Unlocking on-farm composting: Key drivers in Mexico City's peri-urban areas

Abstract

The swift expansion of urban areas, combined with inefficient waste collection and processing systems, results in the substantial buildup of complex solid waste, with over 50 % potentially being organic matter. Transforming organic fraction of Municipal Solid Waste (MSW) into compost offers a sustainable approach to simultaneously addressing waste management challenges and enhancing soil fertility. However, the quality of the compost obtained from MSW can be very poor and cause serious problems in agricultural soils. It is therefore worth asking whether the sustainability of the city should be at the expense of the quality of agricultural soils.

The peri-urban area of Mexico City is at the center of this dilemma, where an important food supply comes from this zone and where farmers receive from the government compost produced from MSW. Through semi-structured interviews we identified farmers' perception of compost, its use, benefit and quality in two boroughs in the peri-urban area of Mexico City.

Negative perceptions about the quality of compost, the impact on crops, and the lack of control over compost quality led us to ask what the socio-economic conditions would be for farmers to make their own compost. Through a logistic model we identified the main drivers to on-farm composting such as selling in local markets, having irrigation, being over 60 years old, having a high school education, being a full-time farmer, having a positive experience in using compost, and having traditionally used organic inputs. Public policy should shift improving the waste separation policy from households and increasing the investment in the composting plant to ensure the production of good quality compost. In addition, there will be a need for improvements in technical capacity and economic incentives for producers to do their own composting.