82 MAINE AGRICULTURAL EXPERIMENT STATION. I9OI. 



In addition to the seaweeds proper which belong to the group 

 of marine algae, the table includes the results of analyses of eel 

 grass. Eel grass is not a true seaweed, but belongs to the pond- 

 weed family, a group of (mostly fresh water) aquatic olants. 

 The seaweeds proper rapidly decompose so that their fertilizing 

 constituents become speedily available, and as they have no 

 power of absorbing liquids, there is no advantage in composting 

 them, and they are best applied directly in the green state. This 

 is not true of eel gress, which more nearlv resembles straw. 

 While chemical analysis shows it to have nearlv as much nitro- 

 gen, phosphoric acid and potash as the seaweeds, it is only with 

 difficulty that they can be made available. Storer says, "It will 

 .hardly rot anywhere, either in the ground, in the hog-sty, or in 

 the manure or compost heap." 



Seaweeds produce their chief effect the first season. This 

 adds to rather than detracts from their value as a fertilizer, since 

 when they can be obtained at all, they can usually be had one 

 year as well as another, and can be applied annually. 



The analyses show that seaweeds are not evenly balanced 

 manures. They contain relatively considerable amounts of 

 nitrogen and potash and but little phosphoric acid. Conse- 

 quently land dressed for a long time with seaweed alone becomes 

 exhausted in phosphoric acid unless a large excess of manure 

 is added whieh would be wasteful of the nitrogen and potash. 

 Excellent results have been obtained by using phosphates with 

 these manures. Dissolved bone or acid South Carolina rock 

 may be used, 300 to 500 pounds to the acre, with 20 to 30 tons of 

 the fresh seaweed. 



With most crops the best results are obtained bv applying the 

 fresh material in the spring and either plowing or harrowing it 

 into the soil, but potatoes and some root crops, like the sugar 

 beet, are said to be injured in quality by spring applications. 

 This is probably due to the large amounts of chlorides of mag- 

 nesia, sodium, etc., they contain, as it is well known that these 

 substances have the effect of depressing the amount of starch in 

 tubers and thereby impairing the quality. Farmers who make 

 use of this material largely for a potato manure overcome this 

 difficulty to a large extent by applying it to the fields in the fall 

 before planting in the spring. In this way potatoes of much 

 better quality, it is claimed, are grown than by applying the sea- 

 weeds at the time of planting. 



