December is the first month of meteorological winter and brings the shortest days of the year, often with cold and snow. Gardens are quiet this month, in comparison to movement seen in autumn (seed dispersal and migrations) and potential seen in spring (swelling buds and emerging sprouts). Garden tasks are limited outdoors. Indoor work – including presentations, research, planning, webinars, workshops, and writing – benefits the garden in the quiet season and beyond.

At the Arboretum, the concept of “land” has a long history and rich meaning. Land includes plants, animals, waters, soils, people – every component of the biotic and abiotic system. The theme of land connections runs through gardening, restoration, research, and education work here. Familiar examples include connections between plants and pollinators, trees and fungi, nodes of food webs, climate change and species distribution, and humans and land stewardship practices.  Each of these, and many others, involve connections that are unknown or little understood.

Robin Wall Kimmerer’s much-anticipated new book, The Serviceberry: Abundance and Reciprocity in the Natural World, was released just before this newsletter deadline. This well-written book is at the top of many winter reading lists. It asks us to rethink economies and explore human choices, actions, and perspectives in relation to stewardship and care for land, community, and planet.

In a detailed example of science serving the public interest, a recent report from the National Academies Press, Exploring Linkages Between Soil Health and Human Health (available as a free PDF), explores land connections related to living soils. Report contributors span a wide range of expertise: the Board on Agriculture and Natural Resources; Food and Nutrition Board; Division on Earth and Life Studies; and the Health and Medicine Division. They based their work on the “One Health concept – that is, the health of humans, other animals, plants, and the wider environment are linked and interdependent.” However, until now, One Health had considered soil as essential for producing food, but not its broader roles in climate regulation, in reducing contaminants, as a source of antibiotics, or as an origin of foodborne pathogens, all of which affect health of other organisms.

Agricultural practices used for decades in larger cropping systems to maximize crop yields have led to poor soil health on farms (significant erosion, loss of soil organic matter, poor soil structure, reduced microbial communities). They also had broader negative effects, damaging human health and the environment (water and air pollution, increased greenhouse gas emissions, and biodiversity loss). Practices that improve soil health (e.g., low till, soybean rotation) may address these problems. The National Academies Press report focuses on what is known about interconnections of microbiomes across soil, plants, humans, and other animals, including how they may improve soil health, food nutrient density, and human health.

Among the many relationships described in the report, I highlight the effects of climate change on soil health and how soil, plant, herbivore, and carnivore microbiomes interact (in Chapter 2); the relationship of healthy soils to climate regulation and the water cycle (in Chapter 3); four soil health principles in agriculture and effects of pesticides on soil biota (in Chapter 4); research and monitoring needed to deal with legacy and novel contaminants (especially in combination) and soils’ capacity for bioremediation (in Chapter 6); and microbiome features that infer health in human and soil systems and knowledge gaps (in Chapter 7).

While not an easy read, this report allows the reader to explore basic ideas or dig deeper, and to learn and appreciate connections between land, management, and health. More broadly, it demonstrates the importance of science to bring understanding we do not yet have about land that is, and sustains, life.

Several brief resources related to these land connections are available on the Arboretum website.

As this cold and dark month sets in, during quiet time that spans reflection, anticipation, and connections, let’s read!

– Susan Carpenter, native plant garden curator