Why we should use Natural Farming then Chemical II

1)fertilizers used on crops will dissolve disappeared into the lake or river &
etc.ini will encourage a lot of algae growth, which will disturb the ecosystem in
this area - eutrophication
2)use of nitrogen fertilizers that too often will lead to greater pest problems such
as increasing the birth, life longivity and durability
3)Concentration to 100 mg / kg cadmium in phosphate minerals with increasing soil
cadmium contamination

if we apply chemical fertilizers, should follow the correct rate ..... but I would prefer we all practice organic farming then chemical

reference:wikipedia