In the last decade, soybean acres have increased by 707,000 acres in NW MN. Spring wheat yields have risen from 47.8 in 2011 to 68.5 bu/acre in 2017, while reported soybean yields are relatively flat ranging from 35.7 in 2007 and 34.1 bu/acre in 2017. A 40 bu/acre soybean crop will require 33.6 # P205 and 52 # K20. With increased wheat yields and the potential increase in soybeans yields, P and K may be a limiting factor for plant growth development and yield in a wheat -soybean crop rotation.

A 2017 AGVISE soil survey in northwest MN indicated 67% had Phosphorus (P) levels of < 10 ppm and 39% had Potassium (K) levels < 150 ppm. This soil survey suggests over 2/3 of the soil samples for P and over 1/3 of samples for K may have fertility levels that limit the production of high yield soybean and wheat. The objective of this project is to utilize a combination of small plot replicated research and large on-farm trials to determine if P and K levels are limiting soybean and wheat yields. Field trials will be conducted over four consecutive years in a wheat-soybean cropping sequence in northwest MN. The 2021 growing season will be year 3 of 4 for this project.

GOAL : Determine optimum levels for Phosphorus (P) and Potassium (K) in a high yield, 4-year wheat-soybean rotation in northwest MN.

OBJECTIVE :
1) Establish long term crop rotation trials (4 year minimum) in wheat and soybeans using a combination of small plot replicated research trials and on-farm research sites
2) Conduct small plot replicated research to determine the influence of elevated levels of P and K on wheat and soybean growth, development, and yield
3) Partner with the MN Wheat On-Farm Research Network (OFRN) to evaluate enhanced P and K fertility utilizing large on-farm research trial methodologies to determine if current P and K recommendations provide adequate fertility in a high yield wheat-soybean crop rotation

The Minnesota Wheat OFRN has an established track record of conducting on-farm research. This project will partner with the MN Wheat OFRN to select farmer cooperators, assistance in site selection, coordination and collection of research results and will assist with data analysis and summaries.

Minnesota Wheat has a tradition of disseminating research results in various methods of communication. Annual project results will be published in the Minnesota Wheat Research Review book (1,200 copies) and in the bi-monthly magazine publication titled: Prairie Grains (18,000 copies printed and mailed). This magazine reaches the spring wheat growing region of MN, MT, ND, and SD. Project presentations will be given at the annual Prairie Grains Conference, organized in part by Minnesota Wheat, Minnesota Soybean, and Minnesota Barley. The Prairie Grains conference is a two-day conference held annually in December at the Alerus Center in Grand Forks, ND. The project results will be presented during the annual half-day OFRN Research Summit (6th annual in 2018 had over 100 attendees). Farmers and interested stakeholders attend this research summit to learn and offer opinions on research priorities to help improve crop production and the “bottom lines” for their operations.
Research results will be printed in the annual On-Farm Research Report and distributed to attendees at the Prairie Grains Conference, and at the Small Grains, Wheat, Soybean and Corn Update Meetings held at 8 locations each January. On average, 50 people/location attend these meetings held in Fergus Falls, Moorhead, Crookston, Ada, Hallock, Argyle, Roseau, and St. Hilaire. Research results be will be presented at the Minnesota Soybean Growers Association regional and county meetings. Project results will be summarized for on-line publication in Minneline (MN Soybean), and U of MN Crops News Blog, and in the smallgrains.org research database (MN Wheat).

Update:

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Update:

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Update:
Goal: To determine optimum levels of Phosphorus (P) and Potassium (K) in a high yield, long term (4 year) cropping sequence of spring wheat and soybeans in northwest Minnesota.

Objectives:

1.) Establish long term crop rotation trials (4 year minimum) in wheat and soybeans using a combination of small plot replicated research trials and on-farm research sites
2.) Conduct small plot replicated research to determine the influence of elevated levels of P and K on wheat and soybean growth, development, and yield
3.) Partner with the MN Wheat On-Farm Research Network (OFRN) to evaluate enhanced P and K fertility utilizing large on-farm research trial methodologies to determine if current P and K recommendations provide adequate fertility in a high yield wheat-soybean crop rotation

1.) Achievements:
November 2022
- Data were analyzed and published in our annual On-farm Research Report. See attachment.

December 2022
- Results were presented during our annual On-farm Research Summit at the Prairie Grains Conference in Grand Forks, ND, on December 7th
- On-farm Research Reports were distributed to growers at the Summit and during the Prairie Grains Conference
- There were about 115 growers attending the Summit this year, and over 700+ attendees at the Prairie Grains conference in total.

January 2022
- Condensed results presented to 229 attendees during the Small Grains Updates meetings in Dilworth, Crookston, Ada, Lancaster, Roseau, and St. Hilaire, MN.
- Annual On-farm Research Reports were distributed to all attendees



2.) Challenges:
- No challenges this quarter. Weather was good for meeting attendance for a change.

3.) Publications or Symposium
NA
4.) Tech Transfer:

- See attached On-farm Research Report booklet distributed to growers

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Update:

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View uploaded report 2

Many farmers in northwestern MN are still only fertilizing enough P and K for a 30 bu yield goal, when in fact the yield potential for the region may be much higher. This research will help benefit soybean growers in northwestern MN to determine if and when then need to be fertilizing more P and K to boost their soybean yields. Many farmers also fertilize two year’s worth of P and K fertilizer (for both the wheat and soybeans) during the wheat year, and this research seeks to determine if the wheat is consuming more P and K than was originally thought, which would mean less P and K would be available for the following soybean crop than was intended.