IMPORTANT TYPES OF PEAT MATKEIAL. 25 



debris iiiidergoing weathering' and disintegration. As surface ma- 

 terial this blackish fine-grained component is almost impervious to 

 water, probably due to the absorption of air. Windbreaks, pref- 

 erably of alder, maple, and willoAV, arc necessary to prevent injury 

 from dust storms to seedling crops, but a rotation which includes 

 broad-leafed crops or plants with a fibrous root system to hold the 

 fine-grained debris would be more advantageous and would aid in 

 maintaining a favorable water content at the surface of the soil if 

 irrigation measures are not feasible. 



The first crop to be planted deserves, therefore, careful considera- 

 tion, as it materially affects the disintegration of the plant remains. 

 On poorly disintegrated, fibrous phases of these peat types, potatoes 

 and corn are considered desirable. Where droughts are of rare 

 occurrence not much trouble has been experienced in keeping the 

 ground water too low to injure crops of value in intensive modes of 

 farming. Ferruginous peat material of these types would, however, 

 prove more profitable if under cultivation for hay and pasture. 



The value of these types for industrial purposes is dependent on 

 several factors, most important of which are the degree of disinte- 

 gration, the ash content, and the impurities. The blaclrish, com- 

 pact, well-decomposed phases with less than 20 per cent of ash 

 produce less soot or ether and alcohol soluble and pitchy substances 

 than the types of peat which contain the resinous and waxy bodies 

 (see Table I). They are therefore considered preferable for the 

 manufacture of power gas in gas producers where by-products are 

 objectionable and their recovery is not contemplated. As machine 

 peat, thoroughly gTound, pulped, and air-dried, they jneld a fuel 

 of good quality, generallj?^ near 3,500 calories; the}^ are clean to 

 handle, give a relatively intense heat, and are well adapted for 

 smaller manufacturing or farming communities and for domestic 

 uses. The brick-shaped blocks of machine peat that are allowed to 

 air-dry slowly contract into a dense mass covered b}' a gelatin- 

 like outer layer which is reported to be a hydrocellulose rather than 

 a resinous substance; it renders the machine-made product almost 

 impervious to water, compact, and more resistant to breakage. 



The coarser textured, partly fibrous phases of peat appear to be 

 preferable for composting and as a filler for tankage or a base for 

 compounding with fine-ground mineral fertilizers. After excava- 

 tion the moist peat material should be piled and stored in mounds 

 20 or 30 feet high and kept under cover if possible for at least six 

 to eight months. During that time the plant remains shrink con- 

 siderably in volume and undergo a slow internal heating, granula- 

 tion, and carbonizing process, which may be aided artificially by 

 means of pipes heated with " exhaust " steam. The material has been 



