SOILS AND FERTILIZERS 



417 



good absorbent, such as loam, muck or peat. It is estimated that 

 the excrements of a man for one year contains about eleven pounds 

 of nitrogen, two and one-half pounds of phosphoric acid and two 

 pounds of potash. 



Muck and Peat. There are names used to designate partially 

 decayed vegetable matter which has accumulated in marches, 

 swamps and shallow ponds. It is quite variable in composition, 

 generally ranging from one-half to two per cent of nitrogen, and 

 only traces of phosphoric acid and potash. They are quite valuable 

 for use on sandy soils, and on very stiff clays. The ^better classes 

 make good bedding and absorbents. 



Leaf Mould. This is a term applied to a more or less decayed 

 accumulation of leaves in the woods. It is especially valuable for 

 some special classes of gardening or truck crops. It is costly to 

 gather, and its removal is more or less harmful to the forest trees. 

 It contains about twenty pounds of nitrogen, three and one-half 

 pounds of phosphoric acid, and twelve pounds of potash per ton. 



Sea Weeds. Along the sea border there is considerable quanti- 

 ties of sea weeds washed ashore from time to time, and most of these 

 are fairly rich in plant food, and afford a good source of manure. 

 They contain from 5 to 12 pounds of nitrogen, two to five pounds 

 of phosphoric acid, six to twelve pounds of potash per ton. 



Comparative Value of Solid and Liquid Parts. It is a fact 

 often lost sight of in practice that the urine of animals is by far the 

 most valuable part of the excreta. In experiments with milch cows 

 at the Pennsylvania Experiment Station it was found that the urine 

 contained more than one-half of the fertilizing matter of the food 

 and nearly two-thirds of that of the total manure (dung and urine). 

 The solid manure (dung) contains, principally, the fertilizing con- 

 stituents of the food which have failed to be digested or absorbed 

 into the animal system and are, therefore, chiefly in' insoluble 

 forms. The urine, on the other hand, contains those fertilizing 

 constituents which have been digested and are largely soluble. The 

 composition of the urine, like that of the dung, varies with the kind 

 and age of 'the animal, but especially with the nature of food, wa- 

 ter drunk, etc. The composition of the urine of different kinds of 

 farm animals has been found by analysis to 'be as shown in the 

 following table: 



Chemical Composition of the Urine of Different Animals. 



The urine of farm animals is practically free from phosphoric 

 acid except in the case of sheep and swine, the urine of which con- 



