Agriculture

Nearly one-quarter of the Bay watershed's land area is devoted to agricultural production. Agriculture is essential to all people; farms supply us with grains, eggs, meat, milk, vegetables. While fertilizers, pesticides, manure and tilled soil are beneficial to crops, they become pollutants when water from irrigation and precipitation washes them into local waterways.

Irrigation

Irrigation is a common method for farmers to water their crops to ensure consistent crop production in a variety of weather conditions. Fruits, vegetables, grains and horticultural plants are the most commonly irrigated crops on Bay watershed farms.

Excess water from irrigation that is not absorbed into the soil may run off fields and into nearby waterways, carrying fertilizers, soil, pesticides and manure along with it. Increased amounts of water soaking into the soil may also transport dissolved nutrients from commercial fertilizers, livestock manure and poultry litter into groundwater supplies.

Fertilizing Soil

Commercially manufactured agricultural fertilizers provide crops with the nutrients they need to grow. When more fertilizer is applied to the soil than crops can absorb, excess nutrients can:

• Be washed off the land via runoff into the nearest water source.
• Soak through soil and bedrock into groundwater supplies.

Excess nutrients like nitrogen and phosphorus fuel the growth of algae, creating dense algae blooms that rob the Bay's aquatic life of sunlight and dissolved oxygen.

Animal Manure

Animal manure is often applied to cropland as a form of fertilizer because it contains nutrients that help crops grow.

• However, when excess manure is carried from the land via runoff, those nutrients, as well as bacteria and pathogens that manure often contains, can end up in our waterways.
• Excess nutrients from manure can also absorb through the soil into groundwater supplies, contaminating local waterways and drinking supplies.

Animal manure and poultry litter contribute about half of the Bay watershed's agricultural nutrient load.

Managing manure and poultry litter is a major component of farms that run animal operations. As cropland is increasingly converted to development and other non-agricultural uses, less cropland is available to efficiently use the manure and litter being produced by animal operations in the watershed. Producers have alternative options for their manure and litter, but transportation costs, access to markets or equipment and infrastructure requirements may prohibit them from taking part.

Applying Pesticides

Chemical pesticides and herbicides help protect crops from insects, weeds and fungus. Just like fertilizers and manure, when pesticides are applied in excess, they can make their way into local rivers and streams and potentially impact aquatic life. Pesticides can also soak into groundwater supplies, a source of drinking water in many Bay watershed communities.

Tilling Cropland

Tillage loosens the soil and makes it easier to uniformly plant crops; but in the process, it leaves soil prone to erosion. Loosened soil that is transported by runoff can cloud the water in rivers, streams and the Bay and limiting the amount of sunlight able to reach underwater bay grasses. River basins in the Bay watershed with the highest percentage of agricultural land yield the highest overall amount of sediment each year.