422 



THE PRACTICE OF GREEN MANURING. 



relative proportions of dry organic and saline matter, capable of be- 

 ing added to the surface soil by a few of those plants which are em- 

 ployed for the purposes of remanuring : — 



Kind of Plant. 



Averaae 1000 lbs. contain 

 produce 

 per imp. 

 acre. 



Spurry 



White Lupin 



Vetch 



Buck-wheat. 

 Rape 



6,500 

 25,000 



11,000 

 8,000 

 16,000 



n the green state Depth of | ;„ ^ 

 Organic Saline Roots. 

 Matter. Matter. 



lbs. 

 199 



188 



233 

 170 

 214 



lbs. 

 21 

 12 



17 

 10 

 16 



m a 

 year. 



inches. 



12 to 152 or 3 

 24 to 26 I or li 



15 to 20 2 



12 to 15 2 

 1 llorU 



Soil for which they are 

 fitted. 



Dry, loose, sandy. 

 Any except marly or 



calcareous. 

 Strong soil. 



Dry, sandy, or moorish. 

 Rich soil. 



§ 5. Of the practice of green manuring. 



In the practical adoption of green manuring it is of importance to 

 bear in mind — 



1°. That a sufficient quantity of seed must be sown to keep the 

 ground well covered, one of the attendant advantages of stubble 

 crops being that they keep the land clean and prevent it from becom- 

 ing a prey to weeds. 



2°. That the plants ought to be mown or harrowed, and at once 

 ploughed in before they come into full flower. The flower-leaves 

 give off nitrogen into the air, and as this element is supposed especi- 

 ally to promote the growth of plants, it is desirable to retain as much 

 of it in the plant and soil as possible. Another reason is that, if al- 

 lowed to ripen, some of the seed may be shed and afterwards infest 

 the land with weeds. 



3°. That they should be ploughed in to the depth of 3 or 4 inches 

 only, that they may be covered sufficiently to prevent waste, and yet be 

 within reach of the air, and of the early roots of the succeeding crop. 



§ 6. O/* natural manuring with recent vegetable matter. 

 Besides the method of ploughing in, which maybe distinguished as 

 artificial green manuring, — there is another mode in which recent ve- 

 getable matter is employed in nature for the purpose of enriching the 

 soil. The natural grasses grow and die upon a meadow or pasture field, 

 and though that which is above the surface may be mowed for hay, or 

 cropped by cattle, yet the roots remain and gradually add to the quantity 

 of vegetable matter beneath. The same is the case to a gr(;ater or less 

 extent with all the artificial corn, grass, and leguminous crops we grow. 

 They all leave their roots in the soil, and if ihe quantity of organic mat- 

 ter which these roots contain be greater than that 'A^hich the crop we car- 

 ry off has derived from the soil, then, instead of exhausting, the growth 

 of this crop will actually enrich the soil in so far as the presence of or- 

 ganic matter is concerned. No crops, perhaps, the whole produce of 

 which is carried off the field, leave a sufficient mass of roots behind them 

 to effect this end, but many plants, when in whole or in part eaten upon 

 tliie field, leave enough in the soil materially to improve the condition of 

 the land — while in all cases those are considered as the least exhaust- 



