OTHER GREEN MANURES 



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and barnyard manure are plowed under, or otherwise mixed with 

 the soil, the vegetable matter may be of very great benefit to the 

 soil. As it rots humus is formed. All soils are improved by the 

 addition of humus unless they are already well supplied. 



It causes them to hold moisture in better form and longer 

 between rains so that plants can use it. The presence of humus 

 also makes a better home for beneficial bacteria; it helps to make 

 plant foods available for the roots to use. 



Fig. 202. — Cowpeaa (left) and soybeans (right) used to improve soils for gardens, orchards, 

 etc. (Tennessee Station.) 



Besides the addition of humus the turning under of green manure 

 will also add all the forms of plant food which they contain. If 

 legumes are turned under the chief plant food is nitrogen, but 

 with all forms of green manure some of all three important fer- 

 tilizers are added, which soon become available for use of the 

 growing crop. That is, nitrogen, phosphate, and potash are al- 

 ways present and as the manure rots it liberates these for the use 

 of the crops. 



Other Green Manures. — It is, therefore, very beneficial to most 

 soils to mix green manure of any kind with them. When winter 

 rye, for example, is grown during the fall, winter, and early spring, 

 and then turned under, it takes from the soil the three main plant 

 foods and saves them for the garden, orchard, or other crop. 

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