Nitrogen, phosphorus, and potassium cycling in pasture ecosystems

Abstract

Inadequate management practices are the main factors that can cause pasture degradation,
and one of the key factors is to understand the nutrient cycling in pasture ecosystems. This review
aimed to describe the cycling processes of important nutrients in pasture ecosystems (nitrogen,
phosphorus, and potassium), analyzing the interactions of soil-plant-animal components. The use of
forage legume species intercropped with grasses is a strategy to increase the nitrogen content in
the soil, minimizing costs with nitrogen fertilization in pastures. Manure and plant residues are great
organic sources of phosphorus and potassium but are also fundamental for supplying microminerals.
Nitrogen losses in pastures are mainly caused by leaching, runoff, and volatilization. The addition of
phosphorus to the soil must be performed carefully, as there is an increase in phosphorus losses with
increasing accumulation in the soil. Phosphorus is often returned to the soil far from where it was used,
so the stock transfer represents a loss in pasture ecosystems that can account for approximately 5%
of the inputs of phosphate fertilizers. Potassium losses mostly occur by leaching and runoff. Improving
management practices is essential for balanced nutrient cycling in pasture ecosystems.