440 TjiAXSACTIOXS OF TUB AjIEIUCAX lySTITUTE. 



scanty and capricious. There is nothing worse in our rural economy 

 than this uncovering of rocky steeps that ought to remain timbered 

 evermore. 



3. There are, moreover, lands too sterile to be cultivated with profit, 

 at least while so much good land lies idle and useless. These lands 

 are often level enough, and not too stony ; but it will cost more to 

 bring them to a proper state of fertility than they will then be worth. 

 Some of these might be, and probably ought forthwith to be, sowed 

 with nuts and tree-seeds, and so covered with timber; probably the 

 plow might be advantageously used in the process ; but it would be 

 unwise to subject them to other culture for ages yet, if ever. 



4. Then there are lands which have a good though shallow surface- 

 soil, but covering a poisonous subsoil, which must not be disturbed. 

 Professor Mapes found such a tract in west Jersey, where a stratum 

 of sulphate of iron (copperas) lay but eight inches below the surface. 

 To plow into this, and mix it with the surface-soil, arrested vege- 

 tation altogether. 



5. And again : There are soils, mainlj- alluvial, at once so mellow 

 and so fertile that the roots of the cereals, and of most plants, will 

 permeate and draw sustenance from them though they are never dis- 

 turbed by the plow. I presume the annually flooded intervale of the 

 ISTile is of this class. I judge that the valley south of Marysville, 

 California, annually covered man^-'feet deep by the turbid floods of 

 the Yuba, Feather, and American rivers, is much the same. There 

 are portions of the intervale of the Illinois where the muck is sixteen 

 feet deep, very loose and rich. I was told in California that the grape, 

 though it had to be watered sparingly during its first two summers, 

 needed no irrigation thereafter in the valleys of that State, though 

 they are dried up in summer to a depth of several feet. The roots 

 strike down through the rich loam below till they find moisture that 

 they can appropriate and thrive upon. I judge that the valley of 

 the Sacramento and its main tributaries is often parched to a depth 

 of four or five feet. 



I have thus fully conceded that deep i)lowing is not everywhere - 

 requisite. Now let me show where and why it is needed : 



1. It has been abundantly demonstrated here that the roots of 

 plants are often found at a distance of several feet from the stem. 

 Any of us may have seen that this is as true of Indian corn as of 

 Canada thistles; with a microscope and due patience, the 'roots of 

 wheat may be traced from four to six feet. Of course, these roots 



