Source: UNIV OF IDAHO submitted to NRP
CEREAL-PEA INTERCROPPING SYSTEMS AS A PROFITABLE CROPPING STRATEGY TO ORGANIC TRANSITIONS AND SOIL HEALTH
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
ACTIVE
Funding Source
OTHER GRANTS
Reporting Frequency
Annual
Accession No.
1027092
Grant No.
2021-51106-35491
Cumulative Award Amt.
$600,000.00
Proposal No.
2021-04806
Multistate No.
(N/A)
Project Start Date
Sep 1, 2021
Project End Date
Aug 31, 2026
Grant Year
2021
Program Code
[112.E]- Organic Transitions
Recipient Organization
UNIV OF IDAHO
875 PERIMETER DRIVE
MOSCOW,ID 83844-9803
Performing Department
(N/A)
Non Technical Summary
Agronomic tools are needed to facilitate the transition from conventional to organic farming. The long-term goal of our project is to develop cereal-pulse intercropping systems under low water availabilities for enhancing agroecosystem sustainability and productivity during the transition to organic farming and thereafter. A three-year field experiment during organic transition and trials on grower-collaborator organic farms will improve our understanding of the effects of cereal-pea intercropping systems on crop productivity, soil health and fertility, greenhouse gas mitigation, and enhanced diversity of crops and soil microbes under well-watered and drought-stressed conditions. The results will provide direct evidence of the effectiveness of cereal-pea intercropping systems to supply a substantial source of biologically fixed nitrogen, mitigate nitrous oxide and methane gas flux, and increase crop and microbial diversity. Such results are presently sparse in the peer-reviewed literature. Net returns and profit risk profiles for each cropping system will be estimated using field-level input usage and yield data as well as market prices. Findings from the project will be transferred to stakeholders and the public through publications, an intercropping website, workshops, on-farm field days, and presentations at other extension events. Growers from other regions will be invited to attend annual workshops and meetings with a focus on intercropping systems, after which they can act as advisors or consultants in their own regions. To educate next-generation scientists, undergraduate and graduate students will be recruited, and project results will be included in university coursework and introduced to middle-school agricultural teachers for their curriculum.
Animal Health Component
70%
Research Effort Categories
Basic
30%
Applied
70%
Developmental
0%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
10215991070100%
Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships;

Subject Of Investigation
1599 - Grain crops, general/other;

Field Of Science
1070 - Ecology;
Goals / Objectives
The long-term goal of our project is to develop cereal-pulse intercropping systems under low water availabilities for enhancing agroecosystem sustainability and productivity during organic transition and in subsequent organic farming. Specific objectives are:Objective 1. Understand the effects of cereal-pea intercropping systems on crop productivity, soil health and fertility, and enhanced diversity of crops and soil microbes under well-watered and drought-stressed conditions during organic transition.Objective 2 Involve undergraduate and graduate students in working on the project and include the project in course materials.Objective 3 Determine the overall economic return of intercropping production under irrigated and dryland conditions during organic transition and on organic farms and transfer findings from the project to stakeholders and the public via a robust extension and outreach plan.
Project Methods
A three-year field experiment will be conducted at the Aberdeen Research & Extension Center, University of Idaho in a field that meets the requirements for organic transition certification. We will establish experimental plots of monoculture and intercropping spring wheat, spring barley, and spring pea under two water regimes. The two water regimes will consist of well-watered and drought-stressed conditions. The experiment will follow a two-factor split-plot design with four replicates and will be repeated for three years. To create intercropping systems, spring wheat (or barley) and spring pea will be planted in alternate rows at four seeding rate compostions, besides the monocropping treatment of each crop. All crops will be planted in mid to late April and harvested in August. During each growing season, no fertilizers will be applied to intercropping plots and organic nutrient products will be applied to monoculture plots based on the pre-planting soil nutrient test.To create the two water regimes, irrigation will be applied at 100 (well-watered) and 50% (drought-stressed) of crop evapotranspiration (ETc). ETc will be calculated by multiplying reference evapotranspiration (ETo) by crop coefficients (Kc) of spring pea and spring grain.Soil moisture will be monitored using a soil moisture probe to quantify soil moisture dynamics throughout each growing season.The date of each crop growth stage in individual plots will be recorded during each growing season. To evaluate crop canopy development, leaf area index and normalized difference vegetation index will be measured at each growth stage. To evaluate the capability of suppressing weed growth in intercropping systems, weed samples will be collected from each plot when the canopy closes. Weeds will be quantified by species and dried for dry matter.Plant aboveground biomass will be sampled in the middle of each plot at the heading stage and physiological maturity of spring grain. Samples collected at physiological maturity will be used to estimate yield component parameters. Biomass samples will be separated into vegetative tissues (leaf and stem) and spikes (cereals) or pods (spring pea), and then dried for dry matter. Representative samples of vegetative tissues collected at physiological maturity will be ground and analyzed for forage nutrients. At physiological maturity, all plots will be harvested using a small-plot combine. Water use efficiency and land equivalent ratio will be calculated in each plot. The harvested wheat grain will be analyzed for end-use quality.Soil samples will be taken in 15 cm increments to a depth of 90 cm during the heading stage of cereals. Roots from each depth will be collected. The roots will be scanned for root length, surface area, and diameter. After measurement for morphological parameters, roots will be dried for dry matter.Soil samples will be taken at 0-15 and 15-30 cm soil depths at planting and harvest. The plant and soil samples will be analyzed for concentrations of C, N, 13C, and 15N to quantify C and N allocation in plants and soil C and N accumulation. Leaves will be sampled during the tillering, stem extension, and boot stages, oven dried, then ground for isotopic analysis (13C and 18O). Photosynthetic 13C discrimination will be calculated.Nutrient concentrations (ammonia and nitrate) of rhizosphere and soil samples will be quantitatively analyzed to assess nutrient availability in the soil and N leaching.Microbial biomass will be extracted from the soil at the 0-15 and 15-30 cm depths. Phospholipid fatty acids will be extracted from the 0-15 cm depths to provides information about the general microbial groups present.We will also measure the soil gas flux of CO2, CH4, and N2O, bi-monthly over the growing season to estimate cumulative values between treatments.On-farm trials will be conducted on three producer collaborators' organic farms during the 3rd and 4th years of the project when promising practices of intercropping systems are identified from the first two years of the field experiment. The three organic growers are located in south and south-central Idaho. Two of them have irrigation on their farms and the other one has dryland cropland. Growers will use their equipment for planting and harvest and follow their typical irrigation scheduling on irrigated farms. Production costs (e.g., labor, equipment adjustment and modification, irrigation, and seeding cleaning, etc.) will be recorded.Soil samples and samples for crop yield and biomass will be taken from the intercropping fields, as well as the monoculture fields on the rest of the producers' farms to serve as a control for each site. The sample analyses will be the same as the field experiment at Aberdeen. Yield will also be recorded from the yield monitoring systems of growers' combines.The economic analysis will be primarily composed of a comparison of profitability of the various types of monoculture versus cereal-pea production systems. The approach will be based on that from a similar study developed by Chavas et al. (2009) in which each cropping system has an associated net return (difference between sales revenues and government payments and operating costs) and risk premium that accounts for variability in net returns associated with changes in key variables such as yields and prices. The results from the economic analysis are expected to enhance the knowledge available to producers for improved decision-making on intercropping production, and therefore also be of interest to extension personnel and other stakeholders in the public and private sectors.The results of this project will be prepared for peer-refereed publications and distilled into peer-reviewed extension articles and trade-journal articles. These publications will be available online, and handouts will also be printed and distributed to producers at field days and other outreach events. The creation of a website will allow producers, partners, researchers, and the public to access information anytime, anywhere. We will use this website to share the aims of the project, and our progress with quarterly updates. The website will include text, video, and audio content.Undergraduate and graduate students will be recruited to work on the project. The project will be introduced to agricultural teachers of pre K-12th grade through visits to our field and labs and as materials and resources for the curriculum. The project will also be incorporated into teaching materials for undergraduate and graduate courses at the University of Idaho.A formative evaluation to monitor the program outcomes will be conducted annually. We will conduct a summative assessment after the completion of the project to develop a final progress report. We will use qualitative, quantitative, and mixed methods to measure project outcomes, success, and challenges.To measure short-term outcomes, pre and post-tests and retrospective surveys will be administered. The video watched and downloads of publications will serve as proxy measures of awareness, knowledge, and audiences' intention-to-adopt intercropping practices. The follow-up evaluations will be conducted at the end of each cropping year to measure the medium-term outcomes, including changes in cereal-pulse intercropping practices, their adoptions, and farm profitability. The long-term impacts of the project will be measured at the end of the project by using surveys, focus groups, and in-depth individual interviews. Additional surveys will be conducted using web-based outreach efforts.

Progress 09/01/24 to 08/31/25

Outputs
Target Audience:We demonstrated our project at multiple events, and the target audiences include growers, crop consultants, industry agronomists, representatives of commodity groups (e.g., Idaho Barley Commission and Idaho Wheat Commission), graduate students, researchers, and the general public. Changes/Problems:We requested and received approval for a no-cost extension for another year, setting our new deadline ito August 31, 2026. One of the co-PIs, Dr. Linda Schott, has left the University of Idaho. The lead PI, Dr. Xi Liang, is now assuming Linda's responsibilities and working with UI Extension Educators to complete the Extension tasks. What opportunities for training and professional development has the project provided?3 Ph.D. students are working on agronomy, crop ecophysiology, and soil health as their dissertation projects. 1 undergraduate worked with Ph.D. students and PIs to assist with plant sample grinding How have the results been disseminated to communities of interest?We demonstrated our project at 8 events below: • Cereal-pea intercropping systems under different water regimes in organic farming. UI Snake River Weed Management Tour, Aberdeen, June 24, 2025; Rupert Field Day, July 8, 2025; Aberdeen Field Day, July 9, 2025; Soda Springs Field Day, July 22, 2025; Tetonia Field Day, July 23, 2025; Parma Field Day, August 14, 2025; Aberdeen Potato IPM Field Day, August 21, 2025. (7 presentations) •Cereal-pulse cropping systems in organic farming. USDA NRCS 5 for 5 Soil Health (webinar). April 2, 2025. (invited) The pea intercropping practices in this project were considered sustainable and incorporated into two projects funded byNRCS: • Climate-Smart Commodities for Idaho: A Public-Private-Tribal Partnership. USDA-NRCS Partnerships for Climate-SmartCommodities. We established demonstration plots of intercropping potatoes (in 2024) and sugar beets (in 2025) with peas. • Expanding the STAR Program across Colorado and the West. USDA-NRCS Partnerships for Climate-SmartCommodities. From 2024 to 2025, we established demonstration plots of mixed barley with spring and winter peas. What do you plan to do during the next reporting period to accomplish the goals?We will complete the analyses of samples and prepare manuscripts for publication. One of the graduate students in Plant Science is expected to graduate in December 2025, while the other Plant Science student successfully passed her Ph.D. preliminary exam this fall andis anticipated to graduate in the summer of 2026. We will continue to share theresults of the intercropping practices from this project at various events and collaborate with organicgrowers to conduct on-farm trials of intercropping methods in southern Idaho. The profitability findings will be presented at different University of Idaho Extension events and publications, including at the Idaho Cereals Conference in February 2026.

Impacts
What was accomplished under these goals? Crop producers need effective agronomic tools to maximize productivity while dealing with limited water availability and maintaining limitedsoil resources in organic farming. This project contributes to organic growers'toolset by focusing on key response variables that matter to producers, including crop yield and quality, water use, soil fertility and health, and the profitability of organic production systems of cereal-peaintercropping. Additionally, this project aims to intensifyand diversifycropping systems for crops that are essential to Idaho's economy and the surrounding region. These results will demonstrate the advantages of an organic production system thatboosts overall cropproductivity, enhances soil fertility and health, and improves crop resilience to drought stress by introducing greater structural andfunctional diversity to agroecosystems. Objective 1: Understand the effects of cereal-pea intercropping systems on crop productivity, soil health and fertility, and enhanced diversity of crops and soil microbes under well-watered and drought-stressed conditions during the organic transition. We have compiled yield data from 2022 to 2024 and conducted statistical analyses. Preliminary results indicate high-proportion wheat treatments (i.e., 75%wheat+25%pea and 75%wheat+75%pea) produced wheat grain yields similar to monocroppedwheat under drought stress, while under well-watered conditions, the grain yield of monocroppedwheat was greater than all the intercropping treatments, except for the 75%wheat+25%pea treatment. Under drought stress, the grain yield of monocropped barley was not different from the 75%barley+25%pea treatment but greater than the other three intercropping treatments, whereas monocroppedbarley produced higher yields than any intercropping treatment under well-watered conditions. Grain yields for both wheat and barley decreased from 2022 to 2024. In contrast to grain yield, the whole-plantbiomass of intercropping treatments (the total biomass of cereals and pea) was generally greater than monocroppedcereals in both water regimes. The nutritive values of plant biomass were significantly influenced by cropping systems. Cropping systems with high peastands (e.g.,monocropping peas) exhibited greater crude protein concentrations in the biomass, whereas cropping systems withhigher proportions of small grains (e.g., monocropping wheat and barley) had greater fiber concentrations. Additionally, significant year effects were observed: crude protein concentration decreased over the years, whereas fiber concentrations increased. We are finalizing the end-use quality analysis of wheat grains from 2024. For the soil health analysis, available Cwas lower in 2022 but increased in 2023 for all cropping system treatments, water regimes,and soil sampling depths. This trend could be due to the input from the diverse crops (e.g., wheat, barley, and pea).Most of the Cwas located at a depth of 0-15 cm, and soil available C also differed between cropping system treatments. Soil inorganic N was high in 2022 but decreased in 2023 for all cropping system treatments, water regimes,and soil depths. This could be due to plant uptake, microbial immobilization, and/or nitrate leaching. Soil inorganic N also differed between cropping system treatments and at different depths.The analyses of soil microbial biomass, totalC and N, available carbon of 2024, and inorganic N of 2024 are still underway. Objective 2: Involve undergraduate and graduate students in working on the project and include the project in course materials. During the reporting period, we engaged 1 undergraduate student and 3 Ph.D. students in this project. Thisproject was featured as a case study in the chapter on Organic Agriculture in a 3-credit course titled Field Crop Production, which took place in the spring of 2025. This semester, a total of 30 students enrolled in the course, comprising 3 graduate students and 27 undergraduates. Objective 3: Determine the overall economic return of intercropping production under irrigated and drylandconditions during organic transition and on organic farms and transfer findings from the project to stakeholders andthe public via a robust extension and outreach plan. We presented our project to stakeholders and the public at 8 events. Some project information has been added to the proposed webpage (https://www.croppingsystems.org/), and moreinformation will be updated over time. We have summarized field trial yield data for the growing seasons of 2022, 2023, and 2024. Production cost data, including seed prices as well asplanting and harvesting costs, has been compiled. Furthermore, we have gathered prices for conventional and organic barley, pea, and wheat for the marketing years from 2022 to2024. The field trial, cost, and price data have been encompassed in an enterprise budget model to estimate the profitability of each treatment. The initial profitability framework based on the establishment year data has been expanded into a three-year budgeting framework with several crop rotation scenarios considered.

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Kazemi, S., J. Piaskowski, X. Liang, Z. Kayler, L.R. Schott. Water use efficiency in cereal-pea intercropping systems. ASA-CSSA-SSSA Annual Meetings. San Antonio, TX, November 10-13, 2024.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Liang, X., S. Kazemi, H. Lee, Z. Kayler, L.R. Schott, P. Hatzenbuehler. Cereal-pea intercropping systems under different water regimes in organic farming. ASA-CSSA-SSSA Annual Meetings. San Antonio, TX, November 10-13, 2024.


Progress 09/01/23 to 08/31/24

Outputs
Target Audience:We demonstrated our project at multiple events, and target audiences include growers, crop consultants, industry agronomists, representatives of commodity groups (i.e., Idaho Barley Commission and Idaho Wheat Commission), graduate students, researchers, and the general public. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?3 Ph.D. students are working on agronomy, crop ecophysiology, and soil health as their dissertation projects. 1 undergraduate worked with Ph.D. students and PIs to assist with plant and soil sample collection and processing (e.g., sample grinding). 2 high-school students worked with Ph.D. students and PI to assist with experiment preparation (e.g., seedpacking for planting) and plant sample collection and processing for biomass accumulation and partitioning, grain quality, yieldcomponents, etc. How have the results been disseminated to communities of interest?We demonstrated our project at 8 events below: Cereal-pea intercropping systems under different water regimes in organic farming. Aberdeen Potato IPM Field Day, Aberdeen, ID. August 22, 2024; Cropping system diversity. Aberdeen Twilight Tour, Aberdeen, ID. July 17, 2024; Cereal-pea intercropping systems as a profitable cropping strategy to organic transitions. Rupert Field day, July 10, 2024; Aberdeen Field Day, July 16, 2024; Tetonia Field Day, July 25, 2024. (3 presentations); Soil Health when Transitioning to Organic Production: Practices and Metrics. Kimberly R&E Center Weed Tour.June 26, 2024. Kimberly, ID; Cereal-pea intercropping systems under different water regimes in organic farming. Western Wheat Work Field Tour, Aberdeen, ID. June 18, 2024 (invited). IAMP Project Overview. Regen Ag Workshop.November 15, 2023. Twin Falls, ID.This intercropping project was highlighted and data from this study was presented due to the stakeholders present The pea intercropping practices in this project have been considered sustainable and incorporated into two projects funded by NRCS: Climate-Smart Commodities for Idaho: A Public-Private-Tribal Partnership. USDA-NRCS Partnerships for Climate-Smart Commodities. Total $55M(2023-2028). (also called Innovative Agriculture and Marketing Partnership, IAMP) Expanding the STAR Program across Colorado and the West. USDA-NRCS Partnerships for Climate-Smart Commodities. Total $25M (2023-2028). What do you plan to do during the next reporting period to accomplish the goals?We will finish the sample processing from the field experiment. With 3-year data (2022-2024) (especially crop yield and quality), we will be more confident in recommending intercropping practices to growers. We will continue to work with organic growers for on-farm trials of intercropping practices in southern Idaho. For economic analyses, we will gather updated data on barley, wheat, and pea prices and fertilizer prices (both conventionaland organic), from which production costs for each treatment in 2022-2024will be estimated. We will evaluate themarketability of produced barley, peas, and wheat, including details on the local market structure, yield variability functionsbased on field data for 2022-2024and price (grains/peas, fertilizer) variability functions based on 5-year historical data, economic returns analysis for each treatment that accounts for variability in yields, grain/pea prices, fertilizer prices.

Impacts
What was accomplished under these goals? Crop producers need robust agronomic tools to achieve high productivity with limitedwater availability while sustaining limited soil resources in organic farming. This project adds to this toolset by focusing on producer-relevant response variables such as crop yield and quality, water use, soil fertility and health, and farming profitability for organic production systems of cereal-pea intercropping. This project also intensifies and diversifies cropping systems for crops critical to Idaho's and the region's economy. Results from this project will highlight the benefits of an organic production system that increases overall crop productivity, enhances soil fertility and health, and improves crop resilience to drought stress, by adding structural and functional diversities to agroecosystems. Objective 1: Understand the effects of cereal-pea intercropping systems on crop productivity, soil health and fertility, and enhanced diversity of crops and soil microbes under well-watered and drought-stressed conditions during the organic transition. The third-year field experiment was successfully established and harvested as we proposed. Plant and soil samples have been collectedfor crop growth and productivity as well as soil health and fertility for 2024 and are being processed. Soil greenhouse gasemissions were measured during the 2024 growing season. Wheat grain yield of 2023 was not affected by cropping systems or water regimes. There were slight differences in barley grain yield in 2023: 75%barly+50%pea under well-watered conditions produced greater yield than 75%barley+75%pea under well-watered conditions and monocropping barley under drought stress. These results are very different from grain yields in the first year (2022).It could be due to the soil residual nutrients from oat green manures in 2020 and 2021 have been depleted in the second growing season. We are looking forwardto results from the third year with more soil nutrient depletion in monocropping treatments, and intercropping treatments ofhigh pea stands may exhibit superiority to monocropping cereals. Whole-plant biomass nutritive values of 2022 were greatly impacted by cropping systems. Cropping systems with high pea stands (e.g., monocropping peas) had greater crude protein concentrations in the biomass, whereas cropping systems with high stands of small grains (e.g., monocropping wheat and barley) had greater fiber concentrations. Objective 2: Involve undergraduate and graduate students in working on the project and include the project in course materials. We have involved 1 undergraduate and 3 Ph.D. students working on this project. Objective 3: Determine the overall economic return of intercropping production under irrigated and dryland conditions during organic transition and on organic farms and transfer findings from the project to stakeholders and the public via a robust extension and outreach plan. Some project information has been added to theproposed webpage(https://www.croppingsystems.org/), and more information will be updated this fall. We demonstrated our project to stakeholders and the public at 8 events.A workshop was hosted during the Magic Valley Soil Health Forum to discuss intercropping practices on February 12, 2024. Attended producers talked about their implementation of pea-small grain and alfalfa-grass intercropping. Discussion afterward generated some interest in cereal-pea intercropping.Participants of our extension events have become more aware of the option of cereal-peaintercropping systems, especially in organic transition and organic farming. Three on-farm trials were implemented for intercropping pulses and small grains in Fairfield, Shoshone, and Twin Falls in southern Idaho. Each utilized fields with low water inputs and low soil fertility values. The producer in Twin Falls had 2 T/A yields of feed barley + pea, which will replace grazable alfalfa as fall forage for his cows. The other two producers had poor stands due to a late frost in June.

Publications

  • Type: Other Status: Published Year Published: 2023 Citation: Liang, X., Z. Kayler, L. Schott, P. Hatenzbuehler, N. Ghimire. Cereal-pea intercropping systems under different water regimes during the organic transition. ASA-CSSA-SSSA Annual Meetings. St. Louis, MO, October 29-November 1, 2023.


Progress 09/01/22 to 08/31/23

Outputs
Target Audience:We demonstrated our project at multiple events, and target audiences include growers, crop consultants, industry agronomists, representatives of commodity groups (i.e., Idaho Barley Commission and Idaho Wheat Commission), graduate students, researchers, and the general public. Changes/Problems:We collected soil cores/root samples from 6 depths: 0-6, 6-12, 12-18, 18-24, 24-30, and 30-36 inches in 2022as we proposed in the proposal.When processing the root samples, we noticed thatthere was almost no root at 30-36 inches. We contacted the program leader to confirm that root samples at 30-36 inches are not critical. So root sampling at 30-36 inches was excluded in 2023. What opportunities for training and professional development has the project provided?3Ph.D. students have been recruited to work on agronomy,crop ecophysiology, and soil health as their dissertation projects. 1 undergraduate worked with Ph.D. students and PIs to assist with plant and soil sample collection andprocessing (e.g., sample grinding). 2 high-school students have been working with Ph.D. studentsand PIto assist with experiment preparation (e.g., seed packing for planting)and plant sample collection andprocessing for biomass accumulation and partitioning, grain quality, yield components, etc. How have the results been disseminated to communities of interest?We demonstrated our project at 11events below: Cereal intercropping systems under well-watered and drought-stressed conditions. Aberdeen Potato IPM field day. August 16, 2023. Cereal intercropping systems under well-watered and drought-stressed conditions. Rupert Field Day, July 11, 2023; Idaho Falls Field Day, July 19, 2023; Aberdeen Field Day, July 20, 2023; Soda Springs Field Day, July 25, 2023; Tetonia Field Day, July 25, 2023. (5 presentations) Cereal-pea intercropping systems in organic farming. UI Pest Management Research Tours, Kimberly, ID, June 28, 2023. Cereal intercropping systems under well-watered and drought-stressed conditions. UI Pest Management Research Tours, Aberdeen, ID, June 27, 2023. Cereal-pea intercropping systems as a profitable cropping strategy to organic transitions and soil health. Magic Valley Organic Field Day, Buhl, ID, June 13, 2023. Cereal intercropping systems under well-watered and drought-stressed conditions. Wheat Field Day. Hermiston, OR, June 12, 2023. (invited) Cereal-pea intercropping systems as a profitable cropping strategy to organic transitions and soil health. USDA NIFA: OREI & ORG Project Directors Meeting. Washington, D.C., April 19-20, 2023. What do you plan to do during the next reporting period to accomplish the goals?We will continue our field experiment for the third year. With 2-year data (2022-2023) (especially crop yield and quality),we will be more confident in recommending intercropping practices to growers in 2024. We will work with 3 organic growers for on-farm trials of intercropping practices in southern Idaho. For economic analyses, we will gather updated data on barley, wheat, and pea prices and fertilizer prices(both conventional and organic), from which production costs for each treatment in 2022 and 2023 will be estimated. We will evaluate the marketability of produced barley, peas, and wheat, including details on the local market structure,yield variability functions based on field data for 2022 and 2023 and price (grains/peas, fertilizer) variability functions based on 5-year historical data, economic returns analysis for each treatment that accounts for variability in yields, grain/pea prices, fertilizer prices.

Impacts
What was accomplished under these goals? Crop producers need robust agronomic tools to achieve high productivityunder low water availabilities while sustaining limited soil resources in organic farming. This project adds to this toolset byfocusing on producer-relevant response variables such as crop yield andquality, water use, soil fertility and health, andfarming profitability for organic production systems of cereal-pulse intercropping. This project also intensifies anddiversifies cropping systems for crops critical to Idaho's and the region's economy. Results from this project will highlight thebenefits of an organic production system that increases overall crop productivity, enhances soil fertility and health, andimproves crop resilience to drought stress, by adding structuraland functional diversitiestoagroecosystems. Objective 1: Understand the effects of cereal-pea intercropping systems on crop productivity, soil health and fertility, and enhanced diversity of crops and soil microbes under well-watered and drought-stressed conditions during the organic transition. The second-year field experiment was successfully established as we proposed. Plant and soil samples have been collected for cropgrowth and productivity as well as soil health and fertility for 2023 and are being processed. Soil greenhouse gas emissions were measured intensively during the 2023 growing season. We are finalizing sample and data analyses for 2022. The grain yield of monocropping wheat in 2022 wasgreater than intercropping treatments of 50%Wheat+50%Pea and 75%Wheat+50%Pea under drought stress. Under well-watered conditions, monocropping wheat producedthe highest grain yield followed by 75%Wheat+25%Pea and 75%Wheat+50%Pea. Barley grain yield under well-watered conditions was greater than drought-stressed conditions in 2022. Among the intercropping treatments,monocroppingbarley produced a greater yield than 50%Barley+50%Pea, 75%barley+75%pea, and 75%barley+50%pea, while no significant difference was found between these three intercropping treatments.Wheat end-use quality (e.g., flour protein, flour yield, and cookie diameter) was not significantly affected by the water regime or cropping system.According to the first-year results, higher intercropping seeding rates of small grains(i.e., 75%cereal+50%pea, and 75%cereal+75%pea) would not return higher cereal yields or quality. Itcould be due to high soil residual nutrients from oat green manures in 2020 and 2021. We are looking forward toresults from years 2 and 3 with more soil nutrient depletion in monocropping treatments, and intercropping treatments of high pea seeding rates may exhibit superiority to monocropping cereals. We also noticed that pea plants grew better than small grains in 2023, probably due to the cool spring that favored pulse crop growth. We expect to see high pea yields this year and large yearly variability. Objective 2: Involve undergraduate and graduate students in working on the project and include the project in course materials. We have involved 1 undergraduate and 3 Ph.D. students working on this project. This project has been incorporated into the chapter on organic farming in PLSC407 Field Crop Production in spring 2023. Objective 3: Determine the overall economic return of intercropping production under irrigated and dryland conditions during organic transition and on organic farms and transfer findings from the project to stakeholders and the public via a robustextension and outreach plan. We demonstrated our project to stakeholders and the public at 11events. The proposed webpage is under development (https://www.croppingsystems.org/). Participants of our extension events have become more aware of the option of cereal-pea intercropping systems, especiallyin organic transition and organic farming. Our project was highlighted in a newspaper article: UI researcher seeks to help farmers overcome a barrier in transitioning to organic. John O'Connell. Intermountain Farm & Ranch, December 1, 2022. https://www.postregister.com/farmandranch/crops/ui-researcher-seeks-to-help-farmers-overcome-a-barrier-in-transitioning-to-organic/article_9084b772-718d-11ed-9265-af93b85772a5.html For economic analyses, we have gathered data on barley, pea, and wheat seed prices as well as fertilizer prices. We have also developed aninitial spreadsheet-based framework for calculating revenues (yield x price) for each treatment based on 2022 field data of average yields.Our team has discussed with growers the potential marketability of barley/pea and wheat/pea harvested simultaneously and sold for use in organic animal feed or soups.

Publications

  • Type: Other Status: Published Year Published: 2022 Citation: Lee, H., X. Liang, Z. Kayler. Crop growth of cereal-pea intercropping systems under drought stress. ASA-CSSA-SSSA Annual Meetings. Baltimore, MD, November 6-9, 2022.


Progress 09/01/21 to 08/31/22

Outputs
Target Audience:We demonstrated our project at multiple events, and target audiences includegrowers, crop consultants, industry agronomists, representatives of commodity groups (i.e., Idaho Barley Commission and Idaho Wheat Commission), graduate students, researchers, and the general public. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?A Ph.D. student has been recruited to work on the agronomy and crop ecophysiology section of the project as her dissertation project. She has been working intensively with PIs. An undergraduate worked closely with the Ph.D. student and PIs to assist with plant and soil sample collection and processing. How have the results been disseminated to communities of interest?We demonstrated our project at the events below: Cereal-based intercropping systems under full and deficit irrigation. Aberdeen Field Day, Aberdeen, ID, July 19, 2022; Tetonia field day, Tetonia, ID, July 27, 2022. (2 presentations) Cropping system diversity. Aberdeen Twilight Tour, Aberdeen, ID. July 13, 2022 Barley-pulse intercropping systems. Scoular Field Day, Jerome, ID, June 28, 2022 Field project updates on cereal intercropping systems. UI Pest Management Research Tours, Aberdeen, ID, June 28, 2022 Cereal-pea intercropping systems in organic transition. UI Pest Management Research Tours, Kimberly, ID, June 22, 2022 Cereal-pulse cropping systems. USDA NRCS 5 for 5 Soil Health (webinar). March 10, 2022 What do you plan to do during the next reporting period to accomplish the goals?With more complete results by the end of 2022, we can incorporate this project into course materials in spring 2023. We can also share the more solid results (e.g., crop yield and quality) with growers at meetings or workshops in fall 2022 and spring 2023.

Impacts
What was accomplished under these goals? Producers in Idaho, other western states, and across the nation need robust agronomic tools to achieve high productivity under different water availabilities while sustaining limited soil resources in organic farming. This project adds to this toolset by focusing on producer-relevant response variables such as crop yield, crop quality, water use, soil fertility and health, and farming profitability for the proposed organic production system of cereal-pulse intercropping.Thisproject also intensifies and diversifies cropping systems for crops critical to Idaho's and the region's economy. Results from this project will highlight the benefits of an organic production system that increases overall crop productivity, enhances soil fertility and health, and improves crop resilience to drought stress, by adding horizontal, vertical, structural, and functional diversity to agroecosystems. Objective 1:Understand the effects of cereal-pea intercropping systems on crop productivity, soil health and fertility, and enhanced diversity of crops and soil microbes under well-watered and drought-stressed conditions during the organic transition. We established the field experimentfor the first year as we proposed. Plant and soil samples havebeen collected for crop growth and productivity as well as soil health and fertility. Soil greenhouse gas emissions were measured at the end of the growing season. We focused our efforts on CO2 since the soils were dry at this time and we did not detect noticeable increases in concentrations of CH4 or N2O. Soil gas flux in full irrigation plots was greater than the deficit, except for monocropping barley where sampling resolution was too small to distinguish the water treatment. The intercropping of cerealsat 75% with peas at 50% produced the largest soil CO2 flux, suggesting a higher metabolic activity for these plots. The majority of weeds were common lambsquarters, and weed biomass from plots of wheat-pea intercropping and monocropping wheat was greater than treatments of 75%barley+25%pea and 75%balrey+75%pea.Weeds were sampled early in the growing season shortly afterirrigation treatments were initiated, so weedbiomass was not strongly affected by irrigation treatment. Significant differences in normalized difference vegetation index (NDVI) were found at stages of stem elongation and heading, and monocropping barley and intercropping barley treatments with high proportions of barley (e.g., 75%barley+75%pea) usually showed greater NDVI than other treatments. Plant biomass at the heading stage was significantly affected by cereal-pea intercropping treatment, and biomass fromtreatments of 75%barley+25%pea, 75%barley+75%pea, monocropping barley, and 50%barley+50%pea was greater than monocropping wheat and pea. At this stage, biomass under full irrigation was slightly greaterthan deficit irrigation. So far, monocropping barley and barley-pea intercropping treatments have shown superiorityto monocropping and/or intercropping wheat treatments in terms of weed suppression, canopy development, and biomass production. Objective 2:Involve undergraduate and graduate students in working on the project and include the project in course materials. We have involved 1 undergraduate and 1 Ph.D. student working on this project. Objective 3:Determine the overall economic return of intercropping production under irrigated and dryland conditions during organic transition and on organic farms and transfer findings from the project to stakeholders and the public via a robust extension and outreach plan. We demonstrated our project to stakeholders and the public at 7 extension events. The proposed webpage is under development.Participants of our extension events have becomeaware of the option of cereal-pea intercropping systems in organic transition and organic farming.

Publications