220 ANNUAL REPORT OF THE Off. Doc. 



about it and tliose who bold to the theory mentioned lose sight 

 of it entirely or scoff at the very idea. The theory of toxines 

 formed by the excreta of plant life is not new, but for a long time 

 was lost sight of in the glare of Liebig's plant food theories. 

 Nevertheless, in spite of adverse criticism and scoffing it has been 

 definitely proven that plants do excrete substances which^re toxic 

 to the same plants, but which may be either beneficial or neutral 

 to another kind of plant. Further, some of these toxines have been 

 actually separated from unproductive soils, their properties deter- 

 mined and their chemical nature and composition defined. Third: 

 Again those who hold to the theory of exhausting the soil of plant 

 food base their calculations on the amount of the plant food ele- 

 ments present in the surface soil alone, not reckoning with the 

 movements of the soil waters and their carrying of these materials 

 u])ward and downward in their action in and through the soil and 

 subsoil. The rains falling on the surface soil cause a downward 

 movement of the soil waters but later as evaporation takes place 

 at the surface that water which was forced downward perhaps to 

 a considerable depth is brought upward again by capillary action, 

 that is, it is passed from one soil grain to the next and so on. 

 This water, when at a depth, must have dissolved some plant food, 

 and when brought back within the root zone of the various plants 

 it is not unreasonable to think that some of it is brought up with 

 the rise of the water, and it is altogether likely that the plants use 

 some of it in their growth. When this happens it must necessarily 

 make a hole "below the water line" in the theory that "there is 

 just so much plant food and it will last just so many years." 



In the practical utilization of our soil resources we must not 

 forget their conservatism for our children, our grandchildren, and 

 their children and grandchildren. In this connection we must re- 

 cognize that we have a clear title to the air over and above our 

 farms as far up as we can see and that this air is four-fifths nitro- 

 gen, that element of plant food for which you pay twenty-five to 

 thirty-five cents a pound when you buy it in a gunny sack. We 

 must bear in mind that this nitrogen in the air is ours and a portion 

 of it at least is for our soils, not for so many cents per pound or 

 dollars a ton, but for the care and skill exercised in providing 

 liberally for legumes in our systems cropping. 



I have already alluded to the question of increasing our farm 

 area by the drainage of swamps and protection of overflow land, but 

 in this discussion I want to speak of drainage from another point 

 of view. I want to speak of lands already classed as farm lands 

 and even in many cases included in improved farm lands. In the 

 first place, there are, on almost every farm, ponds and swampy 

 places varying from a few square rods to several acres in extent. 

 Although, usually no one farm contains much of this waste land, 

 the aggregate area must be very large. The removal of the excess 

 of water from these wet places by drainage would make possible 

 the utilization of an additional large acreage of extremely produc- 

 tive soils and at least several millions of dollars added to the 

 credit of the soil resources annually, where now tMe product is 

 pestilential in its nature and the existence of these spots an eye- 

 sore on the agricultural landscape. In the second place, many 



