338 SOILS 



soil results in fermentation, and the soil becomes 

 more or less acid; and partly because the herbage 

 loosens and dries out the soil before it has become 

 thoroughly decayed. Potatoes and corn do not 

 seem to mind this. In any case it isjbest, if prac- 

 ticable, not to plant a crop for at least two or three 

 weeks after a large amount of herbage has been 

 plowed under, but to keep the land fallow. Lim- 

 ing the soil at the time of green-manuring is often 

 beneficial. If only stubble is plowed under, or a 

 scanty crop of herbage, these precautions are not 

 necessary. 



LEGUMINOUS CROPS FOR GREEN-MANURING 



Red Clover is the king of green-manuring crops, 

 especially in the Northern States. This is partly 

 on account of its very deep root system, which 

 bores through, loosens and drains the subsoil and 

 brings deep-lying plant food to the surface. It 

 does not catch well on soils in bad heart ; such soils 

 must first be improved by plowing under rye and 

 other coarser crops. The seeding is ten to twenty 

 pounds per acre. In the North, seeding is in early 

 spring or in August; in the South, September or 

 October sowing is preferred. Usually the crop is 

 cut or pastured one or two years, and the after- 

 math is plowed under. Unquestionably red clover 

 is the most valuable plant in Northern farming, 

 where the maintenance of soil fertility as well as the 

 largest immediate profits, is considered. If it can 

 be worked into a rotation to advantage this should 

 be done. Be sure the land is not deficient in lime. 



The preeminent value of red clover for improving 

 soils is strikingly illustrated in some experiments 

 by Henry W. Geller. Many pots of ordinary soil 



