78 GENERAL CONSIDERATIONS 



efficient nitrogen gatherer, furnishes much nutritious 

 pasturage, and if planted thick and cut young, it 

 makes good hay. The stems, however, get hard and 

 woody with age. It should always be used in 

 orchards on soils where cowpeas do not thrive, and 

 for orchard purposes it has the considerable advantage 

 of reseeding itself. It is sown broadcast, using about 

 eight quarts per acre. It thrives well in the tropics, 

 where it is an indigenous weed. 



Other Legumes for Green Manuring. — There are 

 many other leguminous plants that are sometimes used 

 for green manuring. Of these Japan clover, bur 

 clover, alfalfa, and the peanut will be discussed under 

 forage plants. On the rotten limestone prairies 

 of Alabama and Mississippi sweet clover (^Melilotus 

 alha) has proved to be the most useful of all legumes. 

 Its long taproots penetrate the hard subsoil, thus 

 making it permeable and greatly improving its me- 

 chanical condition, in addition to adding to its store 

 of nitrogen. At the North this plant is con- 

 sidered a pestiferous weed. In some of the West 

 India islands indigo (^Indigofera anil) has been 

 more or less used as a green manure. Leguminous 

 trees of various kinds are usually chosen by coffee 

 and cacao planters to use as shade trees among their 

 crops. The trees as well as the herbaceous plants be- 

 longing to the LeguminoscB produce root tubercles, 

 and they thus add nitrogen to the soil at the same time 

 that they shade the trees. This family is very 

 largely represented in the natural flora of all tropical 

 countries, the number of species found far exceeding 

 those of temperate latitudes. Very many of them 



