169 



rather more carbohydrates. They also contain nearly three times as 

 much nitrogen and about twice as much potash. It should be remem- 

 bered that under favourable conditions they may draw a huge propor- 

 tion of this nitrogen from the air, instead of depleting the soil, and that 

 their long roots ent.<ble them to feed upon the potash deep down in the 

 sail beyond the reach of surface-feeding plants. 



Summary. 



(1) Green manuring improves the physical properties of the soil by 

 making the soil more porous and adding to its supply of humus. It 

 brings up the dormant plant food from deep down in the soil and 

 deposits it near the surface, where it can be used by plants feeding near 

 the surface. 



(2) Green manuring with buckwheat, Hungrian grass, and other 

 non-leguminous plants adds practically nothing to the soil which was 

 not there before, except a mass of vegetable matter which decays and 

 goes to form humus. 



(3) Green manuring with clovers, peas, beans, lupines, etc. (legumi- 

 nous crops), actually enriches the soil in nitrogen drawn from the air. 

 These plants can grow with very little soil nitrogen. They store up 

 the nitrogen of the air as they grow, and when pLwed under give it 

 up to the soil and to future crops. It is the cheapest means of manur- 

 ing the soil with witrogen. 



(4) But animals, as well as plants, require nitrogen for food. By 

 feeding the crops of clover, cowpea, etc., only about one fourth of the 

 fertilizing materials of the crop is lost if the manure is properly cared 

 for. As the nitrogen of the air is the cheapest source of nitrogen for 

 plants, so it is the cheapest source of protein (nitrogen) for animals 

 The leguminous crop is best utilised when it is fed out on the farm and 

 the manure saved and applied to the soil. The greatest profit is thus 

 secured and nearly the same fertility is maintained as in green 

 mauuring. 



(5) For renovating worn or barren soils, and for maintaining the 

 fertility where the barnyard manure is not properly cared for, green 

 manuring with such h guminous crops as cowpea, clovers, and lupines 

 is recommended. A dressing of potash and phosphates will usually be 

 sufficient for the green manuring crop. 



(6) The practice of green manuring on medium and better classes of 

 soils is irrational and wasteful. The farmer should mend his system 

 so thtit the barnyard manure will be as well cared for as any other farm 

 product. Loss from surface ^ashing, leaching, fermentation, and decay 

 should be guarded against. Then the feeding of richer food will mean 

 richer manuie and better and cheaper erops. 



(7) The system of soiling, or feeding green crops in the barn in place 

 of pasturage, enables a larger number of animals to be kept on a given 

 area of land, and the manure to be more completely saved. For this 

 purpose leguminous crops are extremely valuable. 



(8) Hay from leguminous crops is about twice as rich in protein as 

 hay from grasses. In the one case this protein (niirogen) is obtained 

 very largely from the atmosphere ; in the other it is all drawn from the 

 fertility of the soil. Leguminous crops yield la-ger crops of hay to the 

 acre than grasses. Hence the produc ion of food materials on an acre, 

 -especially protein, is several times larger with leguminous crops. 



