Soils in Urban Agriculture and Community Gardens Challenge: Growing food in degraded urban soil Healthy soil is fundamental to agriculture. For there to be significant improvements in access to healthy food through urban agriculture – soils must be productive. Urban agriculture often takes place on a small scale and will need to make use of dense planting techniques – which require excellent soil fertility.

Challenges – Healthy soil Urban soil has often been both damaged and neglected. Urban populations have generally low environmental literacy and even less understanding about soils. Compaction? Low Nutrients? Poor Drainage? Contamination? What’s a busy urban dweller to do?

The single best solution to the problem of urban soil is to Add Organic Matter (anything that was once alive, containing carbon) Urban centers generate a wide range of organic residuals that have potential utility as soil amendments, including: municipal biosolids yard trimmings and food scraps The single best solution to the problem of urban soil is to Add Organic Matter (anything that was once alive, containing carbon) Urban centers generate a wide range of organic residuals that have potential utility as soil amendments, including: municipal biosolids yard trimmings and food scraps Add Organic Matter – Urban Residuals

Organic Residuals Annually, each person in the US generates an average of: 22 dry kg municipal biosolids (treated sewage) 88 kg yard trimmings and (grass clippings, leaves, etc.) 79 kg food scraps (NEBRA, 2007; USEPA, 2006) Approximately 50% of the biosolids, 98% of the food scraps and 45% of the yard trimmings are currently disposed of or landfilled.

Organic Matter really works to improve urban soil Adding organic matter: Will support an increase in production for urban agriculture by increasing available nutrients and building soil tilth and fertility. Phosphorus is an essential plant nutrient On left: Beets grown with biosolids On right: Beets grown without biosolids

Organic Matter really works to improve urban soil Adding organic matter Will improve how quickly water infiltrates the soil – reducing surface water runoff and allowing water to get to plants. Also improves the soil’s ability to hold water

Organic Matter really works to improve urban soil Adding organic matter: Will store carbon - sequestering carbon in the soil and providing food for soil microbial communities. This also takes it out of the atmosphere where we have an excess and puts it back in the soil where it becomes food for plants.

Besides urban soil: Other benefits to recycling Residuals Reduces the importation of valuable organic matter from rural areas Creates sustainable end-uses for urban residuals Many urban gardeners are new to gardening – available soil products will allow gardeners to have greater success.

A little background on what’s happening in Tacoma TAGRO – Class A biosolids produced by the City of Tacoma. TAGRO has been utilized by the community for decades. WWTP upgrade in 1991 officially made the product “Class A” – safe for use with no restrictions Historically, TAGRO was available in a liquid form for farmland – this is still done but availability is limited Developed dry products beginning in 1995 Diversified product range in 2004 Program has worked to build relationships and gain public support – creating a market

Community Gardening in Tacoma – increasing demand Pink – existing prior to 2008 Yellow – new since 2008 The vast majority are using TAGRO products The combination of urban gardening and urban residuals is contributing to incredible success – for gardeners, government, and the environment.

Education – another incredible opportunity Demand for this information is exploding There is a window of opportunity to connect people to their food supply/environment Also an opportunity to educate people about waste and urban nutrient cycling

What is needed now Investments in Urban residuals – and incredible urban resources that is too often treated as waste and disposed of. Educational resources made available – lack of urban- appropriate resources about both gardening and residuals Support from municipal infrastructure for urban agriculture as a productive use of urban land – low cost way to care for vacant land.

Questions? Questions? Comments? Kristen McIvor, PhC Community Garden Coordinator, Tacoma/Pierce County Cascade Land Conservancy