NATURE OF LEGUMINOUS PLANTS. 13 



sliii<rs or a hayfork. A man upon llio i)latfonii tlii-ows tho material 

 into th(> silo, plac-in^^ it as best he ean. Another man spreads it 

 evenly in the silo and tramps it thoron<rhly. This is i)erhaps the 

 safest method, for there is less ehanee to sliohi the ^vork. For a few 

 days after the silo has been filled, the settlinir of the material will 

 allow the addition of two or three k)ads eaeh day, each load being 

 thoron<rhlv traniDed when added. When the filling is comijleted the 

 top is covered abont 1 foot deep with marsh grass or other waste 

 material that will pack closely and exchide the air. This is wetted 

 thoroughly and trami)ed daily for several days, nsing abont 2 bar- 

 rels of water at each wetting. The writer has seen ensilage of excel- 

 lent (|iiality made from whole grass in this way. He has also seen 

 ensilage made by droi)ping the material into the silo without spread- 

 mg and tramping that was practically a total loss. 



THE NATURE OF LEGUMINOUS PLANTS. 



Plants that produce their seed in two-valved pods, such as peas, 

 beans, vetch, and alfalfa, are called legumes. The value of this 

 family of plants as soil renovators has long been recognized, but in 

 just wdiat way they are capable of restoring fertility to the soil has 

 not been understood until recent years. If the roots of a leguminous 

 plant be carefully removed fi'om the soil little lumps, called nodules 

 or tubercles, will usually be foinid upon them. These nodules vary 

 in size with ditferent legumes and may be found alone or in clusters. 

 On the roots of red clover they are about twice as large as the seed 

 of that plant. The nodules are caused by bacteria that are parasitic 

 in the roots. 



By the aid of the bacteria living in the nodules, leguminous plants 

 are enabled to assimilate atmospheric nitrogen. Since nitrogen con- 

 stitutes approximately four-fifths of the atmosphere this family of 

 plants has an inexhaustible supply of this important plant-food ele- 

 ment. Other plants can not assimilate the nitrogen of the atmos- 

 phere; they can obtain it only from decaying organic matter and 

 from counnercial fertilizers containing nitrogen. Chemical analyses 

 show the tisues of leguminous plants to be very rich in nitrogen; 

 hence the value of these plants when plowed under as green manure. 

 The roots of a clover crop ordinarily contain more nitrogen than the 

 whole crop removes from the soil. As these roots decay, the plant 

 food in them becomes available for other plants. Nitrogen is usually 

 the first element of plant food that needs renewing; hence the great 

 value of leguminous plants as soil renovators. 



Generally speaking, the nodules of each kind of legume are caused 

 by certain kinds of bacteria. Thus there is one kind for alfalfa, 

 another for red clover, another for common vetch, and so on. At 



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