Location: Soil Drainage Research
Project Number: 5080-13210-002-044-A
Project Type: Cooperative Agreement
Start Date: Jun 1, 2020
End Date: May 31, 2024
The over arching objective is to examine the fate of dissolved phosphorus and particulate phosphorus in agricultural drainage ditches. Specifically, the following questions will be answered: 1) What are the uptake rates and residence times of DP in agricultural drainage ditches? 2) What are the residence times of fine particulates in agricultural drainage ditches and potential implications for residence times of total phosphorus? 3) How do ditch characteristics such as aquatic vegetation and flow depth influence DP and fine particulate retention?
At each of 6 sites within the ARS edge-of-field research network, reach-scale tracer experiments will be used to quantify the fate of fine particulates and dissolved phosphorus. Nutrient uptake with short-term nutrient additions involving the injection of potassium phosphate to quantify soluble reactive phosphorus uptake length, uptake velocity, and uptake rate will be measured. Sodium chloride will be added simultaneously to act as a conservative tracer and quantify transient storage metrics such median solute travel time. Surface water will be sampled at high frequency at the upstream and downstream ends of the reaches. Solute and particle breakthrough curves will be analyzed in addition to a stochastic model.