Sustainable Agriculture Demonstration Grant : Final Report 

Project Information

PROJECT SUMMARY

We are testing the effectiveness of sheep grazing on grass cover crops during fallow periods between strawberry rotations as a method of improving soil health, reducing weed pressure, and increasing strawberry poundage per acre.  

We hope to increase the profitability of our farm by grazing sheep on cover crops between rotations of strawberries.  Sheep, being smaller, will not compact the wet soil around the cover crops the way cattle have in past years, and that if we use strictly grass cover crops, we will be able to reduce weed pressure.  We hope the sheep for meat will be profitable as an enterprise, and that the combination of sheep and a specialty crop will be useful for educational outreach and farm risk management. 

PROJECT DESCRIPTION

We are a pick-your-own strawberry farm in west central Minnesota.  In 2013, we started to expand and now have 15 acres in our rotation.  Each year we plant about 3 acres with new strawberry plants, harvest about eight acres of mature strawberry plants, and have about four acres that are in cover crop, resting before being planted again with strawberries. 

Strawberry fields must be rotated on a regular basis to reduce weed pressure and to minimize the replant diseases called black root rot.  We have our strawberries in the ground a little more than three years.  The first year is the establishment year, and the second and third years are used for production.  At the end of the third picking season (early July), the strawberry plants are plowed under and are planted into a series of cover crops for the end of summer and for the following growing season.  We would like to show that grazing sheep on the cover crops will be a profitable use of the strawberry ground in the fallow years while reducing strawberry plant disease, and improving the soil for our strawberry plants.

We, like all MN farmers, have faced increasingly negative weather events over the past two decades, including drought, extreme rain events, deep winter kill, and powerful winds.  Each weather event cost us thousands of dollars in lost revenue.  About five years ago, we enrolled in classes with Thaddeus McCamant at Central Lakes College to learn how to grow stronger plants that could withstand extreme weather and remain productive.  These classes led us to believe that healthy soil is the key to healthy plants, and that healthy plants can withstand adverse weather conditions.  We have a silt loam soil with a pH above 7.2. In some areas of our strawberry field, the plants occasionally become chlorotic due to the high pH.  Chlorosis is a major problem for strawberry growers in western Minnesota, where the soils are heavier and often have a pH above 7.0.  A high pH is the cause, but other factors like soil compaction, soil health, and organic matter can either aggravate or minimize chlorosis.   

The cattle grazing the covercrops caused compaction in the areas around the water troughs, leading to poor strawberry plant establishment.  While compaction is a problem in all soils, it is worse for us, because soil compaction increases chlorosis.  The cattle grazed selectively, leading to heavy weed pressure in new strawberry beds.  In fall 2018, we sold the cattle and purchased a flock of sheep.  

For our project, we are looking at the feasibility of grazing sheep in the cover crops that are planted between strawberry rotations.  Immediately after plowing a strawberry field down, we are seeding the field to sorghum/sudan.  Sorghum/Sudan is an ideal cover crop because it is a warm season grass that grows extremely fast, and it has shown to be one of the most effective cover crops for reducing replant diseases.  Since sorghum grows so fast, it also crowds out many weeds.  We intend to carefully steward this flock, in order that the sheep will be profitable as a separate enterprise, to balance out any losses we incur on our strawberries.    

Farmers are looking for ways to increase production per acre while minimizing risk due to things like unpredictable weather.  We hope the sheep will improve soil, thus profits, while at the same time being profitable as a side business.

Evaluation:

• Track grazing days and feed cost saving in sheep flock. 
• Track weeding labor hours per field block. 
• Sap Testing: Using Sap tests to target nutrient deficiencies and increase poundage per acre. 
• Soil Testing: Using soil tests to track changes caused by grazing and cover crops in soil nutrient levels, organic content, and pH.
• Track student education and social media metrics on the topics of this SADG. 

RESULTS 2019-2021

Grazing & Feed Cost: 

2019: 150 grazing days with 56 sheep at $0.25/head for maintenance hay ration with the result of $2,100.00 saved in sheep feed cost.

2020: 102 grazing days with 85 ewes at $0.18/head for a ¾ maintenance hay ration with the result of $1,560.00 saved in sheep feed.  

2021: data will be added at year’s end. 

Note that in 2019, there was heavy rainfall, and the cover crop grew rapidly.  The sheep were able to eat their fill, thus saving $0.25/head/day.  In 2020, there was less rain, and sheep consumption averaged  ¾ ration from the field, saving about $0.18/head/day. In 2021 we were in drought conditions, reducing grazing potential.  

Weeding Hours/acre:

Field 1: planted in grass cover crop; grazed by sheep in 2019; baby plants in 2020.

Field 2: grazed by cattle on broadleaf cover crops prior to planting strawberries in 2017; horrid weeds 2019; plowed under after harvest June 2020 and covercrops planted; grazed by sheep through December 2020.

Field 3: grazed by cattle on broadleaf cover crops prior to planting strawberries in 2018.

Field 4: corn & beans prior to planting in strawberries. 

Field 5: Soil irredeemably high in pH; Dan plowed it under in Aug/19; planted rye cover crops 2019 & 2020. Grazed by sheep both summers. 

Field 6: corn & beans control ground

Weeding Hour Comparison of Emergent Fields:

2019 Emergent field; planted into cattle grazed land; broadleaf covercrop: 40 weeding hrs/acre

2020 Emergent field: planted into sheep grazed land; broadleaf and rye covercrop:  26 weeding hrs/acre

2021 Emergent field: planted into sheep grazed land; rye only covercrop: weeding data will be added at year’s end

Poundage Per Acre: Our goal is 9000#/acre, as achieved in 2015 and 2016…

2019 strawberry poundage:  3378#/acre.  This is an all-time low, due to incessant rain during our harvest. 

2020 : 4065#/acre; better, but still a lot of room for improvement. 

2021: 243#/acre; terrible!!! Grateful we had sheep enterprise!!! 

Soil and Sap Testing:

Four sap tests per summer informed our foliar feeding regimen throughout the growing season.

Thorough soil analyses were done on all of our crop blocks in 2019 & 2020.  Strawberry plants start developing chlorosis when the soil pH rises above 7.4, and until recently our pH hovered around 7.5.  We had less chlorosis than expected for our soil pH, probably because we also have high organic matter.  This past year, we measured a soil pH of 7.1, which takes us out of the danger zone.   

Student Education: 

2019: I held five farm events for education of the general public, as well as incorporated what I was doing into my 5th grade science classroom.

2020: Due to Covid, I didn’t do public farm tours, but I took a new position as Middle School Science teacher.  Now, I am able to incorporate agricultural sustainability lessons into all of my classes.  My students pulled the actual soil samples that were sent to the lab this year, and learned how to interpret the data, and why.   I post what I am teaching onto my farm Facebook pages, and my customers seem genuinely interested.   

2021: My Middle School students used MudWatts  to experiment with soil health and graph their results using the MudWatt app.  Students extracted strawberry DNA.  They visited the farm during lambing season, and even watched my husband pull a set of twins out of a ewe.  

• Media engagement 2019-2021: 

1.5K views of my Sustainable Agriculture blog posts

27K views of my Sustainable Agriculture social media posts

July 2020 Senator Collin Peterson toured our farm, listened to our concerns, and his aides called us from Washington DC the following day to address our concerns and offer help. 

Summer 2020 a Pioneer PBS TV crew came to our farm three times to film our operation, and conducted interviews of Dan and I, and the Karen refugees who work for us.  

September 2020 Country Acres Newspaper of Sauk Center published an article “Soil Science for Strawberries” that described the SADG program.  https://issuu.com/starpublications/docs/casept4 pages 8-9

Jan. & June 2021 PBS Postcards production on Brouwer Berries aired: https://www.pbs.org/video/brouwer-berries-farm-bwy3b6/

April 2021 PBS Postcards production on refugee employees at Brouwer Berries aired: https://www.pbs.org/video/karen-immigration-storytelling-hngmqe/

West Central Tribune published this interview June 2021 about our failed crop. https://www.wctrib.com/business/agriculture/7072700-No-U-Pick-at-Brouwer-Berries-as-topsy-turvy-spring-weather-and-now-heat-harm-crop

Farm Family of the Year for Kandiyohi County 2021 Honored at Farmfest Aug.4 and the County Fair on Aug. 12 https://extension.umn.edu/farm-families#kandiyohi-county—brouwer-berries-28550630

The following photos show Thaddeus, our crop advisor in the field with Dan, spreading sheep manure on cover crops, students extracting strawberry DNA, Zoom sheep management class on Flock 54 genetic testing programs, Senator Collin Peterson touring our farm with our daughter, spring planting into previously cover cropped and grazed soil.