Brief Summary of Minutes of Annual Meeting

Brief Summary of Minutes of Annual Meeting

The officers selected for 2019 at the 2018 meeting were Sindhu Jagadamma (Chair), University of Tennessee, Knoxville and Mark Coyne (Secretary) University of Kentucky. The 2019 meeting was conducted at the University of Tennessee Plant Biotechnology Building (Room 410) 2505 E J Chapman Dr., Knoxville, TN 37996 on July 9-10, 2019. Sindhu Jagadamma opened the meeting on July 9, 2019 at 9:00 am.   The first order of business was introduction of the attendees. Subsequently, state reports were presented for TN (Jagadamma), WI (Ruark), MI (Tiemann), and MN (Gutknecht) followed by lunch. In the afternoon state reports from KY (Coyne and Poffenbarger) and IL (Ugarte on behalf of Wander) were presented, after which there was a tour of the UTK Gardens.  

On July 10, 2019 the meeting started at 9 am at University of Tennessee Plant Biotechnology Building (Room 410). The remaining state reports for ND (Cihacek), IA (Castellano) and the Iowa USDA-ARS (Olk) were presented. Olk led a detailed discussion about the status, organization, design, and completion of a new publication on soil organic matter microbiological and biochemical analyses with much debate on the merits of a strictly on-line work vs. a more formal book publication. New officers were elected for 2020: Mark Coyne (Chair) University of Kentucky and XX YY (secretary) University of XX. The 2020 meeting will be held in Lexington Kentucky in July while the 2021 meeting place was left indeterminate. The meeting was adjourned at 12 pm by Sindhu Jagadamma.

See Appendix 1 for full meeting minutes

Accomplishments (including shot-term outcomes, outputs, activities and milestones):

A committee effort recently reported ‘Changes in our nation’s research landscape are shifting responsibility for soil stewardship from national and state government backed entities to public-private partnerships. As a result, it is critical to ensure that the data needed to assess soil health are generated by reproducible methods selected through a transparent process, and that data are readily available for public and private sector use. Appropriate methods for engagement need to be applied by public-private research partnerships as they establish and expand coordinated research enterprises that can deliver fact-based interpretation of soil quality indicators within the type of normative soil health framework conceived by USDA over 20 years ago. We look to existing examples as we consider how to put soil health information into the hands of practitioners in a manner that protects soils’ services’ (Wander et al. 2019.)

Committee members worked together under the leadership of Michelle Wander for a presentation at the SSSA meeting in San Diego “NCERA 59's Reflections on Soil Health and Soil Quality” that was based on content being developed for a jointly authored paper that was published in 2019. The title of the paper is “Developments in Soil Quality and Health: Reflections by the Research Committee on Soil Organic Matter Management” published in Frontiers in Environmental Science.

Other Accomplishments by State      

KY:      

Current projects related to soil organic matter

Effects of long-term no-till on optimal nitrogen fertilization practices for corn (2018-2019)

Hanna Poffenbarger and John Grove

No-tillage can increase soil organic matter content, which is an important source of nitrogen for corn (Zea mays L.). However, higher soil organic matter content may not necessarily lead to lower nitrogen fertilizer requirements in no-till soils due to cooler, wetter conditions that can slow nitrogen mineralization during early corn growth. The objective of this study was to determine the effect of long-term no-till on the optimal timing and rate of nitrogen fertilizer for corn. We investigated nitrogen dynamics over two growing seasons within a 48-year field study that comprises a factorial of two tillage treatments (no-tillage and conventional tillage) and four nitrogen rates (0, 84, 168, and 336 kg N ha^-1). In 2018 and 2019, we established two nitrogen fertilization timing treatments within each nitrogen rate: 1) an early application in which all nitrogen was applied at the V3 stage of corn, and 2) a split application in which 56 kg N ha^-1 was applied at V12 and the remaining was applied at V3. Our results suggest that long-term no-till increases nitrogen mineralization, but has minor effect on the yield-maximizing nitrogen rate or on optimal timing of nitrogen fertilization.

Getting to the root of the matter: Linking root traits to soil health (2019-2024)

Hanna Poffenbarger and David McNear

Soil organic matter (SOM) contains large stocks of C and N, represents a major source and sink of atmospheric greenhouse gases, and plays a key role in soil health and fertility. Because SOM content is positively associated with crop yield and yield stability, increasing SOM can benefit farmer income, food security, and resource use efficiency while providing ecosystem services like C sequestration. Most of the organic matter in soil is derived from roots, yet it is unclear how root traits regulate the formation and stability of SOM. This project will advance our understanding of crop root system impacts on SOM. Our objectives are to: 1) quantify variation in root traits among a diverse panel of maize cultivars, 2) determine the effect of root phenotype on SOM dynamics, and 3) determine the interactive effects of specific root characteristics and soil properties on the formation and stability of SOM. Using a diverse panel of 18 open-pollinated varieties and hybrids grown in the greenhouse, we propose to measure changes in exudate production, root architectural traits, and root litter quality due to breeding over the last ~100 years. We will select four hybrids with distinct root systems from this panel for a field study that will test the effects of hybrid, plant density, and aboveground residue removal on SOM storage using natural abundance ¹³C tracing. Lastly, we will perform a laboratory incubation study to investigate the effects of root litter quality on the efficiency of SOM stabilization in different soil types. Through this research, we expect to identify root traits that promote the formation and stability of SOM.

Assessing soil organic carbon responses to synergistic effects of no-tillage and cover crops under climate change (1970-2099): Integration of long-term field trials and agroecosystem modeling

Wei Ren

Climate-smart agriculture management like no-tillage (NT) with cover crop offers multiple benefits (e.g., increase soil carbon stocks) that can help reduce the impacts of climate change on crop production. Through applying agroecosystem modeling in combination with a long-term field experiment (1970-2018), we firstly examined the synergic effect of NT and cover crop on the soil organic carbon (SOC) dynamics over the past fifty years. Both field observations and simulation results show that NT leads to greater carbon gains (0.22 Mg C ha^-1 yr^-1) in the topsoil compared with conventional tillage. Model attribution analysis further explores that 1) soil carbon sequestration was highly correlated to biomass carbon inputs from both winter rye cover crop and corn cropping; 2) elevated CO₂ and warming effects are main contributors to benefiting SOC gains mainly through promoting cover crop growth. We also conducted model projections and the results show that SOC levels under NT-cover crop management would be enhanced with an increasing rate of 0.089 Mg C ha^-1 yr^-1 under high-emissions scenarios (RCP8.5) from 2019 to 2099, largely due to enhanced biomass production of cover crop. Our study indicates that cover crop is of vital importance for soil carbon sequestration; and a combination of NT and cover crop would be an effective management strategy for climate change mitigation.

Also see Appendix 2.

ND:    

N mineralization from long-term no-till crop residues.

A sequence of 5 (5) 12-14 week incubations (Stanford and Smith method) to simulate N mineralization for the 5 “cropping seasons” were conducted with residues applied to the soil surface rather than incorporated.  Residues included corn, soybean, spring wheat, winter wheat, winter pea, and forage radish.  After each incubation cycle, the soils were frozen for three weeks to simulate a winter season.  At the beginning of the next incubation cycle, crop residue was added to the incubation tubes and the incubation was repeated.  During the first three cycles, N mineralization mirrored previous studies where crop residues of high C:N ratio residues (>40) showed N immobilization and low C:N ratio residues (<20) showed net mineralization.  During the fourth and fifth incubation cycles, untreated soil (control soil) N mineralization increased indicating that changes occurred within the soil microbiological community that increased decomposition of inherent organic matter in the absence for added residue.  However, even though base-line N mineralization increased, the N mineralization or immobilization relationships of the residue materials did not change.  (See attached Figures 1 through 6).

N mineralization from farmer soil samples.

 Sixty one (61) farmer samples from across the state of North Dakota with a range of organic matter values obtained by the NDSU Soil Testing Laboratory were subject to 7-day anaerobic incubations to determine potentially mineralizable N (PMN).  Regression analysis of the data indicated that about 7.4 ug N/g soil was mineralized per percent of SOM.  This indicated that as soil health potentially improves by using management practices enhancing soil health, soil test based N fertilizer recommendations may need to be adjusted for PMN availability as soil organic matter increases. (See attached Figure 7).

N mineralization from long-term no-till crop residues.

Several iterations of N mineralizaton have been conducted including characterization of N mineralization rates from selected drop residues, N mineralization characterization from mixed residues and effects of repeated residue applications over simulated growing seasons. Current studies include incubating residues of corn soybean and wheat in simulated common crop rotations over three simulated “growing seasons” with or without cover crop residues in the wheat or soybean phases of the crop rotations.

N mineralization from farmer soil samples.  

PMN evaluations have been completed and the soil samples are being characterized for textural analysis to attempt to relate soil physical property effects on PMN of north Dakota soils.

N mineralization in integrated crop-grazing systems.

No data is being reported for this reporting cycle.  However, data continues to be collected for the ninth and tenth (2019) cropping seasons.

NE:    

My research program addresses the functional significance of soil microbial communities to the management and performance of agricultural and natural ecosystems. A key component is identifying drivers of microbial community composition and processes linked to crop/rangeland productivity and soil health/ecosystem services in maize and grassland systems subjected to intensification, diversification/invasion and climate change. Current projects related to the goals of NCERA59 include:

UNDERSTAND THE ROLE OF ARBUSCULAR MYCORRHIZAL FUNGI IN MANAGED ECOSYSTEMS AND APPLY THIS KNOWLEDGE TO IMPROVE PLANT PRODUCTIVITY AND SOIL SUSTAINABILITY

Our recent work demonstrated an inverse relationship between N fertilizer addition and extra-radical AMF biomass (i.e. in the soil) that was most strongly expressed at maize reproduction.  This led to the hypothesis that N-stressed plants allocate more C to the AMF partner to promote extra-radical mycelial (ERM) growth in the soil and thereby N uptake. To verify that this increase in soil AMF biomass under low N conditions was driven by increased ERM, a study was conducted in eastern NE where long-term continuous maize had received 0, 90, or 180 kg N ha-1. Root exclusion bags were filled with soil from each plot and placed in the maize root zone at the midpoint of vegetative growth (V10) and removed seven weeks later (R3). Lipids were extracted from the soil and the AMF specific fatty acid biomarker C16:1c11 was quantified in neutral, glycol- and phospholipid fractions.  The AMF biomarker only increased in the mesh bags where no N fertilizer had been applied. Hyphal length measurements supported this trend but were not significant.  This data verifies increased ERM growth under conditions of N deficiency and indicates that neutral lipids containing C16:1c11 were transported in the ERM to promote hyphal growth and possibly N uptake. This work was presented at the 2019 SSSA meetings in San Diego.

UNDERSTAND THE IMPACT OF NITROGEN FERTILIZATION AND CROP ROTATION ON SOIL MICROBIAL COMMUNITY STRUCTURE AND FUNCTION IN MANAGED ECOSYSTEMS AND APPLY THIS KNOWLEDGE TO IMPROVE PRODUCTIVITY AND SUSTAINABILITY

Our group is currently exploring how long-term practices of crop rotation and nitrogen fertilization at the USDA-ARS long-term crop rotation field site (CRS) shape distinct soil microbial communities and contribute to aboveground and below-ground ecological processes in dryland no-till maize agroecosystems. Using both fatty acid data and bacterial 16S DNA sequencing, Ashley Stengel found that bacterial communities in continuous corn (CC) plots were distinctly separated by nitrogen fertilization rate, whereas communities in corn following soybean (CSB) did not differ. This pattern suggests that soybean is providing a buffer to nitrogen stress, which is in turn influencing the microbial community composition and could be contributing to the enhanced yields seen in CSB plots over CC plots. A similar pattern has been uncovered in our high yield irrigated systems at maize reproduction, but is accompanied by reduced bacterial and fungal biomass in corn following soybean compared to continuous corn. This work was presented at the 2019 SSSA meetings in San Diego. Understanding the maize-associated soil microbiome under variable and diverse nutrient conditions is important for ascertaining how microbial resiliency and redundancy may promote healthy soils and hardy crops.

IDENTIFY CROP RESIDUE AND/OR COVERCROP MANAGEMENT STRATEGIES WITH POSITIVE IMPACTS ON SOIL HEALTH AND ECOSYSTEM SERVICES VIA ALTERATIONS IN SOIL MICROBIAL COMMUNITY STRUCTURE AND FUNCTION

How we manage crop residues, either via tillage, stover removal and/or grazing may have significant impacts on soil health and function. In collaboration with USDA-ARS we are investigating soil microbial community structure and function in two long-term cropping systems: (1) Corn Stover Removal Study (REAP) and (2) Roger’s Memorial Farm Tillage Crop Rotation Experiment (RMF). Salvador Ramirez has completed a first draft of his REAP manuscript entitled ‘Impact of Corn Stover Removal on Soil Microbial Communities in No-till and Conventional till Continuous Corn’ for submission to Agronomy Journal.

Baling and grazing of maize residues are common practices in irrigated systems to meet increasing demands for forage. In collaboration with Humberto Blanco and his PhD student Manbir Rakkar and Post doc Sabrina Ruis, we examined the impact of maize stover grazing vs. baling on soil microbial biomass (SMB) and community structure in two short-term studies. The second paper by Manbir Rakkar entitled ‘Grazing crop residues has less impact in the short-term on soil properties than baling in the Central Great Plains’ has now been published in Agronomy Journal.

SD:     

Unique project findings - Inclusion of cover crops and grazing with no-till enhanced the soil health parameters.

Cover crops, diverse rotations, and no-till systems are the key components of conservation agricultural systems and improve soil biodiversity, soil organic matter, and nutrient cycling. It is well documented in the literature the benefits of cover crops and grazing on soil health, however, research evaluating how soil health improved through the influence of soil microbial communities remains limited and need attention. Integrating livestock into cropping systems to graze cover crops may enhance soil health through improved soil biodiversity. A study was conducted in South Dakota at three different locations. We investigated the impacts of cover crops and grazing on microbial community structure under different cropping systems using phospholipid fatty acid (PLFA) analysis. Cover crop treatments and no cover crop controls with and without grazing were compared. Cover crops with grazing (Total biomass, 5854.46 ng g^-1; Actinomycetes biomass, 622.31 ng g^-1) had a higher PLFA content than no cover crops (control). Soil biological activity varied with the treatment and significantly recorded higher PLFAs under cover crops with grazing. This study provides a clear link between cover crops, grazing, soil microbial communities, and soil health. This may pave the way for better management of the soil biodiversity (soil microbiome) to enhance sustainable soil health through incorporating cover crops and grazing in the cropping system.

TN:

1. Published 6 peer-reviewed scientific articles in the area of SOC and soil health
2. Delivered 13 conference presentations with a published abstract

• Trained 1 postdoc, 2 Ph.D. students, 2 MS students and 2 undergraduate students in the area of SOC and soil health

1. Received two grants in related areas
2. Co-authored a publication with other NCERA59 participants
3. Hosted NCERA-59 meeting at the University of Tennessee

Peer-reviewed Publications:

Collectively, the committee had one peer-reviewed publication:

Wander, M.M., L. J. Cihacek, M. Coyne, R. A. Drijber, J. M. Grossman, J. Gutknecht, W. R. Horwath, S. Jagadamma, D. C. Olk, L. K. Tiemann, M. Ruark, S. S. Snapp, R. Weil, and R. F. Turco. 2019. Developments in soil quality and health: Reflections by the research committee on soil organic matter management. Frontiers in Environmental Science 7:1-9. doi:10.3389/fenvs.2019.00109.

There were 21 other published or accepted peer-reviewed publications in which one or more committee members were co-authors:

Bai, X., Y. Huang, W. Ren, M. Coyne,  P.-A. Jacinthe,  B. Tao,  D. Hui,  J. Yang, and C. Matocha. 2019. Responses of soil carbon sequestration to climate smart agriculture practices: A meta-analysis" Global Change Biology DOI:10.1111/gcb.14658.

Bakker, E. Findling, B. Lanson, Wander, M.M., and N E. Hubert 2019. Mineralogical differences in a temperate cultivated soil arising from different agronomic processes and plant K-uptake. Geoderma. 347 (2019) 210–219

Baveye, P.C., and M. Wander. 2019. The (bio)chemistry of soil humus and humic substances: Why is the “new view” still considered novel after more than 80 years?  Frontiers in Environmental Science, 06 March 2019  https://doi.org/10.3389/fenvs.2019.00027.

Chen, X., M., Jin, Y. Xu, W. Chu, D.C. Olk, J. Hu, Y. Jiang, J. Mao, H. Gao, and M.L. Thompson. 2019.  Potential alterations in the chemical structure of soil organic matter components during sodium hydroxide extraction.  Journal of Environmental Quality 48: (in press).

Chu, M., Singh, S., Walker, F.R., Eash, N.S., Buschermohle, M.J., Duncan, L.A., and Jagadamma, S. 2019. Soil health and soil fertility assessment by the Haney Soil Health Test in an agricultural soil in west Tennessee. Communications in Soil Science and Plant Analysis 50(9): 1123-1131.

Drijber, R.A., E.S. Jeske. Polarity of chloroform eluent critical to quantification of arbuscular mycorrhizal biomass using the neutral lipid fatty acid biomarker C16:1cis11. Accepted by Soil Biology & Biochemistry.

Florence, A.M., L.G. Higley, R.A. Drijber, C.A. Francis, J.L. Lindquist. 2019. Cover crop mixture diversity, biomass productivity, weed suppression, and stability. Accepted by PLoS One

Jagadamma, S., Essington, M.E., Xu, S., and Yin, X. 2019. Total and active organic carbon from long-term agricultural management practices in West Tennessee. Agricultural and Environmental Letters 4:180062

Kaur, J., A. Chatterjee, D Franzen, and L. J. Cihacek.  2019.  Corn Response to Sulfur Fertilizer in the Red River Valley. Agron. J. doi:10.2134/agronj2018.05.0313.

Lenssen, A.W., D.C. Olk, and D.L. Dinnes.  2019.  Application of a formulated humic product can increase soybean yield. Crop, Forage, & Turfgrass Management: (in press).https://doi.org/10.2134/cftm2018.07.0053

Mahal, N.K., W.R. Osterholz, F.E. Miguez, H.J. Poffenbarger, J.E. Sawyer, D.C. Olk, S. Archontoulis, and M.J. Castellano. 2019. Nitrogen fertilizer suppresses mineralization of soil organic matter in maize agroecosystems.  Frontiers in Ecology and Evolution 7:59.  https://doi.org/10.3389/fevo.2019.00059

Maiga, A., Alhameid, A., Singh, S., Polat, A., Singh, J., Kumar, S. and Osborne, S. 2019. Responses of soil organic carbon, aggregate stability, carbon and nitrogen fractions to 15 and 24 years of no-till diversified crop rotations. Soil Research (In Press).

Miao, F., Li, Y., Cui, S., Jagadamma, S., Yang, G., and Zhang, Q.  2019. Soil extracellular enzyme activities under long-term fertilization management in the croplands of China: A meta-analysis. Nutrient Cycling in Agroecosystems 114(2): 125-138.

Olk, D.C., P.R. Bloom, M. De Nobili, Y. Chen, D. McKnight, M.JM. Wells, J. Weber. 2019. Using humic fractions to understand natural organic matter processes in soil and water: Selected studies and applications. Journal of Environmental Quality 48: (in press).  Doi https://doi.org/10.2134/jeq2019.03.0100

Olk, D.C., D.L. Dinnes, J.R. Scoresby, C.R. Callaway, and J.W. Darlington. 2019. Can humic products substantially improve ecosystem quality and economic yield?  Silva Balcanica: 20(2): 95-110.

Ozlu, E., S. Singh., Kumar, S., and Arriaga, F. J. 2019. Soil health indicators impacted by long-term manure and inorganic fertilizer of corn-soybean rotation in South Dakota. Scientific Reports (In Press).

Rakkar, M.K., H. Blanco-Canqui, R.J. Rasby, K. Ulmer, J. Cox-O’Neill, M.E. Drewnoski, R.A. Drijber, K. Jenkins, J.C. MacDonald. 2018. Grazing crop residues has less impact in the short-term on soil properties than baling in the Central Great Plains. Agronomy Journal, doi:10.2134/agronj2018.03.0224

Sarr* S., M. Gebremedhin, M. Coyne, A. Topè, K. Sistani, and S. Lucas. 2019. Do conservation practices bring quick changes to key soil properties for resource-limited farmers? Journal of the Kentucky Academy of Sciences. (In press 8/29/2019).

Sekaran, U., C. McCoy, S. Kumar, and S. Subramanian. 2019. Soil microbial community structure and enzymatic activity responses to nitrogen management and landscape positions in switchgrass (Panicum virgatum L.). GCB Bioenergy:1-16.

Singh, S., Yan, S., Sorochan, J., Stier, J., Mayes, M.A., Zhuang, J., and Jagadamma, S. 2019. Soil carbon accumulation and nutrient availability in managed and unmanaged ecosystems of East Tennessee. Soil Science Society of America Journal 83:458-465. 

Zou, C., J. H. Grove, R. C. Pearce, and M.S.  Coyne. 2019. What happens to in situ net soil nitrogen mineralization when nitrogen fertility changes? Journal of Plant Nutrition and Soil Sciences. 182:296-306. doi:10.1002/jpln.201800551.

In addition, committee members published 6 manuscripts in 2018 after the submission of the annual report.

Dandan, L., L, Chen, J. Xu, L. Ma, D.C. Olk, B. Zhao, J. Zhang, and X. Xin. 2018. Chemical nature of soil organic carbon under different long-term fertilization regimes is coupled with changes in the bacterial community composition in a Calcaric Fluvisol.  Biology and Fertility of Soils 54:999-1012.  https://doi.org/10.1007/s00374-018-1319-0

Kuar, J., L. Cihacek, and A. Chatterjee.  2018.  Estimation of nitrogen (N) and sulfur (S) mineralization in soils amended with crop residues contributing to N and S nutrition of corn in the north Central U.S. Commun. Soil Sci. Plant Anal. 49(18):2256-2266. 

Rakkar, M.K., H. Blanco-Canqui, R.J. Rasby, K. Ulmer, J. Cox-O’Neill, M.E. Drewnoski, R.A. Drijber, K. Jenkins, J.C. MacDonald. 2018. Grazing crop residues has less impact in the short-term on soil properties than baling in the Central Great Plains. Agronomy Journal, doi:10.2134/agronj2018.03.0224

Ugarte, C.M., H. Kwon, and M.M. Wander. 2018. Conservation management and ecosystem services in Midwest agricultural systems. Journal of Soil and Water Conservation. doi: 10.2489/jswc.73.4.422

Xia, Y., C.M. Ugarte, K. Guan, M. Pentrak, and M.M. Wander. 2018. Developing near- and mid-infrared spectroscopy analysis methods for rapid estimation of soil quality Indicators in Illinois. Soil Science Society of America Journal. doi:10.2136/sssaj2018.05.0175

Xu, S., Jagadamma, S., and Rowntree, J. 2018. Response of grazing land soil health to management strategies: A summary review. Sustainability 10: 4769.