NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665

May 13, 1999

Wet Conditions Require Patience

Demonstrating some patience now will be a key if producers want to avoid potential problems later on in the growing season. Allowing the soil to dry sufficiently before field work will result in more favorable seedbed conditions at planting and help to maximize plant stands and final yields, says an agronomist at North Dakota State University.

"Tillage of wet soils for seedbed preparation can result in excessive clod formation, poor seed-soil contact, an uneven and dried-out seedbed, poor mixing and incorporation of chemicals, uneven and erratic seedling emergence, and reduced plant stands," says Michael Peel, an agronomist with the NDSU Extension Service in Fargo. "Don't be in a big hurry to work wet fields. Waiting one or two additional days usually will not measurably lengthen the growing season, but greatly aid in obtaining a good seedbed for planting and maximizing plant stands."

When planting in compacted wet conditions, the seed is put in an anaerobic environment, Peel explains. When seed germinates in an anaerobic environment, the lack of oxygen generally results in the death of the germ. Seeds that do survive will be weak, and the wet soil conditions may be more favorable for the development of soil-borne diseases that otherwise may not be a problem.

"Germination of wheat or barley in compacted conditions will hinder coleoptilar growth, preventing shoot development and soil penetration of the radicle, retarding root development," Peel says.

In addition, any crusting that occurs will prevent the coleoptile of a small grain plant from emerging, thereby resulting in seedling loss and erratic and reduced stands. Peel says uneven crop stands typically yield lower than uniform stands due to direct competition of plants at different stages of growth growing next to one another.

Effects of Late Planting

• In North Dakota planting small grains after May 15 typically results in a 0.5- to 1.5-percent reduction in yield per day, Peel says. The reduced yield is a result of fewer tillers and smaller heads.
• Yield potential in small grains is a function of three components: head number, kernel number per head and the weight of each kernel. As any one of these components is increased or decreased, yield changes accordingly. Heads produced per unit area is directly related to seeding rate, or crop stand, and tillering during early vegetative development.
• Yield reduction due to late planting is a result of longer days and the increased probability for high, potentially detrimental temperatures during the three- to six-leaf stages. Yield potential (head number and kernel number) is determined during this period. The long days and hot temperatures during early vegetative development results in fewer heads per plant, fewer spikelets per head and a lower yield potential.
• Late planting generally results in higher grain protein. While high protein is a plus in wheat, high-protein barley may not make malt quality. Producers intending to raise barley should plant it first and make sure total nitrogen does not exceed their yield goal.

Late-Planting Recommendations:

1. The seeding rate of small grains should be increased by 5 to 10 percent for every 10 days seeding is delayed beyond May 15. Use 1.25 million plants per acre as the base from which to increase seed rates.
2. Avoid planting in wet, heavily compacted soils.
3. Plant barley before wheat when achieving malting barley is an objective, and use a reasonable yield goal for determining fertilizer rates. Nitrogen recommendations for malting barley are 1.5 pounds/acre for every bushel of expected yield, and 2.5 pounds/acre for every bushel of wheat.

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Source: Michael Peel (701) 231-8037

Editor: Dean Hulse (701) 231-6136