Grazing Management Practices to Enhance Soil Health in the Northern Great Plains

Progress report for LNC19-426

Project Type: Research and Education
Funds awarded in 2019: $198,168.00
Projected End Date: 12/31/2022
Grant Recipient: North Dakota State University
Region: North Central
State: North Dakota
Project Coordinator:
Miranda Meehan
North Dakota State University
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Project Information

Summary:

Cover crops have gained popularity as a practice implemented by producers in North Dakota to improve soil health, increase soil nutrients and soil microbial populations, reduce variability in crop yields, increase crop yields, reduce soil erosion, and increase forage options for livestock. Despite the ecological benefits of incorporating cover crops into a system, the economic benefits may not be realized if livestock are not incorporated into the system. In recent years, producers have expressed an increased interest in integrated crop livestock systems (ICLS) due to their ecological and economical returns. Livestock management decisions, such as stocking rate, utilization and stock density have the potential to impact the environmental and economic sustainability of ICLSs. There is a limited amount of information to support producers in the Northern Great Plains and other semi-arid regions in making these important management decisions. Extension professionals receive numerous inquiries from producers regarding grazing management of cover crops: the most common being related to stocking rate, stock density, and residue management. This producer lead demonstration project will provide insight to aid in the development of best management practices for managing grazing livestock in ICLSs to enhance soil health (physical, chemical and biological properties), livestock production, crop production and economic sustainability. The objective of this project is to identify the impacts of livestock grazing management on the environmental and economic sustainability of an ICLS. Specifically, the influence of stock density and forage utilization of grazing livestock on 1) soil physical,  chemical and biological properties, 2 ) crop production, 3) livestock production and 4) economics. To evaluate the effects of stock density, an annual forage crop will be subjected to the following grazing density treatments:  1) moderate and 2) high.  Additionally, two forage utilization rates will be evaluated 1) 50% and 2) 75%. A non-grazed area will serve as the control.  Project results will be disseminated through cafe talks, workshops, tours, bulletins, news articles, videos, and social media. This producer lead demonstration project will provide insight to aid in the development of best management practices for managing grazing livestock in ICLSs to enhance soil health (physical, chemical and biological properties), livestock production, crop production and economic sustainability.

Project Objectives:

The objective of this project is to identify the impacts of livestock grazing management on the environmental and economic sustainability of an ICLS. Specifically, the influence of stock density and forage utilization of grazing livestock on 1) soil physical and chemical properties, 2 ) crop production, 3) livestock production and 4) economics. This project will provide valuable information on the effects of different grazing management strategies in ICLSs, assisting producers in making management decisions. Project results will be disseminated through cafe talks, workshops, tours, bulletins, news articles, videos, and social media.

Introduction:

Cover crops have gained popularity as a practice implemented by producers across the United States. According to the USDA Census of Agriculture 15.4 million acres were planted to cover crops in 2017, up 50% from the 10.3 million acres in 2012 (USDA, 2019; USDA, 2014). North Dakota is no exception to this trend with producers incorporating cover crops to improve soil health and increase crop production (USDA, 2019; CTIC, 2017). Despite the ecological benefits of incorporating cover crops into a system, the economic benefits may not be realized if livestock are not incorporated into the system (Costa et al., 2014; Franzluebber and Stuedemann, 2015).

The benefits of integrated crop and livestock systems (ICLSs) include enhanced nutrient cycling as well as reduced inputs and livestock feeding costs. The majority of research evaluating ICLSs has been conducted in regions characterized by humid climates. Research on the ecological impacts of ICLSs in semi-arid ecosystems, such as the Northern Great Plains is limited (Faust et al., 2018).

Livestock management decisions, such as stocking rates, stock density and utilization have the potential to impact the environmental and economic sustainability of ICLSs. Limited information is available to producers in the Northern Great Plains to help make these management decisions. This producer-led demonstration project will aid in the development of best management practices for managing grazing livestock in ICLSs to enhance soil health, livestock production, crop production and economic sustainability.

Cooperators

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Research

Hypothesis:

Stock density and forage utilization of grazing livestock will increase the environmental and economic sustainability of annual crop systems as a result of 1) enhanced soil physical, chemical and biological properties, 2) increased crop production, 3) increased livestock production and 4) reduced financial inputs.

Materials and methods:

A three-year ICLS project was initiated during the spring of 2020. NDSU Extension partnered with producers to establish six demonstration sites located in central North Dakota, along with a host site on the main campus of NDSU. An annual forage crop was subjected to two grazing density treatments: 1) moderate and 2) high. Additionally, two forage utilization rates were evaluated: 1) 50% and 2) 75%. A non-grazed treatment served as the control. Treatments will be imposed for two years, followed by a cash crop.

Each location was developed to test grazing density treatments in a split-plot design. Three producers demonstrated the high stock density at two utilization rates (50% and 75%), while three producers demonstrated the moderate stock density at the same two utilization rates. The Fargo location provided a study of all treatments and utilization rates.

Forage Establishment

The annual forage crop planted by mid-June of 2020 and 2021 included and will include oats, sorghum sudangrass, foxtail millet, sunflower, radish, kale, turnip, flax and forage pea seed seeded at a rate of 18, 3, 2, 1.5, 1, 0.75, 0.75, 2 and 10 lbs/ac, respectively. Following two years of an annual forage crop, the planned cash crop will be corn planted in the spring of 2022.

Livestock and Grazing Management

Cattle were randomly assigned to grazing density treatments and carrying capacities were determined based on available forage production and estimated utilization. Stocking rates were determined by dividing the available forage by anticipated dry matter intake per day, then dividing by 30 days of planned grazing to predict the number of cows per plot. The available forage for 50% and 75% utilization treatments was calculated at 35% and 50% of the total forage produced, respectively (Meehan et al., 2018). The estimated dry matter intake was based on recommendations in the Beef Cattle Handbook (National Research Council, 2016). The moderate stock density was based on the recommended stocking rate for a 30 day period. The high stock density was set at double the moderate stock density and the grazing period reduced so as to ensure the treatment was not overgrazed. During 2020, turnout dates ranged from late August to early October.

Electric poly-wire and temporary posts were utilized as portable cross-fence to limit-graze livestock and maintain grazing efficiency. Each treatment was divided into four sections. Windbreak shelters were available for use and continued access to water was provided.

Soil Sampling

Soil samples were collected to characterize physical, chemical and biological properties. Soil physical properties included bulk density, infiltration and soil aggregate stability collected pre- and post-treatment. Six sub-samples were collected from a similar soil series within each treatment prior to seeding of annual forage crop. Samples were also collected from a nearby location that was managed as part of a traditional cash crop system. Soil chemical properties included soil nutrients, pH and organic matter collected annually with assessment of nutrient distribution occurring pre- and post-treatment only. Sub-samples for nutrient distribution were collected from each 1 acre sub-plot, whereas once yearly levels were extracted from a similar soil series within each treatment. Above ground residue was gently removed at each sampling site prior to conducting the sampling technique.

A soil core sampler with hammer attachment was used to measure bulk density at a depth of 0-6 inches. In calculating bulk density, the weight of the oven-dried soil was divided by the volume of the ring to determine lb/ft3.

Soil infiltration was determined by utilizing the Cornell Sprinkle Infiltrometer system (van Es and Shindelbeck, 2003). It consists of a portable rainfall simulator that is placed onto a single 9.5 inch inner diameter infiltration ring and allows for application of a simulated rainfall event. Field-saturated infiltrability reflects the steady-state infiltration capacity of the soil, after wet-up. It is based on the data collected at the end of the measurement period, or whenever steady-state conditions occur. Since the apparatus has a single ring, conversion factors from Reynolds and Elrick (1990) are needed to account for the three-dimensional flow at the bottom of the ring.

Soil aggregate stability samples were collected with a tiling spade to a depth of 0-6 inches. A manual wet sieving method by Six et al. (1998) was used to develop an automated method for assessing aggregate stability. Due to variation in soil across locations, the sand correction procedure by Mikha and Rice (2004) was applied to each sample to remove the sand fraction from the water stable aggregates total.

Soil nitrate nitrogen (NO3-N), carbon (C), phosphorus (P), potassium, pH, organic matter (OM), sulfate-sulfur (SO4-S), zinc and copper (Cu) were determined from samples collected at 0-6 and 6-12 inches with a 0.7 inch diameter soil probe. Soil nitrates (Vendrell and Zupancic, 2008) were measured using the Brinkmann PC910 Colorimeter. This colorimeter was also used to determine levels of P after applying the Olsen Test (Nathan and Gelderman, 2015). Potassium was measured using an atomic absorption spectrophotometer. Zinc and copper were extracted with diethylene triamine penta acetic acid and also measured with an atomic absorption spectrophotometer (Nathan and Gelderman, 2015). Recommended chemical soil test procedures for the North Central Region (Nathan and Gelderman, 2015) were used to analyze C, pH, OM and SO4-S.

 

Forage Production and Utilization

Forage production and utilization of the annual crop was estimated by clipping six 59-inch diameter hoops per experimental treatment. Clipping for peak biomass production occurred during the week prior to grazing and turnout dates ranged from late August to early October. Clipping to determine forage utilization occurred upon removal of cattle from the grazing treatments.

Livestock Performance

Beef cattle were stratified by a 2-day body weight and body condition score at the site in Fargo pre- and post-treatment, whereas cattle at the demonstration sites were scored for their body condition only. A visual scoring system developed by Wagner et al. (1988) was used to assess body condition.

Data Analysis

The demonstrations will be set-up utilizing a randomized split-plot design to evaluate the different stock densities at each location.  Data analysis will be conducted using SAS version 9.4.  Data will be analyzed to assess changes in soil physical properties, soil chemistry and soil biology, forage production, crop production and livestock production.

Economic Analysis

The economic analysis would evaluate the cost and/or revenue advantages of the grazing management practices being evaluated against a baseline system to determine if these strategies pay off based upon livestock and/or crop production advantages. The analysis will also evaluate the circumstances that make the ICLSs being demonstrated profitable or cost effective for producers. This analysis would be based upon historical and projected market prices and production costs for the systems.

Outreach Activities

NDSU Extension will partner with producers to establish several demonstration sites.  Producer involvement will provide a real world perspective of the effects grazing management practices have on ICLSs. The NDSU Central Grasslands Research Extension Center and the NDSU Main Station will also host  sites along with six livestock producers who practice ICLSs.  A series of café talks, workshops and tours will provide opportunities to disseminate results to producers, landowners, local organizations and other stakeholders during years one and two of the project. This outreach will provide stakeholders an opportunity to see the demonstrations in action and have discussions with our partner producers during the project. Other outreach efforts include, but are not limited to, journal articles, extension publications, bulletins, news articles, videos and social media. After project completion, two one-day workshops will be hosted around North Dakota by the project team and partners to comprehensively share what was learned during the on-farm demonstrations. This will allow an opportunity for all the producer partners to gather together and learn from one another as well. These workshops will be open to all local stakeholders as well as those throughout the Northern Great Plains.

Research results and discussion:

Year One

Growing season conditions (Table 1) and field preparation appeared to impact germination of annual forage species and production (Table 2). Stocking rates were adjusted for locations with a significant amount of weed competition as forage utilization was likely reduced. It was also noted that seeding depth impacted germination of brassica species. Any location that seeded the annual forage crop to a depth greater than ¾ inch experienced little to no germination of brassicas.

 

 

Month

 

Location

Rainfall (inches)

May

June

July

August

September

October

Seasonal Total

Fargo1

Total

1.5

2.6

5.3

4.8

0.9

0.9

16.0

Normal Total

2.8

3.9

2.8

2.6

2.6

2.2

16.9

Jamestown1

Total

2.2

0.4

3.5

2.4

0.2

0.4

9.1

Normal Total

2.7

3.5

3.3

2.1

2.3

1.7

15.6

McKenzie1

Total

.7

.9

3.5

0.7

0.5

0.5

6.8

Normal Total

2.4

3.2

2.9

2.3

1.6

1.3

13.7

Napoleon2

Total

2.0

1.5

2.8

2.0

0.7

0.5

9.5

Normal Total

2.8

3.5

3.0

2.2

1.7

1.6

14.8

Lehr1

Total

1.7

1.6

3.1

2.9

0.7

0.2

10.2

Normal Total

2.6

3.0

2.7

2.0

1.3

1.6

13.2

McClusky2

Total

1.0

2.0

2.4

3.8

0.2

0.4

9.8

Normal Total

2.4

3.2

2.6

2.1

1.6

1.4

13.3

Tappen1

Total

1.5

2.4

2.3

4.0

0.3

0.2

10.7

Normal Total

2.6

3.2

3.2

2.2

2.0

1.5

14.7

1 Data obtained from the North Dakota Agricultural Weather Network (2020) from or near specific locations.

2 Data obtained from National Weather Service (2020).

Table 1. Average monthly precipitation levels and seasonal totals (inches) by month at each project location during the 2020 growing season.

 

 

Treatment

 

 

 

Location

Stock
Density

Grazing
Utilization (%)

Peak Production
(lbs/ac)

Carrying Capacity

(AUMs/ac)

Number of

Grazing Days

Degree
of
Use (%)

Fargo

High

50

4892

1.40

11

38

75

5671

2.32

18

58

Moderate

50

6940

1.99

28

63

751

6249

2.56

35

64

Control

0

3914

 

 

 

Jamestown2

High

50

7181

2.06

33

44

75

6490

2.66

33

52

Control

0

6548

 

 

 

McKenzie

High

50

9333

2.68

36

53

75

7714

3.16

41

68

Control

0

8079

 

 

 

Napoleon3

High

50

5593

0.72

30

52

75

4917

0.91

37

66

Control

0

4669

 

 

 

Lehr

Moderate

50

12725

3.65

 

51

75

11017

4.52

 

55

Control

0

14437

 

 

 

McClusky4

Moderate

50

7164

2.06

24

34

755

6893

0.99

24

40

Control

0

6375

 

 

 

Tappen6

Moderate

50

10536

3.02

18

39

75

8782

3.60

18

56

Control

0

6444

 

 

 

1Livestock pulled early due to inclement weather and limited feed.

2Livestock pulled early due to inclement weather and limited feed.

3Forage production consisted of 50-60% weeds. Stocking rate was adjusted accordingly.

4Livestock pulled early due to inclement weather.

5Forage production consisted of 65% weeds. Stocking rate was adjusted accordingly.

6Livestock pulled early due to issues with water. Degree of use is based on the first two sections within each treatment.

Table 2. Average forage production (lbs/ac), carrying capacity (AUMs/ac), number of grazing days and degree of use (%) by grazing treatment and location during 2020.

Grazing start dates ranged from late August to early October 2020. The annual forage mix was designed to not only meet nutrient requirements of beef cattle, but also to maintain or improve ecological benefits. These objectives are difficult to achieve when growing season conditions or field preparation negatively impact brassica germination. An early September frost also slowed down or halted plant growth which impacted the forage quality available to livestock. In year two, we hope to maintain a consistent depth of seeding across locations and begin grazing the treatments by mid- to late-August.

Soil samples were collected to characterize physical, chemical and biological properties in both ICLS sites and nearby cash crop systems. Baseline data for soil nutrients is reported in Table 3. Data associated with soil physical characteristics is still being processed. Information collected in year one will serve as a baseline for evaluating response to treatments.

Location

Cropping System

Soil
Ecological
Type

Depth (in)

NO3-N
(lbs/ac)

P
(ppm)

K
(ppm)

pH

OM
(%)

SO4-S
(lbs/ac)

Zn
(ppm)

Cu
(ppm)

Tappen

ICLS

Very Droughty Loam

0-6

20

7.5

243

7.5

3.9

7.1

1.37

0.54

6-12

12

6.0

162

7.8

2.0

5.5

0.42

0.55

Annual Crop

0-6

12

14.7

348

7.9

3.1

6.8

1.68

0.45

6-12

8

2.7

195

8.1

2.3

5.3

0.66

0.48

Napoleon

ICLS

Droughty Loam

0-6

20

11.8

205

6.2

3.6

10.0

0.91

0.73

6-12

9

4.0

137

6.6

2.8

5.4

0.40

0.69

Annual Crop

0-6

14

6.3

138

6.4

4.7

6.0

1.01

0.72

6-12

9

3.0

84

6.8

3.5

7.5

0.40

0.61

Wishek

ICLS

Loam

0-6

17

7.2

256

7.3

4.3

93.8

0.96

0.95

6-12

7

2.6

173

7.6

2.9

86.2

0.57

0.96

Annual Crop

0-6

6

4.0

220

7.7

2.6

3.0

0.76

0.80

6-12

10

1.7

143

7.8

2.0

17.2

0.37

0.69

Jamestown

ICLS

Loam

0-6

5

16.9

248

6.6

3.5

59.3

1.26

0.78

6-12

5

4.9

139

7.1

2.2

86.1

0.53

0.70

Annual Crop

0-6

12

23.5

290

6.4

4.0

7.8

1.53

0.59

6-12

13

7.7

177

6.7

2.5

6.5

0.68

0.58

McKenzie

ICLS

Loam

0-6

14

4.2

215

5.8

2.6

6.1

0.56

0.51

6-12

8

2.2

110

5.9

1.7

6.9

0.25

0.52

Annual Crop

Very Droughty Loam

0-6

15

2.8

124

6.0

2.4

4.7

0.63

0.45

6-12

9

1.2

71

6.9

1.5

6.2

0.25

0.45

McClusky

ICLS

Loam

0-6

31

9.7

427

7.0

3.9

27.1

1.04

0.61

6-12

16

5.0

285

7.4

2.9

6.7

0.39

0.66

Annual Crop

0-6

22

11.3

328

6.8

3.9

5.5

0.56

0.83

6-12

12

4.3

216

7.1

3.4

4.7

0.30

0.81

Fargo

ICLS

Clayey Subsoil

0-6

7

8.5

315

7.3

5.3

14.1

0.90

2.19

6-12

5

5.0

244

7.7

3.8

35.0

0.50

2.80

Annual Crop

0-6

53

22.4

385

7.3

5.7

11.4

1.22

2.79

6-12

17

11.6

278

7.4

3.9

16.6

0.63

2.90

Table 3. Soil nutrient and biological analysis at 0-6 and 6-12 inches (in) sampled within a similar soil series at each project location.

Livestock performance data was collected and will be provided in secondary reports. The best way to share this information is still being determined since the type of cattle (e.g. cow-calf pairs, bred heifers, fall calving cows, etc.) used for grazing was and will continue to be variable.

Participation Summary
6 Farmers participating in research

Education

Educational approach:

In 2020 we hosted a webinar series on grazing cover crops. Participated in nine cafe talks and panel discussion on livestock integration into cropping systems. Developed an in-service training, cover crop kits, cover crop cost calculator and Extension publication to utilized in Extension outreach. The project team filmed six video on grazing cover crops. In addition six news releases and seven media interview were completed.

Project Activities

Grazing Cover Crops Webinar Series
Cover Crop In-Service
Annual Cover Crop Options for Grazing and Haying in the Northern Plains

Educational & Outreach Activities

9 Curricula, factsheets or educational tools
8 On-farm demonstrations
6 Published press articles, newsletters
15 Webinars / talks / presentations
2 podcast, in-service training

Participation Summary

341 Farmers
519 Ag professionals participated
Education/outreach description:

Summary of Extension activities completed in 2020:

  • 9 café talks focused on livestock integration with 217 participants.
  • Grazing cover crop panel during DIRT workshop had 303 participants
  • Hosted Cover Crop In-Service for Extension, NRCS and SCD personnel that was attended by 45 people
  • Created a Cover Crop Cost Calculator for producers
  • Revised the Annual Cover Crop Options for Grazing in the Northern Plains publication, accessed 642 times online and 50 print copies were distributed.
  • Created kits for Extension agents, NRCS and SCD personnel to grow cover crops to use in their programing efforts, distributed kits to 15 participants.
  • Hosted a Grazing Cover Crop Webinar Series that reached 392 participants that increased participants knowledge of grazing cover crops between 51 and 97 percent. The recordings received 1,030 views.
  • Wrote 6 articles and news releases about grazing cover crops that reached an estimated 160,000 individuals.
  • Conducted 7 media interviews about grazing cover crops that reached an estimated 302,000 individuals.
  • Filmed 6 videos on grazing cover crops that had 1,717 views.
  • The NDSU Stutsman County Extension agent presented to 32 individuals at 2 meetings on cover crop selections. Producers that attended the meeting increased their ability to select cover crops was rated 53% before and 80% after the workshop.

Outreach activities planned for 2021 include virtual discussions, shop talks, tours of demonstration sites and meetings.

Learning Outcomes

81 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation
259 Service providers reported changes in knowledge, attitudes, skills and/or awareness as a result of project outreach
259 Agricultural service providers reported changes in knowledge, skills, and/or attitudes as a result of their participation
Key areas taught:
  • Calculating forage production and stock rates for grazing cover crops.
  • Selecting cover crop species for grazing.
  • Soil health and economic benefits of grazing cover crops.
  • Potential toxicity issues when grazing cover crops.
  • Grazing management considerations for integrated crop livestock systems.
Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.