I50 



MISSOURI AGRICULTURAL REPORT. 



From this table it will be observed that there existed in the four good 

 soils very much more of all the essential plant food elements in a form 

 which could be recovered with pure water than were carried in the poor 

 soils. In the aggregate the water-soluble plant food elements from the 

 good soils exceeded those recovered from the poor soils more than 2.8 

 times, while the yield of corn and potatoes was nearly 2.5 times greater. 



The figures given above refer to the surface foot only, but it must 

 be remembered that the roots of crops penetrate the soil to a depth even 

 greater than four feet; and further than this, through capillary move- 

 ment of the soil moisture the dissolved plant food materials are car- 

 ried from the fourth, third and second feet upward into the surface 

 foot. Because of these relations the surface four feet of these 8 soil 

 types were examined to determine the amount of the different plant 

 food elements which could be recovered from them by treating them 

 only 3 minutes in five times their weight of water. The total amounts 

 so recovered are given in the next table. 



Plant food elements recovered from the surface 4 feet of 8 soil 

 types by washing but 3 minutes in 5 times their weight of pure water. 



Amount in pounds per acre of surface four foot. 



Number of crops of ivheat required to remove the above amoimts. 



Good soils. 

 Poor soils. 



n.i 

 6.2 



130.3 

 50.7 



130.0 

 66.2 



1.2 

 .45 



9.7 

 5.5 



298.5 

 84.1 



Here again it is seen that the good soils have yielded to the 3-minutc 

 washing in pure water more of the essential plant food elements than 

 the poor soils did, and also more than enough from the surface 4 feet 

 of soil of each and every element for a crop of 40 bushels of wlual 

 and 3,660 pounds of straw per acre. Indeed, there was recovered of 

 both potash and phosphoric acid enough for 9 such crops; and there 

 is little doubt but that if the washing of the same samples had been 

 repeated 11 times in corresponding amounts of Avater. as was done in 

 the first series cited, nearly t i times as nuicli of lliesc two elements 

 would have been recovered ; and wr see that while the plant food 

 elements carried in soluble form in soil is small in coini)arison with 

 the amounts present which are not readily soluble in water, these forms 

 are nevertheless large in the good soils and in the surface four feet 



