2018 Louisiana Soil Health and Cover Crop Conference BMPs for Reducing Nutrient Runoff and Improving Water Quality in Louisiana Agricultural Watershed Changyoon Jeong Red River Research Station, LSU AgCenter

Human Health Climate Changes Food Security Soil Management Nutrient Management Nutrient Loss Control Diseases Control Water Management

Best Management Practices (BMPs) BMPs are practices to control the transmission of excessive nutrients from agricultural activities to watersheds. Excessive nitrogen and phosphorus concentrations in water can accelerate algae and plant growth in streams and lakes, resulting in oxygen depletion or critically low dissolved oxygen levels - Hypoxia. Sediment runoff reduction is one of the most important practices (an economic and environmental perspective). Based on volume, sediment is the largest pollutant of surface water in the nation. The loss of nutrient-rich soil into rivers and streams is a financial loss. Conserve as much soil as possible can reduce the amount of fertilizers and other soil amendments to maintain adequate crop production.

BMPs Avoiding Controlling Trapping Nutrient management Rate, Timing, Form, Methods Controlling Residue & Tillage Managements Drainage Water Management Trapping Buffers Wetland designed for nutrient removal

Filter strip 23 acres of Sugarcane field Runoff water to Filter Strip. Outlet: 24 inch flumes Inlet 68 ft 283 ft 2 % slope Removed sediment from filter strip during 3 years study. Pensacola Bahiagrass at a rate of 40 lbs per acre. A complete fertilizer ( 16-16-16) was added at a rate of 180 lbs. per acre.

Hydrograph vs. concentration

Reduction Rate TSS and Nutrients Filter Strip.   In Out % of reduction (mg L-1) TSS 1668 1251 25 TN 3.2 2.9 8.1 TP 0.33 0.28 15

On-Farm Tailwater Recovery System: Rice – Soybean Rotational Fields Locations of the BMP site: NW of Kaplan, 30° 03' 12.82" N, 92° 14' 51.43" W ).

Irrigation well Rice Soybean Rice Site 1 Drainage : Pump Site 9 Drainage Ditch Site 2: Constructed wetland: Tailwater Recovery Reservoir Site 6 Drainage Ditch Site 3: Soybean Irrigation well Riser & well Site 5: Soybean Irrigation pipeline Rice Soybean Site 4: Rice Rice Acres of surface water recycled from 4 sites. Site 8 Drainage Ditch Site 7: Rice

Average NO3-N concentration in tailwater irrigation site Site No. Description 1 Drainage A site + all other drainage 2 Constructed Wetland 3 Soybean West 4 Rice West 5 Soybean East 6 Drainage B off-site 80% 7 Rice East 8 Drainage C 80% off-site 9 Drainage D100% off-site 24% higher in closed system 17% higher Rice Field Rice Field

Average PO4-P concentration in tailwater irrigation site. Site No. Description 1 Drainage A site + all other drainage 2 Constructed Wetland 3 Soybean West 4 Rice West 5 Soybean East 6 Drainage B off-site 80% 7 Rice East 8 Drainage C 80% off-site 9 Drainage D100% off-site 75% higher in runoff 66 % reduction 24% higher soybean Constructed reservoir rice

Fertilized Re-flooded August 2015 Clipped Rice Stubble Site 7: Rice Harvested Fertilized

Crop Fertilized

Summary The positive benefit of the BMPs on Nutrient loss and surface water quality from the filter strip & tailwater recovery irrigation system at the on-farm scale research. Rice field water retained a significantly high concentration of N and P. The constructed reservoir was significantly mitigated SRP and TP concentration. Continuous BMP efforts are required to improve crop productivity and decrease NPS pollution.

Thank you ! Protect Our Watershed Email: cjeong@agcenter.lsu.edu