Leveraging agricultural land’s natural ability to recapture and store previously lost soil organic carbon (SOC) is one of the most efficient, feasible, and scalable “natural climate solutions” at humanity’s disposal. While croplands keep expanding globally, cropland abandonment is a global phenomenon that naturally recaptures part of the more than 100 Pg of soil carbon historically lost through traditional agriculture. Yet the extent and duration of agricultural land abandonment and the potential of soils to store carbon following abandonment have not been quantified, and there is no consensus about the best strategies to maximize SOC recovery after abandonment.

This project will resolve this uncertainty by:
1) mapping cropland abandonment,
2) modeling and mapping SOC sequestration potentials in abandoned croplands.

This project leverages Earth Observation and ground-based data with machine-learning to inform policy and guide sustainable land management. We will identify hotspots for carbon sequestration, best practices, and provide farmers, corporations and governments a scientific tool to economically incentivize the protection of ecosystems undergoing land use changes that promote carbon sequestration.

Forest restoration holds major potential to capture carbon from the atmosphere. But nature-based solutions related to forest restoration also have major pitfalls when the “how, where, and who” aspects of implementation are inappropriate. Our lab is studying a potential win-win for both the climate and biodiversity crisis: natural forest regrowth. Under this approach, forests are allowed to regrow through the natural dispersal of seeds, rather than through tree planting by people.

In this research project, we are targeting a feedback between biodiversity and carbon storage involving seed dispersal by animals. About half of plant species – and over 90% of tree species in many tropical forests – rely on animals for seed dispersal. Allowing forests to regenerate naturally following deforestation and other disturbances holds potential to increase the biodiversity of plants in a forest and their resilience to climate change. Yet the success of natural forest regrowth may also depend on the biodiversity and movement patterns of seed-dispersing animals in an area. Our ongoing research seeks to model seed dispersal by animals and its influence on the carbon trajectory of tropical forests. This work aims to increase the predictability of natural forest regrowth trajectories and identify regions where this restoration approach can be most effective.

Previous research determined that nutrients such as nitrogen are an important co-factor of plant growth, and therefore, plant carbon sequestration. Substantial efforts have been devoted to introduce nitrogen as a co-factor in the most used carbon cycle (CMIP) and vegetation models (TRENDY). Despite of it, the amount of nitrogen plants are taking from the soil to be part of its tissue remains unquantified.

Most of the nitrogen on earth can be found in the atmosphere in gas form (N₂), comprising more than 70% of the atmosphere. Even if abundant, N₂ is not available to be absorbed by plants, and biotic soil processes led by microorganisms are necessary to transform this nitrogen in plant-friendly forms such as ammonium or nitrate. Aside from these nitrogen-fixing microorganisms, we can also find other microorganisms that compete for organically bound nitrogen of which only part of it is going to available for plants to be absorbed.

We are aiming to leverage published field data accounting for plant biomass increase in roots, wood (if woody plant) and leaves as well as for the nitrogen contained in these tissues to train a machine-learning model. There we will be determining the drivers that affect this relation, creating an upscaled map of nitrogen uptake worldwide and comparing the differences these results suppose to global change calculations.

The terrestrial system is considered a net carbon sink in the global carbon cycle, referred to as “the missing link”. However, whether the global soil carbon pool is a net sink or source is still not clear. Our lack of understanding in the fate of plant biomass after plant lifetime and its transformation into soil organic matter makes this challenge more difficult. We explore the temporal change of SOC in response to climate. Knowing the change of SOC storage in the past few decades can help us understand the potential amount of soil carbon sequestration in the next decades and provide benchmarking information to current SOC Earth System Models.