Integrating livestock and cover crops into irrigated crop rotations

Progress report for SW18-021

Project Type: Research and Education
Funds awarded in 2018: $249,954.00
Projected End Date: 03/31/2022
Grant Recipient: University of Wyoming
Region: Western
State: Wyoming
Principal Investigator:
Dr. Jay Norton
University of Wyoming
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Project Information

Abstract:

Changing markets, technology, and attitudes are creating opportunities for new paradigms
supporting wider adoption of soil-building practices, but there is little science-based information
about integrating livestock and cover crops into irrigated crop rotations. While a few producers
in the sugarbeet/malting barley production area of northwestern Wyoming and south central
Montana experiment with cover crops following barley harvest for soil cover and livestock
forage, uncertainties about costs and benefits, and how to navigate options, mean that intensive
tillage and expansive bare soil are still the norm in this region. To address questions about effects
of different cover crop options on subsequent cash crops, soil quality, forage yield and quality,
and farm economics we will establish an on-station trial in a producer-driven long-term rotation
experiment at the University of Wyoming Powell Research and Extension Center, an on-farm
experiment with at least five producers, and innovative education programs and products. We
will evaluate four types of cover crops following barley in systems where sugarbeet is the
subsequent crop. Cover crop types include volunteer barley regrowth, replanted barley, soil
building mix, and livestock production mix. The on-station experiment will be embedded in the
long-term rotation experiment where half of each cover crop plot will remain unharvested and
half will be harvested for hay. The on-farm experiments will be established after harvest of
irrigated barley where producers winter graze replanted barley. On-farm plots will be split, with
half ungrazed in 0.1-acre exclosures and half winter grazed with the rest of the field. The
participatory research will creating settings for farmer inquiry, peer-to-peer learning, and lasting
relationships. We will optimize those opportunities by 1) expanding our technological exchange
created for the long-term rotation experiment; 2) field-based hands-on workshops; 3) Extension
and research publications; and 4) impact evaluation with on-going responsive adjustments to
research and extension activities.

Project Objectives:

This project will provide producers with knowledge to implement soil-building practices for
more sustainable irrigated cropping systems. Specific objectives include quantifying and
comparing effects of four types of cover crops (volunteer barley, replanted barley, and two cover
crop mixes) and three residue treatments (hay, grazed, and no harvest) on:
1. Yield and quality of subsequent crops;
2. Soil quality and organic matter cycling;
3. Forage quality and quantity of the four cover crop types;
4. Water use efficiency in subsequent sugarbeets;
5. Costs and benefits of different cover crop/forage options;

Cooperators

Click linked name(s) to expand

Research

Hypothesis:

A cover crop mix planted after barley harvest in sugarbeet-barley rotations will improve soil quality compared with no cover crop and with replanted or volunteer barley regrowth. Further, soil quality improvements will vary with management of cover crops for green manure, hay, or grazing.

Materials and methods:

During the 2020 growing season we tracked the plots established in 2018 through sugarbeet planting and harvest on the University of Wyoming Powell Research and Extension Center (PREC) at Powell, WY. We established new cover crop plots in the barley phase of the on-station long-term rotation experiment at PREC and sampled soils, biomass, and yields through the 2020 season. 

M.S student Taylor Bush completed and defended his thesis in April, 2020. Ph.D. student Dixie Crowe is building upon Taylor’s work with two more field seasons (2020 and 2021) at the PREC field as well as expanding on the paired site study. She is communicating with cooperating farmers, NRCS, the PREC farm crew and others to locate fields with long-term soil-health practices and paired conventional fields to assess impacts of cover crops and minimum tillage on soil health indicators in the study area.

Precautions associated with COVID-19 limited our ability to carryout outreach and extension activities during 2020, but we received a one-year no-cost extension and intend to focus on outreach activities during the summer and fall of 2021. An advantage to this is that we will have a more complete dataset and results to share.

During the 2021 season we intend to continue the on-station experiment by tracking the sugarbeets that follow the 2020 cover crops and by establishing a new set of cover crop plots in the 2021 barley phase of the crop rotation experiment. We also plan to expand upon the paired site study and have identified additional study sites on farms in the study area. We postponed this paired-site sampling from 2020 to 2021 when we received the no-cost extension. 

Research results and discussion:

While research and extension activities were limited by COVID-19, we did accomplish all the seasonal soil and crop sampling for the ongoing on-station experiment during 2020. All samples were processed and time-sensitive lab work was completed, but laboratory restrictions and lack of student lab assistants have delayed final laboratory analyses and data interpretation. We are completing that work this winter and will present interim results at the 2021 Western Nutrient Management Conference, to be held online in March. 

Taylor Bush completed his MS thesis in April, 2021, reporting on 1) his paired-site study of two farms with long-term minimum-till and cover crop practices with adjacent conventionally tilled fields and 2) the first two years of the on-station study and the two-year on-farm study. We are preparing a “how-to successfully grow annual forage cover crops following irrigated small grains” extension bulletin based on Taylor’s results and the experience we gained.

Results of the paired site study show that, while variable, soil-health practices are increasing soil organic carbon within 5 to 7 years of implementation. Surface soils (0-15 cm) at the farm near Ralston, Wyoming, indicated that 5 years of strip-till plus cover crops following barley in the sugarbeet-corn-barley-sunflower rotation increased SOC to 16.6 Mg SOC ha-1 compared with 11.6 Mg SOC ha-1 in the adjacent conventionally tilled field under a similar crop rotation, a significant increase of 43%. Surface soils at the no-till sugarbeet-barley-corn farm near Fromberg, Montana, did not contain more SOC than those of the adjacent conventionally managed field, possibly due to recent sediment deposits after a very intense rain event earlier in the year. Soil-health practices at both locations led to higher whole-soil-profile carbon stocks, with 17 and 7 Mg SOC ha-1 at the Ralston soil health and conventional fields, respectively, and 50 vs. 40 Mg SOC ha-1 at the Fromberg soil health and conventional fields, respectively.

The short-term study on six cooperating farms and the PREC station did not lead to significant differences in soil properties or subsequent sugarbeet yields, which is not surprising because, with the crop rotations being practiced, the study actually consisted of a one-year experiment on each of the study plots. Also, the plots with and without grazing and cover crops were imposed on fields already under minimum tillage and annual forage/cover crops following barley. Forage quality analysis indicated that the five-species cover crop mix was more productive and had much higher crude protein, relative feed value, and other quality indicators than barley alone. 

Jacob Asay is currently completing his MS thesis in Agricultural Economics under direction of Co-PI Dr. John Ritten. Jacob and John created partial budgets to estimate the relative profitability of the various cover crop options (volunteer barley, replanted barley, cover crop mix) in combination with different management options (green manure, haying, and grazing).  Preliminary results suggest the options that provide the most revenue (e.g. haying) provides the most incentive to adopt cover cropping in the short term.  They are currently working to determine the longer-term implications of cover crop adoption. 

Participation Summary

Education

Educational approach:

We have an active “network for technological exchange” with frequent communication among researchers and cooperators. COVID-19 prevented the extension events we had planned for 2020, but our one-year no-cost extension will allow us to hold better events with more complete results near the end of the 2021 field season. Rather than hold virtual events, we focused on the research during 2020 and will hold on-farm mini-field days on cooperating farms that utilize the soil health practices, as well as on our PREC plots, and during research station field days in Wyoming and Montana. Norton recorded a “how-to” presentation in December, 2020, for our University of Wyoming Extension conference held in early January, 2021.

Educational & Outreach Activities

30 Consultations
2 Curricula, factsheets or educational tools
1 Online trainings
2 Webinars / talks / presentations

Participation Summary

Education/outreach description:

Our education and outreach activities were minimal this year because COVID-19 precautions. Taylor Bush completed his thesis, available on ProQuest, and we are preparing an extension bulletin based on his work. 

Learning Outcomes

Key areas taught:
  • We did not record learning outcomes in 2020.
Key changes:
  • Cover crop selection, establishment, and management.

Project Outcomes

Project outcomes:

Our activities this year focused on the research aspects because COVID-19 made interactions with our target audience difficult or impossible. We are very hopeful that we will be able to fulfill planned outcomes during late summer and fall, 2021.

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.