70 MAINE AGRICULTURAL EXPERIMENT STATION. I9OI. 



would be poorer than other parts in plant food. In selecting 

 samples for analysis great care needs to be taken in order to be 

 sure the sample fairly represents the whole. 



The potash insoluble in water is chiefly the silicate of potash 

 which is only slowly if at all available to plants. The phosphoric 

 acid is all in insoluble form and how readily available is not 

 known. 



In addition to their manurial value, ashes have a decided effect 

 upon the capillary power of the soils. If a solution of carbonate 

 of potash, such as potash of wood ashes, is poured upon loam, it 

 will be made muddier and stickier than it would be if moistened 

 with water. Milton Whitney of the United States Depart- 

 ment of Agriculture has investigated this subject and finds 

 that alkaline solutions seem to loosen the particles of the clayey 

 soil from the particles of sand and float off the clay particles, so 

 as to fill up the spaces between the sand grains. As a result of 

 this clogging of the pores, the circulation of the water is 

 much retarded. That this action of an alkali is sometimes of 

 great practical importance is attested by the fact observed by 

 Whitney, that soils are met with in which the particles of clay 

 are held so closely to the grains of sand that the soil has the 

 appearance and properties of a sandy soil, although it may act- 

 ually contain as much clay as many so-called clay soils. Car- 

 bonate of potash has a tendency to keep clay in a "puddled" con- 

 dition. A ball or lump of moist clay, held together with alkaline 

 carbonate does not tend to crumble during the process of drying, 

 but remains a hard lump. As unleached ashes carry large 

 amounts of potash lye, the application of ashes may have practi- 

 cally the same effect upon soils as the addition of carbonate of 

 potash. 



Potash soils also have a decided action upon soil nitrogen. 

 These alkaline solutions have great power to dissolve organic 

 matters and render unavailable nitrogen available. This ten- 

 dency of potash to promote rank growth is well illustrated 

 wherever the land has been recently cleared of wood and the logs 

 burned. The rankness of growth which follows is probably due 

 not only to the available potash thus returned to the soil, but also 

 to the superabundant supply of nitrogenous food made available 

 by the action of the alkali upon the soil humus and to the fact 

 that alkali has a tendency to retain moisture. 



