THE LAY OF THE LAND 139 



Outspread before us as we look abroad over the landscape, 

 with its levels of checkered fields, its patched and pie-bald 

 hills, its willow-bordered streams and reedy swales, is this 

 blanket of soil, which seems so permanent, yet which is 

 forever shifting to lower levels. 



Water, descending, follows the lines of least resistance .- 

 Hence, from every high point, slopes fall away in all direc- 

 tions. Some are turned southward toward the sun, and 

 are outspread in fields that are warm and dry; others face 

 the north, and receive the sun's rays more obliquely, and are 

 shadowy, moist, and cool. Some are exposed to the sweep of 

 the prevailing wintry winds ; others are sheltered therefrom. 

 Some are high and dry; others are low and moist. 



Nature has her own crops, suited to each situation; sedges 

 where it is wet; grasses where it is dry; spike-nard in the 

 shade; clovers in the sun. None of them alone (as we raise 

 plants) nor in rectangular fields, but each commingled with 

 others of like requirements, and each distributed according 

 to conditions of soil, moisture and exposure. One may see 

 how nature disposes them by comparing the life in wet marsh 

 and dry upland; or that of sunny and shaded sides of a 

 wooded glen. 



Under natural conditions the soil of the gentler slopes 

 remains in comparative rest, for it is held together by a net- 

 work of roots of living plants; these never (except under 

 the plow) let go all at once. One dies here and there, now 

 and then, and adds its contribution of humus to the topmost 

 soil layer. Under natural management, the fields are 

 permanently occupied and never exhausted. The richness 

 of the soil is ever increasing. Our stirring of the top soil 

 enormously accelerates erosion. Our four-square fields 

 and cross-lot tillage are well enough on the upland and low- 

 land levels where conditions are fairly uniform and the 

 loosened topsoil cannot slip away into the stream; but 



