Building climate-smart agriculture with compost

Symptoms of climate change are increasingly visible. Increased temperatures, precipitation variability, wildfire intensity, storm anomalies, and seawater intrusion into groundwater aquifers all pose severe threats to the wellbeing of human and non-human communities in our area. The impacts of climate change on the agricultural industry and the ability of agricultural communities to adapt to climate change are of major concern for our economic and ecological wellbeing. Adapting and changing practices locally is no longer a good idea, it is now imperative to lessen the impact of climate change to our businesses.

Increasing organic matter in agricultural soils is a key strategy to mitigate some impacts wrought by climate change – with both on- and off-farm benefits. Farmers, scientists, and agricultural professionals have long recognized the benefits of increasing Soil Organic Material (SOM). While SOM often constitutes less than 5% of farmed soil by weight, it is the tiny superhero of the soil. SOM increases water infiltration and water holding capacity, improves nutrient cycling and crop nutrient availability, enhances quantity and diversity of soil biota, and more. SOM is particularly important to building farm resilience to climatic changes as it reduces irrigation demands and buffers against precipitation variability.

By holding water, SOM reduces leaching of water pollutants that can harm downstream communities. Overall, in these times of uncertain water availability, building SOM can support both operational economic viability and the ecological health of the region.

Laura Murphy, soil scientist on staff with the Resource Conservation District of Monterey County (RCDMC), suggests that one simple way to build SOM in agricultural fields is to add compost, a soil amendment that is primarily composed of organic materials. She says, “Implementing conservation practices in intensively managed vegetable production systems has always been difficult, but the application of compost can provide producers with very much needed flexibility to increase conservation goals and simultaneously develop farm resiliency to the symptoms of climate change.” While compost use in agricultural systems has been shown to be profitable for farmers, the California Department of Food and Agriculture (CDFA) offers additional incentives to farmers who are willing to apply compost to their fields. The state’s Healthy Soils Program offers small grants to farmers to offset the costs of applying compost with the understanding that building SOM is key to developing a resilient food system in the face of climate change. The

RCDMC will offer technical assistance to farmers in the Salinas Valley who wish to apply for a Healthy Soils Program grant during the upcoming grant cycle.

The use of compost in agricultural fields also diverts organic materials away from landfills, which itself is an opportunity to mitigate climate change. Food scraps, yard waste, landscape, and pruning waste, and other kinds of organic waste materials decompose in landfills and contribute to global greenhouse gas emissions. Local recycling programs such as Salinas Valley Recycles use industrial composting facilities to turn these materials into safe and stable compost, which can be used as a soil amendment.

Local availability of compost offers a promising opportunity to close the loop between wasted food and agricultural soil health, with the potential to create a food system that can adapt to, and even mitigate, the effects of climate change.

Information about the Healthy Soils Program can be found at https:// www.cdfa.ca.gov/oefi/ healthysoils/. Farmers interested in applying for financial assistance for use of compost can contact Laura Murphy at laura. murphy@rcdmonterey.org for help with their applications. Information about Salinas Valley Recycles’ compost & recycling programs can be found at SalinasValleyRecycles.org.