HUM 



HUS 



Humus, i. c, vegetable mould, has 

 been highly commended as the food 

 of plants, some people imagining that 

 in the soluble state it entered the 

 root and fed the tissues ; this view, ; 

 propagated for the purpose of exem- 

 plifying the utility of applying all ma- 

 nures in the state of solution, is a 

 ridiculous absurdity. That solutions 

 of humus find their way into the in- 

 terior of plants, is very true ; but it 

 has never been shown that such so- 

 lution was in any way necessary to 

 vigorous growth. Indeed, plants set 

 in soils containing only insoluble hu- ; 

 mus (humate of lane) are as healthy 

 and vigorous as those growing un- 

 der the influence of solutions. Nu- 

 merous plants require no iiumus, as 

 grasses, clovers, various forest-trees ; 

 these, indeed, by their dead leaves 

 and roots, produce and accumulate 

 humus. Charcoal powder, which is 

 insoluble, answers, in many cases, 

 equally well with humus. 



The real utility of humus, irrespect- 

 ive of the ashes which mould con- 

 tains, arises from the following ef- 

 fects : 1st. It is constantly decaying, 

 and thus producing carbonic acid and 

 water, which feed the plant and moist- 

 en the soil. 2d. Durmg decay it con- 

 stantly absorbs nitrogen from the air, 

 which becomes converted into am- 

 monia and nitric acid, and is thus ad- 

 mirably fitted to sustain vegetation. 

 3d. It not only imparts valuable me- 

 chanical qualities to the soil by in- 

 creasing its warmth, porosity, and 

 friability, but the carbonic acid pro- 

 duced, as well as the nitric acid, by 

 acting on the insoluble minerals of 

 the soil, as the silicates of potash, 

 soda, lime, and its bone earth and 

 other phosphates, dissolves or decom- 

 poses them, rendering them food for 

 plants. In this manifold way humus 

 becomes of great utility to culture, 

 but is neither the only manure, nor 

 competent of itself to produce fertil- 

 ity ; for accumulations of humus are 

 by no means desirable : 10 per cent, 

 in the soil is an abundance, and two 

 to three per cent, is quite enough for 

 most plants. Potatoes, the roots, 

 corn, cotton, tobacco, cruciferous 



plants, and wheat, are most partial 

 to this body ; Ihcy are all plants de- 

 veloped by culture, and require a sup- 

 ply of food by the roots as well as 

 leaves. Grasses, clovers, and many 

 beans increase instead of exhausting 

 the soil of humus ; hence their utility 

 in rotations. 



The amount of humus in the soil is 

 readily increased by green fallows, by 

 ploughing in straw, prepared peat, 

 and all vegetable rubbish. The great- 

 er part of the solid matter of all pu- 

 trescent manures is humus, decayed 

 wood, the rotten interior of the trunk 

 and branches, &c. 



Humus IS hastened in its decay, and 

 consequently in the several effects it 

 produces, by liming and the use of ash- 

 es, as well as by hoeing and all means 

 that increase the quantity of air ad- 

 mitted to the soil. Indeed, much of 

 the surprising effect that lime often 

 exhibits arises from its action on the 

 vegetable matter in the soil ; even 

 cornstalks and twigs of trees are 

 rapidly reduced by its action when in 

 the earth. 



HUNDRED WEIGHT, or CWT. 

 112 pounds avoirdupois. It is com- 

 mon in the United States to speak of 

 hundreds, or 100 pounds ; and 100 

 pounds is frequently called a hundred 

 weight. 



HUNGER-ROT. Disease occa- 

 sioned in sheep by bad keeping ; star- 

 vation. 



HUNGRY SOIL. Poor, sandy, or 

 gravelly soil, requiring frequent ma- 

 nuring. 



HURDLE. A light, moveable 

 fence of wood, iron, or wire ; it re- 

 sembles a light gate, and is some- 

 times made of osiers, woven like a 

 basket. Hce Fence. Sheep are hurdled, 

 folded, or enclosed on turnips, clo- 

 vers, grass, &c.,by means of hurdles, 

 and readily shifted from place to 

 place. The shifting often takes place 

 daily, and if the manure dropped be 

 ploughed in as soon as the shift is 

 made, a considerable economy is 

 practised ; but if it be left to dry and 

 waste, the plan is bad. 



HUSi3ANDRY. Agriculture. The 

 following short sketch of British hus- 



407 



