A Closer Look
The need to implement practices to reduce nutrient loss is one of the key points related to agriculture in Iowa's Nutrient Reduction Strategy (NRS).
The science assessment done in conjunction with the strategy's development identified effective nutrient reduction practices in three categories - nitrogen and phosphorus management, land use, and edge-of-field/erosion control. The science assessment also identified benefits and limitations, and developed estimated costs for practice adoption.
The list of nutrient reduction practices could be very long when considering variations and combinations of practices. The practices listed here are based on research and are those that have the greatest potential to make a significant impact on reducing the loss of nitrogen (nitrates) and phosphorus (phosphates) into the water supply. These practices are applicable to large portions of Iowa.
Management practices focus on the most effective or efficient use of nitrogen (N) and phosphorus (P). These practices involve application rate, timing, and method, plus cover crops and reduced tillage.
Note: Some management practices impact only nitrogen or phosphorus, while some impact both. This is indicated by the inclusion of N or P in the practice titles.
General Management Resources | 4Rs Nutrient Stewardship
Nutrient Management BMPs | Iowa State University Extension
Spring Applied Nitrogen
Site-specific P Management
Nitrogen Application Rate
Land use options physically change the nitrogen (N) and phosphorus (P) dynamics by changing the vegetative cover. These practices include perennial energy crops, extended rotations, grazed pastures and land retirement.
Note: Some land use practices impact only nitrogen or phosphorus, while some impact both. This is indicated by the inclusion of N or P in the practice titles.
Edge-of-field and erosion control technologies provide opportunities to remove nitrate (N) and phosphorus (P) from water leaving production fields. These practices involve drainage water management, wetlands, bioreactors, buffers, terraces and sediment control.
Note: Some edge-of-field and erosion control technologies impact only nitrogen or phosphorus, while some impact both. This is indicated by the inclusion of N or P in the practice titles.
Terraces, Waterways, Sediment Control Structures
Drainage Water Management