EECLAIMABLE LANDS 331 



COST OF SCREENING. 

 In the economic loss caused by mosquitoes there should be included the outlay 

 for protective measures. All over the United States, for these insects, and for 

 the house fly as well, it has become necessary to screen habitations. The cost 

 of screening houses alone must surely exceed ten millions of dollars per annum, 

 especially if we add the expense of screening rain-water tanks in the Southern 

 cities. 



THE VALUE OF RECLAIMED LANDS.* 



" The general value of lands reclaimed from swamps is obvious. Practically 

 all of Holland has been reclaimed from the sea. Large areas of the most valu- 

 able farming land in the world have been reclaimed from nonproductive swamps. 

 To the nonproductiveness of swamp land must be added the great danger that 

 exists in its continuance through the invariable presence of disease-bearing mos- 

 quitoes. The drainage of swamps not only destroys unlimited breeding places 

 of mosquitoes, but vastly increases the value of the land for farming purposes 

 and for other utilitarian uses. Either reason amply pays for the operation. The 

 late Prof. IST. S. Shaler, in his report to the North Shore Improvement Associa- 

 tion, showed that fields gained by marsh drainage possess the greatest fertility 

 and their endurance to cropping without manuring exceeds that of any other 

 agricultural land except possibly arid regions which are irrigated. The range 

 of crops is great and includes all ordinary farm and garden crops except in some 

 places Indian corn. Reclaimed swamp lands are especially adapted for truck 

 farming, because it is easy to maintain the level of under-ground water where 

 the roots of the plants can reach it. Professor Shaler shows that the larger part 

 of the best irrigable land in Holland, and much of that in Belgium, northern 

 Germany and eastern England has been gained from what was originally tidal 

 fields. He estimates not less than 10,000 square miles in those countries to have 

 been redeemed in this way. 



" The only large example of diked and improved marshes in the northeastern 

 United States is at Green Harbor, Mass., where 1,200 acres have been won to 

 tillage, about one-half being used for hay fields and the other for difi'erent crops. 

 The result obtained in the farming of this land is excellent. Asparagus has 

 produced large crops continuously for more than twenty years without the use 

 of any fertilizer. 



" Prof. Milton Whitney, Chief of the Bureau of Soils, of the United States 

 Department of Agriculture, some years ago drew up the following statement at 

 the request of the writer, concerning the value of reclaimed swamp land : 



" ' Swamp lands, by virtue of their position, become the repository of highly 

 fertile material washed from the uplands by the rains. As a general rule, the 

 immediate surface of any soil is the most fertile portion of that soil, resulting 

 from the fact that this surface material is in physical condition, and most ex- 

 posed to the action of the weather, the sun, rains, and air. This surface is the 

 first portion removed during rains, and is the portion carried down into the 

 swamps and deposited. When erosion goes on at such a rapid rate that both the 

 surface and the underlying raw soil are washed away, the resulting bottom land 

 deposit is frequently sterile. Witness the mud flats and swamps along the 

 Sacramento River, in California, which have been covered with mud from the 

 hydraulic mines of the Sierra Nevadas. Here large areas have been ruined by 

 the mud, and will not become fertile until the weather has acted upon the 

 material long enough to make the soil an acceptable medium for plant growth. 



* Quoted from Howard, L. O., Preventive and remedial work against mosquitoes. U. S. Dept. 

 Agr., Bur. Ent., Bull. 88, pp. 53-62, 1910. 



