332 BOARD OF AGRICULTURE. 



point, found them more or less of a clayish character. The 

 clays proved to be deficient in lime and humus, but rich in 

 phosphoric acid and potassa (from 1 to 1.5 per cent). The 

 last two constituents were due to a fine white mica, which, as 

 a constant admixture, in common with quartz-sand, consti- 

 tuted the main bulk of the mineral species which modified 

 the soil. The humus contained in these fertile sandy clays 

 was found as low as 0.66 per cent., and rarely rose beyond 

 3.66 per cent. ; local accumulations of black peaty layers, 

 rich in humus, interfered seriously with their productiveness. 

 The most characteristic crop of these marshes is grass ; trees 

 are scarce ; the birch is seen here and there along the borders, 

 where the soil is of a turfy and deeper character. Wherever 

 the soil is cultivated, barn-yard manure and marl are almost 

 exclusively the fertilizers used. One-fifth of the area of the 

 farm is usually kept as a permanent pasture, and the remain- 

 ing four-fifths are, for four or five years, cultivated for other 

 products. After the expiration of that period they are seeded 

 down for from two to three years with grass. The usual 

 rotation of crops, in case of new lands, is : oats two years in 

 succession ; then rape ; subsequently wheat, and finally beans. 

 The best results have been obtained by raising grain crops 

 alternately with broad-leafed plants. 



Changes in the character of the indigenous vegetation of 

 salt marshes are, as a general rule, under ordinary circum- 

 stances, slow; for they depend on a gradual alteration in the 

 physical and chemical condition of their soil. Sudden exclu- 

 sion of the salt water, by dikes or otherwise, only produced 

 different results. The extensive salt marshes along the North 

 Sea, being of different elevations, represent distinctly their 

 various stages of Growth. The vegetation which covers fehern 

 presents to the careful observer unmistakable features in re- 

 gard to the predominating varieties of plants at different 

 levels. This fact is so striking, that the appearance of certain 

 plants serves to the intelligent farmer as a guide in the selec- 

 tion of his industry. As long as the salt water still finds fre- 

 quent access to the marshes, genuine salt plants, like Salicornia 

 herbacea (Samphire) and Aster trifolium, are of frequent oc- 

 currence. As soon as the ordinary high tide no longer passes 

 over their surface, Poa maritima and other fodder-grasses 



