16 BULLETIN 802, U. S. DEPARTMENT OF AGRICULTURE. 



siclerable thicknesses. The high content of organically combined 

 nitrogenous substances is mainly related to the botanical composi- 

 tion of the plant remains and their slow disintegration capacity. 

 They are largely of protein origin, but partly chitinous, " coprog- 

 enous," in nature, being skeletal portions and egg cases of insect 

 and other animal life, and to some extent derived from spores and 

 mycelial components. They are extremely resistant to decomposition. 

 A high content .of nitrogenous peat substances should not be looked 

 upon necessarily as an important factor in judging the manurial or 

 soil value of peat and muck. Materials from other types of plant 

 remains, though exhibiting smaller values of resistant organic nitro- 

 gen, offer greater possibilities for meeting the agricultural and other 

 requirements for soluble nitrogen. 



Features such as those described above, especially regarding the 

 ether and alcohol soluble component, make the material valuable for 

 fuel as peat powder or as machine peat in the form of air-dried 

 brick-shaped blocks and for coking or distillation products, pro- 

 vided the ash content is low. They are relatively less desirable 

 for agricultural purposes or for use in gas generators on account of 

 the presence of the resistant components and pitch-yielding and 

 soot-forming by-products. 



Frequently the material shows a mottled coloring on account of the 

 presence of sulphur accumulating either in a finely divided form, as 

 small nodules, as crystals of iron and lime compounds, or in organic 

 combination. Ferruginous inclusions are likely to be unavailable 

 or injurious when available; they generally add some shade of red 

 or yellow to the peat material when air dry, or, more rarely, the 

 bluish tint of the phosphatic iron compound " vivianite " (blue iron 

 earth). Contaminations of that kind in fields not suitably drained 

 retard considerably the growth of crops unless the peat material is 

 well aerated, underdrained, limed, or supplied with finely ground 

 rock phosphate and potash-bearing minerals. As mud baths, the 

 saline phases of these t3'pes are reported to have proved medicinally 

 valuable, and in European countries they have become the centers 

 of health resorts. 



MACEBATED TYPE. 



" Mudde," " Saproppl," " Gyttja." 



Reddish brown to deep brown, more or less macerated plant re- 

 mains with a fine-grained, oozelike plastic to sticky ground mass in 

 various proportions, which occurs as a filler or binding material in 

 the interstices between the less easily destructible fragments of plant 

 tissue. The material is derived indiscriminately from vegetation 

 units bordering open water. Some of the original identity and 

 form is retained in spores, pollen grains, seeds, leafy and other frag- 



