GREEN MANURES 625 



The furrow ordinarily should be turned only partly 

 over, and thrown against and on its neighbor. The green 

 manure is then distributed evenly from the surface down- 

 ward to the bottom of the furrow. When decomposition 

 occurs the humic materials are evenly mixed with the 

 whole furrow slice. Moreover, this method of plowing 

 does not interfere with the capillary movements of water, 

 and in actual practice is a great aid in drainage and 

 aeration. 



529. Green manures and lime. — The decay of organic 

 matter in the soil is always accompanied by the produc- 

 tion of organic acids. Such acids tend to form in large 

 amount, especially if the fermenting matter is of a suc- 

 culent nature. The need of plenty of lime under such 

 conditions is clearly apparent, as a soil of a neutral or an 

 acid character may assume a bad condition during the 

 process of humic decay. Lime may be added to the green- 

 manure seeding and be turned under with that crop. 

 The amendment would thus be in very close contact with 

 the decaying vegetable tissue. Ordinarily, however, the 

 application of lime at some point in the rotation is suffi- 

 cient. 



530. Green manure and the rotation. — Very often it 

 is somewhat of a problem as to when, in an ordinary rota- 

 tion, a green manure may be introduced so that it may 

 fit in well with the crops grown. In a rotation of corn, 

 oats, wheat, and two years of hay, a green manure might 

 be introduced after the corn. This would not be a very 

 good practice, however, as a cultivated crop should 

 usually follow a green manure so as to facilitate decom- 

 position and decay. In such a rotation the plowing- 

 under of the hay stubble is really a form of green-manur- 

 ing, there being a considerable accumulation of roots, 



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