Agriculture Research Articles
Pronounced surface stratification of soil phosphorus, potassium and sulfur under pastures upstream of a eutrophic wetland and estuarine system
Document Type
Article
Publication Date
3-15-2017
Journal Title
Soil Research
ISSN
Print: 1838-675X Electronic: 1838-6768
Keywords
eutrophication, nutrient stratification, organic matter, pH, surface soil
Disciplines
Agronomy and Crop Sciences
Abstract
High concentrations of nutrients in surface soil present a risk of nutrient movement into waterways through surface water pathways and leaching. Phosphorus (P) is of particular concern because of its role in aquatic system eutrophication. We measured nutrients under annual pastures on a beef farm and a dairy farm in the Peel–Harvey catchment, Western Australia. Soils were sampled in 10-mm increments to 100 mm depth in March, June and September. Plant litter contained approximately 300–550 mg kg–1 Colwell-extractable P. Extractable soil P was strongly stratified, being approximately 100–225 mg kg–1 (dairy) and 50–110 mg kg–1 (beef) in the top 10 mm and <40 mg kg–1 at 40–50 mm depth. Total P and extractable potassium were also highly stratified, whereas sulfur was less strongly stratified. Shoot nutrient concentrations indicated that nitrogen was often limiting and sulfur was sometimes limiting for pasture growth: concentrations of P were often much greater than required for adequate growth (>4 mg g–1). We conclude that high P concentrations at the soil surface and in litter and shoots are a source of risk for movement of P from farms into waterways in the Peel–Harvey catchment.
Recommended Citation
Ryan Megan H., Tibbett Mark, Lambers Hans, Bicknell David, Brookes Phillip, Barrett-Lennard Edward G., Ocampo Carlos, Nicol Dion (2017) Pronounced surface stratification of soil phosphorus, potassium and sulfur under pastures upstream of a eutrophic wetland and estuarine system. Soil Research 55, 657-669. https://doi.org/10.1071/SR16144
