Carbon Farm Planning - Carbon & Maximizing Biodiversity on Working Lands

Carbon & Maximizing Biodiversity on Working Lands

Soil Biodiversity, or the makeup of different organisms within the soil, constitute a food web that is ultimately fueled by the sun through the action of primary producers: photosynthetic organisms (plants) that capture solar energy and carbon dioxide from the atmosphere and transform it into organic compounds that drive other components of the food web. Soil organisms play a critical role in supporting soil health including decomposing and transforming organic matter, cycling nutrients, enhancing soil structure, and controlling soil organism populations

Producers can diversify their farm system through introducing diversified crop rotations and cover crops, adding structural diversity in the form of woody components, such as windbreaks and shelterbelts, and by integrating livestock into their operations, depending on their cropping system, soil types and location. Diversified farms see:

Enhanced nutrient cycling
Higher levels of soil organic carbon
Improved rates of carbon sequestration
Greater resilience to weather and market fluctuations.

Through implementing these types of conservation practices, the soil food web tends to become more diverse and more resilient to disturbance.

Graphic created by Ellie Ellie at Colorado State University.

Maximizing biodiversity and carbon capture opportunities through cover cropping and conservation crop rotation

Implementing cover crops and crop rotations "feed" the soil by increasing soil organic carbon content and improving aggregate stability. When combined with other conservation practices, such as residue and tillage management or compost amendments, these soil benefits are maximized. A collection of long-term studies from the book Soil Health and Intensification of Agroecosystems, illustrates various soil types with diverse crop rotations. These studies found higher levels of soil organic carbon in systems with higher crop diversity (19).

The long-term study to the right (also under Resources tab) compared the following crop rotations in three Iowa sites (20):

Continuous corn, silage (with and without nitrogen additions)
Continuous corn, grain (with and without nitrogen additions)
Corn- Soybean
Corn- Corn- Oat- Meadow
Corn- Oat- Meadow- Meadow

While initial soil organic carbon stocks varied on location, they found that continuous corn led to a consistent loss of SOC, whereas the diversified four-year rotations had the highest levels of SOC. Additional factors that contributed to the increased SOC in the four-year crop rotations include implementing common conservation practices such as residue and tillage management (view under Resources).

Thinking back to the previous sections, plants incorporate carbon into the soil through photosynthesis. Implementing diverse crop rotations and cover crops can supply the soil with increased carbon inputs. As soil organic carbon content increases with diversified crop rotations and cover crops, additional soil health indicators begin to improve.

Improved Aggregate Stability

Through increased carbon content by adding additional crops into the rotation and implement cover crops, aggregate stability also improves. In this study to the left, soil aggregation improved corn crop as crop rotations diversified in the Pennsylvania study on the the second image below. Crops with differing root structures impact the soil differently allowing for varying poor structure at different soil depths (NRCS).

Graphic: Pennsylvania NRCS- Diversifying crop rotations

Yield Co-benefits

With increased carbon inputs from diversifying a crop rotation and ensuring continuous living roots and improved aggregate stability, yield/productivity also improves. In the study to the right, increased crop rotation diversity improved corn yields in this long-term crop rotation trial in Pennsylvania.

Graphic: Pennsylvania NRCS (t.ly/dXou)

Nutrient Co-benefits

With increased carbon inputs from diversifying a crop rotation and ensuring continuous living roots, nutrient cycling improves due to increased energy source for microbes. By incorporating leguminous cover crops into the rotation, the need for nitrogen fertilizers is reduced as these crops fix atmospheric nitrogen through their symbiotic relationship with rhizobium bacteria.

Graphic: NRCS Credit: Stephen Temple, New Mexico State University.

Pest Management Co-benefits

Due to range of management practices needed to accommodate different crops when implementing a diverse crop rotation, weeding and insect control

Graphic: USDA Crop Rotation

Other Carbon Farming and Conservation Practices to Maximize Carbon Capture and Biodiversity

While some carbon farming practices maximize biodiversity through adding species to the working lands inherently increasing biodiversity, other practices ensure the existing biodiversity can thrive in existing conditions, such as residue and tillage management. This is not an exhaustive list of carbon farming and conservation practices that increase biodiversity, there are other practices we will explore the following practices throughout module 2.

Residue and Tillage Management (CPS 329/345)
Conservation Cover (CPS 327)
Contour Buffer Strips (CPS 332)
Field Border (CPS 386)
Grassed Waterways (CPS 412)
Forage and Biomass Planting (CPS 512)
Range Planting (CPS 550)
Herbaceous wind barriers (CPS 603)
Riparian Herbaceous cover (CPS 390)
Soil Carbon Amendment

‼️ Stop and Think: Can you think of other carbon farming and conservation practices that maximize biodiversity on working lands?

Maximizing Biodiversity through Integrating Agroforestry

While including diversified crop rotations, cover crops, and integrating livestock serve as common ways to increase biodiversity of a farm, carbon farm planning emphasizes a creative approach to viewing the landscape through a carbon lens. By deliberately incorporating woody species into a farming or ranching operation, agroforestry promotes increased biodiversity and provides an opportunity for increased carbon sequestration through permanent vegetation. The COMET-Planner report on the right demonstrates the estimated carbon sequestration and greenhouse gas emission reductions associated with the given agroforestry practice standards in Tazewell, Illinois.

Additional co-benefits of agroforestry practices include:

improved wildlife habitat
improved forage diversity for livestock (practice and species choice dependent)
potential to provide producer with additional products
reduced soil erosion and improved crop protection from wind
shelter and shade protection for livestock

Agroforestry conservation practices to consider when striving to increase biodiversity include: windbreaks and shelter-belts, tree/shrub establishment, riparian restoration and forest buffers, silvopasture, alley cropping, and hedgerow planting.

For more information on NRCS Conservation Practice Standards for Agroforestry specific to your region, please go to this USDA site.

Scroll through the image carousel for additional agroforestry practices to maximize carbon capture opportunities and biodiversity

1 - Alley cropping; 2 - Windbreak; 3 - Silvopasture; 4 - Hedgerows; 5 - Riparian forest buffer

Livestock Integration

Integrating livestock into a system through prescribed grazing can increase ecological interactions leading to improved soil health and nutrient cycling, a reduction in soil erosion, increased soil fertility, increased crop production and improvements to forage quality for grazing animals (19). The study on the right compares microbial biomass carbon and nitrogen between integrated livestock cropping systems and continuous cotton intercropped with wheat (20). Through the addition of intermittent grazing periods, the perennial pasture and crop rotations saw a higher soil microbial biomass C than that of the continuous cotton (21). Grazing animals return nutrients to the soil as manure which serves as a natural soil amendment to enhance soil organic carbon stocks, and can transform less persistent plant biomass carbon to more recalcitrant manure.

Similar to this study, conservation practices often compliment each other when used in concert. For example, increasing the biodiversity of the system through prescribed grazing can compliment intensive crop rotations that include cover crops instead of fallow fields. This practice opens the opportunity for not only improved soil health from enhanced nutrient cycling, but also increasing producer profits from lower fertilizer needs and new income associated with grazing the cover crops.

Similar letter at same depth indicates no significant differences (LSD) at P<0.05. (Zobeck et al. 2004) (21)

‼️ Stop and Think: Planning through a carbon lens: If approaching the system in the study above through a carbon lens, can you see other opportunities for a conservation practices to support increased carbon capture?

While integrating livestock to diversity the farm can contribute to a reduction in greenhouse gas emissions or an increase in carbon sequestration, supporting practices such as the addition of fencing or improvements to watering infrastructure may be needed. These supporting practices can improve the establishment of the conservation practice, but do not have quantifiable greenhouse gas emissions benefits and therefore are not included in the COMET-Tools.

❓Check your knowledge!

Using the graphic under Improved Aggregate Stability, answer the following question:

As the diversity of the cropping system increases, the soil aggregate stability [decreases/increases]. Based on what you have reviewed in the curriculum thus far and assuming nutrient amendment remain the same between systems, soil carbon likely [decreases/increases] as diversity increases.

‼️ Stop and think: Can you think of ways livestock could be integrated into this system? What about agroforestry practices?

Return to

Maximize Soil Cover & Living Continuous Living Roots

Discussion board: If you have any questions throughout Module 1, please use the discussion board below to post.

Continue to

Carbon Farming on Your Farm

Citations

(1) M. Al-Kaisi, B. Lowery. 2017. Soil Health and Intensification of Agroecosystems. Elsevier Inc.
(2) Robinson, C., Cruse, R. Ghaffarzadeh, M., Soil Science Society of America. “Cropping System and Nitrogen Effects on Mollisol Organic Carbon.” Soil Science Society of America journal. 60.1 (1996): 264–269. Web.
(3) Zobeck, TM et al. “Soil Microbial, Chemical and Physical Properties in Continuous Cotton and Integrated Crop-Livestock Systems.” Soil Science Society of America journal 68.6 (2004): 1875–1884. Web.

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