Phosphorus in agricultural ditch soil and potential implications for water quality

Drainage ditches can transport water and nutrients within agricultural watersheds. Thus, it is important to consider ditch soil phosphorus (P) characteristics, as these can impact water quality. Objectives of this study were to determine (1) P characteristics of agricultural ditch soils in the Lake Okeechobee Basin, Florida; (2) what controls soil P; (3) relationships between different ditch soil P fractions; and (4) compare ditch soil characteristics with upland and wetland soil characteristics. Ditch soils had medium to low total P content (<600 mg kg−1 [<600 ppm]) with organic matter and soil metal content important for predicting soil total P. Degree P Saturation of soils suggests dairy and improved pasture soils could impact water quality. In general, ditch soil characteristics were more similar to upland soils rather than wetland soils. In-ditch management practices, such as the use of soil amendments and/or controlled drainage, could be useful to reduce P loss from ditch soils.