18 Kansas Academy of Science. 



cent, but it requires organic matter to make this potassium 

 available in crop production. 



Miss Meeker inquired about the value of fallen leaves, and 

 asked if they v^ould introduce too much of acid elements. 



Professor Swanson thought the lime in the soil will suf- 

 ficiently neutralize the acids, and it was a good plan to save 

 the fallen leaves and organic matter from stables and apply to 

 the soil. Professor Swanson called attention to the govern- 

 ment activities in getting potash from the kelp on our Pacific 

 coast to secure the supplies of potassium needed in our fer- 

 tilizers and other industries. Some things that do not enter 

 into the constitution of plants are yet essential to their growth, 

 e. g., lime. 



Professor Risser said that while sugar does not contain 

 potash, yet the soil in which beets grow must contain it to 

 make a good growth. 



Professor Bailey remarked that the substances added to 

 soils to improve their fertility must be in a soluble form. 

 Now feldspar contains potassium, but is insoluble, and must 

 be broken down before it is available. There are certain or- 

 ganic acids — humic acid and compounds of that class — in the 

 soil which with manure from animals hasten the chemical 

 action which breaks down the insoluble compounds. 



Professor Swanson said that peat was old organic matter 

 which decays very slowly, and is much more available when 

 mixed with manure when it is added to worn soils. 



Professor Twenhofel said that on the northern shores of 

 Russia they have long used the sea weed, washed up on shore 

 by the winds, as a fertilizer. The farmers spread it, finely 

 broken up, on their fields. In the blue-grass region of Ken- 

 tucky, famed for its fertility, it takes forty feet of limestone 

 to produce one foot of soil, and required 4500 years to pro- 

 duce the soil of the blue-grass region. This demonstrates the 

 immense value of the soil — the production of millions of years. 

 One other point in soil fertility is the need of moisture. In 

 some of the arid regions they can never get a crop. By storing 

 the water a large per cent of these arid regions can be brought 

 to fertility. 



Professor Sayre spoke of a farm in Michigan with very deep 

 black muck soil. The proprietor said he used a fertilizer rich 

 in potash and continued to get good crops of peppermint, 

 which he was cultivating. 



