Progress 10/01/19 to 09/30/20
Outputs
Target Audience:Research products/outcomes was directed to graduate students, extension specialists, farmers, and the general public. Results were also delivered to the academic communities through publications in peer-review journals and presentations in professional conferences. Changes/Problems:No changes were made in approach. However, the Covid-19 pandemic and modified operations of the Univeristy may continue to affect our plans. We will followUniveristy policy and continue the essential work as much as possible. What opportunities for training and professional development has the project provided?A MS graduate student (Binaya Parajuli) worked on this project graduated. The student attended the 2020 SSSA Annual Conference by presenting his research. How have the results been disseminated to communities of interest?In 2019, an on-site field day demonstration (by the PI) was conducted at the Pee Dee Research and Education Center, Clemson University, Florence, SC, during which the project was introduced to local farmers, extension agents, and general public. An extension press was also published introducing the importance of cover crop managment to optimize its nutrient benefits. Peer-reviewed research articles were submited (2) or published (2) to disseminate the results to academic communities. The research results were also delivered to acadmic commmunities by three presentationsat the 2020 ASA-CSA-SSSA Annual Conference. What do you plan to do during the next reporting period to accomplish the goals?Despite the uncertain constrains of the Covid-19 pandemic, we plan to do the following to accomplish the goals, Continue to work with graduate students to analyze the collected samples and data from this reporting period; Continue field and laboratory study on how clay amendment affects microbial decomposition and the stability of soil organic carbon; Investigate how the cover crop functional trait diversity affect microbial diversity, carbon sequestration, and nutrient cycling in the context of improving agronomic and environmental outcomes; Submit/Publish 2-3 peer-reviewed articles; Present the resultsat the 2021 SSSA Annual Meeting; Field demonstration of soil management impacts on soil health and resilience (may be virtually);
Impacts
What was accomplished under these goals?
To achieve the major goals, both field and laboratory experiments were conducted during this reporting period. The work has been focused on evaluating the long-term and short-term impacts of conservation management practices (i.e. reduced-tillage, residue return, and cover cropping) on soil physical-biogeochemical properties. The long-term impacts are being carried out on a 40-year research plot, where conservation tillage was originally designed to compare with conventional tillage on soil organic carbon dynamics. We evaluated how the 40-year conservation tillage changes the pool sizes of various chemically-defined phosphorus fractions, carbon distribution in soil aggregates, and the overall soil health. The data suggested that long-term conservation tillage increase soil carbon, but mostly in the surface soils (0-5 cm), especially in the microaggregates, while similarly cover cropping for 4-year also promoting the accumulation of phosphorus stocks in surface soils. Unexpectedly, long-term conservation management did not improve the overall soil health at the tillage layer (0-15 cm) in the tested sandy soils. The combination of reduced-tillage along with increased carbon inputs (e.g. organic amendment, composted materials, and cover cropping) may be essential to make significant changes. The experiments on short-term impacts are trying to understand whether and how soil management practices (i.e. cover cropping and clay amendment) improve the typical degraded sandy soils in the southeastern USA, in the context of soil organic carbon content, soil structure, microbial diversity, and nitrogen cycling. We are testing eight treatments of different cover crop combinations, while investigating whether clay soils amendment increase the preservation of organic inputs in the soils. Despite the Covid-19 pandemic, we were able to establish and maintain the fields, collect soil and plant samples, but only able to complete some of the laboratory analyses. The preliminary data suggested that cover crop mixtures diversify the organic and nutrient inputs to the soils, affecting soil microbial activities and the associated soil carbon and nutrient processes, while clay amendment improve soil structure, but suppressed microbial activities (described by enzyme activities and respiration) promoting carbon preservations. The data suggest the importance of soil structure and organic inputs in maintaining or improving soil health of the sandy Ultisols.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
2. Ye, R., Parajuli, B., Ducey, T., Novak, J., Bauer, P., Szogi, A., 2020. Cover cropping increased phosphorus stocks in surface sandy Ultisols under long-term conservation and conventional tillage. Agronomy Journal. 2020;00:00-00. https://doi.org/10.1002/agj2.20227
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Poudel, P., Ye, R., Park, D., Parajuli, B., 2020. Management practices affecting the nutrient provision capacity of cover crops. Clemson (SC): Clemson Cooperative Extension, Land-Grant Press by Clemson Extension; LGP 1087.
- Type:
Journal Articles
Status:
Under Review
Year Published:
2020
Citation:
Ye, R., Parajuli, B., Szogi, A., Sigua, G., Ducey, T. Soil health assessment after 40 years of conservation and conventional tillage management in southeastern coastal plain soils. Soil Science Society of America Journal
- Type:
Journal Articles
Status:
Under Review
Year Published:
2020
Citation:
Parajuli, B., Luo, M., Ye, R., Ducey, T., Smith, M., Park, D. Aggregate distribution and the associated carbon in Norfolk soils under long-term conservation tillage and short-term cover cropping. Communications in Soil Science and Plant Analysis
- Type:
Theses/Dissertations
Status:
Accepted
Year Published:
2020
Citation:
Parajuli, B. Carbon and nitrogen in soils under 40-year conservation managements.
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