The composition of municipal sewage sludge and its effect on plant growth,soil fertility and agro environments were studied by filed.greenhouse and incubation experiments.The results showed that sewage sludge contained quite a lot of organic matter and plant nutrients such as nitrogen and phosphrous.Bioavailabilities of N and P of sludge origin were higher than those from ordinary farmyard manures.Sewage sludge significantly improved soil physical,chemical and biological properties by in...