Manures and Manuring 



149 



Many experiments have been carried out to prove the value of "green 

 manuring", and an interesting paper on the subject will be found in the 

 Journal of the Board of Agriculture, for June, 1897. The following figures 

 show how a soil may be enriched in nitrogen and other foods when a 

 green crop is incorporated with it: 



From this experiment it would appear that Peas are the best crop to 

 use as a green manure. Not only is there a larger supply of dry substance 

 (over 3 tons per acre), but nearly 200 Ib. of nitrogen is fixed in the soil. 

 This is equal to over ton of nitrate of soda. Reckoning the value of 

 nitrate of soda at 10 per ton, the pea crop yielded up nitrogen to the 

 value of 5 per acre, in addition to the other foods supplied by the decay- 

 ing stems, leaves, and roots. The Yellow Lupins supplied over 5000 Ib. 

 of dry matter, and 130 Ib. of nitrogen to the acre, and is thus the poorest 

 of the leguminous fertilizers. Notwithstanding this fact it appears that 

 any of the green manures mentioned are capable of supplying more 

 nitrogen to the soil than is needed by most crops. Hops require about 

 200 Ib. of nitrogen per acre, and this quantity can be supplied in advance 

 by a crop of Peas. But Potatoes require from 50 Ib. to 120 Ib. of nitrogen 

 per acre, and leguminous crops can supply far larger quantities as shown. 

 The value of leguminous crops as manure was well known to the ancients, 

 and Virgil in his "Georgics" refers to them thus: 



" At least where Vetches, Pulse, and Tares have stood, 

 And stalks of Lupines grew (a stubborn wood), 

 The ensuing season, in return, may bear 

 The bearded product of the golden year ". 



Leaves as a " Green Crop ". The subject of 

 carried further than is generally supposed. There 

 whether fruits, flowers, or vegetables, that cannot 

 green manure. Even the weeds and herbage from 

 can be turned to good account as soil fertilizers, 

 only pay as a green manure but will also remove 

 places for many garden pests. 



Taking cultivated crops, the leaves of many of 

 in autumn and when decayed form an excellent 



green manuring may be 

 is scarcely a crop grown, 

 be utilized in part as a 

 the banks and waysides 

 and if utilized will not 

 one of the chief nesting 



them drop to the ground 

 vegetable mould or leaf 



