256 STATE BOARD OF AGRICULTURE. 



The weights of forage and roots made when the samples were taken, gives 

 the relation between the weight of forage and roots. It is possible, therefore, 

 to construct the next table which gives the amount of nitrogen, phosphoric acid 

 and potash in a ton of the dry matter of the forage and the roots which accom- 

 panies that quantity of forage. In other words, using a ton of the dry matter 

 of the given legume as a basis, the amount of green forage is calculated; there- 

 after, the number of pounds of roots which naturally accompanies this quantity 

 of forage is calculated and its content of nitrogen, phosphoric acid and potash 

 added to the amount of these materials in the forage. The sums are set forth 

 in the following table: 



Legume. Nitrogen, lbs. 



Medium green soy 64.97 



Ogemaw soy 42.41 



Cowpeas 52.98 



Vetch 64 25 



Second crop clover 64.34 



Clover, new seeding 56.52 



This table seems to show that in a ton of the dry matter of the legumes known 

 to be inoculated, there is something over 64 pounds of nitrogen in the medium 

 green soy, the vetch and the second crop clover. The new seeding clover and the 

 cowpeas fall somewhat behind, while the Ogemaw soy, perhaps largely because 

 at the date harvested, the variety had lost some of its leaves and was not 

 inoculated, returns but 42.41 pounds of nitrogen in a ton of dry matter of the 

 forage with the roots and nodules accompanying. 



Were it possible to determine what an average crop of the several legumes 

 under study really was, it would be interesting to compare the amount of nitro- 

 gen, phosphoric acid and potash supplied per acre by these plants used as green 

 manure.^ An attempt to do this is made in the next table. The yields of the 

 soy bean on acre areas on the college farm is known. The per cent of water 

 in the hay was 20 per cent and the yield 5,860 pounds. The cowpeas yielded 

 much less, the average being approximately 3.575 pounds of hay, 20 per cent 

 water. The yields of the vetch were estimated from several square rods measured 

 and weighed. The green crop of the Y. globosa used in the experiment was 

 approximately 8 tons per acre, with the per cent of water given in the former 

 table. 



In this particular year the new seeding of clover was very heavy. After the 

 wheat was cut off .Tuly 15 the growth was fairly rank, so much so that the 

 crop had to be cut and carried off the field to prevent smothering during the 

 following winter. The approximate yields were, for the second crop clover, one 

 ton per acre and for the new seeding 2,170 pounds of hay, 20 per cent moisture. 

 It is not assumed that the yields given are typical or that they fairly represent 

 the average yields of these crops over the State Taking these yields as a basis 

 and adding to the fertilizing ingredients in the forage the amounts that would 

 be found in the weight of roots going with that amount of forage, the following 

 table is constructed to show the amount of nitrogen, phosphoric acid and potash 

 that would be supplied to the soil by the amounts of hay of the several legumes 

 mentioned were the entire plants plowed under: 



Legumes. Hay, lbs. Nitrogen, lbs. Phosphoric acid, lbs. Potash, lbs. 



Medium green soy 5,860 152.29 27.38 100.89 



Ogemaw soy 3.480 59.03 23.04 29.34 



Cowpeas 3,575 61.90 15.45 77.20 



Vetch 3,000 77 10 18.58 63.12 



Second crop, clover 2.000 51.47 12.05 36.18 



Clover, new seeding 2,170 49.06 11.61 63.55 



If these crops are plowed under it must l)e remembered that the nitrogen ig 

 in organic form and will be available for subsequent crops very slowly. Bacteria 

 must work upon the organic matter, digest and, by the decay, reduce the nitro- 

 gen to nitrate form. The other ingredients will also be inert and useless to 

 crops until the organic matter shall have decomposed. This fact gives to the 

 green manure plowed under certain advantages and certain disadvantages. The 



