For one thing, farmers are at the mercy of unpredictable weather. A farmer can do everything right when producing a crop and still have a negative outcome. For example, we know that efficient nitrogen management is critical to optimize economic yields. Yet maximizing crop recovery of nitrogen in commercial fertilizer and manure can be challenging. One reason is Delaware's variable weather.
Problems arise when nutrients are applied and there is no rain.
Nutrients cannot be taken up by a dying crop, leaving the fertilizer in the soil to be transported into the groundwater when the rains do come. Despite our best scientific knowledge, a good decision to use nitrogen in the beginning is overridden by natural forces. University of Delaware and U.S. Soil Conservation Service scientists have developed a site index system that rates Delaware soils in terms of their potential to deliver phosphorus to the Inland Bays and other water bodies. High levels of phosphorus are a major cause of the degradation of such bodies of water. The site index makes it possible to prioritize phosphorus pollution control efforts.