechanical weeding of solo-seeded oats can improve annual broadleaf control.

The climbing growth habit of some viny legumes such as vetch can contribute to lodging and make oat grain harvest difficult. If you’re growing the legume for seed, the oats can serve as a natural trellis that eases combining.

Other Options
There are many low-cost, regionally adapted and widely available oat varieties, so you have hay, straw, forage or grain options. Select for cultural and local considerations that best fit your intended uses. Day-length, stalk height, resistance to disease, dry matter yield, grain test weight and other traits may be important considerations. In the Deep South, fast-growing black oats (Avena strigosa) look promising as a weed-suppressive cover for soybeans. See Up-and-Coming Cover Crops.

If seeding oats as a fall nurse crop for a legume, a low rate (1 to 2 bushels per acre) works well.

In another Alberta study, allowing wild oat to grow to the two-leaf stage and then destroying it with either tillage or herbicides prior to seeding rapeseed resulted in good control with little or no crop yield loss (Darwent and Smith, 1985). Waiting until wild oat was in the three- to four-leaf stage resulted in good control, but some yield loss.

Seeding should not be delayed too long, or yield loss will result.

Research Results

A four year study was conducted at Brandon using 6 crop rotations with varying seeding dates and number of years of wild oat herbicides as outlined below

A Manitoba study on oat found that wild oat populations were reduced drastically by delaying seeding from early May to late May, without sacrificing crop yield (Fig. 1; Schoofs et al., 2002).

wo herb =years of targeted wild oat herbicide applications
s wht =spring wheat, w wht =winter wheat, millet =proso millet, millet g.feed = "German millet ",
s canola =spring canola, d canola =fall dormant seeded canola, fall rye =fall rye grown for green feed, std =standard