The Journey from Peruvian Guano to Artificial Fertilizer Ends with Too Much Nitrogen in the Chesapeake Bay

Abstract

By the mid-nineteenth century, farmers in the Chesapeake Bay Watershed began importing fertilizers to restore productivity to depleted fields. This began with guano from remote Peruvian shores, which created a market for soil amendments that switched to artificial fertilizer in the twentieth century. The widespread use of artificial fertilizers and animal manures to supply reactive forms of nitrogen to crops resulted in increased productivity per unit area, but also many unintended consequences including; pollution of ground and surface waters, increases in weeds and agricultural pests, air pollution, reduced biodiversity and release of global warming gases. Nitrogen pollution of the Chesapeake Bay caused the onset of persistent eutrophication in the later half of the twentieth century. The USEPA is working with jurisdictions to reduce nitrogen pollution through a series of best management practices that facilitate preserving the current food system while reducing its impact on the environment. Moving the food system away from a focus on animal agriculture and toward producing crops for a whole-food-plant-based-diet will speed the recovery of the Chesapeake Bay ecosystem from the ravages of excessive reactive nitrogen.

The element nitrogen is essential to all life on earth.

But most of that what’s in the air doesn’t seem much worth.

The dinitrogen that dominates the atmosphere is joined together by a triple bond.

Of this plants are not very fond.

They need the help of bacteria to make that airy nitrogen reactive for them to use.

Or an artificial process to make synthetic nitrogen for people to abuse.

Reactive nitrogen from the chemist does require lots of fossil fuel to make.

And it changes form in the soil, leaving more air pollution in its wake.

When applied as a fertilizer it makes crops and weeds grow fast.

And turns the water so green with algae that it looks nothing like in the past.