CARBONATE OF LIME. 133 



or there marked by a paucity In both organisms and cultural 

 possibilities. In whatever sense my hearers may conceive of the 

 earth, whether here covered by a wide range of growing species 

 of trees, shrubs, herbs and grasses, and there bedecked within the 

 range of a single farm with a number of fields in different crops, 

 say of potatoes, corn, oats, wheat, clover, hay and the like, In 

 like degree do I ask them to conceive of the vastly richer co- 

 incident microscopic life present within these highly cultivated 

 soils working ceaselessly and ever and anon multiplying 

 in incalculable numbers, yet ever, so long as favorable cultural 

 conditions are possible, maintaining themselves both as to the 

 variety and number of sorts. 



Granting once this conception of the soil, we can understand 

 that It is an enclosing nidus as well as a nutrient medium which 

 supports this life within and upon it. This nidus may be here 

 rendered highly acid in reaction by the decomposition of vegeta- 

 ble tissues that are Incorporated in it or there become excessively 

 alkaline if no soil leaching may occur, as with certain alkali 

 soils of the west. But conceive In this same connection the great 

 difference as a result of years of culture that will Come about in 

 a soil deficient in available bases which may at all times be 

 relied upon to correct automatically the acids produced by the 

 fermentations and decompositions taking place In the soil, as 

 compared with a soil at the outset very largely composed of in- 

 soluble silica or sand, and lacking In these same automatic cor- 

 rections of cultural tendencies. I would here again Insist that 

 these abandoned farms as farm lands are abandoned, because 

 they come soon to lack that biologic balance In these nidus rela- 

 tions and in their contained organic life as well. 



May we not add that the practice of rotative farming, of 

 which this region shows an advanced type, has its justification 

 and its profit in the very biologic balance maintained thereby? 

 May we not go even further and point to continuous cropping in 

 a single species as an extreme disturbance of this balance of soil 

 organisms at the same time that it uses up particular soil con- 

 stituents? I am convinced that In both cases we may reply in 

 the afiirmative and that fuller knowledge of soil life may show 

 most strikingly the mistake of continuous cropping just as the 

 breeding and introduction of so many soil diseases of the special 

 crop have so often shown its economic disaster. 



What has just been stated with some fullness Is not given as 

 a proven thesis; rather as a suggestion that has for many years 

 been driven step by step Into the writer's soil conceptions in the 

 course of somewhat extended observation and reading upon farm 



