On the other hand phospor deficiency is easy to come by with smallish amounts of phosporous. Only at hard deficiency the yield will suffer strongly. The nutrien

On the other hand phospor deficiency is easy to come by with smallish amounts of phosporous. Only at hard deficiency the yield will suffer strongly. The nutrient supply-yield curve is very steep in the lower end of supply and shallow in the range of optimal supply. Check Sonneveld et.al. What I am trying to say is that we sure would like to give optimal supply to out plants, but slight undersupply will still give reasonable yields. Profitability issue? Yes! Problem with feeding the world? Rather not.