ARPA-E goes back to the ROOTS in $30M bid to transform carbon sequestration

In Washington, ARPA-E announced that it will invest $30 million in new awards for ROOTS — (Rhizosphere Observations Optimizing Terrestrial Sequestration), aimed at developing new integrated technologies to sequester added carbon in the soil. More roots, goes the theory, equals more carbon stored in the soil, healthier plants that can better withstand drought, and better conditions underground for nitrogen and water efficiency.

ARPA-E anticipates making approximately 8-12 awards, varying between $250,000 and $10 million

Those who have followed the travails of the carbon debate will recall, as ARPA-E reminds us in the ROOTS concept paper:

“While most of the man-caused increase in GHGs has been due to fossil fuel use, land use (including agriculture) currently accounts for about 25% of total GHG emissions. In addition, analyses included in the recent IPCC 5th Climate Change Assessment report suggests that it may not be possible to achieve large enough emissions reductions in the energy, transport and industrial sectors alone to stabilize GHG concentrations at a level commensurate with a less than 2oC global average temperature increase, without the help of a substantial CO2 sink (i.e., atmospheric CO2 removal) from the land use sector. One of the potential carbon sinks that could contribute to this goal is increasing C storage in soil organic matter on managed lands. “

The soil carbon problem

According to ARPA-E, the debate over increasing soil carbon is limited by current technology to a debate over land cover. That is, convert cropland to perennial grasses or more forest — rainforest’s carbon contribution, if you will. The debate thereby has polarized those seeking a carbon sink and those who seek increased agricultural intensification for food, fiber, and fuels.

There’s another way, ARPA-E says: “modify, through targeted breeding and plant selection, crop plants to produce more roots, deeper in the soil profile where decomposition rates are slower compared to surface horizons, as an analogous strategy to increase soil C storage. “

According to the agency’s preliminary scoping analysis, around 87% of total US cropland (major annual crops plus hay/pasture land) had soils of sufficient depth and lacking major root-restricting soil layers to allow for crops with enhanced phenotypes.

Whoa, Nelly, what’s a phenotype?

Genotype, that’s your genetic identity, comes courtesy of your DNA. Twins have the same DNA but go through different life experiences. A complex interaction of your genotype, the environment you live in, and how you manage your health — that’s your phenotype and that’s why twins don’t have the same health, fertility and life outcomes.

Why is that important in the field, with crops? Because two exact clones might be created but will never experience exactly the same conditions even if grown a few hundred yards away. Microbial life, soil quality, water flows and retention, nutrient availability and transport — all this happens underneath the soil and the variances are large, and it is phenotypes that are grown and harvested in the end.

Why is this a problem? Well, for one, we understand genotype far more than phenotype, and partly that is because phenotype is something that happens field by field. Selecting and optimizing phenotypes — that’s the observational part of plant breeding that’s been going on forever, but the underground part is not so easy to observe without destroying the soil complex and the microbial environment. In short, you change the advantaged environment in order to analyze it, and thereby rob it of the advantage you seek to understand.

Traditional methods have been lab-based or field based. Lab experiments include growing plants in glass environments. Sort of like an ant farm. But it’s artificially controlled and bounded, and no one quite replicates the real wild world, so you get weird outcomes. Conversely, there’s shovel-omics. That is, digging the root system up with a shovel or a soil coring tool, and the more of that you do, the more you get precise data about the operation of a microbial community you’ve just destroyed forever.

The advances sought

ARPA-E has established ROOTS to seek three types of advances, preferably in combination.

Component A (Sensors): Advanced sensors and imaging technology for characterization of roots and soils. The terms “sensors” and “imaging technology” are meant to be broadly interpreted as referring to any method of measurement (direct or indirect) with breeding relevance. Submissions should explain their strategy for moving sensors from proof-of-principle to in-field and also for automatically collecting, analyzing, and reducing their data.

Component B (Models): Predictive and extensible models of plants and soils to accelerate root breeding programs. Models that predict how traits will react to novel conditions or which traits are desirable in a given geography could limit the number of field trials that are needed to advance a new cultivar. Modeling may also be used during measurements by guiding to sensors toward areas most likely to be informative.

Component C (Genetics and Environment): Genetic resources and characterization of germplasm performance in multiple environments and/or management regimes for phenotypes that address ROOTS biogeochemical goals. Submissions should justify the specific phenotypes or soil characteristics targeted. While ARPA-E expects novel sensors developed in a project should be integrated into a projects’ genetic strategy, projects may initially utilize pre-existing technology.

The aspirational outcome?

Crops that enable a 50% increase in carbon deposition depth and accumulation, a 50% decrease in fertilizer N2O emissions, and a 25% increase in water productivity. Taken over the 160 million hectares of actively managed U.S. cropland, such advances could mitigate ~10% of total U.S. greenhouse gas emissions (GHG) annually over a multi-decade period, while also improving the climate resiliency of U.S. agricultural production.

Wouldn’t it be nice?

We’d like to get beyond the false choice of agricultural intensification and sustainable lands. To that end, the more we understand of the soils and plants who live there, the more we can develop high-yield plants that store more carbon  and take better advantage of the world they live in, and thereby require less intensive inputs to thrive at high yields.

In the Digest, we’ve been asking, where are the feedstocks for the Advanced Bioeconomy, and here’s a long-term project that intends to provide a more sustainable feedstock base.

So, this is a project that probably everyone can get behind.

More on the story

ROOTS: The funding opportunity announce is here.