SOILS AND FERTILIZERS 367 



water very slowly, and a large amount will run off and carry with 

 it the best soil. Silt and clay soils are much more liable to wash 

 than sandy ones. While it is impossible to change the inorganic 

 constituents of soils to any appreciable extent, yet they may be 

 treated in such a way as to change the texture in a few years. This 

 may be done by incorporating organic matter in them. The partly 

 decayed material cements the soil particles into granules, and thus 

 checks washing. 



It is a well-known principle that dark surfaces absorb the sun's 

 heat, while white surfaces reflect it. As a rule the more organic 

 matter a soil contains the darker it is, and this makes it a good ab- 

 sorber of heat. Consequently dark or black soils become warmer 

 than those of the same, physical composition but lighter in color. 

 This difference in temperature noticeably affects the germination 

 and growth of plants. The difference between times of germina- 

 tion on light and dark soils is a matter of common observation. In 

 spring when corn begins to come up the rows may be seen sooner 

 upon the low, black soil than upon the higher, lighter colored soils, 

 provided the conditions of moisture are about the same for each. 

 This is usually attributed to the fact that the black soil is the richer, 

 but the amount of plant food in the soil has very little to do with 

 the growth of corn up to the time when it may be seen in rows. It 

 will reach this stage in pure sand devoid of any plant food. (Univ. 

 111. B. 82, 119; Fla. E. S. B. 48; Iowa Col. B. 82.) 



TREATMENT OF MUCK SOILS. 



Muck soils are widely distributed, in small or large areas, in the 

 United States. When properly drained and handled they are in 

 many cases extremely productive. The amount of muck land re- 

 claimed by drainage and brought under cultivation is rapidly in- 

 creasing, and it is becoming a matter of considerable importance to 

 know the best methods of utilizing such lands. Extensive areas of 

 muck soils are found in Florida. 



It is recognized that proper drainage is a necessary prerequisite 

 to the use of muck soils, for if muck soils are to be cultivated it is 

 obvious that they must first be drained. This is necessary in order 

 that they may become the home of the various kinds of micro- 

 organisms that play an important part in the making of a fertile 

 soil. These micro-organisms need moisture, but they can not de- 

 velop in mud or standing water. The method of cultivation requires 

 particular attention. 



Cultivation should be deep, especially at first, in order that the 

 air may thoroughly penetrate the soil. Muck soils often contain 

 substances that are injurious and even poisonous to plants. When 

 these poisonous substances are exposed to the air they are probably 

 oxidized to a considerable extent and thus destroyed. A free cir- 

 culation of the air also improves the conditions for the development 

 of the useful micro-organisms. 



The great value of these soils when properly reclaimed has led 

 European farmers and investigators to devote much attention to 

 their utilization, and increased attention is being directed to the 



