22 Circular 111 



able. The deeper salt holes are drained by spurs from the 

 nearest unit ditch. The shallow and small salt holes are filled 

 with sod taken from the ditching. The distance between drain- 

 age ditches varies from 75 to 400 feet, depending upon the 

 porosity of the particular salt marsh. Most marshes require the 

 drains 150 feet apart. 



The trenches described in the preceding paragraph can be 

 and often are, dug with ordinary garden spades. It is usually 

 more economical, however, to use special tools which have been 

 perfected for this type of work during the last 12 years. There 

 are at the present time in use on the salt marshes of New York 

 and New Jersey, one type of one-man spade, two types of two- 

 man spades, a three-man spade and a power ditcher. The power 

 ditcher under some conditions is the most efficient of these tools. 





Fig. 9. Hay Yield of a Salt-Marsh Which Has Been Drained 

 For Several Years 



With this machine an average of 5000 lineal feet of 10 by 30-inch 

 ditching can be cut in a day of 10 hours. 



Salt-marsh Mosquito Trenching Increases The Yield of Salt Hay 



Some salt-marsh owners think that the mosquito drainage 

 as laid out above will damage the present productivity of the 

 salt-marsh. This is most decidedly a mistake. The income from 

 the salt-marsh is at present derived from salt-marsh hay. A very 

 large proportion of the marsh is now covered with coarse grass 

 utterly unfit for hay and many areas are too soft to permit har- 

 vesting: even if the hav thev bear made harvesting worth while. 



