Recipient Organization
SOUTH DAKOTA STATE UNIVERSITY
PO BOX 2275A
BROOKINGS,SD 57007
Performing Department
Plant Science
Non Technical Summary
Soil organic carbon (SOC) is the largest terrestrial carbon pool and it plays a critical role in determining ecosystem productivity, sustainability, and resilience. As a major component of soil organic matter, SOC regulates multiple soil functions such as nutrient and water supply and dynamics, soil structure, and microorganism composition and activities. SOC is also an important indicator of soil health, which is defined as the continued ability of soils to support agroecosystems for a good productivity. Healthy soils are also recalcitrant to wind and water erosion, recover rapidly from disturbances such as tillage and grazing, and protect the environment by conserving water and nutrients. Land-use conversion and management may result in higher SOC loss and CO2 emission, while improved management strategies can promote SOC sequestration and mitigate greenhouse gas emissions. Considering the challenges in increasing agricultural production with limited nutrient, water, and land resources, and the desire to enhance ecosystem sustainability and resilience to disturbance and climate extremes, it is critical to develop and adopt management strategies to improve SOC sequestration and overall soil health.To promote our understanding of SOC and soil health responses to agroecosystem management, this project will collaborate with the NC1178 Multi-State project. Targeted agroecosystem management practices include currently adopted approaches in farmlands, and advanced techniques developed by scientists, farmers, and extension experts. These practices include diverse crop rotations, cover cropping, livestock integration, grazing management, reduced fertilizer input, precision farming, conservation tillage, biochar application, etc. These management approaches influence above ground (plant litter) and belowground (root) carbon input, SOC decomposition, soil structure, water retention, and microbial diversity, which can directly and indirectly impact SOC sequestration and soil health. The SOC stocks and distribution into active and stable soil organic matter pools, SOC accumulation and loss through CO2 emission over time, and the mechanisms regulating these changes by microorganisms will be studied. Moreover, overall soil health in agroecosystems, indicated by physical (e.g. compaction, aggregation), chemical (e.g. nutrient, acidity), and biological (e.g. respiration, microbial community composition) properties and processes in soils will be assessed.This project aims to: 1) help farmers and rangeland managers better understand impacts of their management practices on the sustainability and resilience of farmlands regulated by SOC and soil health, and 2) provide information to diverse stakeholders on the effects of advanced management strategies on SOC sequestration and soil health. It is expected that society will be benefited with greater profitability and environment conservation through adopting sustainable management strategies that enhance ecosystem functions.
Animal Health Component
25%
Research Effort Categories
Basic
70%
Applied
25%
Developmental
5%
Goals / Objectives
Evaluate the impact of intensifying agroecosystems (e.g. increased crop rotations/double cropping, and management integration) on soil organic C, soil health, productivity, the environment, and profitability. (MI, SD, ND, FL, IA, GU, KS)
Assess management effects (e.g. crop residue, tillage, cover crops,) on soil organic C, environmental footprints (e.g. GHG emissions, water quality, water quantity, soil erosion, input use efficiency), and productivity. (SD, ND, FL, MN, IA, GU, SC, KS)
Project Methods
Studies will be conducted to investigate SOC and soil health under various agroecosystem management practices in South Dakota and other collaborating states. Multiple on-going research projects at Dakota Lakes Research Farm will be continued. These projects are investigating nutrient management, grazing management and livestock integration, and SOC and soil health assessment under different tillage management practices. These projects are supported by South Dakota Nutrient Research and Education Council (NREC), NRCS, and the International Arid Lands Consortium (IALC). The PI of this project will communicate with other scientists in South Dakota and NC 1178 members to generate collaboration opportunities and obtain feedback and comments on the on-going programs. The progress of this project and the results will be reported to NC1178 annual meetings.Objective 1. Evaluate the impact of intensifying agroecosystems (e.g. increased crop rotations/double cropping, and management integration) on soil organic C, soil health, productivity, the environment, and profitability.Farmers manage their ecosystems with different levels of intensity and diversity, according to their needs, resources, and management skills. Some producers make use of diversified crop rotations, double cropping, cover cropping, perennial incorporation in annual row crops, and livestock integration to improve productivity and sustainability. Other producers have yet to embrace the use of increased crop types and complexity in the agroecosystems they manage. Yet other producers manage native grasslands that intrinsically have high diversity.Soil organic carbon (SOC) varies with different agroecosystem management practices, climate conditions, and soil types, and will also change over time. Thus, to understand the response of SOC to management practices, soils will be collected over consecutive years to measure SOC concentrations and total SOC mass at different soil depths. The dynamics of SOC change are typically slow and may not be easily detected, especially if the changes are small compared to a large baseline amount of SOC. Therefore we will also monitor SOC distribution in various soil fractions based on size (macro-aggregates vs. micro-aggregate) and density (light free vs. heavy). We will also monitor SOC in active and stable pools (permanganate oxidizable carbon, particulate organic matter vs. mineral associated fraction), and seek to understand the chemical structure of SOC via solid state 13C nuclear magnetic resonance spectroscopy). Furthermore, soil respiration (CO2 emission) will be measured in situ or in lab incubation experiments to understand soil organic matter decomposition and greenhouse gas emission under various management practices.To further understand the impacts of agroecosystem management on ecosystem services, soil health will be assessed by measuring multiple physical, chemical, and biological indicators. Examples of physical indicators include bulk density, penetration, aggregation, and water infiltration, while chemical indicators include extractable phosphorus, potassium, mineral nitrogen, and other nutrients, pH, and salinity. Biological indicators include microbial biomass, community structure (phospholipid fatty acid), enzyme activities, nitrogen mineralization, and soil respiration. Soil health index will be estimated by utilizing the Soil Management Assessment Framework (SMAF) developed by USDA-NRCS. Both short-term and long-term studies will be conducted to understand the response of soil health to various agroecosystem management practices.The soil microbial community and activities regulate SOC accumulation and decomposition. For this project, microbial biomass and community structure will be measured using chloroform fumigation, phospholipid fatty acid (PLFA) analysis, and 16s rRNA. Microbial activities, such as potential mineralizable carbon and respiration under controlled temperature and moisture conditions, will be studied to understand the SOC resilience to climate extremes. Further, enzyme activities associated with SOC cycling, such as α-glucosidase, β-glucosidase, β-D-cellubiosidase, β-xylosidase will be analyzed. The results from measured microbial community and activities will be correlated with changes in SOC and soil health to explore the mechanism and the impacts of agroecosystem management practices.Objective 2. Assess management effects (e.g. crop residue, tillage, cover crops) on soil organic C, environmental footprints (e.g. GHG emissions, water quality, soil erosion, input use efficiency), and productivity.Management strategies are developed to improve agricultural productivity for higher economic returns. It is critical to ensure these techniques can improve ecosystem sustainability and are also environmentally friendly. Thus, studies will be conducted to develop and investigate the impacts of the new management practices on SOC sequestration, greenhouse gas mitigation, and soil health. The management approaches will be developed according to communication and suggestions from agronomists, extension experts, farmers, and land managers. Examples of the advanced management practices include a wise strategy of cover cropping, fertilizer application, irrigation, grazing management, etc. Total SOC and its distribution in stable fractions, decomposition, CO2 emission, the overall SOC sequestration rate, and its resilience to disturbance and climate extremes will be evaluated to identify more advanced management strategies. Soil health assessment and microbial analysis will be conducted according to the methods described in Objective 1.