Embedding circularity into the transition towards sustainable agroforestry systems in Peru

Area of Science:

• Agricultural Science
• Environmental Science
• Waste Management

Background:

• Peru aims to reduce tropical deforestation by promoting agroforestry systems among smallholder farmers.
• Smallholders often face challenges with soil conservation and nutrient management, hindering agroforestry success.
• Municipal biowaste presents a potential resource for soil amendment in these systems.

Purpose of the Study:

• To evaluate the feasibility of using composted municipal biowaste as a soil amendment in Peruvian coffee agroforestry and silvopastoral systems.
• To assess the greenhouse gas (GHG) implications of composting versus traditional waste disposal methods.
• To determine the potential contribution of compost to nutrient requirements in agricultural lands.

Main Methods:

• Analysis of municipal biowaste composting potential in four Peruvian regions and their most populous cities.
• Calculation of compost nutrient contributions (90 kg N ha⁻¹ for coffee, 40 kg P ha⁻¹ for pastures).
• Comparison of GHG emissions from composting versus deep dumping and landfilling.

Main Results:

• Composting municipal biowaste can significantly reduce GHG emissions (5-10% of landfill emissions).
• The available compost is insufficient to meet the needs of the target agroforestry and silvopastoral areas (fertilizing <3% of coffee areas, 4% of pastures).
• Transportation of compost from major cities like Lima increases GHG emissions by 15-60%.

Conclusions:

• While composting municipal biowaste offers GHG benefits, its current scale is insufficient for widespread agricultural application in Peru.
• Logistical challenges, including transportation, negatively impact the environmental advantages of compost use.
• Compost requires supplementation with nitrogen-rich sources to enhance its nutrient quality for effective soil amendment.