Mandatory Legal Approaches to Agricultural Nutrient Management

Nutrients such as nitrogen and phosphorous are vital to agricultural crop production in the United States but have also detrimentally impacted water quality. Excessive nitrogen and phosphorous in water can lead to eutrophication and the growth of harmful algal blooms that can contaminate surface and drinking water supplies and potentially harm both animal and human health (CRS Report R43919, 2016). Attention to solving nutrient pollution problems has intensified in recent years.  However, while the Clean Water Act gives the federal government a role in directing solutions for point source effects on water in the U.S., the states maintain primary legal authority over nonpoint sources of nutrient pollution such as farmland and runoff from farmland.  States play a critical role in addressing the impacts of agricultural nutrients on water quality.

How are states responding to the water quality challenges posed by agricultural nutrients? Our research project attempts to answer this question.  We found that many of the states have responded by encouraging farm operators to engage in voluntary practices that can reduce runoff and loss of agricultural nutrients from farmland to waters and waterways.  But states are also relying on mandatory approaches that require specific actions or inactions regarding agricultural nutrients.   This state compilation presents the mandatory laws and regulations we identified that address the use of agricultural nutrients at the ground level—on the farm. The compilation includes state government laws and regulations that relate to minimizing water impacts from the use of nutrients, including both commercial fertilizers and animal manure, on agricultural lands.

We categorized the legal approaches we found into three broad categories that are based on the nature of the particular activity the law or regulation affects: nutrient management planning, certification of nutrient applicators, and nutrient application restrictions.  The first category of “nutrient management plans” encompasses laws and regulations that mandate the development of written plans that manage the amount, source, placement and timing of plant nutrients and soil amendments. “Application restrictions” comprise the second category, which includes laws and regulations that place limitations on the physical application of agricultural nutrients to land.  Our third category of “applicator certification” contains laws and regulations that establish minimum knowledge standards for the individuals who apply agricultural nutrients to land.

The chart below identifies whether a state has laws and regulations in each of the three categories of mandatory approaches. A “Yes” in a column signifies that the state has laws and regulations in that category. Click on the “Yes” to access the state’s laws and regulations for that category.  The resources in this chart were last updated in June, 2020.

For further explanation of this compilation, refer to our national report on “State Legal Approaches to Reducing Water Quality Impacts from the Use of Agricultural Nutrients on Farmland,” available here.  The report reviews and highlights mandatory approaches states are taking to address agricultural nutrient impacts and also provides examples of voluntary approaches we identified in our research.