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Checking For Adequate Stands Of Small Grains

Plantings of small grains are ahead of average and have emerged in many fields. Though somewhat on the dry side, conditions have generally been good for small grain emergence. Pounding rains that cause crusting and excess moisture that causes waterlogging have not be deterrents this year. Furthermore, the warm soil temperatures this past week have hastened emergence. After planting, barley requires about 176 GDDs before emergence occurs and 245 GDDs before reaching the first leaf stage. Factors such as depth of planting, soil blackness and soil temperature can of course influence the actual GDDs needed before emergence. Wheat takes slightly more GDDs (180) before it emerges and reaches the first leaf stage (252 GDDs). Perhaps the biggest concern for small grain establishment this year will be the dryness of the soil. After emergence, evaluating plant stands is essential to gauge crop productivity and to determine if remedial action is needed as a result of less than desirable emergence.
Quantifying plant establishment also will give you a good idea of the effectiveness of your planting equipment and process. Though a cursory look from the end of a field will give you an idea if you have stand problems, to get an accurate assessment of plant stands will require some actual counting. Counting plants is easier when plants have just emerged and there are no tillers to confuse the process. Four or five randomly selected samples within a field using a three foot length of row or a 1 square yard quadrant as a sample size should be sufficient to estimate plant numbers. Counting multiple sample areas will also give you a feel for any variability within the field. If there are problems areas that might need to be replanted, handle those separately.
The optimum range in plant populations are summarized in Table 1. For spring planted small grains use the following guidelines to determine if you should replant: 1- If the reduced stand is uniform (i.e. no big gaps in the field), keep stands of 15 plants per square foot, 2- If skips are large (3 to 6 ft), or gaps are 4 to 6 ft in diameter and the stand is 18 plants per square foot or less, replant if moisture is adequate.
Slightly more than 40% of the winter wheat crop was rate fair to poor in the last NASS report. The lack of snow this past winter took a toll on our winter wheat. In one of my research locations where winter wheat was planted into a legume stubble (not recommended), most of the varieties that were rated as having fair winter hardiness did not make it through the winter.
Even with the paucity of snowfall in general, planting into erect stubble seemed to have helped the winter wheat survive this past year. Winter wheat has the ability to fill in gaps better than spring planted small grains. If stands are reduced uniformly across the field, stands of 17 plants/ft2 can still produce near maximum grain yields. Even stands as low as 11 plants/ft2 can still produce a 40 bu/A.
For fields with small patches of poor stands of winter wheat, the best option is probably to leave the field and do a good job of weed control. For fields with very large patches with few or no plants, planting something to reduce weed growth and soil erosion is recommended. Some farmers have reported good results from planting spring wheat to fill in such gaps. Nevertheless, spring wheat matures later than winter wheat so harvest can be problematic (in fact you should probably plan on harvesting them on separate dates). Furthermore, mixing wheat classes can cause problems at the elevator.
Planting winter wheat into large gaps can also be an option. Winter wheat planted in the spring will not vernalize so it will not produce a head (or very few heads depending on the variety planted), but will provide ground cover until harvest.
Table 1. Plant stands at harvest for optimum productivity of different small grain crops.
CropPlants per acrePlants per sq. ft
Winter wheat0.90-1.0021-23
Spring wheat1.30-1.4030-32


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