G78 STATE BOARD OF AGRICULTURE. 



As shown by the data the concentration of the soil solution in the soils 

 was found to vary especially in the surface layer. With the exception 

 of the virgin sample of Miami silt loam, there was a larger amount 

 of soluble material present in the surface; soil on -June IW(\ than there was 

 in the early spring. From June J>rd to July 2nd there was more varia- 

 tion in tlie behavior of tlie soils, the majority showing a decrease in tlic 

 concentration of the soil solution while several showed a further increase. 

 During August, September and October the amount of soluble material 

 present in practically all the soils was quite small and showed no great 

 tendency to vary. This tendency for the soil solution to reach a maxi- 

 mum concentration in the early summer, when plant growth is at a maxi- 

 mum is extremely interesting. The behavior of the muck soil was rad- 

 ically different from that of the mineral soils, especially during the 

 latter part of the season, when a decided tendency for the concentration 

 of the soil solution to increase still further was manifested. It is inter- 

 esting to note that the fluctuations in concentration of the soil solution 

 of the soils previously cultivated were much more marked than those from 

 the virgin areas. This may possibly be due to the distribution of the 

 organic matter to a greater depth thus affording a large zone of action 

 to the soil organisms. 



The concentration of the soil solution of the lower la^^er of the soils 

 studied showed no tendency to increase in June and July. In fact in 

 several cases a slight decrease was noted. During the remainder of the 

 season the variations in the amount of soluble material present were also 

 quite small. There seemed a tendency for a slight decrease in concen- 

 tration on September 3rd, but the amount of change was almost negli- 

 gible. Aside from the lack of variation in the concentration of the soil 

 solution in this layer of soil the most interesting point brought out is the 

 small amount of soluble material present during the growing season. 

 The muck soil again is at variance with the mineral soils, it containing 

 much more soluble material and showing somewhat more of a tendency 

 for the amount present to vary. 



The results of this study indicate that the changes in concentration 

 of the soil solution of soils free of vegetation and unfilled are confined 

 mainly to the surface layer. These changes are more pronounced during 

 the period from March twenty-second until July second, although the 

 precipitation data in table 84 should be considered in this connection. 

 Moreover, the soils which had been under cultivation a number of years 

 showed a greater activity in this respect than the corresponding virgin 

 soils. Tliese studies together with additional ones are being continued. 



