On-farm trial identifies better yielding potato varieties under naturally grown practices

A farmer from Michigan’s Upper Peninsula used an NCR SARE Farmer Rancher Grant to compare potato varieties in a replicated trial.

Mike WixtromMike Wixtrom wanted to find out which potato varieties would be best for his new farm in Republic, Mich. This Marquette County farmer ramped up his “naturally grown” potato production to 12 acres this year. Wixtrom is farming on land once owned by his grandfather, who operated a dairy and potato farm. The land changed hands for several years since that time, and fields have been sadly run down by grazing and hay harvest without adequate inputs and rotations.

Wixtrom was able to buy back a part of the farm, including the house and buildings, a few years ago. He has settled on potatoes as a crop with good market potential. Wixtrom hopes to gain organic certification in the future. For now, he is using organic techniques and selling his farm products as naturally grown.

With assistance from the North Central Region Sustainable Agriculture Research and Education (NCR SARE) Farmer Rancher Grant Program and Michigan State University Extension, Wixtrom tested nine potato varieties in 2013. The test consisted of a set of plots, one row by 40 feet, replicated four times. Cultural practices in the plots were identical to the rest of Wixtrom’s fields. Currently without a source of livestock manure, Wixtrom uses purchased organic fertilizers and crop rotation to provide plant nutrients. No irrigation is available yet.

A field day was held on Aug. 17, 2013, to give the public an opportunity to visit the farm and see the SARE-funded variety trial. The plots were harvested on Oct. 9, graded and weighed on Nov. 7. Resulting plot weights are converted to hundred weights (CWT) per acre in the table below.

Variety

Grades A+B+C
(CWT/acre)*

Grade A

Grade B

Grade C

Pickouts

King Harry

79.50

71.6

6.63

1.27

0.18

Elba

57.34

44.29

10.17

2.91

0.18

German Butterball

52.27

8.55

18.42

25.32

0.37

Adirondack Blue

44.20

18.69

19.03

6.54

0.46

Purple Sun

44.01

34.12

8.44

1.45

0.00

Desiree

40.29

18.24

15.34

6.72

0.46

Reba

39.20

24.14

11.53

3.54

0.54

Canela Russet

33.31

8.53

16.06

8.71

1.45

Green Mountain

33.04

9.26

13.89

9.89

1.00

*LSD = 13.1 (P=0.05)

Planting Harvesting Grading

Statistically, there were real differences among the varieties. When grades A, B and C were combined (column two in the table above), the coefficient of variation was 19.09 percent and the least significant difference was 13.1. King Harry, Elba and German Butterball were the best performing varieties in the trial.

Keep in mind that this trial is only an indicator for one year and one location. The results are most meaningful on the Wixtrom farm since they reflect those specific growing conditions. However, for farms with similar conditions, the comparisons are of interest. The low yields are a result of low soil fertility. However, Wixtrom works hard to develop good paying markets for his potatoes and receives excellent prices, both retail and wholesale. This project is a great example of the value of on-farm crop trials to help producers identify best management practices for their own, specific farming conditions.

A more detailed report will be available on the NCR SARE website soon. Visit the NCR SARE Farmer Rancher Grant Program website for more information on the Farmer Rancher Grant Program. Farmer Rancher Grant Program proposals are due in mid-November for projects to be done the following year.

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