NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665
April 6, 2000
Choosing the correct planting rate to establish stands that ensure optimum yields is critical for hard red spring wheat producers. North Dakota State University research shows that in the high-yield environment (45 to 60 bushels per acre) of northeastern North Dakota, planting to achieve plant populations of 34 plants per square foot produces optimum yields.
Bryan Hanson, agronomist at the NDSU Langdon Research Extension Center, says that while 34 plants per square foot was found to be optimum, there was really no significant difference in a range between 26 and 41 established plants per square foot. This suggests that growers need to establish stands of at least 26 plants per square foot, but no significant yield advantage results from stands heavier than 34 plants per square foot (1.48 million plants per acre).
The planting rate study, which involved 16 research locations across northeastern North Dakota, compared planting at rates of 0.5, 1.0, 1.5 and 2.0 million seeds per acre. The lowest planting rate yielded significantly less than all other rates. The 2.0 million seeds per acre rate yielded significantly higher than the 1.0 million seeds rate, but there was not a significant difference between the 1.5 and 2.0 million seeds per acre.
The producer's goal when selecting a planting rate is to establish a desired plant stand. The percentage of the planted seed that emerges can have a dramatic effect on final plant stands, and large differences in emergence can occur from field to field, making selecting the best planting rate difficult, Hanson says. The varying factors involved, such as depth of seeding, soil crusting, dry seedbeds and herbicide injury, make predicting percent emergence virtually impossible.
"Seedbed conditions at planting will dictate the planting rate that a producer chooses. A favorable seedbed may allow producers to reduce planting rates and still obtain target plant populations," says Hanson.
Established plant populations below 26 plants per acre may force growers to consider replanting, he says. Stands of 15 plants per acre, compared to more optimum stands of over 26 plants, could result in a yield loss of about 9 percent, or 4.7 bushels per acre from a yield potential of 52 bushels per acre.
Even so, potential yield loss from late planting, in addition to seed, tillage and labor expense, may easily raise replanting costs to more than the potential yield loss. Weed control costs may be higher in low plant stands, however.
"Producers must carefully consider these factors before replanting," Hanson says.
Source: Bryan Hanson (701) 256-2582
Editor: Gary Moran (701) 231-7865