FORTY-SECOND ANNUAL REPORT. 135 



also be true that in this case phosphoric acid is being brought up 

 from much lower depths by the capillary water faster than it is being 

 used and is therefore, increasing in the surface soil. However, the 

 point I wish to make in this connection is this: This orchard set 20 

 years ago on soil that would classify as poor from the plant-food stand- 

 point, is today, one of the finest looking orchards in the whole state 

 and I know of no one who would presume to say or even venture the 

 opinion that had the same trees been planted in a soil with twice the 

 amount of plant-food as was contained in this soil No. 5 they would 

 have produced any more fruit. Sample No. 8 is from a farm in Kala- 

 mazoo county. It is of a very different character than the soils previous- 

 ly considered, being a clay loam, and it contains a considerably larger 

 amount of plant-food. The productiveness of this soil has been increased, 

 by the present owner by practicing good methods of farm management 

 and not by increasing the amount of plant-food. 



I desire to call your attention particularly to samples 9 and 10, which 

 were taken from adjacent farms in Barry county. These soils would 

 be classified as sand but number 9 was producing in the neighborhood 

 of 30 bushels of wheat per acre while number 10 was producing less 

 than 10 bushels per acre. In seeking for an explanation for this differ- 

 ence it is very apparant that it is not due to a difference in the amounts 

 of nitrogen and phosphoric acid and in all probabilities there is no ap- 

 preciable difference in the amounts of potash in the two soils. 



I regret that I am unable to say what is the cause of the difference 

 in productiveness in these two soils as we have only had time to make 

 the analyses referred 1o. However, this one example serves to illus- 

 trate hundreds and thousands of similar conditions. I presume there 

 is not a farmer within this sound of my voice that has not some places 

 on his farm that fail to produce as abundant crops as the adjoining 

 areas. Such cases cannot, certainly, be explained by any marked differ- 

 ences in the amounts of nitrogen, phosphoric acid and* potash. We must 

 seek further for an explanation of these differences. 



While it has long been recognized that the organic matter of the 

 soil has a great influence upon the productiveness of the soil it has been 

 looked upon as influencing the physical condition of the soil rather 

 more than the chemical. Though in more recent years the turning under 

 of leguminous crops, as a source of nitrogen, has been receiving more 

 and more attention. During the past few years, however, a critical 

 study has been undertaken in a few laboratories of this country to find 

 out more about the nature of the organic matter of the soils and its 

 influence upon fertility. The result of this work, so far, has been that 

 quite a large number of organic compounds have been isolated from 

 soils and some of them have been found to have a decided injurious 

 effect upon plants while there are others that have as decided beneficial 

 effects. These compounds have resulted from the decomposition, in the 

 soil, of organic matter turned under as green manure or introduced as 

 barnyard manure. 



It is not at all strange that these compounds should be found in the 

 soil, but, on the other hand, it would be decidedly strange if we failed to 

 find, at least some, of these compounds, for when these same materials 

 (green manures) are allowed to decompose in the laboratory many of 

 these same compounds are formed. The process of decomposition in 



