256 STATE BOARD OF AGRICULTURE 



of oil in peppermint and spearmint. In some instances the use of muck 

 fertilizers resulted in a lower oil production whereas in others it re- 

 sulted in striking and profitable increase. In some cases acid phosphate 

 was all that was needed to cause satisfactory production but usually 

 fertilization with potash was essential and in still others both acid 

 phosphate and potash were needed. Climate plays a tremendous role 

 in the manufacture of oil by these plants. Experiments to determine 

 the effect of rolling or comporting of muck soils on crop production and 

 moisure and nitrate relationship were inaugurated. 



Dr. Bouyoucos studied the degree of change brought about in soils 

 by igniting them at different degrees of temperature. As a measure 

 of this change three distinct physical properties were used for com- 

 parative study. These are heat of wetting, unfree water, and plasticity. 

 The temperatures used w^ere 110°C, 170°, 230°, 485° and 850°. The 

 results obtained show that no appreciable change in the above properties 

 takes place until the temperature of about 230° is reached. This is about 

 the initial temperature where a change commences to take place in all 

 three properties. . This change increases in degree until about a tem- 

 perature of 800°C is reached where it is completed and the properties 

 of heat of wetting, plasticity and unfree water are almost or com- 

 pletely destroyed and they disappear. 



He has found that different soils de]>lay marked degree of physical 

 reaction. Two soils, for instance, may be exactly alike in texture and 

 structure and yet they may have greatly different reactivity towards 

 water. Our investigations as to the cause of the difference in re- 

 activity seem to show that it is due to the difference in activated sur- 

 faces in the soils. In other words, the surface of one soil particle may 

 be inert or inactive, while that of another is active. Hence the re- 

 activity of the former will be greater than that of the latter. 



The study of the factors governing structure and plasticity in soils 

 has yielded very interesting results and some new theories have been 

 evolved to explain the property of plasticity. It would take too much 

 space to present in this report the results and theories. 



Considerable chemical research work has been done during the year. 

 Spurway has examined the horizons of several soil types in attempting 

 to obtain basic infonuation on the factors that cause soil variation as 

 well as the variations in the media in which crops grow. It has been 

 brought out that the solubility of acid phosphate varies greatly when 

 applied to soils of different constitution both naturally and artificially. 

 His perfection of the Soiltex method for determining the reaction of 

 soils has been favorably received by county agents, numerous farmers 

 and several investigators in other States. When properly made use of 

 this method is very valuable and has and no doubt will in the future 

 do much toward bettering soil conditions in the State. Weidemann 

 has found tremendous differences in the ability of muck soils to fix 

 phosphorous and potassium which is contrary to the popular conception 

 that all soil organic matter is effective in holding various elements of 

 plant food. His physical studies have furnished us with information 

 of value in the classification of muck soils. It is evident that the classi- 

 fication of such on the basis of original plant material is not ample in 

 as much as horizons have developed in many through their weathering. 



