A Maximum Produce. 25 



show that this may be corrected by interposing 

 a heavily dunged green crop, such as mangold, 

 while the introduction of red clover between the 

 corn-crops is also found to add greatly to the 

 corn-producing power of the soil. To attain a 

 maximum paying produce, he finds that the 

 land should be dunged heavily for mangold, to 

 be followed with wheat, or barley, or oats, 

 according to soil and climate, for several years 

 in succession ; then interpose clover, and follow 

 it with corn-crops, keeping the land perfectly 

 clean, and manuring all the corn-crops with 

 nitrate of soda and superphosphate. When the 

 land shows need of change, begin again with 

 heavily dunged green crops. Successive crops of 

 barley he finds to pay better, and are more cer- 

 tain than either wheat or oats, and give more corn 

 in proportion to straw. If a heavily dunged green 

 crop is occasionally introduced, it is not neces- 

 sary to give any other manure to the corn-crops 

 than nitrate of soda and superphosphate. Potash 

 (which may be supplied by dung) is very neces- 

 sary in a grass-manure, especially for clover, 

 which, unlike corn, is injured by ammonia. The 



