University of Minnesota Extension
http://www.extension.umn.edu

### June 12, 2009 10:00 PM

The challenging spring in Northwest Minnesota has forced many to seed their wheat and barley under less than ideal conditions and into poor seedbeds. Now is the time to evaluate how well your seeding operation went and what the attained stands are. This is important as the decision about inputs further into the season will depend on the yield potential that is left.

Stand counts are simple to do and take just a little extra effort while you are scouting for weeds and/or early season fungal diseases. The easiest time to do a stand count is probably when the crop is in the two- to three-leaf stage since tillers are not visible yet, and counting is easier.

To do a stand count, use one of the following two methods:

1) Count the number of plants in a foot of row at several locations in the field. Take an average and convert to plants per acre using Table 1.
2) Take a hula-hoop, let it fall, and count the number of plants inside the hoop. Repeat this at random several times across the field and calculate an average. Use Table 2 to convert the count to an approximate population per square foot or acre.

Table 1 - Average number of plants per foot of row for different row spacing and plant densities per acre

Table 2 - Adjustment factors to multiply the number of plants inside a hoop and convert the number to number of plants per acre

Widespread wheat fields in Minnesota and North Dakota have small to large areas where wheat plants have either failed to emerge or have emerged but were delayed. These spots are easily visible from the road while traveling in excess of the speed limit.

This is the result of receiving rain after planting but before plants could emerge. Low spots and ditches in fields likely remained saturated for an extended period. Factors contributing to poor stands include soil saturation, soil crusting, and maybe even weak seed. The first two factors (saturation and crusting) are intuitive—the other one (weak seed) perhaps not.

Seedlings rely on energy sources contained within the seed for their support until they can establish sufficient green tissues for photosynthesis. If the soil environment is hostile in some manner (saturated, compacted, crusted), seedling growth is slowed or impaired. Plants may run out of reserves before hard fought emergence is won.

From samples submitted to my lab, affected plant roots and coleoptile tissues are sound, so disease isn’t the problem. I’d be mighty interested to know if this issue is variety dependent. Wouldn’t you?

Char,

Thanks for your question. The short answer is that the issue can be variety specific. There is some evidence in the literature that there are genetic differences in seedling vigor. However, the causes of the observed emergence problems go beyond seedling diseases or genetic differences in vigor. I'll try to address this in my next blog entry.