Pesticides, fertilizers, soil and antibiotics

Summary of the issue:

Farmers and foresters often depend on agrochemicals (pesticides and fertilizers) to combat pests and diseases, boost productivity, and improve crop quality, while livestock producers and aquaculturists frequently depend on antibiotics to fight bacterial infections and promote animal growth. Unfortunately, mismanagement of agrochemicals and antibiotics has serious negative consequences for environmental and human health.

Indiscriminate pesticide use disrupts pollinators and natural pest-control mechanisms, impacts farm worker health, and places farmers on a treadmill of escalating chemical use that is neither environmentally nor economically sound. The overapplication of fertilizers causes nutrients to accumulate in waterways resulting in algal blooms that kill fish and other aquatic organisms, while underuse can lead to poor yields. Overuse of non-therapeutic antibiotics – an increasing concern in the livestock and aquaculture sectors – results in the development of resistant strains of bacteria that cannot be controlled by pharmaceuticals, with dangerous public health impacts.

Soil health is a separate but related issue. Healthy soils lead to higher yields and better-quality crops, reducing the need for nutrient inputs. Because healthy soils contain more organic matter, they are also a critical component of regenerative agriculture, helping build resilience of agroecosystems to climate change. Poor quality soils with low organic matter, on the other hand, are prone to erosion, which is made worse when farmers over-till or plant crops on streambanks, or when foresters log trees on steep slopes. Eroding soil carries nutrients along with it, increasing the need for additional agrochemical inputs and exacerbating the cycle of fertilizer overuse.

Careful agrochemical and antibiotic use and protection of soil health are critical to sustainable farming, forestry, livestock production and aquaculture. As a result, most market-based sustainability approaches – from certification programs to company sourcing codes and industry roundtables in the beef sector – contain provisions that aim to address these issues. Many agricultural standards ban highly toxic pesticides, include strict requirements for safe handling and storage of other agrochemicals, and promote integrated pest management (IPM) practices that reduce pesticide use. To boost soil health, many programs encourage the use of soil tests to assess fertilizer requirements, promote organic fertilizer use, and include provisions for erosion control. In the livestock sector, some programs ban antibiotics altogether, while others require producers to monitor and reduce antibiotic use over time.

The question of how these programs impact agrochemical use, antibiotic use, and soil health was examined in an Evidensia review. The section below provides a summary of the results of this review and the key evidence gaps remaining.