A recent On Gardening column draw attention to California’s Healthy Soils Initiative, which is part of “California’s strategy to reduce greenhouse gas emissions by increasing carbon sequestration in and on natural and working lands. “ The Initiative is part of the state’s Climate Smart Agriculture programs, which include coordinated work on efficient water usage, conservation of farmlands, capture of methane emissions, and alternative practices for manure management.
California funds Climate Smart Agriculture and other Climate Change Strategies through its cap-and-trade program, a market-based regulation designed to reduce greenhouse gases (GHGs) from multiple sources. Cap-and-trade sets a firm limit or cap on GHGs and minimizes the compliance costs of achieving the state’s goals for reducing GFGs. The legislature and Governor Brown are working toward extending this program beyond 2020.
The Climate Change Strategies target large-scale operations in several industrial fields, but all could be implemented on an individual level. The Healthy Soils Initiative has particular relevance for individuals. It doesn’t offer public funding for home gardeners, but it aligns completely with the best practices for sustainable and more successful gardening.
The payoffs include improving plant health and yields, increasing water infiltration and retention, sequestering and reducing greenhouse gases, reducing sediment erosion and dust, improving water and air quality, and improving biological diversity and wildlife habitat.
Here is an overview of recommendations to develop healthy soils:
Protect the natural structure of the soil. This is easy because means avoiding or at least minimizing tilling of the soil. Some gardeners have adopted the practice of turning over the soil regularly, using a mechanical device or a shovel or garden fork. “Breaking up the soil” has been equated with improving it by mixing in amendments and facilitating the spread of plant roots. While these seem like desirable outcomes, tilling actually pulverizes soil aggregates which are groups of soil particles that bind to each other more strongly than to adjacent particles. Spaces between the aggregates provide pores for retention and exchange of air and water. Tilling, therefore, adds excess oxygen to the soil and increases respiration and carbon dioxide emission. It also disrupts fungal communities.
Increase soil fertility. For vegetable gardeners, this involves growing cover crops during periods after harvesting one crop and planting another, digging in the cover crop to add nitrogen and other nutrients to the soil. The same practice is recommended when ornamental gardens are being renovated. Other methods for increasing soil fertility include adding compost and animal manures to restore the plant/soil microbiome. A three- or four-inch layer of such amendments will contribute nutrients without digging it in. This practice includes avoiding uses of synthetic fertilizers, which distort soil microbial communities, in addition to consuming energy for production and distribution, migrating into water resources and the atmosphere, and accelerating the decomposition of organic matter.
Build biological ecosystem diversity. For farmers, this practice includes rotating crops, avoiding mono-cropping, and planting borders to accommodate bees and other beneficial insects. For the home gardener, the parallel actions include losing the lawn (which is mono-cropping), providing foods, water and habitats for birds, bees, butterflies and beneficial insects and small animals. A helpful related resource is the National Wildlife Federation.
Manage grazing for soil regeneration. The parallel practice in this area for home gardeners applies only to those who grow chickens, ducks or rabbits, or perhaps other smaller creatures. The basic idea is to move them around the property for their own health and the production of healthy soil. For growers of commercial livestock, it’s a significant part of soil regeneration.