Figure 4. Simplified cycle of phosphorus in agriculture based on data from Cordell et al, 2009 and Cordell et al, 2011. Red arrows represent losses into water systems ultimately, and green arrows represent current recoveries into arable land from the different subsystems. The percentages under the red arrows
represent the percentage losses from each subsystem, and shown in brackets are the percentage losses relative to the total input into agriculture land. For
example, the livestock system loses about 45% of the phosphorus entering the livestock system itself, and this represents about a 29% loss of the phosphorus
entering the agriculture system overall. (We have excluded the flow up to the input into farm system, but for example, losses in phosphorus mining and processing
can also be significant.)