Source: UNIVERSITY OF KENTUCKY submitted to
THE HEMP EFFECT: WHAT IMPACT WILL INCORPORATING HEMP INTO TRADITIONAL CROP ROTATIONS HAVE ON THE PROVISIONING OF AGROECOSYSTEM SERVICES?
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
NEW
Funding Source
Reporting Frequency
Annual
Accession No.
1022071
Grant No.
2020-67013-30863
Project No.
KY0MOE02
Proposal No.
2019-06664
Multistate No.
(N/A)
Program Code
A1102
Project Start Date
May 1, 2020
Project End Date
Apr 30, 2025
Grant Year
2020
Project Director
Moe, L. A.
Recipient Organization
UNIVERSITY OF KENTUCKY
500 S LIMESTONE 109 KINKEAD HALL
LEXINGTON,KY 40526-0001
Performing Department
Plant and Soil Sciences
Non Technical Summary
As acreage devoted to industrial hemp increases across the US, it is incumbent upon agricultural scientists to understand the impact that incorporation of hemp into management systems will have on rotational crop yield and agroecosystem services such as soil health and function. Further, there is a dramatic paucity of knowledge in general on industrial hemp and its agronomic value. The proposed work will establish a necessary framework for studying industrial hemp, generate knowledge on the sustainability of industrial hemp as a rotation crop, train scientists in hemp agronomy and agroecosystem services, and strengthen collaborative work between the two land-grant institutions in the state of Kentucky. This project will incorporate both hemp for fiber and hemp for grain into conventional crop rotations (corn-wheat-soybean) at two established Kentucky research farm sites. The impact of hemp on grain crop yield, as well as on hemp fiber biomass will be assessed to determine profitability, and identify changes to provisioning services compared to a conventional rotation. Agroecosystem services related to sustainability and soil health and function will be measured, including soil physical, chemical, and biological parameters. Weed pressure and diversity will be measured to determine how the lack of allowable pesticide use on hemp impacts weeds in hemp and subsequent crops
Animal Health Component
0%
Research Effort Categories
Basic
75%
Applied
25%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2050110106035%
2051599114015%
2051730106035%
6011730106015%
Goals / Objectives
As acreage devoted to industrial hemp increases across the US, it is incumbent upon agricultural scientists to understand the impact that incorporation of hemp into management systems will have on rotational crop yield and agroecosystem services such as soil health and function. Further, there is a dramatic paucity of knowledge in general on industrial hemp and its agronomic value. The proposed work will establish a necessary framework for studying industrial hemp, generate knowledge on the sustainability of industrial hemp as a rotation crop, train scientists in hemp agronomy and agroecosystem services, and strengthen collaborative work between the two land-grant institutions in the state of Kentucky. This project will incorporate both hemp for fiber and hemp for grain into conventional crop rotations (corn-wheat-soybean) at two established Kentucky research farm sites. The impact of hemp on grain crop yield, as well as on hemp fiber biomass will be assessed to determine profitability, and identify changes to provisioning services compared to a conventional rotation. Agroecosystem services related to sustainability and soil health and function will be measured, including soil physical, chemical, and biological parameters. Weed pressure and diversity will be measured to determine how the lack of allowable pesticide use on hemp impacts weeds in hemp and subsequent crops.
Project Methods
To test our hypothesis, that incorporating hemp into traditional Kentucky crop rotations will have a positive effect on agroecosystem regulating and supporting services, such as promoting soil carbon accumulation and reducing soil-to-atmosphere greenhouse gas fluxes, and will not negatively impact provisioning services, such as crop yield of subsequent rotations, we will deploy a crop rotation scheme including fiber and grain hemp at two field sites in Kentucky.Five replicate blocks of the six crop rotation treatments will be planted at each site, in a randomized complete block design. Plots will be 17 ft x 30 ft, and will include 10 ft buffers. All crops will be planted by standard no-till practices to be consistent with how grain and fiber hemp are typically managed in Kentucky rotations. Each crop (corn, soybean, grain hemp, fiber hemp) will be harvested at maturity and/or when field moisture levels support storage. One 5m2 area within each plot will be hand-harvested to determine crop yields and will be reported in dry yield/A. Harvest sample area will be randomly selected avoiding no less than two border rows in the y plane and 1m in the x plane. For fiber hemp plots the stalks will be cut from the defined harvest area and weighed to determine fresh weight. The stalks will be loosely bundled, tagged, and returned to the harvest area for retting. The remaining border area will be cut and left to ret in place. After 3 to 4 weeks of retting, stalks from the defined harvest area will be weighed again to estimate retted stalk yields and then dried in crop dryer to determine dry weight yield. Retted stalks in the border area will be removed to simulate complete harvest. Grain hemp yield will be determined by hand harvesting grain heads in the defined harvest area, drying and threshing with a stationary thresher. Grain heads will be removed from the border areas to simulate a complete grain harvest. Remaining crop residue (leaves, stalks) will be chopped in place and left on the plot similar to crop residue management for corn and soybean. Winter wheat will be established as a cover crop for all treatments post-harvest, and is not used here as a harvested commodity crop. We have chosen to use a cover crop to provide uniformity to treatments, and to be in line with common agricultural practices in Kentucky.Aim 1: Impact of industrial hemp rotation on crop productivity and profitabilityTo test our hypothesis that incorporation of hemp into the common corn-wheat-soybean rotation will not negatively impact the yield of commodity crops, we will measure biomass or grain production of crops in our experimental crop rotation scheme. A profitability model will be set up to assess profitability of all experimental crop rotation schemes. Data will be analyzed using a mixed linear model (Proc Mixed) procedure in the SAS statistical package (SAS Institute, v.9.1., Cary, NC). Yield, biomass, and root production will be analyzed using crop rotation treatment as a fixed effect and block as a random effect. Overall F-tests will be used to assess significant differences between treatments, and when significant, pairwise comparisons using protected LSD will be performed. Normality and homogeneity of variance will be assessed on all measured parameters, with transformation occurring as necessary.Aim 2: Impact of industrial hemp on weed pressure and diversityWe will assess whether incorporation of hemp into traditional Kentucky crop rotations affects weed abundance and diversity in subsequent crops. To do so, we will randomly locate two 0.5m2 quadrats within the interior of each plot and visually estimate cover (to 1%) of all weed species present. Weed species richness per sampling period will be calculated (sum of all weed species encountered in a plot) and is a representation of species diversity.The same Proc Mixed linear models as developed for the yield methods will be utilized here, except in this case a repeated measures time element will be incorporated for relevant parameters (e.g., for weed abundance over the two or more time periods sampled per crop rotation). It is possible that a non-metric multi-dimensional scaling ordination approach might help visualize some of the trends in the data, in which case we will utilize PC-ORD.Aim 3: Impact of industrial hemp on soil health and functioningWe hypothesize that incorporation of hemp into Kentucky crop rotations will have a positive impact on soil health parameters and soil functioning. We will measure a variety of soil chemical, biological, and physical parameters across our experimental design.Soil chemical parameters - Soil pH, extractable cations, total N and soil test P and K will be measured on composite 0-10cm samples taken upon experiment initiation and then at harvest for all subsequent crops for each crop rotation treatment at both sites (total soil samples = 480). We will sample one meter deep soil core from each plot at the initiation and end of the project for quantification of any deeper changes in these parameters. These will be sent to Regulatory Services on the UK campus for routine soil analysis and processed using standard procedures (http://soils.rs.uky.edu/ ).Soil biological parameters - In order to assess differences in microbiota across crop rotations, culture-independent bacterial community analysis will be carried out on rhizosphere samples from each plot at each site during the wheat crop for each year. We also will measure both AMF root colonization rates and soil extraradical hyphal length. We will utilize a 1412 Infrared Photoacoustic Spectroscopy gas analyzer (Innova Air Tech Instruments, Ballerup, Denmark) which is equipped to measure CO2 and N2O simultaneously. Soil organic matter parameters - We will measure several organic matter pools on a sub-sample of the same surface, 0-10cm composite soil samples that will be taken for the soil fertility analyses. We will measure permanganate oxidizeable carbon according to published procedures (Weil, Islam et al., 2003). We will also perform organic matter separations as per (Six, Elliot et al., 2000) and determine total C and macro- and micro-aggregate C (Iqbal, Siegrist et al., 2012). Soil aggregate stability - We will measure aggregate stability on each plot at the beginning of the trial and following the final harvest as an indicator of the cumulative effects of carbon flux on soil structure in the different rotations. Ten soil cores (5 cm diameter) will be collected from the 0-10 cm depth of each plot, gently broken apart by hand and passed through a 10 mm sieve to remove large rocks and roots. Samples will be kept at field moisture and stored at 4° C until wet sieving. Samples will be wet sieved through a series of sieves to obtain four aggregate size fractions: (i) > 2000 µm (large macroaggregates), (ii) 250 to 2000 µm (small macroaggregates), (iii) 53 to 250 µm (microaggregates), and (iv) < 3 µm (silt plus clay-sized particles) (Elliott, 1986).The same statistical approach developed for the previous aims will also be deployed here - linear mixed models including a repeated measures design if/when appropriate and ordinations for multidimensional data, such as the bacterial community analyses. Data resulting from microbial community analysis will be linked to measured soil biological and chemical parameters using MRPP and ordination analysis to identify statistically significant trends relating microbial communities (16S rRNA data) to functional gene data (qPCR data), AMF data, greenhouse gas emission, and soil chemistry as outlined above (see, for example, Law, Fisher, et al., 2016).

Progress 05/01/21 to 04/30/22

Outputs
Target Audience:The target audience served by this project will include the following: agricultural researchers interested in optimizing crop rotations to benefit profitability and increase crop diversity; agroecologists interested in understanding the myriad roles of crop rotations in affecting the ecology of agroecosystems; environmental microbiologists interested in the impact of certain crops on soil health and greenhouse gas emission; weed scientists interested in the impact that hemp inclusion has on weed pressure; and farmers interested in how they can optimize crop rotations including hemp. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?PhD student Kent Pham (University of Kentucky) has had the opportunity to participate in a UK NSF funded research traineeship (NRT) focused at the nexus of food, energy, and water systems. As part of this traineeship, he has had the opportunity to participate in professional development seminars and has been part of a team that wrote a proposal that was funded by the NRT to explore revegetation of spoiled mine lands. Kent also wrote up an application for an NSF graduate research fellowship that was submitted this year. He will be presenting his work at the American Society for Microbiology meeting during the Summer of 2022. Kent also mentored an undergraduate student in research during the Spring 2022 semester. MS student Micheal Adeniji (Kentucky State University) started his thesis project during this reporting period. He is working under Co-Investigator Shawn Lucas. Micheal presented his work at the20th Research Symposium of the Association of 1890 Research Directors in Atlanta, GA, on April 3, 2022. How have the results been disseminated to communities of interest?Unfortunately the University of Kentucky did not have a hemp field day in 2021, owing to COVID concerns. Field days are one means by which we disseminate our research to producers. There is a hemp field day scheduled for September 2022. Regarding dissemination to the broader scientific community, MS student Micheal Adeniji disseminated work from our group at the20th Research Symposium of the Association of 1890 Research Directors in Atlanta, GA, on April 3, 2022. What do you plan to do during the next reporting period to accomplish the goals?During the period from May 1, 2022 to April 30, 2023, we will continue with our crop rotation scheme and data collection as described above. This summer we will also initiate greenhouse gas measurements in the plots at the University of Kentucky research farm. Many members of our team will be participating in conferences during the summer of 2022 as well, and will be disseminating results in this way.

Impacts
What was accomplished under these goals? As of April 30, 2022, year 1 field work has been completed. At Fall 2021 harvest, the following data was collected: crop yield (hemp grain, hemp fiber, corn, and soybean), soil fertility measurements, soil root cores were taken, POX-C measurements, and nutrient loss for retting hemp. All plots were put into winter wheat, and rhizosphere samples from all wheat plots were collected prior to wheat glyphosate burndown. The rhizosphere samples represent the second sampling, with the first being from Spring 2020, which was the preliminary winter wheat cover prior to onset of the rotation scheme for year 1. The year 1 rhizosphere samples have been processed and 16S rRNA gene amplicon sequencing has been completed. As expected, microbial communities are quite similar between plots at the same site, but differences exist between plots at the different sites.

Publications


    Progress 05/01/20 to 04/30/21

    Outputs
    Target Audience:The target audience served by this project will include the following: agricultural researchers interested in optimizing crop rotations to benefit profitability and increase crop diversity; agroecologists interested in understanding the myriad roles of crop rotations in affecting the ecology of agroecosystems; environmental microbiologists interested in the impact of certain crops on soil health and greenhouse gas emission; weed scientists interested in the impact that hemp inclusion has on weed pressure; and farmers interested in how they can optimize crop rotations including hemp. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Graduate student Kent Pham joined the project in the Fall of 2020 and has taken graduate classes and has participated in the plot establishment and sampling strategies. Kent is also participating in a new graduate level certificate program related to research at the nexus of food, energy, and water systems. As part of this program he participated in a professional development seminar and wrote up a collaborative research proposal with peers from the program. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?The next reporting period will see our first year harvest, initiation of the weed science portion of the project, and soil/rhizosphere sampling. We will also initiate the greenhouse gas sampling strategies from the plots at the University of Kentucky research farm.

    Impacts
    What was accomplished under these goals? Cover crops were established on all plots during the Fall of 2020. Soil and rhizosphere sampling occurred from the cover crops prior to cover crop burndown by glyphosate in Spring 2021. Plots were planted with corn, soybean, grain hemp, and fiber hemp during the Spring of 2021.

    Publications