The Watershed Impact Trial is a comparison of organic and conventional agricultural systems to determine their relative impacts on the environment, especially water quality.
The trial is located on 40 acres of sloped land at the Natural Lands’ Stroud Preserve in Chester County, Pennsylvania. At such a scale, we can extrapolate data to apply to large farms. The topography of the preserve enables us to recreate common conditions, as most runoff occurs on slope.
On four large plots, we are growing grain crops using four different management systems: organic with tillage, organic with reduced/rotational tillage, conventional with tillage, and conventional or “conservation” no-till.
The trial will run for a minimum of 6 years.
Pictured: 2018 crop plan for the Watershed Impact Trial
What We’re Measuring
Quantity and composition of runoff
Residues of pesticides, fungicides, and herbicides on crops and in the water and soil
Stream water quality, or the presence of harmful microbes in the water
Physical, chemical, and biological properties of soil, including water infiltration
Emissions and energy use
The Impacts of Farming on Water
Chemical fertilizers and herbicides have the potential to run off into nearby bodies of water and infiltrate groundwater.
When used, cover crops can help increase soil fertility and reduce the risk of soil erosion.
Healthy soils that have maintained their nutrients are more stable and hold more water, decreasing the risk of runoff.
What’s at stake?
The nitrogen and phosphorus in chemical fertilizers that runoff into waterways cause algae to grow faster than ecosystems can handle, decreasing the oxygen that fish and aquatic life need to survive and causing “dead zones.” The dead zone in the Gulf of Mexico, not even the largest in the world, covers more than 8,500 square miles.
Looking upstream at the way we farm can have a huge impact on the quality and quantity of clean, fresh water available worldwide.