Laccifer lacca(Kerr)is a important ecomonical resource insect,no matter from the historcial datum or the present-day scientific reserch data to see,the South China is it important original producing area aii the while.The culturing methord of Laccifer lacca(Kerr)in ancient China is scientific,the Application is very wide,In shading,medical,construction,painting,and so has its shadow,For the development of Chinese civilization,has made an important contribution to the heritage.
Since the late Ming dynasty to 1856 Qing dynasty,"shu shui gong sha"is the authentic theorem of water-control in lower reaches of Huang-he river,but plan was always used period of time which appeared problem and to be fail.Based History geography’s view,we can see it was resulted in land-increasing and bayou-extending from bedload which be eroded by water.In Ming and Qing dynasty,the coastline varied prodigiouss near the bayou,the bayou reached 90 km eastwardly,which elongated the riverway in lower reaches of Huang-he river in disguised form,caused the gradient minish,the water flowed slowly,the bedload deposited on riverbed,which conduced the bank bursted easily in the flood season,result flood in a high frequency.Finally,the river to be hang river,the bank difficult to be maintained,the Huang-he river be compelled to flow northly to the Bo-hai sea,the "shu shui gong sha" failed.
